X format descriptor without count field
FORMAT specifications
FORMAT specifications
LOGICAL and INTEGER values
CONVERT specifier
%VAL, %REF and %LOC
ABORT — Abort the program
ABS — Absolute value
ACCESS — Checks file access modes
ACHAR — Character in ASCII collating sequence
ACOS — Arccosine function
ACOSH — Hyperbolic arccosine function
ADJUSTL — Left adjust a string
ADJUSTR — Right adjust a string
AIMAG — Imaginary part of complex number
AINT — Truncate to a whole number
ALARM — Execute a routine after a given delay
ALL — All values in MASK along DIM are true
ALLOCATED — Status of an allocatable entity
AND — Bitwise logical AND
ANINT — Nearest whole number
ANY — Any value in MASK along DIM is true
ASIN — Arcsine function
ASINH — Hyperbolic arcsine function
ASSOCIATED — Status of a pointer or pointer/target pair
ATAN — Arctangent function
ATAN2 — Arctangent function
ATANH — Hyperbolic arctangent function
BESJ0 — Bessel function of the first kind of order 0
BESJ1 — Bessel function of the first kind of order 1
BESJN — Bessel function of the first kind
BESY0 — Bessel function of the second kind of order 0
BESY1 — Bessel function of the second kind of order 1
BESYN — Bessel function of the second kind
BIT_SIZE — Bit size inquiry function
BTEST — Bit test function
C_ASSOCIATED — Status of a C pointer
C_FUNLOC — Obtain the C address of a procedure
C_F_PROCPOINTER — Convert C into Fortran procedure pointer
C_F_POINTER — Convert C into Fortran pointer
C_LOC — Obtain the C address of an object
CEILING — Integer ceiling function
CHAR — Character conversion function
CHDIR — Change working directory
CHMOD — Change access permissions of files
CMPLX — Complex conversion function
COMMAND_ARGUMENT_COUNT — Get number of command line arguments
COMPLEX — Complex conversion function
CONJG — Complex conjugate function
COS — Cosine function
COSH — Hyperbolic cosine function
COUNT — Count function
CPU_TIME — CPU elapsed time in seconds
CSHIFT — Circular shift elements of an array
CTIME — Convert a time into a string
DATE_AND_TIME — Date and time subroutine
DBLE — Double conversion function
DCMPLX — Double complex conversion function
DFLOAT — Double conversion function
DIGITS — Significant digits function
DIM — Positive difference
DOT_PRODUCT — Dot product function
DPROD — Double product function
DREAL — Double real part function
DTIME — Execution time subroutine (or function)
EOSHIFT — End-off shift elements of an array
EPSILON — Epsilon function
ERF — Error function
ERFC — Error function
ETIME — Execution time subroutine (or function)
EXIT — Exit the program with status.
EXP — Exponential function
EXPONENT — Exponent function
FDATE — Get the current time as a string
FLOAT — Convert integer to default real
FGET — Read a single character in stream mode from stdin
FGETC — Read a single character in stream mode
FLOOR — Integer floor function
FLUSH — Flush I/O unit(s)
FNUM — File number function
FPUT — Write a single character in stream mode to stdout
FPUTC — Write a single character in stream mode
FRACTION — Fractional part of the model representation
FREE — Frees memory
FSEEK — Low level file positioning subroutine
FSTAT — Get file status
FTELL — Current stream position
GAMMA — Gamma function
GERROR — Get last system error message
GETARG — Get command line arguments
GET_COMMAND — Get the entire command line
GET_COMMAND_ARGUMENT — Get command line arguments
GETCWD — Get current working directory
GETENV — Get an environmental variable
GET_ENVIRONMENT_VARIABLE — Get an environmental variable
GETGID — Group ID function
GETLOG — Get login name
GETPID — Process ID function
GETUID — User ID function
GMTIME — Convert time to GMT info
HOSTNM — Get system host name
HUGE — Largest number of a kind
IACHAR — Code in ASCII collating sequence
IAND — Bitwise logical and
IARGC — Get the number of command line arguments
IBCLR — Clear bit
IBITS — Bit extraction
IBSET — Set bit
ICHAR — Character-to-integer conversion function
IDATE — Get current local time subroutine (day/month/year)
IEOR — Bitwise logical exclusive or
IERRNO — Get the last system error number
INDEX — Position of a substring within a string
INT — Convert to integer type
INT2 — Convert to 16-bit integer type
INT8 — Convert to 64-bit integer type
IOR — Bitwise logical or
IRAND — Integer pseudo-random number
IS_IOSTAT_END — Test for end-of-file value
IS_IOSTAT_EOR — Test for end-of-record value
ISATTY — Whether a unit is a terminal device.
ISHFT — Shift bits
ISHFTC — Shift bits circularly
ISNAN — Test for a NaN
ITIME — Get current local time subroutine (hour/minutes/seconds)
KILL — Send a signal to a process
KIND — Kind of an entity
LBOUND — Lower dimension bounds of an array
LEN — Length of a character entity
LEN_TRIM — Length of a character entity without trailing blank characters
LGAMMA — Logarithm of the Gamma function
LGE — Lexical greater than or equal
LGT — Lexical greater than
LINK — Create a hard link
LLE — Lexical less than or equal
LLT — Lexical less than
LNBLNK — Index of the last non-blank character in a string
LOC — Returns the address of a variable
LOG — Logarithm function
LOG10 — Base 10 logarithm function
LOGICAL — Convert to logical type
LONG — Convert to integer type
LSHIFT — Left shift bits
LSTAT — Get file status
LTIME — Convert time to local time info
MALLOC — Allocate dynamic memory
MATMUL — matrix multiplication
MAX — Maximum value of an argument list
MAXEXPONENT — Maximum exponent of a real kind
MAXLOC — Location of the maximum value within an array
MAXVAL — Maximum value of an array
MCLOCK — Time function
MCLOCK8 — Time function (64-bit)
MERGE — Merge variables
MIN — Minimum value of an argument list
MINEXPONENT — Minimum exponent of a real kind
MINLOC — Location of the minimum value within an array
MINVAL — Minimum value of an array
MOD — Remainder function
MODULO — Modulo function
MOVE_ALLOC — Move allocation from one object to another
MVBITS — Move bits from one integer to another
NEAREST — Nearest representable number
NEW_LINE — New line character
NINT — Nearest whole number
NOT — Logical negation
NULL — Function that returns an disassociated pointer
OR — Bitwise logical OR
PACK — Pack an array into an array of rank one
PERROR — Print system error message
PRECISION — Decimal precision of a real kind
PRESENT — Determine whether an optional dummy argument is specified
PRODUCT — Product of array elements
RADIX — Base of a model number
RAN — Real pseudo-random number
RAND — Real pseudo-random number
RANDOM_NUMBER — Pseudo-random number
RANDOM_SEED — Initialize a pseudo-random number sequence
RANGE — Decimal exponent range of a real kind
REAL — Convert to real type
RENAME — Rename a file
REPEAT — Repeated string concatenation
RESHAPE — Function to reshape an array
RRSPACING — Reciprocal of the relative spacing
RSHIFT — Right shift bits
SCALE — Scale a real value
SCAN — Scan a string for the presence of a set of characters
SECNDS — Time function
SECOND — CPU time function
SELECTED_INT_KIND — Choose integer kind
SELECTED_REAL_KIND — Choose real kind
SET_EXPONENT — Set the exponent of the model
SHAPE — Determine the shape of an array
SIGN — Sign copying function
SIGNAL — Signal handling subroutine (or function)
SIN — Sine function
SINH — Hyperbolic sine function
SIZE — Determine the size of an array
SIZEOF — Size in bytes of an expression
SLEEP — Sleep for the specified number of seconds
SNGL — Convert double precision real to default real
SPACING — Smallest distance between two numbers of a given type
SPREAD — Add a dimension to an array
SQRT — Square-root function
SRAND — Reinitialize the random number generator
STAT — Get file status
SUM — Sum of array elements
SYMLNK — Create a symbolic link
SYSTEM — Execute a shell command
SYSTEM_CLOCK — Time function
TAN — Tangent function
TANH — Hyperbolic tangent function
TIME — Time function
TIME8 — Time function (64-bit)
TINY — Smallest positive number of a real kind
TRANSFER — Transfer bit patterns
TRANSPOSE — Transpose an array of rank two
TRIM — Remove trailing blank characters of a string
TTYNAM — Get the name of a terminal device.
UBOUND — Upper dimension bounds of an array
UMASK — Set the file creation mask
UNLINK — Remove a file from the file system
UNPACK — Unpack an array of rank one into an array
VERIFY — Scan a string for the absence of a set of characters
XOR — Bitwise logical exclusive OR
This manual documents the use of gfortran, the GNU Fortran compiler. You can find in this manual how to invoke gfortran, as well as its features and incompatibilities.
Part I: Invoking GNU Fortran
Part II: Language Reference
The GNU Fortran compiler front end was designed initially as a free replacement for, or alternative to, the unix f95 command; gfortran is the command you'll use to invoke the compiler.
The GNU Fortran compiler is still in an early state of development. It can generate code for most constructs and expressions, but much work remains to be done.
When the GNU Fortran compiler is finished, it will do everything you expect from any decent compiler:
The compiler will also attempt to diagnose cases where the user's program contains a correct usage of the language, but instructs the computer to do something questionable. This kind of diagnostics message is called a warning message.
The GNU Fortran compiler consists of several components:
GNU Fortran is a part of GCC, the GNU Compiler Collection. GCC consists of a collection of front ends for various languages, which translate the source code into a language-independent form called GENERIC. This is then processed by a common middle end which provides optimization, and then passed to one of a collection of back ends which generate code for different computer architectures and operating systems.
Functionally, this is implemented with a driver program (gcc) which provides the command-line interface for the compiler. It calls the relevant compiler front-end program (e.g., f951 for Fortran) for each file in the source code, and then calls the assembler and linker as appropriate to produce the compiled output. In a copy of GCC which has been compiled with Fortran language support enabled, gcc will recognize files with .f, .for, .ftn, .f90, .f95, and .f03 extensions as Fortran source code, and compile it accordingly. A gfortran driver program is also provided, which is identical to gcc except that it automatically links the Fortran runtime libraries into the compiled program.
Source files with .f, .for, .fpp, .ftn, .F, .FOR, .FPP, and .FTN extensions are treated as fixed form. Source files with .f90, .f95, .f03, .F90, .F95, and .F03 extensions are treated as free form. The capitalized versions of either form are run through preprocessing. Source files with the lower case .fpp extension are also run through preprocessing.
This manual specifically documents the Fortran front end, which handles the programming language's syntax and semantics. The aspects of GCC which relate to the optimization passes and the back-end code generation are documented in the GCC manual; see Introduction. The two manuals together provide a complete reference for the GNU Fortran compiler.
Many Fortran compilers including GNU Fortran allow passing the source code
through a C preprocessor (CPP; sometimes also called the Fortran preprocessor,
FPP) to allow for conditional compilation. In the case of GNU Fortran,
this is the GNU C Preprocessor in the traditional mode. On systems with
case-preserving file names, the preprocessor is automatically invoked if the
file extension is .F, .FOR, .FTN, .F90,
.F95 or .F03; otherwise use for fixed-format code the option
-x f77-cpp-input and for free-format code -x f95-cpp-input.
Invocation of the preprocessor can be suppressed using -x f77 or
-x f95.
If the GNU Fortran invoked the preprocessor, __GFORTRAN__
is defined and __GNUC__, __GNUC_MINOR__ and
__GNUC_PATCHLEVEL__ can be used to determine the version of the
compiler. See Overview for details.
While CPP is the de-facto standard for preprocessing Fortran code, Part 3 of the Fortran 95 standard (ISO/IEC 1539-3:1998) defines Conditional Compilation, which is not widely used and not directly supported by the GNU Fortran compiler. You can use the program coco to preprocess such files (http://users.erols.com/dnagle/coco.html).
The GNU Fortran compiler is the successor to g77, the Fortran 77 front end included in GCC prior to version 4. It is an entirely new program that has been designed to provide Fortran 95 support and extensibility for future Fortran language standards, as well as providing backwards compatibility for Fortran 77 and nearly all of the GNU language extensions supported by g77.
As soon as gfortran can parse all of the statements correctly, it will be in the “larva” state. When we generate code, the “puppa” state. When gfortran is done, we'll see if it will be a beautiful butterfly, or just a big bug....–Andy Vaught, April 2000
The start of the GNU Fortran 95 project was announced on the GCC homepage in March 18, 2000 (even though Andy had already been working on it for a while, of course).
The GNU Fortran compiler is able to compile nearly all standard-compliant Fortran 95, Fortran 90, and Fortran 77 programs, including a number of standard and non-standard extensions, and can be used on real-world programs. In particular, the supported extensions include OpenMP, Cray-style pointers, and several Fortran 2003 features such as enumeration, stream I/O, and some of the enhancements to allocatable array support from TR 15581. However, it is still under development and has a few remaining rough edges.
At present, the GNU Fortran compiler passes the NIST Fortran 77 Test Suite, and produces acceptable results on the LAPACK Test Suite. It also provides respectable performance on the Polyhedron Fortran compiler benchmarks and the Livermore Fortran Kernels test. It has been used to compile a number of large real-world programs, including the HIRLAM weather-forecasting code and the Tonto quantum chemistry package; see http://gcc.gnu.org/wiki/GfortranApps for an extended list.
Among other things, the GNU Fortran compiler is intended as a replacement for G77. At this point, nearly all programs that could be compiled with G77 can be compiled with GNU Fortran, although there are a few minor known regressions.
The primary work remaining to be done on GNU Fortran falls into three categories: bug fixing (primarily regarding the treatment of invalid code and providing useful error messages), improving the compiler optimizations and the performance of compiled code, and extending the compiler to support future standards—in particular, Fortran 2003.
The GNU Fortran compiler implements ISO/IEC 1539:1997 (Fortran 95). As such, it can also compile essentially all standard-compliant Fortran 90 and Fortran 77 programs. It also supports the ISO/IEC TR-15581 enhancements to allocatable arrays, and the OpenMP Application Program Interface v2.5 specification.
In the future, the GNU Fortran compiler may also support other standard variants of and extensions to the Fortran language. These include ISO/IEC 1539-1:2004 (Fortran 2003).
The gfortran command supports all the options supported by the gcc command. Only options specific to GNU Fortran are documented here.
See GCC Command Options, for information on the non-Fortran-specific aspects of the gcc command (and, therefore, the gfortran command).
All GCC and GNU Fortran options are accepted both by gfortran and by gcc (as well as any other drivers built at the same time, such as g++), since adding GNU Fortran to the GCC distribution enables acceptance of GNU Fortran options by all of the relevant drivers.
In some cases, options have positive and negative forms; the negative form of -ffoo would be -fno-foo. This manual documents only one of these two forms, whichever one is not the default.
Here is a summary of all the options specific to GNU Fortran, grouped by type. Explanations are in the following sections.
-fall-intrinsics -ffree-form -fno-fixed-form
-fdollar-ok -fimplicit-none -fmax-identifier-length
-std=std -fd-lines-as-code -fd-lines-as-comments
-ffixed-line-length-n -ffixed-line-length-none
-ffree-line-length-n -ffree-line-length-none
-fdefault-double-8 -fdefault-integer-8 -fdefault-real-8
-fcray-pointer -fopenmp -fno-range-check -fbackslash -fmodule-private
-fmax-errors=n
-fsyntax-only -pedantic -pedantic-errors
-Wall -Waliasing -Wampersand -Wcharacter-truncation -Wconversion
-Wimplicit-interface -Wline-truncation -Wnonstd-intrinsics -Wsurprising
-Wno-tabs -Wunderflow -Wunused-parameter
-fdump-parse-tree -ffpe-trap=list
-fdump-core -fbacktrace
-Idir -Jdir -Mdir -fintrinsic-modules-path dir
-static-libgfortran
-fconvert=conversion -frecord-marker=length
-fmax-subrecord-length=length -fsign-zero
-fno-automatic -ff2c -fno-underscoring
-fsecond-underscore
-fbounds-check -fmax-stack-var-size=n
-fpack-derived -frepack-arrays -fshort-enums -fexternal-blas
-fblas-matmul-limit=n -frecursive -finit-local-zero
-finit-integer=n -finit-real=<zero|inf|-inf|nan>
-finit-logical=<true|false> -finit-character=n
The following options control the details of the Fortran dialect accepted by the compiler:
-ffree-form-ffixed-form-fall-intrinsics-fd-lines-as-code-fd-lines-as-commentsd or D
in fixed form sources. If the -fd-lines-as-code option is
given they are treated as if the first column contained a blank. If the
-fd-lines-as-comments option is given, they are treated as
comment lines.
-fdefault-double-8DOUBLE PRECISION type to an 8 byte wide type.
-fdefault-integer-8-fdefault-real-8-fdollar-ok-fbackslash-fmodule-privatePRIVATE.
Use-associated entities will not be accessible unless they are explicitly
declared as PUBLIC.
-ffixed-line-length-nPopular values for n include 72 (the
standard and the default), 80 (card image), and 132 (corresponding
to “extended-source” options in some popular compilers).
n may also be ‘none’, meaning that the entire line is meaningful
and that continued character constants never have implicit spaces appended
to them to fill out the line.
-ffixed-line-length-0 means the same thing as
-ffixed-line-length-none.
-ffree-line-length-n-fmax-identifier-length=n-fimplicit-noneIMPLICIT statements. This is the equivalent of adding
implicit none to the start of every procedure.
-fcray-pointer-fopenmp!$omp directives
in free form
and c$omp, *$omp and !$omp directives in fixed form,
!$ conditional compilation sentinels in free form
and c$, *$ and !$ sentinels in fixed form,
and when linking arranges for the OpenMP runtime library to be linked
in. The option -fopenmp implies -frecursive.
-fno-range-checka = 1. / 0.
With this option, no error will be given and a will be assigned
the value +Infinity. If an expression evaluates to a value
outside of the relevant range of [-HUGE():HUGE()],
then the expression will be replaced by -Inf or +Inf
as appropriate.
Similarly, DATA i/Z'FFFFFFFF'/ will result in an integer overflow
on most systems, but with -fno-range-check the value will
“wrap around” and i will be initialized to -1 instead.
-std=stdErrors are diagnostic messages that report that the GNU Fortran compiler cannot compile the relevant piece of source code. The compiler will continue to process the program in an attempt to report further errors to aid in debugging, but will not produce any compiled output.
Warnings are diagnostic messages that report constructions which are not inherently erroneous but which are risky or suggest there is likely to be a bug in the program. Unless -Werror is specified, they do not prevent compilation of the program.
You can request many specific warnings with options beginning -W, for example -Wimplicit to request warnings on implicit declarations. Each of these specific warning options also has a negative form beginning -Wno- to turn off warnings; for example, -Wno-implicit. This manual lists only one of the two forms, whichever is not the default.
These options control the amount and kinds of errors and warnings produced by GNU Fortran:
-fmax-errors=n-fsyntax-only-pedantic#include.
Valid Fortran 95 programs should compile properly with or without this option. However, without this option, certain GNU extensions and traditional Fortran features are supported as well. With this option, many of them are rejected.
Some users try to use -pedantic to check programs for conformance. They soon find that it does not do quite what they want—it finds some nonstandard practices, but not all. However, improvements to GNU Fortran in this area are welcome.
This should be used in conjunction with -std=f95 or
-std=f2003.
-pedantic-errors-Wall-WaliasingINTENT(IN) and a dummy argument with INTENT(OUT) in a call
with an explicit interface.
The following example will trigger the warning.
interface
subroutine bar(a,b)
integer, intent(in) :: a
integer, intent(out) :: b
end subroutine
end interface
integer :: a
call bar(a,a)
-Wampersand-Wcharacter-truncation-Wconversion-Wimplicit-interface-Wnonstd-intrinsics-WsurprisingThis currently produces a warning under the following circumstances:
-Wtabs-Wunderflow-Wunused-parameterPARAMETER values.
-Wunused-parameter is not included in -Wall but is
implied by -Wall -Wextra.
-WerrorSee Options to Request or Suppress Errors and Warnings, for information on more options offered by the GBE shared by gfortran, gcc and other GNU compilers.
Some of these have no effect when compiling programs written in Fortran.
GNU Fortran has various special options that are used for debugging either your program or the GNU Fortran compiler.
-fdump-parse-tree-ffpe-trap=listSQRT(-1.0)), ‘zero’ (division by
zero), ‘overflow’ (overflow in a floating point operation),
‘underflow’ (underflow in a floating point operation),
‘precision’ (loss of precision during operation) and ‘denormal’
(operation produced a denormal value).
Some of the routines in the Fortran runtime library, like
‘CPU_TIME’, are likely to to trigger floating point exceptions when
ffpe-trap=precision is used. For this reason, the use of
ffpe-trap=precision is not recommended.
-fbacktrace-fdump-coreSee Options for Debugging Your Program or GCC, for more information on debugging options.
These options affect how GNU Fortran searches
for files specified by the INCLUDE directive and where it searches
for previously compiled modules.
It also affects the search paths used by cpp when used to preprocess Fortran source.
-IdirINCLUDE directive
(as well as of the #include directive of the cpp
preprocessor).
Also note that the general behavior of -I and
INCLUDE is pretty much the same as of -I with
#include in the cpp preprocessor, with regard to
looking for header.gcc files and other such things.
This path is also used to search for .mod files when previously
compiled modules are required by a USE statement.
See Options for Directory Search, for information on the
-I option.
-Mdir-JdirUSE
statement.
The default is the current directory.
-J is an alias for -M to avoid conflicts with existing
GCC options.
-fintrinsic-modules-path dirThese options come into play when the compiler links object files into an executable output file. They are meaningless if the compiler is not doing a link step.
-static-libgfortranThese options affect the runtime behavior of programs compiled with GNU Fortran.
-fconvert=conversionThis option has an effect only when used in the main program.
The CONVERT specifier and the GFORTRAN_CONVERT_UNIT environment
variable override the default specified by -fconvert.
-frecord-marker=length-fmax-subrecord-length=length-fsign-zerofno-sign-zero does not print the negative sign of zero values for
compatibility with F77. Default behavior is to show the negative sign.
These machine-independent options control the interface conventions used in code generation.
Most of them have both positive and negative forms; the negative form of -ffoo would be -fno-foo. In the table below, only one of the forms is listed—the one which is not the default. You can figure out the other form by either removing no- or adding it.
-fno-automaticSAVE statement were specified for every local variable and array
referenced in it. Does not affect common blocks. (Some Fortran compilers
provide this option under the name -static or -save.)
The default, which is -fautomatic, uses the stack for local
variables smaller than the value given by -fmax-stack-var-size.
Use the option -frecursive to use no static memory.
-ff2cThe calling conventions used by g77 (originally implemented
in f2c) require functions that return type
default REAL to actually return the C type double, and
functions that return type COMPLEX to return the values via an
extra argument in the calling sequence that points to where to
store the return value. Under the default GNU calling conventions, such
functions simply return their results as they would in GNU
C—default REAL functions return the C type float, and
COMPLEX functions return the GNU C type complex.
Additionally, this option implies the -fsecond-underscore
option, unless -fno-second-underscore is explicitly requested.
This does not affect the generation of code that interfaces with the libgfortran library.
Caution: It is not a good idea to mix Fortran code compiled with
-ff2c with code compiled with the default -fno-f2c
calling conventions as, calling COMPLEX or default REAL
functions between program parts which were compiled with different
calling conventions will break at execution time.
Caution: This will break code which passes intrinsic functions
of type default REAL or COMPLEX as actual arguments, as
the library implementations use the -fno-f2c calling conventions.
-fno-underscoringWith -funderscoring in effect, GNU Fortran appends one underscore to external names with no underscores. This is done to ensure compatibility with code produced by many UNIX Fortran compilers.
Caution: The default behavior of GNU Fortran is incompatible with f2c and g77, please use the -ff2c option if you want object files compiled with GNU Fortran to be compatible with object code created with these tools.
Use of -fno-underscoring is not recommended unless you are experimenting with issues such as integration of GNU Fortran into existing system environments (vis-à-vis existing libraries, tools, and so on).
For example, with -funderscoring, and assuming other defaults like
-fcase-lower and that j() and max_count() are
external functions while my_var and lvar are local variables,
a statement like
I = J() + MAX_COUNT (MY_VAR, LVAR)
is implemented as something akin to:
i = j_() + max_count__(&my_var__, &lvar);
With -fno-underscoring, the same statement is implemented as:
i = j() + max_count(&my_var, &lvar);
Use of -fno-underscoring allows direct specification of user-defined names while debugging and when interfacing GNU Fortran code with other languages.
Note that just because the names match does not mean that the interface implemented by GNU Fortran for an external name matches the interface implemented by some other language for that same name. That is, getting code produced by GNU Fortran to link to code produced by some other compiler using this or any other method can be only a small part of the overall solution—getting the code generated by both compilers to agree on issues other than naming can require significant effort, and, unlike naming disagreements, linkers normally cannot detect disagreements in these other areas.
Also, note that with -fno-underscoring, the lack of appended underscores introduces the very real possibility that a user-defined external name will conflict with a name in a system library, which could make finding unresolved-reference bugs quite difficult in some cases—they might occur at program run time, and show up only as buggy behavior at run time.
In future versions of GNU Fortran we hope to improve naming and linking
issues so that debugging always involves using the names as they appear
in the source, even if the names as seen by the linker are mangled to
prevent accidental linking between procedures with incompatible
interfaces.
-fsecond-underscoreThis option has no effect if -fno-underscoring is in effect. It is implied by the -ff2c option.
Otherwise, with this option, an external name such as MAX_COUNT
is implemented as a reference to the link-time external symbol
max_count__, instead of max_count_. This is required
for compatibility with g77 and f2c, and is implied
by use of the -ff2c option.
-fbounds-checkSome checks require that -fbounds-check is set for the compilation of the main program.
In the future this may also include other forms of checking, e.g., checking
substring references.
-fmax-stack-var-size=nThis option currently only affects local arrays declared with constant bounds, and may not apply to all character variables. Future versions of GNU Fortran may improve this behavior.
The default value for n is 32768.
-fpack-derived-frepack-arraysThis should result in faster accesses to the array. However it can introduce
significant overhead to the function call, especially when the passed data
is noncontiguous.
-fshort-enumsINTEGER kind a given
enumerator set will fit in, and give all its enumerators this kind.
-fexternal-blasMATMUL, instead of using our own
algorithms, if the size of the matrices involved is larger than a given
limit (see -fblas-matmul-limit). This may be profitable if an
optimized vendor BLAS library is available. The BLAS library will have
to be specified at link time.
-fblas-matmul-limit=nThe default value for n is 30.
-frecursive-finit-local-zero-finit-integer=n-finit-real=<zero|inf|-inf|nan>-finit-logical=<true|false>-finit-character=nINTEGER, REAL, and COMPLEX
variables to zero, LOGICAL variables to false, and
CHARACTER variables to a string of null bytes. Finer-grained
initialization options are provided by the
-finit-integer=n,
-finit-real=<zero|inf|-inf|nan> (which also initializes
the real and imaginary parts of local COMPLEX variables),
-finit-logical=<true|false>, and
-finit-character=n (where n is an ASCII character
value) options. These options do not initialize components of derived
type variables, nor do they initialize variables that appear in an
EQUIVALENCE statement. (This limitation may be removed in
future releases).
Note that the -finit-real=nan option initializes REAL
and COMPLEX variables with a quiet NaN.
See Options for Code Generation Conventions, for information on more options offered by the GBE shared by gfortran, gcc, and other GNU compilers.
The gfortran compiler currently does not make use of any environment variables to control its operation above and beyond those that affect the operation of gcc.
See Environment Variables Affecting GCC, for information on environment variables.
See Runtime, for environment variables that affect the run-time behavior of programs compiled with GNU Fortran.
The behavior of the gfortran can be influenced by environment variables.
Malformed environment variables are silently ignored.
This environment variable can be used to select the unit number preconnected to standard input. This must be a positive integer. The default value is 5.
This environment variable can be used to select the unit number preconnected to standard output. This must be a positive integer. The default value is 6.
This environment variable can be used to select the unit number preconnected to standard error. This must be a positive integer. The default value is 0.
This environment variable controls where library output is sent. If the first letter is ‘y’, ‘Y’ or ‘1’, standard error is used. If the first letter is ‘n’, ‘N’ or ‘0’, standard output is used.
This environment variable controls where scratch files are created. If this environment variable is missing, GNU Fortran searches for the environment variable TMP. If this is also missing, the default is /tmp.
This environment variable controls whether all I/O is unbuffered. If the first letter is ‘y’, ‘Y’ or ‘1’, all I/O is unbuffered. This will slow down small sequential reads and writes. If the first letter is ‘n’, ‘N’ or ‘0’, I/O is buffered. This is the default.
The environment variable named GFORTRAN_UNBUFFERED_PRECONNECTED controls whether I/O on a preconnected unit (i.e STDOUT or STDERR) is unbuffered. If the first letter is ‘y’, ‘Y’ or ‘1’, I/O is unbuffered. This will slow down small sequential reads and writes. If the first letter is ‘n’, ‘N’ or ‘0’, I/O is buffered. This is the default.
If the first letter is ‘y’, ‘Y’ or ‘1’, filename and line numbers for runtime errors are printed. If the first letter is ‘n’, ‘N’ or ‘0’, don't print filename and line numbers for runtime errors. The default is to print the location.
If the first letter is ‘y’, ‘Y’ or ‘1’, a plus sign is printed where permitted by the Fortran standard. If the first letter is ‘n’, ‘N’ or ‘0’, a plus sign is not printed in most cases. Default is not to print plus signs.
This environment variable specifies the default record length, in
bytes, for files which are opened without a RECL tag in the
OPEN statement. This must be a positive integer. The
default value is 1073741824 bytes (1 GB).
This environment variable specifies the separator when writing list-directed output. It may contain any number of spaces and at most one comma. If you specify this on the command line, be sure to quote spaces, as in
$ GFORTRAN_LIST_SEPARATOR=' , ' ./a.out
when a.out is the compiled Fortran program that you want to run. Default is a single space.
By setting the GFORTRAN_CONVERT_UNIT variable, it is possible to change the representation of data for unformatted files. The syntax for the GFORTRAN_CONVERT_UNIT variable is:
GFORTRAN_CONVERT_UNIT: mode | mode ';' exception | exception ;
mode: 'native' | 'swap' | 'big_endian' | 'little_endian' ;
exception: mode ':' unit_list | unit_list ;
unit_list: unit_spec | unit_list unit_spec ;
unit_spec: INTEGER | INTEGER '-' INTEGER ;
The variable consists of an optional default mode, followed by
a list of optional exceptions, which are separated by semicolons
from the preceding default and each other. Each exception consists
of a format and a comma-separated list of units. Valid values for
the modes are the same as for the CONVERT specifier:
NATIVE Use the native format. This is the default.
SWAP Swap between little- and big-endian.
LITTLE_ENDIAN Use the little-endian format
for unformatted files.
BIG_ENDIAN Use the big-endian format for unformatted files.
BIG_ENDIAN.
Examples of values for GFORTRAN_CONVERT_UNIT are:
'big_endian' Do all unformatted I/O in big_endian mode.
'little_endian;native:10-20,25' Do all unformatted I/O
in little_endian mode, except for units 10 to 20 and 25, which are in
native format.
'10-20' Units 10 to 20 are big-endian, the rest is native.
Setting the environment variables should be done on the command line or via the export command for sh-compatible shells and via setenv for csh-compatible shells.
Example for sh:
$ gfortran foo.f90
$ GFORTRAN_CONVERT_UNIT='big_endian;native:10-20' ./a.out
Example code for csh:
% gfortran foo.f90
% setenv GFORTRAN_CONVERT_UNIT 'big_endian;native:10-20'
% ./a.out
Using anything but the native representation for unformatted data carries a significant speed overhead. If speed in this area matters to you, it is best if you use this only for data that needs to be portable.
See CONVERT specifier, for an alternative way to specify the
data representation for unformatted files. See Runtime Options, for
setting a default data representation for the whole program. The
CONVERT specifier overrides the -fconvert compile options.
Note that the values specified via the GFORTRAN_CONVERT_UNIT environment variable will override the CONVERT specifier in the open statement. This is to give control over data formats to users who do not have the source code of their program available.
If the GFORTRAN_ERROR_DUMPCORE variable is set to ‘y’, ‘Y’ or ‘1’ (only the first letter is relevant) then library run-time errors cause core dumps. To disable the core dumps, set the variable to ‘n’, ‘N’, ‘0’. Default is not to core dump unless the -fdump-core compile option was used.
If the GFORTRAN_ERROR_BACKTRACE variable is set to ‘y’, ‘Y’ or ‘1’ (only the first letter is relevant) then a backtrace is printed when a run-time error occurs. To disable the backtracing, set the variable to ‘n’, ‘N’, ‘0’. Default is not to print a backtrace unless the -fbacktrace compile option was used.
Although GNU Fortran focuses on implementing the Fortran 95 standard for the time being, a few Fortran 2003 features are currently available.
command_argument_count, get_command,
get_command_argument, get_environment_variable, and
move_alloc.
[...] rather
than (/.../).
FLUSH statement.
IOMSG= specifier for I/O statements.
ENUM and ENUMERATOR statements. Interoperability with
gcc is guaranteed also for the case where the
-fshort-enums command line option is given.
OPEN statement supports the ACCESS='STREAM' specifier,
allowing I/O without any record structure.
PROTECTED statement and attribute.
VALUE statement and attribute.
VOLATILE statement and attribute.
IMPORT statement, allowing to import
host-associated derived types.
USE statement with INTRINSIC and NON_INTRINSIC
attribute; supported intrinsic modules: ISO_FORTRAN_ENV,
OMP_LIB and OMP_LIB_KINDS.
USE statement.
The two sections below detail the extensions to standard Fortran that are implemented in GNU Fortran, as well as some of the popular or historically important extensions that are not (or not yet) implemented. For the latter case, we explain the alternatives available to GNU Fortran users, including replacement by standard-conforming code or GNU extensions.
GNU Fortran implements a number of extensions over standard Fortran. This chapter contains information on their syntax and meaning. There are currently two categories of GNU Fortran extensions, those that provide functionality beyond that provided by any standard, and those that are supported by GNU Fortran purely for backward compatibility with legacy compilers. By default, -std=gnu allows the compiler to accept both types of extensions, but to warn about the use of the latter. Specifying either -std=f95 or -std=f2003 disables both types of extensions, and -std=legacy allows both without warning.
GNU Fortran allows old-style kind specifications in declarations. These look like:
TYPESPEC*size x,y,z
where TYPESPEC is a basic type (INTEGER, REAL,
etc.), and where size is a byte count corresponding to the
storage size of a valid kind for that type. (For COMPLEX
variables, size is the total size of the real and imaginary
parts.) The statement then declares x, y and z to
be of type TYPESPEC with the appropriate kind. This is
equivalent to the standard-conforming declaration
TYPESPEC(k) x,y,z
where k is equal to size for most types, but is equal to
size/2 for the COMPLEX type.
GNU Fortran allows old-style initialization of variables of the form:
INTEGER i/1/,j/2/
REAL x(2,2) /3*0.,1./
The syntax for the initializers is as for the DATA statement, but
unlike in a DATA statement, an initializer only applies to the
variable immediately preceding the initialization. In other words,
something like INTEGER I,J/2,3/ is not valid. This style of
initialization is only allowed in declarations without double colons
(::); the double colons were introduced in Fortran 90, which also
introduced a standard syntax for initializing variables in type
declarations.
Examples of standard-conforming code equivalent to the above example are:
! Fortran 90
INTEGER :: i = 1, j = 2
REAL :: x(2,2) = RESHAPE((/0.,0.,0.,1./),SHAPE(x))
! Fortran 77
INTEGER i, j
REAL x(2,2)
DATA i/1/, j/2/, x/3*0.,1./
Note that variables which are explicitly initialized in declarations
or in DATA statements automatically acquire the SAVE
attribute.
GNU Fortran fully supports the Fortran 95 standard for namelist I/O including array qualifiers, substrings and fully qualified derived types. The output from a namelist write is compatible with namelist read. The output has all names in upper case and indentation to column 1 after the namelist name. Two extensions are permitted:
Old-style use of ‘$’ instead of ‘&’
$MYNML
X(:)%Y(2) = 1.0 2.0 3.0
CH(1:4) = "abcd"
$END
It should be noted that the default terminator is ‘/’ rather than ‘&END’.
Querying of the namelist when inputting from stdin. After at least one space, entering ‘?’ sends to stdout the namelist name and the names of the variables in the namelist:
?
&mynml
x
x%y
ch
&end
Entering ‘=?’ outputs the namelist to stdout, as if
WRITE(*,NML = mynml) had been called:
=?
&MYNML
X(1)%Y= 0.000000 , 1.000000 , 0.000000 ,
X(2)%Y= 0.000000 , 2.000000 , 0.000000 ,
X(3)%Y= 0.000000 , 3.000000 , 0.000000 ,
CH=abcd, /
To aid this dialog, when input is from stdin, errors send their
messages to stderr and execution continues, even if IOSTAT is set.
PRINT namelist is permitted. This causes an error if
-std=f95 is used.
PROGRAM test_print
REAL, dimension (4) :: x = (/1.0, 2.0, 3.0, 4.0/)
NAMELIST /mynml/ x
PRINT mynml
END PROGRAM test_print
Expanded namelist reads are permitted. This causes an error if -std=f95 is used. In the following example, the first element of the array will be given the value 0.00 and the two succeeding elements will be given the values 1.00 and 2.00.
&MYNML
X(1,1) = 0.00 , 1.00 , 2.00
/
X format descriptor without count fieldTo support legacy codes, GNU Fortran permits the count field of the
X edit descriptor in FORMAT statements to be omitted.
When omitted, the count is implicitly assumed to be one.
PRINT 10, 2, 3
10 FORMAT (I1, X, I1)
FORMAT specificationsTo support legacy codes, GNU Fortran allows the comma separator
to be omitted immediately before and after character string edit
descriptors in FORMAT statements.
PRINT 10, 2, 3
10 FORMAT ('FOO='I1' BAR='I2)
FORMAT specificationsTo support legacy codes, GNU Fortran allows missing periods in format specifications if and only if -std=legacy is given on the command line. This is considered non-conforming code and is discouraged.
REAL :: value
READ(*,10) value
10 FORMAT ('F4')
To support legacy codes, GNU Fortran allows the input item list
of the READ statement, and the output item lists of the
WRITE and PRINT statements, to start with a comma.
Besides decimal constants, Fortran also supports binary (b),
octal (o) and hexadecimal (z) integer constants. The
syntax is: ‘prefix quote digits quote’, were the prefix is
either b, o or z, quote is either ' or
" and the digits are for binary 0 or 1, for
octal between 0 and 7, and for hexadecimal between
0 and F. (Example: b'01011101'.)
Up to Fortran 95, BOZ literals were only allowed to initialize
integer variables in DATA statements. Since Fortran 2003 BOZ literals
are also allowed as argument of REAL, DBLE, INT
and CMPLX; the result is the same as if the integer BOZ
literal had been converted by TRANSFER to, respectively,
real, double precision, integer or complex.
As GNU Fortran extension the intrinsic procedures FLOAT,
DFLOAT, COMPLEX and DCMPLX are treated alike.
As an extension, GNU Fortran allows hexadecimal BOZ literal constants to
be specified using the X prefix, in addition to the standard
Z prefix. The BOZ literal can also be specified by adding a
suffix to the string, for example, Z'ABC' and 'ABC'Z are
equivalent.
Furthermore, GNU Fortran allows using BOZ literal constants outside
DATA statements and the four intrinsic functions allowed by Fortran 2003.
In DATA statements, in direct assignments, where the right-hand side
only contains a BOZ literal constant, and for old-style initializers of
the form integer i /o'0173'/, the constant is transferred
as if TRANSFER had been used; for COMPLEX numbers, only
the real part is initialized unless CMPLX is used. In all other
cases, the BOZ literal constant is converted to an INTEGER value with
the largest decimal representation. This value is then converted
numerically to the type and kind of the variable in question.
(For instance real :: r = b'0000001' + 1 initializes r
with 2.0.) As different compilers implement the extension
differently, one should be careful when doing bitwise initialization
of non-integer variables.
Note that initializing an INTEGER variable with a statement such
as DATA i/Z'FFFFFFFF'/ will give an integer overflow error rather
than the desired result of -1 when i is a 32-bit integer
on a system that supports 64-bit integers. The ‘-fno-range-check’
option can be used as a workaround for legacy code that initializes
integers in this manner.
As an extension, GNU Fortran allows the use of REAL expressions
or variables as array indices.
As an extension, GNU Fortran allows unary plus and unary minus operators to appear as the second operand of binary arithmetic operators without the need for parenthesis.
X = Y * -Z
LOGICAL and INTEGER values
As an extension for backwards compatibility with other compilers, GNU
Fortran allows the implicit conversion of LOGICAL values to
INTEGER values and vice versa. When converting from a
LOGICAL to an INTEGER, .FALSE. is interpreted as
zero, and .TRUE. is interpreted as one. When converting from
INTEGER to LOGICAL, the value zero is interpreted as
.FALSE. and any nonzero value is interpreted as .TRUE..
LOGICAL :: l
l = 1
INTEGER :: i
i = .TRUE.
However, there is no implicit conversion of INTEGER values in
if-statements, nor of LOGICAL or INTEGER values
in I/O operations.
GNU Fortran supports Hollerith constants in assignments, function
arguments, and DATA and ASSIGN statements. A Hollerith
constant is written as a string of characters preceded by an integer
constant indicating the character count, and the letter H or
h, and stored in bytewise fashion in a numeric (INTEGER,
REAL, or complex) or LOGICAL variable. The
constant will be padded or truncated to fit the size of the variable in
which it is stored.
Examples of valid uses of Hollerith constants:
complex*16 x(2)
data x /16Habcdefghijklmnop, 16Hqrstuvwxyz012345/
x(1) = 16HABCDEFGHIJKLMNOP
call foo (4h abc)
Invalid Hollerith constants examples:
integer*4 a
a = 8H12345678 ! Valid, but the Hollerith constant will be truncated.
a = 0H ! At least one character is needed.
In general, Hollerith constants were used to provide a rudimentary
facility for handling character strings in early Fortran compilers,
prior to the introduction of CHARACTER variables in Fortran 77;
in those cases, the standard-compliant equivalent is to convert the
program to use proper character strings. On occasion, there may be a
case where the intent is specifically to initialize a numeric variable
with a given byte sequence. In these cases, the same result can be
obtained by using the TRANSFER statement, as in this example.
INTEGER(KIND=4) :: a
a = TRANSFER ("abcd", a) ! equivalent to: a = 4Habcd
Cray pointers are part of a non-standard extension that provides a C-like pointer in Fortran. This is accomplished through a pair of variables: an integer "pointer" that holds a memory address, and a "pointee" that is used to dereference the pointer.
Pointer/pointee pairs are declared in statements of the form:
pointer ( <pointer> , <pointee> )
or,
pointer ( <pointer1> , <pointee1> ), ( <pointer2> , <pointee2> ), ...
The pointer is an integer that is intended to hold a memory address.
The pointee may be an array or scalar. A pointee can be an assumed
size array—that is, the last dimension may be left unspecified by
using a * in place of a value—but a pointee cannot be an
assumed shape array. No space is allocated for the pointee.
The pointee may have its type declared before or after the pointer statement, and its array specification (if any) may be declared before, during, or after the pointer statement. The pointer may be declared as an integer prior to the pointer statement. However, some machines have default integer sizes that are different than the size of a pointer, and so the following code is not portable:
integer ipt
pointer (ipt, iarr)
If a pointer is declared with a kind that is too small, the compiler will issue a warning; the resulting binary will probably not work correctly, because the memory addresses stored in the pointers may be truncated. It is safer to omit the first line of the above example; if explicit declaration of ipt's type is omitted, then the compiler will ensure that ipt is an integer variable large enough to hold a pointer.
Pointer arithmetic is valid with Cray pointers, but it is not the same as C pointer arithmetic. Cray pointers are just ordinary integers, so the user is responsible for determining how many bytes to add to a pointer in order to increment it. Consider the following example:
real target(10)
real pointee(10)
pointer (ipt, pointee)
ipt = loc (target)
ipt = ipt + 1
The last statement does not set ipt to the address of
target(1), as it would in C pointer arithmetic. Adding 1
to ipt just adds one byte to the address stored in ipt.
Any expression involving the pointee will be translated to use the value stored in the pointer as the base address.
To get the address of elements, this extension provides an intrinsic
function LOC(). The LOC() function is equivalent to the
& operator in C, except the address is cast to an integer type:
real ar(10)
pointer(ipt, arpte(10))
real arpte
ipt = loc(ar) ! Makes arpte is an alias for ar
arpte(1) = 1.0 ! Sets ar(1) to 1.0
The pointer can also be set by a call to the MALLOC intrinsic
(see MALLOC).
Cray pointees often are used to alias an existing variable. For example:
integer target(10)
integer iarr(10)
pointer (ipt, iarr)
ipt = loc(target)
As long as ipt remains unchanged, iarr is now an alias for
target. The optimizer, however, will not detect this aliasing, so
it is unsafe to use iarr and target simultaneously. Using
a pointee in any way that violates the Fortran aliasing rules or
assumptions is illegal. It is the user's responsibility to avoid doing
this; the compiler works under the assumption that no such aliasing
occurs.
Cray pointers will work correctly when there is no aliasing (i.e., when they are used to access a dynamically allocated block of memory), and also in any routine where a pointee is used, but any variable with which it shares storage is not used. Code that violates these rules may not run as the user intends. This is not a bug in the optimizer; any code that violates the aliasing rules is illegal. (Note that this is not unique to GNU Fortran; any Fortran compiler that supports Cray pointers will “incorrectly” optimize code with illegal aliasing.)
There are a number of restrictions on the attributes that can be applied
to Cray pointers and pointees. Pointees may not have the
ALLOCATABLE, INTENT, OPTIONAL, DUMMY,
TARGET, INTRINSIC, or POINTER attributes. Pointers
may not have the DIMENSION, POINTER, TARGET,
ALLOCATABLE, EXTERNAL, or INTRINSIC attributes.
Pointees may not occur in more than one pointer statement. A pointee
cannot be a pointer. Pointees cannot occur in equivalence, common, or
data statements.
A Cray pointer may also point to a function or a subroutine. For example, the following excerpt is valid:
implicit none
external sub
pointer (subptr,subpte)
external subpte
subptr = loc(sub)
call subpte()
[...]
subroutine sub
[...]
end subroutine sub
A pointer may be modified during the course of a program, and this will change the location to which the pointee refers. However, when pointees are passed as arguments, they are treated as ordinary variables in the invoked function. Subsequent changes to the pointer will not change the base address of the array that was passed.
CONVERT specifier
GNU Fortran allows the conversion of unformatted data between little-
and big-endian representation to facilitate moving of data
between different systems. The conversion can be indicated with
the CONVERT specifier on the OPEN statement.
See GFORTRAN_CONVERT_UNIT, for an alternative way of specifying
the data format via an environment variable.
Valid values for CONVERT are:
CONVERT='NATIVE' Use the native format. This is the default.
CONVERT='SWAP' Swap between little- and big-endian.
CONVERT='LITTLE_ENDIAN' Use the little-endian representation
for unformatted files.
CONVERT='BIG_ENDIAN' Use the big-endian representation for
unformatted files.
Using the option could look like this:
open(file='big.dat',form='unformatted',access='sequential', &
convert='big_endian')
The value of the conversion can be queried by using
INQUIRE(CONVERT=ch). The values returned are
'BIG_ENDIAN' and 'LITTLE_ENDIAN'.
CONVERT works between big- and little-endian for
INTEGER values of all supported kinds and for REAL
on IEEE systems of kinds 4 and 8. Conversion between different
“extended double” types on different architectures such as
m68k and x86_64, which GNU Fortran
supports as REAL(KIND=10) and REAL(KIND=16), will
probably not work.
Note that the values specified via the GFORTRAN_CONVERT_UNIT environment variable will override the CONVERT specifier in the open statement. This is to give control over data formats to users who do not have the source code of their program available.
Using anything but the native representation for unformatted data carries a significant speed overhead. If speed in this area matters to you, it is best if you use this only for data that needs to be portable.
OpenMP (Open Multi-Processing) is an application programming interface (API) that supports multi-platform shared memory multiprocessing programming in C/C++ and Fortran on many architectures, including Unix and Microsoft Windows platforms. It consists of a set of compiler directives, library routines, and environment variables that influence run-time behavior.
GNU Fortran strives to be compatible to the OpenMP Application Program Interface v2.5.
To enable the processing of the OpenMP directive !$omp in
free-form source code; the c$omp, *$omp and !$omp
directives in fixed form; the !$ conditional compilation sentinels
in free form; and the c$, *$ and !$ sentinels
in fixed form, gfortran needs to be invoked with the
-fopenmp. This also arranges for automatic linking of the
GNU OpenMP runtime library libgomp.
The OpenMP Fortran runtime library routines are provided both in a
form of a Fortran 90 module named omp_lib and in a form of
a Fortran include file named omp_lib.h.
An example of a parallelized loop taken from Appendix A.1 of the OpenMP Application Program Interface v2.5:
SUBROUTINE A1(N, A, B)
INTEGER I, N
REAL B(N), A(N)
!$OMP PARALLEL DO !I is private by default
DO I=2,N
B(I) = (A(I) + A(I-1)) / 2.0
ENDDO
!$OMP END PARALLEL DO
END SUBROUTINE A1
Please note:
%VAL, %REF and %LOC
GNU Fortran supports argument list functions %VAL, %REF
and %LOC statements, for backward compatibility with g77.
It is recommended that these should be used only for code that is
accessing facilities outside of GNU Fortran, such as operating system
or windowing facilities. It is best to constrain such uses to isolated
portions of a program–portions that deal specifically and exclusively
with low-level, system-dependent facilities. Such portions might well
provide a portable interface for use by the program as a whole, but are
themselves not portable, and should be thoroughly tested each time they
are rebuilt using a new compiler or version of a compiler.
%VAL passes a scalar argument by value, %REF passes it by
reference and %LOC passes its memory location. Since gfortran
already passes scalar arguments by reference, %REF is in effect
a do-nothing. %LOC has the same effect as a fortran pointer.
An example of passing an argument by value to a C subroutine foo.:
C
C prototype void foo_ (float x);
C
external foo
real*4 x
x = 3.14159
call foo (%VAL (x))
end
For details refer to the g77 manual http://gcc.gnu.org/onlinedocs/gcc-3.4.6/g77/index.html#Top.
Also, the gfortran testsuite c_by_val.f and its partner c_by_val.c are worth a look.
The long history of the Fortran language, its wide use and broad userbase, the large number of different compiler vendors and the lack of some features crucial to users in the first standards have lead to the existence of an important number of extensions to the language. While some of the most useful or popular extensions are supported by the GNU Fortran compiler, not all existing extensions are supported. This section aims at listing these extensions and offering advice on how best make code that uses them running with the GNU Fortran compiler.
STRUCTURE and RECORDStructures are user-defined aggregate data types; this functionality was standardized in Fortran 90 with an different syntax, under the name of “derived types”. Here is an example of code using the non portable structure syntax:
! Declaring a structure named ``item'' and containing three fields:
! an integer ID, an description string and a floating-point price.
STRUCTURE /item/
INTEGER id
CHARACTER(LEN=200) description
REAL price
END STRUCTURE
! Define two variables, an single record of type ``item''
! named ``pear'', and an array of items named ``store_catalog''
RECORD /item/ pear, store_catalog(100)
! We can directly access the fields of both variables
pear.id = 92316
pear.description = "juicy D'Anjou pear"
pear.price = 0.15
store_catalog(7).id = 7831
store_catalog(7).description = "milk bottle"
store_catalog(7).price = 1.2
! We can also manipulates the whole structure
store_catalog(12) = pear
print *, store_catalog(12)
This code can easily be rewritten in the Fortran 90 syntax as following:
! ``STRUCTURE /name/ ... END STRUCTURE'' becomes
! ``TYPE name ... END TYPE''
TYPE item
INTEGER id
CHARACTER(LEN=200) description
REAL price
END TYPE
! ``RECORD /name/ variable'' becomes ``TYPE(name) variable''
TYPE(item) pear, store_catalog(100)
! Instead of using a dot (.) to access fields of a record, the
! standard syntax uses a percent sign (%)
pear%id = 92316
pear%description = "juicy D'Anjou pear"
pear%price = 0.15
store_catalog(7)%id = 7831
store_catalog(7)%description = "milk bottle"
store_catalog(7)%price = 1.2
! Assignments of a whole variable don't change
store_catalog(12) = pear
print *, store_catalog(12)
ENCODE and DECODE statements
GNU Fortran doesn't support the ENCODE and DECODE
statements. These statements are best replaced by READ and
WRITE statements involving internal files (CHARACTER
variables and arrays), which have been part of the Fortran standard since
Fortran 77. For example, replace a code fragment like
INTEGER*1 LINE(80)
REAL A, B, C
c ... Code that sets LINE
DECODE (80, 9000, LINE) A, B, C
9000 FORMAT (1X, 3(F10.5))
with the following:
CHARACTER(LEN=80) LINE
REAL A, B, C
c ... Code that sets LINE
READ (UNIT=LINE, FMT=9000) A, B, C
9000 FORMAT (1X, 3(F10.5))
Similarly, replace a code fragment like
INTEGER*1 LINE(80)
REAL A, B, C
c ... Code that sets A, B and C
ENCODE (80, 9000, LINE) A, B, C
9000 FORMAT (1X, 'OUTPUT IS ', 3(F10.5))
with the following:
INTEGER*1 LINE(80)
REAL A, B, C
c ... Code that sets A, B and C
WRITE (UNIT=LINE, FMT=9000) A, B, C
9000 FORMAT (1X, 'OUTPUT IS ', 3(F10.5))
The intrinsic procedures provided by GNU Fortran include all of the intrinsic procedures required by the Fortran 95 standard, a set of intrinsic procedures for backwards compatibility with G77, and a small selection of intrinsic procedures from the Fortran 2003 standard. Any conflict between a description here and a description in either the Fortran 95 standard or the Fortran 2003 standard is unintentional, and the standard(s) should be considered authoritative.
The enumeration of the KIND type parameter is processor defined in
the Fortran 95 standard. GNU Fortran defines the default integer type and
default real type by INTEGER(KIND=4) and REAL(KIND=4),
respectively. The standard mandates that both data types shall have
another kind, which have more precision. On typical target architectures
supported by gfortran, this kind type parameter is KIND=8.
Hence, REAL(KIND=8) and DOUBLE PRECISION are equivalent.
In the description of generic intrinsic procedures, the kind type parameter
will be specified by KIND=*, and in the description of specific
names for an intrinsic procedure the kind type parameter will be explicitly
given (e.g., REAL(KIND=4) or REAL(KIND=8)). Finally, for
brevity the optional KIND= syntax will be omitted.
Many of the intrinsic procedures take one or more optional arguments. This document follows the convention used in the Fortran 95 standard, and denotes such arguments by square brackets.
GNU Fortran offers the -std=f95 and -std=gnu options, which can be used to restrict the set of intrinsic procedures to a given standard. By default, gfortran sets the -std=gnu option, and so all intrinsic procedures described here are accepted. There is one caveat. For a select group of intrinsic procedures, g77 implemented both a function and a subroutine. Both classes have been implemented in gfortran for backwards compatibility with g77. It is noted here that these functions and subroutines cannot be intermixed in a given subprogram. In the descriptions that follow, the applicable standard for each intrinsic procedure is noted.
ABORT — Abort the programABORT causes immediate termination of the program. On operating
systems that support a core dump, ABORT will produce a core dump,
which is suitable for debugging purposes.
CALL ABORT
program test_abort
integer :: i = 1, j = 2
if (i /= j) call abort
end program test_abort
ABS — Absolute valueABS(X) computes the absolute value of X.
RESULT = ABS(X)
| X | The type of the argument shall be an INTEGER(*),
REAL(*), or COMPLEX(*).
|
REAL(*) for a
COMPLEX(*) argument.
program test_abs
integer :: i = -1
real :: x = -1.e0
complex :: z = (-1.e0,0.e0)
i = abs(i)
x = abs(x)
x = abs(z)
end program test_abs
| Name | Argument | Return type | Standard
|
CABS(Z) | COMPLEX(4) Z | REAL(4) | F77 and later
|
DABS(X) | REAL(8) X | REAL(8) | F77 and later
|
IABS(I) | INTEGER(4) I | INTEGER(4) | F77 and later
|
ZABS(Z) | COMPLEX(8) Z | COMPLEX(8) | GNU extension
|
CDABS(Z) | COMPLEX(8) Z | COMPLEX(8) | GNU extension
|
ACCESS — Checks file access modesACCESS(NAME, MODE) checks whether the file NAME
exists, is readable, writable or executable. Except for the
executable check, ACCESS can be replaced by
Fortran 95's INQUIRE.
RESULT = ACCESS(NAME, MODE)
| NAME | Scalar CHARACTER with the file name.
Tailing blank are ignored unless the character achar(0) is
present, then all characters up to and excluding achar(0) are
used as file name.
|
| MODE | Scalar CHARACTER with the file access mode,
may be any concatenation of "r" (readable), "w" (writable)
and "x" (executable), or " " to check for existence.
|
INTEGER, which is 0 if the file is
accessible in the given mode; otherwise or if an invalid argument
has been given for MODE the value 1 is returned.
program access_test
implicit none
character(len=*), parameter :: file = 'test.dat'
character(len=*), parameter :: file2 = 'test.dat '//achar(0)
if(access(file,' ') == 0) print *, trim(file),' is exists'
if(access(file,'r') == 0) print *, trim(file),' is readable'
if(access(file,'w') == 0) print *, trim(file),' is writable'
if(access(file,'x') == 0) print *, trim(file),' is executable'
if(access(file2,'rwx') == 0) &
print *, trim(file2),' is readable, writable and executable'
end program access_test
ACHAR — Character in ASCII collating sequenceACHAR(I) returns the character located at position I
in the ASCII collating sequence.
RESULT = ACHAR(I)
| I | The type shall be INTEGER(*).
|
CHARACTER with a length of one. The
kind type parameter is the same as KIND('A').
program test_achar
character c
c = achar(32)
end program test_achar
ACOS — Arccosine functionACOS(X) computes the arccosine of X (inverse of COS(X)).
RESULT = ACOS(X)
| X | The type shall be REAL(*) with a magnitude that is
less than one.
|
REAL(*) and it lies in the
range 0 \leq \acos(x) \leq \pi. The kind type parameter
is the same as X.
program test_acos
real(8) :: x = 0.866_8
x = acos(x)
end program test_acos
| Name | Argument | Return type | Standard
|
DACOS(X) | REAL(8) X | REAL(8) | F77 and later
|
ACOSH — Hyperbolic arccosine functionACOSH(X) computes the hyperbolic arccosine of X (inverse of
COSH(X)).
RESULT = ACOSH(X)
| X | The type shall be REAL(*) with a magnitude that is
greater or equal to one.
|
REAL(*) and it lies in the
range 0 \leq \acosh (x) \leq \infty.
PROGRAM test_acosh
REAL(8), DIMENSION(3) :: x = (/ 1.0, 2.0, 3.0 /)
WRITE (*,*) ACOSH(x)
END PROGRAM
| Name | Argument | Return type | Standard
|
DACOSH(X) | REAL(8) X | REAL(8) | GNU extension
|
ADJUSTL — Left adjust a stringADJUSTL(STR) will left adjust a string by removing leading spaces.
Spaces are inserted at the end of the string as needed.
RESULT = ADJUSTL(STR)
| STR | The type shall be CHARACTER.
|
CHARACTER where leading spaces
are removed and the same number of spaces are inserted on the end
of STR.
program test_adjustl
character(len=20) :: str = ' gfortran'
str = adjustl(str)
print *, str
end program test_adjustl
ADJUSTR — Right adjust a stringADJUSTR(STR) will right adjust a string by removing trailing spaces.
Spaces are inserted at the start of the string as needed.
RESULT = ADJUSTR(STR)
| STR | The type shall be CHARACTER.
|
CHARACTER where trailing spaces
are removed and the same number of spaces are inserted at the start
of STR.
program test_adjustr
character(len=20) :: str = 'gfortran'
str = adjustr(str)
print *, str
end program test_adjustr
AIMAG — Imaginary part of complex numberAIMAG(Z) yields the imaginary part of complex argument Z.
The IMAG(Z) and IMAGPART(Z) intrinsic functions are provided
for compatibility with g77, and their use in new code is
strongly discouraged.
RESULT = AIMAG(Z)
| Z | The type of the argument shall be COMPLEX(*).
|
program test_aimag
complex(4) z4
complex(8) z8
z4 = cmplx(1.e0_4, 0.e0_4)
z8 = cmplx(0.e0_8, 1.e0_8)
print *, aimag(z4), dimag(z8)
end program test_aimag
| Name | Argument | Return type | Standard
|
DIMAG(Z) | COMPLEX(8) Z | REAL(8) | GNU extension
|
IMAG(Z) | COMPLEX(*) Z | REAL(*) | GNU extension
|
IMAGPART(Z) | COMPLEX(*) Z | REAL(*) | GNU extension
|
AINT — Truncate to a whole numberAINT(X [, KIND]) truncates its argument to a whole number.
RESULT = AINT(X [, KIND])
| X | The type of the argument shall be REAL(*).
|
| KIND | (Optional) An INTEGER(*) initialization
expression indicating the kind parameter of
the result.
|
AINT(X) returns zero. If the
magnitude is equal to or greater than one, then it returns the largest
whole number that does not exceed its magnitude. The sign is the same
as the sign of X.
program test_aint
real(4) x4
real(8) x8
x4 = 1.234E0_4
x8 = 4.321_8
print *, aint(x4), dint(x8)
x8 = aint(x4,8)
end program test_aint
| Name | Argument | Return type | Standard
|
DINT(X) | REAL(8) X | REAL(8) | F77 and later
|
ALARM — Execute a routine after a given delayALARM(SECONDS, HANDLER [, STATUS]) causes external subroutine HANDLER
to be executed after a delay of SECONDS by using alarm(2) to
set up a signal and signal(2) to catch it. If STATUS is
supplied, it will be returned with the number of seconds remaining until
any previously scheduled alarm was due to be delivered, or zero if there
was no previously scheduled alarm.
CALL ALARM(SECONDS, HANDLER [, STATUS])
| SECONDS | The type of the argument shall be a scalar
INTEGER. It is INTENT(IN).
|
| HANDLER | Signal handler (INTEGER FUNCTION or
SUBROUTINE) or dummy/global INTEGER scalar. The scalar
values may be either SIG_IGN=1 to ignore the alarm generated
or SIG_DFL=0 to set the default action. It is INTENT(IN).
|
| STATUS | (Optional) STATUS shall be a scalar
variable of the default INTEGER kind. It is INTENT(OUT).
|
program test_alarm
external handler_print
integer i
call alarm (3, handler_print, i)
print *, i
call sleep(10)
end program test_alarm
This will cause the external routine handler_print to be called after 3 seconds.
ALL — All values in MASK along DIM are trueALL(MASK [, DIM]) determines if all the values are true in MASK
in the array along dimension DIM.
RESULT = ALL(MASK [, DIM])
| MASK | The type of the argument shall be LOGICAL(*) and
it shall not be scalar.
|
| DIM | (Optional) DIM shall be a scalar integer
with a value that lies between one and the rank of MASK.
|
ALL(MASK) returns a scalar value of type LOGICAL(*) where
the kind type parameter is the same as the kind type parameter of
MASK. If DIM is present, then ALL(MASK, DIM) returns
an array with the rank of MASK minus 1. The shape is determined from
the shape of MASK where the DIM dimension is elided.
ALL(MASK) is true if all elements of MASK are true.
It also is true if MASK has zero size; otherwise, it is false.
ALL(MASK,DIM) is equivalent
to ALL(MASK). If the rank is greater than one, then ALL(MASK,DIM)
is determined by applying ALL to the array sections.
program test_all
logical l
l = all((/.true., .true., .true./))
print *, l
call section
contains
subroutine section
integer a(2,3), b(2,3)
a = 1
b = 1
b(2,2) = 2
print *, all(a .eq. b, 1)
print *, all(a .eq. b, 2)
end subroutine section
end program test_all
ALLOCATED — Status of an allocatable entityALLOCATED(X) checks the status of whether X is allocated.
RESULT = ALLOCATED(X)
| X | The argument shall be an ALLOCATABLE array.
|
LOGICAL with the default logical
kind type parameter. If X is allocated, ALLOCATED(X)
is .TRUE.; otherwise, it returns .FALSE.
program test_allocated
integer :: i = 4
real(4), allocatable :: x(:)
if (allocated(x) .eqv. .false.) allocate(x(i))
end program test_allocated
AND — Bitwise logical ANDAND.
This intrinsic routine is provided for backwards compatibility with
GNU Fortran 77. For integer arguments, programmers should consider
the use of the IAND intrinsic defined by the Fortran standard.
RESULT = AND(I, J)
| I | The type shall be either INTEGER(*) or LOGICAL.
|
| J | The type shall be either INTEGER(*) or LOGICAL.
|
INTEGER(*) or LOGICAL after
cross-promotion of the arguments.
PROGRAM test_and
LOGICAL :: T = .TRUE., F = .FALSE.
INTEGER :: a, b
DATA a / Z'F' /, b / Z'3' /
WRITE (*,*) AND(T, T), AND(T, F), AND(F, T), AND(F, F)
WRITE (*,*) AND(a, b)
END PROGRAM
ANINT — Nearest whole numberANINT(X [, KIND]) rounds its argument to the nearest whole number.
RESULT = ANINT(X [, KIND])
| X | The type of the argument shall be REAL(*).
|
| KIND | (Optional) An INTEGER(*) initialization
expression indicating the kind parameter of
the result.
|
ANINT(X) returns AINT(X+0.5). If X is
less than or equal to zero, then it returns AINT(X-0.5).
program test_anint
real(4) x4
real(8) x8
x4 = 1.234E0_4
x8 = 4.321_8
print *, anint(x4), dnint(x8)
x8 = anint(x4,8)
end program test_anint
| Name | Argument | Return type | Standard
|
DNINT(X) | REAL(8) X | REAL(8) | F77 and later
|
ANY — Any value in MASK along DIM is trueANY(MASK [, DIM]) determines if any of the values in the logical array
MASK along dimension DIM are .TRUE..
RESULT = ANY(MASK [, DIM])
| MASK | The type of the argument shall be LOGICAL(*) and
it shall not be scalar.
|
| DIM | (Optional) DIM shall be a scalar integer
with a value that lies between one and the rank of MASK.
|
ANY(MASK) returns a scalar value of type LOGICAL(*) where
the kind type parameter is the same as the kind type parameter of
MASK. If DIM is present, then ANY(MASK, DIM) returns
an array with the rank of MASK minus 1. The shape is determined from
the shape of MASK where the DIM dimension is elided.
ANY(MASK) is true if any element of MASK is true;
otherwise, it is false. It also is false if MASK has zero size.
ANY(MASK,DIM) is equivalent
to ANY(MASK). If the rank is greater than one, then ANY(MASK,DIM)
is determined by applying ANY to the array sections.
program test_any
logical l
l = any((/.true., .true., .true./))
print *, l
call section
contains
subroutine section
integer a(2,3), b(2,3)
a = 1
b = 1
b(2,2) = 2
print *, any(a .eq. b, 1)
print *, any(a .eq. b, 2)
end subroutine section
end program test_any
ASIN — Arcsine functionASIN(X) computes the arcsine of its X (inverse of SIN(X)).
RESULT = ASIN(X)
| X | The type shall be REAL(*), and a magnitude that is
less than one.
|
REAL(*) and it lies in the
range -\pi / 2 \leq \asin (x) \leq \pi / 2. The kind type
parameter is the same as X.
program test_asin
real(8) :: x = 0.866_8
x = asin(x)
end program test_asin
| Name | Argument | Return type | Standard
|
DASIN(X) | REAL(8) X | REAL(8) | F77 and later
|
ASINH — Hyperbolic arcsine functionASINH(X) computes the hyperbolic arcsine of X (inverse of SINH(X)).
RESULT = ASINH(X)
| X | The type shall be REAL(*), with X a real number.
|
REAL(*) and it lies in the
range -\infty \leq \asinh (x) \leq \infty.
PROGRAM test_asinh
REAL(8), DIMENSION(3) :: x = (/ -1.0, 0.0, 1.0 /)
WRITE (*,*) ASINH(x)
END PROGRAM
| Name | Argument | Return type | Standard
|
DASINH(X) | REAL(8) X | REAL(8) | GNU extension.
|
ASSOCIATED — Status of a pointer or pointer/target pairASSOCIATED(PTR [, TGT]) determines the status of the pointer PTR
or if PTR is associated with the target TGT.
RESULT = ASSOCIATED(PTR [, TGT])
| PTR | PTR shall have the POINTER attribute and
it can be of any type.
|
| TGT | (Optional) TGT shall be a POINTER or
a TARGET. It must have the same type, kind type parameter, and
array rank as PTR.
|
ASSOCIATED(PTR) returns a scalar value of type LOGICAL(4).
There are several cases:
ASSOCIATED(PTR) program test_associated
implicit none
real, target :: tgt(2) = (/1., 2./)
real, pointer :: ptr(:)
ptr => tgt
if (associated(ptr) .eqv. .false.) call abort
if (associated(ptr,tgt) .eqv. .false.) call abort
end program test_associated
ATAN — Arctangent functionATAN(X) computes the arctangent of X.
RESULT = ATAN(X)
| X | The type shall be REAL(*).
|
REAL(*) and it lies in the
range - \pi / 2 \leq \atan (x) \leq \pi / 2.
program test_atan
real(8) :: x = 2.866_8
x = atan(x)
end program test_atan
| Name | Argument | Return type | Standard
|
DATAN(X) | REAL(8) X | REAL(8) | F77 and later
|
ATAN2 — Arctangent functionATAN2(Y,X) computes the arctangent of the complex number
X + i Y.
RESULT = ATAN2(Y,X)
| Y | The type shall be REAL(*).
|
| X | The type and kind type parameter shall be the same as Y.
If Y is zero, then X must be nonzero.
|
program test_atan2
real(4) :: x = 1.e0_4, y = 0.5e0_4
x = atan2(y,x)
end program test_atan2
| Name | Argument | Return type | Standard
|
DATAN2(X) | REAL(8) X | REAL(8) | F77 and later
|
ATANH — Hyperbolic arctangent functionATANH(X) computes the hyperbolic arctangent of X (inverse
of TANH(X)).
RESULT = ATANH(X)
| X | The type shall be REAL(*) with a magnitude
that is less than or equal to one.
|
REAL(*) and it lies in the
range -\infty \leq \atanh(x) \leq \infty.
PROGRAM test_atanh
REAL, DIMENSION(3) :: x = (/ -1.0, 0.0, 1.0 /)
WRITE (*,*) ATANH(x)
END PROGRAM
| Name | Argument | Return type | Standard
|
DATANH(X) | REAL(8) X | REAL(8) | GNU extension
|
BESJ0 — Bessel function of the first kind of order 0BESJ0(X) computes the Bessel function of the first kind of order 0
of X.
RESULT = BESJ0(X)
| X | The type shall be REAL(*), and it shall be scalar.
|
REAL(*) and it lies in the
range - 0.4027... \leq Bessel (0,x) \leq 1.
program test_besj0
real(8) :: x = 0.0_8
x = besj0(x)
end program test_besj0
| Name | Argument | Return type | Standard
|
DBESJ0(X) | REAL(8) X | REAL(8) | GNU extension
|
BESJ1 — Bessel function of the first kind of order 1BESJ1(X) computes the Bessel function of the first kind of order 1
of X.
RESULT = BESJ1(X)
| X | The type shall be REAL(*), and it shall be scalar.
|
REAL(*) and it lies in the
range - 0.5818... \leq Bessel (0,x) \leq 0.5818 .
program test_besj1
real(8) :: x = 1.0_8
x = besj1(x)
end program test_besj1
| Name | Argument | Return type | Standard
|
DBESJ1(X) | REAL(8) X | REAL(8) | GNU extension
|
BESJN — Bessel function of the first kindBESJN(N, X) computes the Bessel function of the first kind of order
N of X.
If both arguments are arrays, their ranks and shapes shall conform.
RESULT = BESJN(N, X)
| N | Shall be a scalar or an array of type INTEGER(*).
|
| X | Shall be a scalar or an array of type REAL(*).
|
REAL(*).
program test_besjn
real(8) :: x = 1.0_8
x = besjn(5,x)
end program test_besjn
| Name | Argument | Return type | Standard
|
DBESJN(X) | INTEGER(*) N | REAL(8) | GNU extension
|
REAL(8) X |
|
BESY0 — Bessel function of the second kind of order 0BESY0(X) computes the Bessel function of the second kind of order 0
of X.
RESULT = BESY0(X)
| X | The type shall be REAL(*), and it shall be scalar.
|
REAL(*).
program test_besy0
real(8) :: x = 0.0_8
x = besy0(x)
end program test_besy0
| Name | Argument | Return type | Standard
|
DBESY0(X) | REAL(8) X | REAL(8) | GNU extension
|
BESY1 — Bessel function of the second kind of order 1BESY1(X) computes the Bessel function of the second kind of order 1
of X.
RESULT = BESY1(X)
| X | The type shall be REAL(*), and it shall be scalar.
|
REAL(*).
program test_besy1
real(8) :: x = 1.0_8
x = besy1(x)
end program test_besy1
| Name | Argument | Return type | Standard
|
DBESY1(X) | REAL(8) X | REAL(8) | GNU extension
|
BESYN — Bessel function of the second kindBESYN(N, X) computes the Bessel function of the second kind of order
N of X.
If both arguments are arrays, their ranks and shapes shall conform.
RESULT = BESYN(N, X)
| N | Shall be a scalar or an array of type INTEGER(*).
|
| X | Shall be a scalar or an array of type REAL(*).
|
REAL(*).
program test_besyn
real(8) :: x = 1.0_8
x = besyn(5,x)
end program test_besyn
| Name | Argument | Return type | Standard
|
DBESYN(N,X) | INTEGER(*) N | REAL(8) | GNU extension
|
REAL(8) X |
|
BIT_SIZE — Bit size inquiry functionBIT_SIZE(I) returns the number of bits (integer precision plus sign bit)
represented by the type of I.
RESULT = BIT_SIZE(I)
| I | The type shall be INTEGER(*).
|
INTEGER(*)
program test_bit_size
integer :: i = 123
integer :: size
size = bit_size(i)
print *, size
end program test_bit_size
BTEST — Bit test functionBTEST(I,POS) returns logical .TRUE. if the bit at POS
in I is set.
RESULT = BTEST(I, POS)
| I | The type shall be INTEGER(*).
|
| POS | The type shall be INTEGER(*).
|
LOGICAL
program test_btest
integer :: i = 32768 + 1024 + 64
integer :: pos
logical :: bool
do pos=0,16
bool = btest(i, pos)
print *, pos, bool
end do
end program test_btest
C_ASSOCIATED — Status of a C pointerC_ASSOICATED(c_prt1[, c_ptr2]) determines the status of the C pointer c_ptr1
or if c_ptr1 is associated with the target c_ptr2.
RESULT = C_ASSOICATED(c_prt1[, c_ptr2])
| c_ptr1 | Scalar of the type C_PTR or C_FUNPTR.
|
| c_ptr2 | (Optional) Scalar of the same type as c_ptr1.
|
LOGICAL; it is .false. if either
c_ptr1 is a C NULL pointer or if c_ptr1 and c_ptr2
point to different addresses.
subroutine association_test(a,b)
use iso_c_binding, only: c_associated, c_loc, c_ptr
implicit none
real, pointer :: a
type(c_ptr) :: b
if(c_associated(b, c_loc(a))) &
stop 'b and a do not point to same target'
end subroutine association_test
C_FUNLOC — Obtain the C address of a procedureC_FUNLOC(x) determines the C address of the argument.
RESULT = C_FUNLOC(x)
| x | Interoperable function or pointer to such function.
|
C_FUNPTR and contains the C address
of the argument.
module x
use iso_c_binding
implicit none
contains
subroutine sub(a) bind(c)
real(c_float) :: a
a = sqrt(a)+5.0
end subroutine sub
end module x
program main
use iso_c_binding
use x
implicit none
interface
subroutine my_routine(p) bind(c,name='myC_func')
import :: c_funptr
type(c_funptr), intent(in) :: p
end subroutine
end interface
call my_routine(c_funloc(sub))
end program main
C_F_PROCPOINTER — Convert C into Fortran procedure pointerC_F_PROCPOINTER(cptr, fptr) Assign the target of the C function pointer
cptr to the Fortran procedure pointer fptr.
Note: Due to the currently lacking support of procedure pointers in GNU Fortran
this function is not fully operable.
CALL C_F_PROCPOINTER(cptr, fptr)
| cptr | scalar of the type C_FUNPTR. It is
INTENT(IN).
|
| fptr | procedure pointer interoperable with cptr. It is
INTENT(OUT).
|
program main
use iso_c_binding
implicit none
abstract interface
function func(a)
import :: c_float
real(c_float), intent(in) :: a
real(c_float) :: func
end function
end interface
interface
function getIterFunc() bind(c,name="getIterFunc")
import :: c_funptr
type(c_funptr) :: getIterFunc
end function
end interface
type(c_funptr) :: cfunptr
procedure(func), pointer :: myFunc
cfunptr = getIterFunc()
call c_f_procpointer(cfunptr, myFunc)
end program main
C_F_POINTER — Convert C into Fortran pointerC_F_POINTER(cptr, fptr[, shape]) Assign the target the C pointer
cptr to the Fortran pointer fptr and specify its
shape.
CALL C_F_POINTER(cptr, fptr[, shape])
| cptr | scalar of the type C_PTR. It is
INTENT(IN).
|
| fptr | pointer interoperable with cptr. It is
INTENT(OUT).
|
| shape | (Optional) Rank-one array of type INTEGER
with INTENT(IN). It shall be present
if and only if fptr is an array. The size
must be equal to the rank of fptr.
|
program main
use iso_c_binding
implicit none
interface
subroutine my_routine(p) bind(c,name='myC_func')
import :: c_ptr
type(c_ptr), intent(out) :: p
end subroutine
end interface
type(c_ptr) :: cptr
real,pointer :: a(:)
call my_routine(cptr)
call c_f_pointer(cptr, a, [12])
end program main
C_LOC — Obtain the C address of an objectC_LOC(x) determines the C address of the argument.
RESULT = C_LOC(x)
| x | Associated scalar pointer or interoperable scalar
or allocated allocatable variable with TARGET
attribute.
|
C_PTR and contains the C address
of the argument.
subroutine association_test(a,b)
use iso_c_binding, only: c_associated, c_loc, c_ptr
implicit none
real, pointer :: a
type(c_ptr) :: b
if(c_associated(b, c_loc(a))) &
stop 'b and a do not point to same target'
end subroutine association_test
CEILING — Integer ceiling functionCEILING(X) returns the least integer greater than or equal to X.
RESULT = CEILING(X [, KIND])
| X | The type shall be REAL(*).
|
| KIND | (Optional) An INTEGER(*) initialization
expression indicating the kind parameter of
the result.
|
INTEGER(KIND)
program test_ceiling
real :: x = 63.29
real :: y = -63.59
print *, ceiling(x) ! returns 64
print *, ceiling(y) ! returns -63
end program test_ceiling
CHAR — Character conversion functionCHAR(I [, KIND]) returns the character represented by the integer I.
RESULT = CHAR(I [, KIND])
| I | The type shall be INTEGER(*).
|
| KIND | (Optional) An INTEGER(*) initialization
expression indicating the kind parameter of
the result.
|
CHARACTER(1)
program test_char
integer :: i = 74
character(1) :: c
c = char(i)
print *, i, c ! returns 'J'
end program test_char
CHDIR — Change working directoryThis intrinsic is provided in both subroutine and function forms; however,
only one form can be used in any given program unit.
CALL CHDIR(NAME [, STATUS])
|
STATUS = CHDIR(NAME)
|
| NAME | The type shall be CHARACTER(*) and shall
specify a valid path within the file system.
|
| STATUS | (Optional) INTEGER status flag of the default
kind. Returns 0 on success, and a system specific
and nonzero error code otherwise.
|
PROGRAM test_chdir
CHARACTER(len=255) :: path
CALL getcwd(path)
WRITE(*,*) TRIM(path)
CALL chdir("/tmp")
CALL getcwd(path)
WRITE(*,*) TRIM(path)
END PROGRAM
CHMOD — Change access permissions of filesCHMOD changes the permissions of a file. This function invokes
/bin/chmod and might therefore not work on all platforms.
This intrinsic is provided in both subroutine and function forms; however,
only one form can be used in any given program unit.
CALL CHMOD(NAME, MODE[, STATUS])
|
STATUS = CHMOD(NAME, MODE)
|
| NAME | Scalar CHARACTER with the file name.
Trailing blanks are ignored unless the character achar(0) is
present, then all characters up to and excluding achar(0) are
used as the file name.
|
| MODE | Scalar CHARACTER giving the file permission.
MODE uses the same syntax as the MODE argument of
/bin/chmod.
|
| STATUS | (optional) scalar INTEGER, which is
0 on success and nonzero otherwise.
|
0 on success and nonzero
otherwise.
CHMOD as subroutine
program chmod_test
implicit none
integer :: status
call chmod('test.dat','u+x',status)
print *, 'Status: ', status
end program chmod_test
CHMOD as function:
program chmod_test
implicit none
integer :: status
status = chmod('test.dat','u+x')
print *, 'Status: ', status
end program chmod_test
CMPLX — Complex conversion functionCMPLX(X [, Y [, KIND]]) returns a complex number where X is converted to
the real component. If Y is present it is converted to the imaginary
component. If Y is not present then the imaginary component is set to
0.0. If X is complex then Y must not be present.
RESULT = CMPLX(X [, Y [, KIND]])
| X | The type may be INTEGER(*), REAL(*),
or COMPLEX(*).
|
| Y | (Optional; only allowed if X is not
COMPLEX(*).) May be INTEGER(*)
or REAL(*).
|
| KIND | (Optional) An INTEGER(*) initialization
expression indicating the kind parameter of
the result.
|
COMPLEX type, with a kind equal to
KIND if it is specified. If KIND is not specified, the
result is of the default COMPLEX kind, regardless of the kinds of
X and Y.
program test_cmplx
integer :: i = 42
real :: x = 3.14
complex :: z
z = cmplx(i, x)
print *, z, cmplx(x)
end program test_cmplx
COMMAND_ARGUMENT_COUNT — Get number of command line argumentsCOMMAND_ARGUMENT_COUNT() returns the number of arguments passed on the
command line when the containing program was invoked.
RESULT = COMMAND_ARGUMENT_COUNT()
| None
|
INTEGER(4)
program test_command_argument_count
integer :: count
count = command_argument_count()
print *, count
end program test_command_argument_count
COMPLEX — Complex conversion functionCOMPLEX(X, Y) returns a complex number where X is converted
to the real component and Y is converted to the imaginary
component.
RESULT = COMPLEX(X, Y)
| X | The type may be INTEGER(*) or REAL(*).
|
| Y | The type may be INTEGER(*) or REAL(*).
|
INTEGER type, then the return
value is of default COMPLEX type.
If X and Y are of REAL type, or one is of REAL
type and one is of INTEGER type, then the return value is of
COMPLEX type with a kind equal to that of the REAL
argument with the highest precision.
program test_complex
integer :: i = 42
real :: x = 3.14
print *, complex(i, x)
end program test_complex
CONJG — Complex conjugate functionCONJG(Z) returns the conjugate of Z. If Z is (x, y)
then the result is (x, -y)
Z = CONJG(Z)
| Z | The type shall be COMPLEX(*).
|
COMPLEX(*).
program test_conjg
complex :: z = (2.0, 3.0)
complex(8) :: dz = (2.71_8, -3.14_8)
z= conjg(z)
print *, z
dz = dconjg(dz)
print *, dz
end program test_conjg
| Name | Argument | Return type | Standard
|
DCONJG(Z) | COMPLEX(8) Z | COMPLEX(8) | GNU extension
|
COS — Cosine functionCOS(X) computes the cosine of X.
RESULT = COS(X)
| X | The type shall be REAL(*) or
COMPLEX(*).
|
REAL(*) and it lies in the
range -1 \leq \cos (x) \leq 1. The kind type
parameter is the same as X.
program test_cos
real :: x = 0.0
x = cos(x)
end program test_cos
| Name | Argument | Return type | Standard
|
DCOS(X) | REAL(8) X | REAL(8) | F77 and later
|
CCOS(X) | COMPLEX(4) X | COMPLEX(4) | F77 and later
|
ZCOS(X) | COMPLEX(8) X | COMPLEX(8) | GNU extension
|
CDCOS(X) | COMPLEX(8) X | COMPLEX(8) | GNU extension
|
COSH — Hyperbolic cosine functionCOSH(X) computes the hyperbolic cosine of X.
X = COSH(X)
| X | The type shall be REAL(*).
|
REAL(*) and it is positive
( \cosh (x) \geq 0 .
program test_cosh
real(8) :: x = 1.0_8
x = cosh(x)
end program test_cosh
| Name | Argument | Return type | Standard
|
DCOSH(X) | REAL(8) X | REAL(8) | F77 and later
|
COUNT — Count functionCOUNT(MASK [, DIM [, KIND]]) counts the number of .TRUE.
elements of MASK along the dimension of DIM. If DIM is
omitted it is taken to be 1. DIM is a scaler of type
INTEGER in the range of 1 /leq DIM /leq n) where n
is the rank of MASK.
RESULT = COUNT(MASK [, DIM [, KIND]])
| MASK | The type shall be LOGICAL.
|
| DIM | (Optional) The type shall be INTEGER.
|
| KIND | (Optional) An INTEGER initialization
expression indicating the kind parameter of
the result.
|
INTEGER and of kind KIND. If
KIND is absent, the return value is of default integer kind.
The result has a rank equal to that of MASK.
program test_count
integer, dimension(2,3) :: a, b
logical, dimension(2,3) :: mask
a = reshape( (/ 1, 2, 3, 4, 5, 6 /), (/ 2, 3 /))
b = reshape( (/ 0, 7, 3, 4, 5, 8 /), (/ 2, 3 /))
print '(3i3)', a(1,:)
print '(3i3)', a(2,:)
print *
print '(3i3)', b(1,:)
print '(3i3)', b(2,:)
print *
mask = a.ne.b
print '(3l3)', mask(1,:)
print '(3l3)', mask(2,:)
print *
print '(3i3)', count(mask)
print *
print '(3i3)', count(mask, 1)
print *
print '(3i3)', count(mask, 2)
end program test_count
CPU_TIME — CPU elapsed time in secondsREAL(*) value representing the elapsed CPU time in
seconds. This is useful for testing segments of code to determine
execution time.
If a time source is available, time will be reported with microsecond
resolution. If no time source is available, TIME is set to
-1.0.
Note that TIME may contain a, system dependent, arbitrary offset
and may not start with 0.0. For CPU_TIME, the absolute
value is meaningless, only differences between subsequent calls to
this subroutine, as shown in the example below, should be used.
CALL CPU_TIME(TIME)
| TIME | The type shall be REAL(*) with INTENT(OUT).
|
program test_cpu_time
real :: start, finish
call cpu_time(start)
! put code to test here
call cpu_time(finish)
print '("Time = ",f6.3," seconds.")',finish-start
end program test_cpu_time
CSHIFT — Circular shift elements of an arrayCSHIFT(ARRAY, SHIFT [, DIM]) performs a circular shift on elements of
ARRAY along the dimension of DIM. If DIM is omitted it is
taken to be 1. DIM is a scaler of type INTEGER in the
range of 1 /leq DIM /leq n) where n is the rank of ARRAY.
If the rank of ARRAY is one, then all elements of ARRAY are shifted
by SHIFT places. If rank is greater than one, then all complete rank one
sections of ARRAY along the given dimension are shifted. Elements
shifted out one end of each rank one section are shifted back in the other end.
RESULT = CSHIFT(ARRAY, SHIFT [, DIM])
| ARRAY | Shall be an array of any type.
|
| SHIFT | The type shall be INTEGER.
|
| DIM | The type shall be INTEGER.
|
program test_cshift
integer, dimension(3,3) :: a
a = reshape( (/ 1, 2, 3, 4, 5, 6, 7, 8, 9 /), (/ 3, 3 /))
print '(3i3)', a(1,:)
print '(3i3)', a(2,:)
print '(3i3)', a(3,:)
a = cshift(a, SHIFT=(/1, 2, -1/), DIM=2)
print *
print '(3i3)', a(1,:)
print '(3i3)', a(2,:)
print '(3i3)', a(3,:)
end program test_cshift
CTIME — Convert a time into a stringCTIME converts a system time value, such as returned by
TIME8(), to a string of the form ‘Sat Aug 19 18:13:14 1995’.
This intrinsic is provided in both subroutine and function forms; however,
only one form can be used in any given program unit.
CALL CTIME(TIME, RESULT).
|
RESULT = CTIME(TIME), (not recommended).
|
| TIME | The type shall be of type INTEGER(KIND=8).
|
| RESULT | The type shall be of type CHARACTER.
|
program test_ctime
integer(8) :: i
character(len=30) :: date
i = time8()
! Do something, main part of the program
call ctime(i,date)
print *, 'Program was started on ', date
end program test_ctime
DATE_AND_TIME — Date and time subroutineDATE_AND_TIME(DATE, TIME, ZONE, VALUES) gets the corresponding date and
time information from the real-time system clock. DATE is
INTENT(OUT) and has form ccyymmdd. TIME is INTENT(OUT) and
has form hhmmss.sss. ZONE is INTENT(OUT) and has form (+-)hhmm,
representing the difference with respect to Coordinated Universal Time (UTC).
Unavailable time and date parameters return blanks.
VALUES is INTENT(OUT) and provides the following:
VALUE(1): | The year
| |
VALUE(2): | The month
| |
VALUE(3): | The day of the month
| |
VALUE(4): | Time difference with UTC in minutes
| |
VALUE(5): | The hour of the day
| |
VALUE(6): | The minutes of the hour
| |
VALUE(7): | The seconds of the minute
| |
VALUE(8): | The milliseconds of the second
|
CALL DATE_AND_TIME([DATE, TIME, ZONE, VALUES])
| DATE | (Optional) The type shall be CHARACTER(8) or larger.
|
| TIME | (Optional) The type shall be CHARACTER(10) or larger.
|
| ZONE | (Optional) The type shall be CHARACTER(5) or larger.
|
| VALUES | (Optional) The type shall be INTEGER(8).
|
program test_time_and_date
character(8) :: date
character(10) :: time
character(5) :: zone
integer,dimension(8) :: values
! using keyword arguments
call date_and_time(date,time,zone,values)
call date_and_time(DATE=date,ZONE=zone)
call date_and_time(TIME=time)
call date_and_time(VALUES=values)
print '(a,2x,a,2x,a)', date, time, zone
print '(8i5))', values
end program test_time_and_date
DBLE — Double conversion functionDBLE(X) Converts X to double precision real type.
RESULT = DBLE(X)
| X | The type shall be INTEGER(*), REAL(*),
or COMPLEX(*).
|
program test_dble
real :: x = 2.18
integer :: i = 5
complex :: z = (2.3,1.14)
print *, dble(x), dble(i), dble(z)
end program test_dble
DCMPLX — Double complex conversion functionDCMPLX(X [,Y]) returns a double complex number where X is
converted to the real component. If Y is present it is converted to the
imaginary component. If Y is not present then the imaginary component is
set to 0.0. If X is complex then Y must not be present.
RESULT = DCMPLX(X [, Y])
| X | The type may be INTEGER(*), REAL(*),
or COMPLEX(*).
|
| Y | (Optional if X is not COMPLEX(*).) May be
INTEGER(*) or REAL(*).
|
COMPLEX(8)
program test_dcmplx
integer :: i = 42
real :: x = 3.14
complex :: z
z = cmplx(i, x)
print *, dcmplx(i)
print *, dcmplx(x)
print *, dcmplx(z)
print *, dcmplx(x,i)
end program test_dcmplx
DFLOAT — Double conversion functionDFLOAT(X) Converts X to double precision real type.
RESULT = DFLOAT(X)
| X | The type shall be INTEGER(*).
|
program test_dfloat
integer :: i = 5
print *, dfloat(i)
end program test_dfloat
DIGITS — Significant digits functionDIGITS(X) returns the number of significant digits of the internal model
representation of X. For example, on a system using a 32-bit
floating point representation, a default real number would likely return 24.
RESULT = DIGITS(X)
| X | The type may be INTEGER(*) or REAL(*).
|
INTEGER.
program test_digits
integer :: i = 12345
real :: x = 3.143
real(8) :: y = 2.33
print *, digits(i)
print *, digits(x)
print *, digits(y)
end program test_digits
DIM — Positive differenceDIM(X,Y) returns the difference X-Y if the result is positive;
otherwise returns zero.
RESULT = DIM(X, Y)
| X | The type shall be INTEGER(*) or REAL(*)
|
| Y | The type shall be the same type and kind as X.
|
INTEGER(*) or REAL(*).
program test_dim
integer :: i
real(8) :: x
i = dim(4, 15)
x = dim(4.345_8, 2.111_8)
print *, i
print *, x
end program test_dim
| Name | Argument | Return type | Standard
|
IDIM(X,Y) | INTEGER(4) X,Y | INTEGER(4) | F77 and later
|
DDIM(X,Y) | REAL(8) X,Y | REAL(8) | F77 and later
|
DOT_PRODUCT — Dot product functionDOT_PRODUCT(X,Y) computes the dot product multiplication of two vectors
X and Y. The two vectors may be either numeric or logical
and must be arrays of rank one and of equal size. If the vectors are
INTEGER(*) or REAL(*), the result is SUM(X*Y). If the
vectors are COMPLEX(*), the result is SUM(CONJG(X)*Y). If the
vectors are LOGICAL, the result is ANY(X.AND.Y).
RESULT = DOT_PRODUCT(X, Y)
| X | The type shall be numeric or LOGICAL, rank 1.
|
| Y | The type shall be numeric or LOGICAL, rank 1.
|
INTEGER(*), REAL(*), or COMPLEX(*). If the arguments are
LOGICAL, the return value is .TRUE. or .FALSE..
program test_dot_prod
integer, dimension(3) :: a, b
a = (/ 1, 2, 3 /)
b = (/ 4, 5, 6 /)
print '(3i3)', a
print *
print '(3i3)', b
print *
print *, dot_product(a,b)
end program test_dot_prod
DPROD — Double product functionDPROD(X,Y) returns the product X*Y.
RESULT = DPROD(X, Y)
| X | The type shall be REAL.
|
| Y | The type shall be REAL.
|
REAL(8).
program test_dprod
real :: x = 5.2
real :: y = 2.3
real(8) :: d
d = dprod(x,y)
print *, d
end program test_dprod
DREAL — Double real part functionDREAL(Z) returns the real part of complex variable Z.
RESULT = DREAL(Z)
| Z | The type shall be COMPLEX(8).
|
REAL(8).
program test_dreal
complex(8) :: z = (1.3_8,7.2_8)
print *, dreal(z)
end program test_dreal
DTIME — Execution time subroutine (or function)DTIME(TARRAY, RESULT) initially returns the number of seconds of runtime
since the start of the process's execution in RESULT. TARRAY
returns the user and system components of this time in TARRAY(1) and
TARRAY(2) respectively. RESULT is equal to TARRAY(1) +
TARRAY(2).
Subsequent invocations of DTIME return values accumulated since the
previous invocation.
On some systems, the underlying timings are represented using types with sufficiently small limits that overflows (wrap around) are possible, such as 32-bit types. Therefore, the values returned by this intrinsic might be, or become, negative, or numerically less than previous values, during a single run of the compiled program.
Please note, that this implementation is thread safe if used within OpenMP
directives, i. e. its state will be consistent while called from multiple
threads. However, if DTIME is called from multiple threads, the result
is still the time since the last invocation. This may not give the intended
results. If possible, use CPU_TIME instead.
This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit.
TARRAY and RESULT are INTENT(OUT) and provide the following:
TARRAY(1): | User time in seconds.
| |
TARRAY(2): | System time in seconds.
| |
RESULT: | Run time since start in seconds.
|
CALL DTIME(TARRAY, RESULT).
|
RESULT = DTIME(TARRAY), (not recommended).
|
| TARRAY | The type shall be REAL, DIMENSION(2).
|
| RESULT | The type shall be REAL.
|
program test_dtime
integer(8) :: i, j
real, dimension(2) :: tarray
real :: result
call dtime(tarray, result)
print *, result
print *, tarray(1)
print *, tarray(2)
do i=1,100000000 ! Just a delay
j = i * i - i
end do
call dtime(tarray, result)
print *, result
print *, tarray(1)
print *, tarray(2)
end program test_dtime
EOSHIFT — End-off shift elements of an arrayEOSHIFT(ARRAY, SHIFT[,BOUNDARY, DIM]) performs an end-off shift on
elements of ARRAY along the dimension of DIM. If DIM is
omitted it is taken to be 1. DIM is a scaler of type
INTEGER in the range of 1 /leq DIM /leq n) where n is the
rank of ARRAY. If the rank of ARRAY is one, then all elements of
ARRAY are shifted by SHIFT places. If rank is greater than one,
then all complete rank one sections of ARRAY along the given dimension are
shifted. Elements shifted out one end of each rank one section are dropped. If
BOUNDARY is present then the corresponding value of from BOUNDARY
is copied back in the other end. If BOUNDARY is not present then the
following are copied in depending on the type of ARRAY.
| Array Type | Boundary Value
|
| Numeric | 0 of the type and kind of ARRAY.
|
| Logical | .FALSE..
|
| Character(len) | len blanks.
|
RESULT = EOSHIFT(ARRAY, SHIFT [, BOUNDARY, DIM])
| ARRAY | May be any type, not scaler.
|
| SHIFT | The type shall be INTEGER.
|
| BOUNDARY | Same type as ARRAY.
|
| DIM | The type shall be INTEGER.
|
program test_eoshift
integer, dimension(3,3) :: a
a = reshape( (/ 1, 2, 3, 4, 5, 6, 7, 8, 9 /), (/ 3, 3 /))
print '(3i3)', a(1,:)
print '(3i3)', a(2,:)
print '(3i3)', a(3,:)
a = EOSHIFT(a, SHIFT=(/1, 2, 1/), BOUNDARY=-5, DIM=2)
print *
print '(3i3)', a(1,:)
print '(3i3)', a(2,:)
print '(3i3)', a(3,:)
end program test_eoshift
EPSILON — Epsilon functionEPSILON(X) returns a nearly negligible number relative to 1.
RESULT = EPSILON(X)
| X | The type shall be REAL(*).
|
program test_epsilon
real :: x = 3.143
real(8) :: y = 2.33
print *, EPSILON(x)
print *, EPSILON(y)
end program test_epsilon
ERF — Error functionERF(X) computes the error function of X.
RESULT = ERF(X)
| X | The type shall be REAL(*), and it shall be scalar.
|
REAL(*) and it is positive
( - 1 \leq erf (x) \leq 1 .
program test_erf
real(8) :: x = 0.17_8
x = erf(x)
end program test_erf
| Name | Argument | Return type | Standard
|
DERF(X) | REAL(8) X | REAL(8) | GNU extension
|
ERFC — Error functionERFC(X) computes the complementary error function of X.
RESULT = ERFC(X)
| X | The type shall be REAL(*), and it shall be scalar.
|
REAL(*) and it is positive
( 0 \leq erfc (x) \leq 2 .
program test_erfc
real(8) :: x = 0.17_8
x = erfc(x)
end program test_erfc
| Name | Argument | Return type | Standard
|
DERFC(X) | REAL(8) X | REAL(8) | GNU extension
|
ETIME — Execution time subroutine (or function)ETIME(TARRAY, RESULT) returns the number of seconds of runtime
since the start of the process's execution in RESULT. TARRAY
returns the user and system components of this time in TARRAY(1) and
TARRAY(2) respectively. RESULT is equal to TARRAY(1) + TARRAY(2).
On some systems, the underlying timings are represented using types with sufficiently small limits that overflows (wrap around) are possible, such as 32-bit types. Therefore, the values returned by this intrinsic might be, or become, negative, or numerically less than previous values, during a single run of the compiled program.
This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit.
TARRAY and RESULT are INTENT(OUT) and provide the following:
TARRAY(1): | User time in seconds.
| |
TARRAY(2): | System time in seconds.
| |
RESULT: | Run time since start in seconds.
|
CALL ETIME(TARRAY, RESULT).
|
RESULT = ETIME(TARRAY), (not recommended).
|
| TARRAY | The type shall be REAL, DIMENSION(2).
|
| RESULT | The type shall be REAL.
|
program test_etime
integer(8) :: i, j
real, dimension(2) :: tarray
real :: result
call ETIME(tarray, result)
print *, result
print *, tarray(1)
print *, tarray(2)
do i=1,100000000 ! Just a delay
j = i * i - i
end do
call ETIME(tarray, result)
print *, result
print *, tarray(1)
print *, tarray(2)
end program test_etime
EXIT — Exit the program with status.EXIT causes immediate termination of the program with status. If status
is omitted it returns the canonical success for the system. All Fortran
I/O units are closed.
CALL EXIT([STATUS])
| STATUS | Shall be an INTEGER of the default kind.
|
STATUS is passed to the parent process on exit.
program test_exit
integer :: STATUS = 0
print *, 'This program is going to exit.'
call EXIT(STATUS)
end program test_exit
EXP — Exponential functionEXP(X) computes the base e exponential of X.
RESULT = EXP(X)
| X | The type shall be REAL(*) or
COMPLEX(*).
|
program test_exp
real :: x = 1.0
x = exp(x)
end program test_exp
| Name | Argument | Return type | Standard
|
DEXP(X) | REAL(8) X | REAL(8) | F77 and later
|
CEXP(X) | COMPLEX(4) X | COMPLEX(4) | F77 and later
|
ZEXP(X) | COMPLEX(8) X | COMPLEX(8) | GNU extension
|
CDEXP(X) | COMPLEX(8) X | COMPLEX(8) | GNU extension
|
EXPONENT — Exponent functionEXPONENT(X) returns the value of the exponent part of X. If X
is zero the value returned is zero.
RESULT = EXPONENT(X)
| X | The type shall be REAL(*).
|
INTEGER.
program test_exponent
real :: x = 1.0
integer :: i
i = exponent(x)
print *, i
print *, exponent(0.0)
end program test_exponent
FDATE — Get the current time as a stringFDATE(DATE) returns the current date (using the same format as
CTIME) in DATE. It is equivalent to CALL CTIME(DATE,
TIME()).
This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit.
DATE is an INTENT(OUT) CHARACTER variable.
CALL FDATE(DATE).
|
DATE = FDATE(), (not recommended).
|
| DATE | The type shall be of type CHARACTER.
|
program test_fdate
integer(8) :: i, j
character(len=30) :: date
call fdate(date)
print *, 'Program started on ', date
do i = 1, 100000000 ! Just a delay
j = i * i - i
end do
call fdate(date)
print *, 'Program ended on ', date
end program test_fdate
FLOAT — Convert integer to default realFLOAT(I) converts the integer I to a default real value.
RESULT = FLOAT(I)
| I | The type shall be INTEGER(*).
|
REAL.
program test_float
integer :: i = 1
if (float(i) /= 1.) call abort
end program test_float
FGET — Read a single character in stream mode from stdinThis intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit.
Note that the FGET intrinsic is provided for backwards compatibility with
g77. GNU Fortran provides the Fortran 2003 Stream facility.
Programmers should consider the use of new stream IO feature in new code
for future portability. See also Fortran 2003 status.
CALL FGET(C [, STATUS])
| C | The type shall be CHARACTER.
|
| STATUS | (Optional) status flag of type INTEGER.
Returns 0 on success, -1 on end-of-file, and a
system specific positive error code otherwise.
|
PROGRAM test_fget
INTEGER, PARAMETER :: strlen = 100
INTEGER :: status, i = 1
CHARACTER(len=strlen) :: str = ""
WRITE (*,*) 'Enter text:'
DO
CALL fget(str(i:i), status)
if (status /= 0 .OR. i > strlen) exit
i = i + 1
END DO
WRITE (*,*) TRIM(str)
END PROGRAM
FGETC — Read a single character in stream modeThis intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit.
Note that the FGET intrinsic is provided for backwards compatibility
with g77. GNU Fortran provides the Fortran 2003 Stream facility.
Programmers should consider the use of new stream IO feature in new code
for future portability. See also Fortran 2003 status.
CALL FGETC(UNIT, C [, STATUS])
| UNIT | The type shall be INTEGER.
|
| C | The type shall be CHARACTER.
|
| STATUS | (Optional) status flag of type INTEGER. Returns 0 on success,
-1 on end-of-file and a system specific positive error code otherwise.
|
PROGRAM test_fgetc
INTEGER :: fd = 42, status
CHARACTER :: c
OPEN(UNIT=fd, FILE="/etc/passwd", ACTION="READ", STATUS = "OLD")
DO
CALL fgetc(fd, c, status)
IF (status /= 0) EXIT
call fput(c)
END DO
CLOSE(UNIT=fd)
END PROGRAM
FLOOR — Integer floor functionFLOOR(X) returns the greatest integer less than or equal to X.
RESULT = FLOOR(X [, KIND])
| X | The type shall be REAL(*).
|
| KIND | (Optional) An INTEGER(*) initialization
expression indicating the kind parameter of
the result.
|
INTEGER(KIND)
program test_floor
real :: x = 63.29
real :: y = -63.59
print *, floor(x) ! returns 63
print *, floor(y) ! returns -64
end program test_floor
FLUSH — Flush I/O unit(s)CALL FLUSH(UNIT)
| UNIT | (Optional) The type shall be INTEGER.
|
FLUSH
statement that should be preferred over the FLUSH intrinsic.
FNUM — File number functionFNUM(UNIT) returns the POSIX file descriptor number corresponding to the
open Fortran I/O unit UNIT.
RESULT = FNUM(UNIT)
| UNIT | The type shall be INTEGER.
|
INTEGER
program test_fnum
integer :: i
open (unit=10, status = "scratch")
i = fnum(10)
print *, i
close (10)
end program test_fnum
FPUT — Write a single character in stream mode to stdoutThis intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit.
Note that the FGET intrinsic is provided for backwards compatibility with
g77. GNU Fortran provides the Fortran 2003 Stream facility.
Programmers should consider the use of new stream IO feature in new code
for future portability. See also Fortran 2003 status.
CALL FPUT(C [, STATUS])
| C | The type shall be CHARACTER.
|
| STATUS | (Optional) status flag of type INTEGER. Returns 0 on success,
-1 on end-of-file and a system specific positive error code otherwise.
|
PROGRAM test_fput
CHARACTER(len=10) :: str = "gfortran"
INTEGER :: i
DO i = 1, len_trim(str)
CALL fput(str(i:i))
END DO
END PROGRAM
FPUTC — Write a single character in stream modeThis intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit.
Note that the FGET intrinsic is provided for backwards compatibility with
g77. GNU Fortran provides the Fortran 2003 Stream facility.
Programmers should consider the use of new stream IO feature in new code
for future portability. See also Fortran 2003 status.
CALL FPUTC(UNIT, C [, STATUS])
| UNIT | The type shall be INTEGER.
|
| C | The type shall be CHARACTER.
|
| STATUS | (Optional) status flag of type INTEGER. Returns 0 on success,
-1 on end-of-file and a system specific positive error code otherwise.
|
PROGRAM test_fputc
CHARACTER(len=10) :: str = "gfortran"
INTEGER :: fd = 42, i
OPEN(UNIT = fd, FILE = "out", ACTION = "WRITE", STATUS="NEW")
DO i = 1, len_trim(str)
CALL fputc(fd, str(i:i))
END DO
CLOSE(fd)
END PROGRAM
FRACTION — Fractional part of the model representationFRACTION(X) returns the fractional part of the model
representation of X.
Y = FRACTION(X)
| X | The type of the argument shall be a REAL.
|
X is returned;
it is X * RADIX(X)**(-EXPONENT(X)).
program test_fraction
real :: x
x = 178.1387e-4
print *, fraction(x), x * radix(x)**(-exponent(x))
end program test_fraction
FREE — Frees memoryMALLOC(). The FREE
intrinsic is an extension intended to be used with Cray pointers, and is
provided in GNU Fortran to allow user to compile legacy code. For
new code using Fortran 95 pointers, the memory de-allocation intrinsic is
DEALLOCATE.
CALL FREE(PTR)
| PTR | The type shall be INTEGER. It represents the
location of the memory that should be de-allocated.
|
MALLOC for an example.
FSEEK — Low level file positioning subroutineSEEK_SET,
if set to 1, OFFSET is taken to be relative to the current position
SEEK_CUR, and if set to 2 relative to the end of the file SEEK_END.
On error, STATUS is set to a nonzero value. If STATUS the seek
fails silently.
This intrinsic routine is not fully backwards compatible with g77.
In g77, the FSEEK takes a statement label instead of a
STATUS variable. If FSEEK is used in old code, change
CALL FSEEK(UNIT, OFFSET, WHENCE, *label)
to
INTEGER :: status
CALL FSEEK(UNIT, OFFSET, WHENCE, status)
IF (status /= 0) GOTO label
Please note that GNU Fortran provides the Fortran 2003 Stream facility.
Programmers should consider the use of new stream IO feature in new code
for future portability. See also Fortran 2003 status.
CALL FSEEK(UNIT, OFFSET, WHENCE[, STATUS])
| UNIT | Shall be a scalar of type INTEGER.
|
| OFFSET | Shall be a scalar of type INTEGER.
|
| WHENCE | Shall be a scalar of type INTEGER.
Its value shall be either 0, 1 or 2.
|
| STATUS | (Optional) shall be a scalar of type
INTEGER(4).
|
PROGRAM test_fseek
INTEGER, PARAMETER :: SEEK_SET = 0, SEEK_CUR = 1, SEEK_END = 2
INTEGER :: fd, offset, ierr
ierr = 0
offset = 5
fd = 10
OPEN(UNIT=fd, FILE="fseek.test")
CALL FSEEK(fd, offset, SEEK_SET, ierr) ! move to OFFSET
print *, FTELL(fd), ierr
CALL FSEEK(fd, 0, SEEK_END, ierr) ! move to end
print *, FTELL(fd), ierr
CALL FSEEK(fd, 0, SEEK_SET, ierr) ! move to beginning
print *, FTELL(fd), ierr
CLOSE(UNIT=fd)
END PROGRAM
FSTAT — Get file statusFSTAT is identical to STAT, except that information about an
already opened file is obtained.
The elements in BUFF are the same as described by STAT.
This intrinsic is provided in both subroutine and function forms; however,
only one form can be used in any given program unit.
CALL FSTAT(UNIT, BUFF [, STATUS])
| UNIT | An open I/O unit number of type INTEGER.
|
| BUFF | The type shall be INTEGER(4), DIMENSION(13).
|
| STATUS | (Optional) status flag of type INTEGER(4). Returns 0
on success and a system specific error code otherwise.
|
FTELL — Current stream positionThis intrinsic is provided in both subroutine and function forms; however,
only one form can be used in any given program unit.
CALL FTELL(UNIT, OFFSET)
|
OFFSET = FTELL(UNIT)
|
| OFFSET | Shall of type INTEGER.
|
| UNIT | Shall of type INTEGER.
|
PROGRAM test_ftell
INTEGER :: i
OPEN(10, FILE="temp.dat")
CALL ftell(10,i)
WRITE(*,*) i
END PROGRAM
GAMMA — Gamma functionGAMMA(X) computes Gamma (\Gamma) of X. For positive,
integer values of X the Gamma function simplifies to the factorial
function \Gamma(x)=(x-1)!.
X = GAMMA(X)
| X | Shall be of type REAL and neither zero
nor a negative integer.
|
REAL of the same kind as X.
program test_gamma
real :: x = 1.0
x = gamma(x) ! returns 1.0
end program test_gamma
| Name | Argument | Return type | Standard
|
GAMMA(X) | REAL(4) X | REAL(4) | GNU Extension
|
DGAMMA(X) | REAL(8) X | REAL(8) | GNU Extension
|
GERROR — Get last system error messagestrerror(3) in C.
CALL GERROR(RESULT)
| RESULT | Shall of type CHARACTER(*).
|
PROGRAM test_gerror
CHARACTER(len=100) :: msg
CALL gerror(msg)
WRITE(*,*) msg
END PROGRAM
GETARG — Get command line argumentsThis intrinsic routine is provided for backwards compatibility with
GNU Fortran 77. In new code, programmers should consider the use of
the GET_COMMAND_ARGUMENT intrinsic defined by the Fortran 2003
standard.
CALL GETARG(POS, VALUE)
| POS | Shall be of type INTEGER and not wider than
the default integer kind; POS \geq 0
|
| VALUE | Shall be of type CHARACTER(*).
|
GETARG returns, the VALUE argument holds the
POSth command line argument. If VALUE can not hold the
argument, it is truncated to fit the length of VALUE. If there are
less than POS arguments specified at the command line, VALUE
will be filled with blanks. If POS = 0, VALUE is set
to the name of the program (on systems that support this feature).
PROGRAM test_getarg
INTEGER :: i
CHARACTER(len=32) :: arg
DO i = 1, iargc()
CALL getarg(i, arg)
WRITE (*,*) arg
END DO
END PROGRAM
F2003 functions and subroutines: GET_COMMAND, GET_COMMAND_ARGUMENT, COMMAND_ARGUMENT_COUNT
GET_COMMAND — Get the entire command lineCALL GET_COMMAND(CMD)
| CMD | Shall be of type CHARACTER(*).
|
PROGRAM test_get_command
CHARACTER(len=255) :: cmd
CALL get_command(cmd)
WRITE (*,*) TRIM(cmd)
END PROGRAM
GET_COMMAND_ARGUMENT — Get command line argumentsCALL GET_COMMAND_ARGUMENT(N, ARG)
| N | Shall be of type INTEGER(4), N \geq 0
|
| ARG | Shall be of type CHARACTER(*).
|
GET_COMMAND_ARGUMENT returns, the ARG argument holds the
Nth command line argument. If ARG can not hold the argument, it is
truncated to fit the length of ARG. If there are less than N
arguments specified at the command line, ARG will be filled with blanks.
If N = 0, ARG is set to the name of the program (on systems
that support this feature).
PROGRAM test_get_command_argument
INTEGER :: i
CHARACTER(len=32) :: arg
i = 0
DO
CALL get_command_argument(i, arg)
IF (LEN_TRIM(arg) == 0) EXIT
WRITE (*,*) TRIM(arg)
i = i+1
END DO
END PROGRAM
GETCWD — Get current working directoryThis intrinsic is provided in both subroutine and function forms; however,
only one form can be used in any given program unit.
CALL GETCWD(CWD [, STATUS])
| CWD | The type shall be CHARACTER(*).
|
| STATUS | (Optional) status flag. Returns 0 on success,
a system specific and nonzero error code otherwise.
|
PROGRAM test_getcwd
CHARACTER(len=255) :: cwd
CALL getcwd(cwd)
WRITE(*,*) TRIM(cwd)
END PROGRAM
GETENV — Get an environmental variableThis intrinsic routine is provided for backwards compatibility with
GNU Fortran 77. In new code, programmers should consider the use of
the GET_ENVIRONMENT_VARIABLE intrinsic defined by the Fortran
2003 standard.
CALL GETENV(ENVVAR, VALUE)
| ENVVAR | Shall be of type CHARACTER(*).
|
| VALUE | Shall be of type CHARACTER(*).
|
PROGRAM test_getenv
CHARACTER(len=255) :: homedir
CALL getenv("HOME", homedir)
WRITE (*,*) TRIM(homedir)
END PROGRAM
GET_ENVIRONMENT_VARIABLE — Get an environmental variableCALL GET_ENVIRONMENT_VARIABLE(ENVVAR, VALUE)
| ENVVAR | Shall be of type CHARACTER(*).
|
| VALUE | Shall be of type CHARACTER(*).
|
PROGRAM test_getenv
CHARACTER(len=255) :: homedir
CALL get_environment_variable("HOME", homedir)
WRITE (*,*) TRIM(homedir)
END PROGRAM
GETGID — Group ID functionRESULT = GETGID()
GETGID is an INTEGER of the default
kind.
GETPID for an example.
GETLOG — Get login nameCALL GETLOG(LOGIN)
| LOGIN | Shall be of type CHARACTER(*).
|
geteuid and getpwuid are not available, and
the getlogin function is not implemented either, this will
return a blank string.)
PROGRAM TEST_GETLOG
CHARACTER(32) :: login
CALL GETLOG(login)
WRITE(*,*) login
END PROGRAM
GETPID — Process ID functionRESULT = GETPID()
GETPID is an INTEGER of the default
kind.
program info
print *, "The current process ID is ", getpid()
print *, "Your numerical user ID is ", getuid()
print *, "Your numerical group ID is ", getgid()
end program info
GETUID — User ID functionRESULT = GETUID()
GETUID is an INTEGER of the default
kind.
GETPID for an example.
GMTIME — Convert time to GMT infoTIME8()
intrinsic), fills TARRAY with values extracted from it appropriate
to the UTC time zone (Universal Coordinated Time, also known in some
countries as GMT, Greenwich Mean Time), using gmtime(3).
CALL GMTIME(STIME, TARRAY)
| STIME | An INTEGER(*) scalar expression
corresponding to a system time, with
INTENT(IN).
|
| TARRAY | A default INTEGER array with 9 elements,
with INTENT(OUT).
|
HOSTNM — Get system host nameThis intrinsic is provided in both subroutine and function forms; however,
only one form can be used in any given program unit.
CALL HOSTNM(NAME[, STATUS])
|
STATUS = HOSTNM(NAME)
|
| NAME | Shall of type CHARACTER(*).
|
| STATUS | (Optional) status flag of type INTEGER.
Returns 0 on success, or a system specific error
code otherwise.
|
HUGE — Largest number of a kindHUGE(X) returns the largest number that is not an infinity in
the model of the type of X.
RESULT = HUGE(X)
| X | Shall be of type REAL or INTEGER.
|
program test_huge_tiny
print *, huge(0), huge(0.0), huge(0.0d0)
print *, tiny(0.0), tiny(0.0d0)
end program test_huge_tiny
IACHAR — Code in ASCII collating sequenceIACHAR(C) returns the code for the ASCII character
in the first character position of C.
RESULT = IACHAR(C [, KIND])
| C | Shall be a scalar CHARACTER, with INTENT(IN)
|
| KIND | (Optional) An INTEGER initialization
expression indicating the kind parameter of
the result.
|
INTEGER and of kind KIND. If
KIND is absent, the return value is of default integer kind.
program test_iachar
integer i
i = iachar(' ')
end program test_iachar
IAND — Bitwise logical andAND.
RESULT = IAND(I, J)
| I | The type shall be INTEGER(*).
|
| J | The type shall be INTEGER(*), of the same
kind as I. (As a GNU extension, different kinds are also
permitted.)
|
INTEGER(*), of the same kind as the
arguments. (If the argument kinds differ, it is of the same kind as
the larger argument.)
PROGRAM test_iand
INTEGER :: a, b
DATA a / Z'F' /, b / Z'3' /
WRITE (*,*) IAND(a, b)
END PROGRAM
IARGC — Get the number of command line argumentsIARGC() returns the number of arguments passed on the
command line when the containing program was invoked.
This intrinsic routine is provided for backwards compatibility with
GNU Fortran 77. In new code, programmers should consider the use of
the COMMAND_ARGUMENT_COUNT intrinsic defined by the Fortran 2003
standard.
RESULT = IARGC()
INTEGER(4).
F2003 functions and subroutines: GET_COMMAND, GET_COMMAND_ARGUMENT, COMMAND_ARGUMENT_COUNT
IBCLR — Clear bitIBCLR returns the value of I with the bit at position
POS set to zero.
RESULT = IBCLR(I, POS)
| I | The type shall be INTEGER(*).
|
| POS | The type shall be INTEGER(*).
|
INTEGER(*) and of the same kind as
I.
IBITS — Bit extractionIBITS extracts a field of length LEN from I,
starting from bit position POS and extending left for LEN
bits. The result is right-justified and the remaining bits are
zeroed. The value of POS+LEN must be less than or equal to the
value BIT_SIZE(I).
RESULT = IBITS(I, POS, LEN)
| I | The type shall be INTEGER(*).
|
| POS | The type shall be INTEGER(*).
|
| LEN | The type shall be INTEGER(*).
|
INTEGER(*) and of the same kind as
I.
IBSET — Set bitIBSET returns the value of I with the bit at position
POS set to one.
RESULT = IBSET(I, POS)
| I | The type shall be INTEGER(*).
|
| POS | The type shall be INTEGER(*).
|
INTEGER(*) and of the same kind as
I.
ICHAR — Character-to-integer conversion functionICHAR(C) returns the code for the character in the first character
position of C in the system's native character set.
The correspondence between characters and their codes is not necessarily
the same across different GNU Fortran implementations.
RESULT = ICHAR(C [, KIND])
| C | Shall be a scalar CHARACTER, with INTENT(IN)
|
| KIND | (Optional) An INTEGER initialization
expression indicating the kind parameter of
the result.
|
INTEGER and of kind KIND. If
KIND is absent, the return value is of default integer kind.
program test_ichar
integer i
i = ichar(' ')
end program test_ichar
CHARACTER value '154', obtaining an INTEGER or
REAL value with the value 154, or vice versa. Instead, this
functionality is provided by internal-file I/O, as in the following
example:
program read_val
integer value
character(len=10) string, string2
string = '154'
! Convert a string to a numeric value
read (string,'(I10)') value
print *, value
! Convert a value to a formatted string
write (string2,'(I10)') value
print *, string2
end program read_val
IDATE — Get current local time subroutine (day/month/year)IDATE(TARRAY) Fills TARRAY with the numerical values at the
current local time. The day (in the range 1-31), month (in the range 1-12),
and year appear in elements 1, 2, and 3 of TARRAY, respectively.
The year has four significant digits.
CALL IDATE(TARRAY)
| TARRAY | The type shall be INTEGER, DIMENSION(3) and
the kind shall be the default integer kind.
|
program test_idate
integer, dimension(3) :: tarray
call idate(tarray)
print *, tarray(1)
print *, tarray(2)
print *, tarray(3)
end program test_idate
IEOR — Bitwise logical exclusive orIEOR returns the bitwise boolean exclusive-OR of I and
J.
RESULT = IEOR(I, J)
| I | The type shall be INTEGER(*).
|
| J | The type shall be INTEGER(*), of the same
kind as I. (As a GNU extension, different kinds are also
permitted.)
|
INTEGER(*), of the same kind as the
arguments. (If the argument kinds differ, it is of the same kind as
the larger argument.)
IERRNO — Get the last system error numbererrno()
function.
RESULT = IERRNO()
INTEGER and of the default integer
kind.
INDEX — Position of a substring within a stringRESULT = INDEX(STRING, SUBSTRING [, BACK [, KIND]])
| STRING | Shall be a scalar CHARACTER(*), with
INTENT(IN)
|
| SUBSTRING | Shall be a scalar CHARACTER(*), with
INTENT(IN)
|
| BACK | (Optional) Shall be a scalar LOGICAL(*), with
INTENT(IN)
|
| KIND | (Optional) An INTEGER initialization
expression indicating the kind parameter of
the result.
|
INTEGER and of kind KIND. If
KIND is absent, the return value is of default integer kind.
INT — Convert to integer typeRESULT = INT(A [, KIND))
| A | Shall be of type INTEGER(*),
REAL(*), or COMPLEX(*).
|
| KIND | (Optional) An INTEGER(*) initialization
expression indicating the kind parameter of
the result.
|
INTEGER(*) variable or array under
the following rules:
INTEGER(*), INT(A) = A
REAL(*) and |A| < 1, INT(A) equals 0.
If |A| \geq 1, then INT(A) equals the largest integer that does not exceed
the range of A and whose sign is the same as the sign of A.
COMPLEX(*), rule B is applied to the real part of A.
program test_int
integer :: i = 42
complex :: z = (-3.7, 1.0)
print *, int(i)
print *, int(z), int(z,8)
end program
| Name | Argument | Return type | Standard
|
IFIX(A) | REAL(4) A | INTEGER | F77 and later
|
IDINT(A) | REAL(8) A | INTEGER | F77 and later
|
INT2 — Convert to 16-bit integer typeKIND=2 integer type. This is equivalent to the
standard INT intrinsic with an optional argument of
KIND=2, and is only included for backwards compatibility.
The SHORT intrinsic is equivalent to INT2.
RESULT = INT2(A)
| A | Shall be of type INTEGER(*),
REAL(*), or COMPLEX(*).
|
INTEGER(2) variable.
INT8 — Convert to 64-bit integer typeKIND=8 integer type. This is equivalent to the
standard INT intrinsic with an optional argument of
KIND=8, and is only included for backwards compatibility.
RESULT = INT8(A)
| A | Shall be of type INTEGER(*),
REAL(*), or COMPLEX(*).
|
INTEGER(8) variable.
IOR — Bitwise logical orIOR returns the bitwise boolean inclusive-OR of I and
J.
RESULT = IOR(I, J)
| I | The type shall be INTEGER(*).
|
| J | The type shall be INTEGER(*), of the same
kind as I. (As a GNU extension, different kinds are also
permitted.)
|
INTEGER(*), of the same kind as the
arguments. (If the argument kinds differ, it is of the same kind as
the larger argument.)
IRAND — Integer pseudo-random numberIRAND(FLAG) returns a pseudo-random number from a uniform
distribution between 0 and a system-dependent limit (which is in most
cases 2147483647). If FLAG is 0, the next number
in the current sequence is returned; if FLAG is 1, the generator
is restarted by CALL SRAND(0); if FLAG has any other value,
it is used as a new seed with SRAND.
This intrinsic routine is provided for backwards compatibility with
GNU Fortran 77. It implements a simple modulo generator as provided
by g77. For new code, one should consider the use of
RANDOM_NUMBER as it implements a superior algorithm.
RESULT = IRAND(FLAG)
| FLAG | Shall be a scalar INTEGER of kind 4.
|
INTEGER(kind=4) type.
program test_irand
integer,parameter :: seed = 86456
call srand(seed)
print *, irand(), irand(), irand(), irand()
print *, irand(seed), irand(), irand(), irand()
end program test_irand
IS_IOSTAT_END — Test for end-of-file valueIS_IOSTAT_END tests whether an variable has the value of the I/O
status “end of file”. The function is equivalent to comparing the variable
with the IOSTAT_END parameter of the intrinsic module
ISO_FORTRAN_ENV.
RESULT = IS_IOSTAT_END(I)
| I | Shall be of the type INTEGER.
|
LOGICAL of the default kind, which .TRUE. if
I has the value which indicates an end of file condition for
IOSTAT= specifiers, and is .FALSE. otherwise.
PROGRAM iostat
IMPLICIT NONE
INTEGER :: stat, i
OPEN(88, FILE='test.dat')
READ(88, *, IOSTAT=stat) i
IF(IS_IOSTAT_END(stat)) STOP 'END OF FILE'
END PROGRAM
IS_IOSTAT_EOR — Test for end-of-record valueIS_IOSTAT_EOR tests whether an variable has the value of the I/O
status “end of record”. The function is equivalent to comparing the
variable with the IOSTAT_EOR parameter of the intrinsic module
ISO_FORTRAN_ENV.
RESULT = IS_IOSTAT_EOR(I)
| I | Shall be of the type INTEGER.
|
LOGICAL of the default kind, which .TRUE. if
I has the value which indicates an end of file condition for
IOSTAT= specifiers, and is .FALSE. otherwise.
PROGRAM iostat
IMPLICIT NONE
INTEGER :: stat, i(50)
OPEN(88, FILE='test.dat', FORM='UNFORMATTED')
READ(88, IOSTAT=stat) i
IF(IS_IOSTAT_EOR(stat)) STOP 'END OF RECORD'
END PROGRAM
ISATTY — Whether a unit is a terminal device.RESULT = ISATTY(UNIT)
| UNIT | Shall be a scalar INTEGER(*).
|
.TRUE. if the UNIT is connected to a terminal
device, .FALSE. otherwise.
PROGRAM test_isatty
INTEGER(kind=1) :: unit
DO unit = 1, 10
write(*,*) isatty(unit=unit)
END DO
END PROGRAM
ISHFT — Shift bitsISHFT returns a value corresponding to I with all of the
bits shifted SHIFT places. A value of SHIFT greater than
zero corresponds to a left shift, a value of zero corresponds to no
shift, and a value less than zero corresponds to a right shift. If the
absolute value of SHIFT is greater than BIT_SIZE(I), the
value is undefined. Bits shifted out from the left end or right end are
lost; zeros are shifted in from the opposite end.
RESULT = ISHFT(I, SHIFT)
| I | The type shall be INTEGER(*).
|
| SHIFT | The type shall be INTEGER(*).
|
INTEGER(*) and of the same kind as
I.
ISHFTC — Shift bits circularlyISHFTC returns a value corresponding to I with the
rightmost SIZE bits shifted circularly SHIFT places; that
is, bits shifted out one end are shifted into the opposite end. A value
of SHIFT greater than zero corresponds to a left shift, a value of
zero corresponds to no shift, and a value less than zero corresponds to
a right shift. The absolute value of SHIFT must be less than
SIZE. If the SIZE argument is omitted, it is taken to be
equivalent to BIT_SIZE(I).
RESULT = ISHFTC(I, SHIFT [, SIZE])
| I | The type shall be INTEGER(*).
|
| SHIFT | The type shall be INTEGER(*).
|
| SIZE | (Optional) The type shall be INTEGER(*);
the value must be greater than zero and less than or equal to
BIT_SIZE(I).
|
INTEGER(*) and of the same kind as
I.
ISNAN — Test for a NaNISNAN tests whether a floating-point value is an IEEE
Not-a-Number (NaN).
ISNAN(X)
| X | Variable of the type REAL.
|
LOGICAL. The returned value is TRUE
if X is a NaN and FALSE otherwise.
program test_nan
implicit none
real :: x
x = -1.0
x = sqrt(x)
if (isnan(x)) stop '"x" is a NaN'
end program test_nan
ITIME — Get current local time subroutine (hour/minutes/seconds)IDATE(TARRAY) Fills TARRAY with the numerical values at the
current local time. The hour (in the range 1-24), minute (in the range 1-60),
and seconds (in the range 1-60) appear in elements 1, 2, and 3 of TARRAY,
respectively.
CALL ITIME(TARRAY)
| TARRAY | The type shall be INTEGER, DIMENSION(3)
and the kind shall be the default integer kind.
|
program test_itime
integer, dimension(3) :: tarray
call itime(tarray)
print *, tarray(1)
print *, tarray(2)
print *, tarray(3)
end program test_itime
KILL — Send a signal to a processkill(2).
This intrinsic is provided in both subroutine and function forms; however,
only one form can be used in any given program unit.
CALL KILL(PID, SIGNAL [, STATUS])
| PID | Shall be a scalar INTEGER, with
INTENT(IN)
|
| SIGNAL | Shall be a scalar INTEGER, with
INTENT(IN)
|
| STATUS | (Optional) status flag of type INTEGER(4) or
INTEGER(8). Returns 0 on success, or a
system-specific error code otherwise.
|
KIND — Kind of an entityKIND(X) returns the kind value of the entity X.
K = KIND(X)
| X | Shall be of type LOGICAL, INTEGER,
REAL, COMPLEX or CHARACTER.
|
INTEGER and of the default
integer kind.
program test_kind
integer,parameter :: kc = kind(' ')
integer,parameter :: kl = kind(.true.)
print *, "The default character kind is ", kc
print *, "The default logical kind is ", kl
end program test_kind
LBOUND — Lower dimension bounds of an arrayRESULT = LBOUND(ARRAY [, DIM [, KIND]])
| ARRAY | Shall be an array, of any type.
|
| DIM | (Optional) Shall be a scalar INTEGER(*).
|
| KIND | (Optional) An INTEGER initialization
expression indicating the kind parameter of
the result.
|
INTEGER and of kind KIND. If
KIND is absent, the return value is of default integer kind.
If DIM is absent, the result is an array of the lower bounds of
ARRAY. If DIM is present, the result is a scalar
corresponding to the lower bound of the array along that dimension. If
ARRAY is an expression rather than a whole array or array
structure component, or if it has a zero extent along the relevant
dimension, the lower bound is taken to be 1.
LEN — Length of a character entityL = LEN(STRING [, KIND])
| STRING | Shall be a scalar or array of type
CHARACTER(*), with INTENT(IN)
|
| KIND | (Optional) An INTEGER initialization
expression indicating the kind parameter of
the result.
|
INTEGER and of kind KIND. If
KIND is absent, the return value is of default integer kind.
LEN_TRIM — Length of a character entity without trailing blank charactersRESULT = LEN_TRIM(STRING [, KIND])
| STRING | Shall be a scalar of type CHARACTER(*),
with INTENT(IN)
|
| KIND | (Optional) An INTEGER initialization
expression indicating the kind parameter of
the result.
|
INTEGER and of kind KIND. If
KIND is absent, the return value is of default integer kind.
LGAMMA — Logarithm of the Gamma functionGAMMA(X) computes the natural logrithm of the absolute value of the
Gamma (\Gamma) function.
X = LGAMMA(X)
| X | Shall be of type REAL and neither zero
nor a negative integer.
|
REAL of the same kind as X.
program test_log_gamma
real :: x = 1.0
x = lgamma(x) ! returns 0.0
end program test_log_gamma
| Name | Argument | Return type | Standard
|
LGAMMA(X) | REAL(4) X | REAL(4) | GNU Extension
|
ALGAMA(X) | REAL(4) X | REAL(4) | GNU Extension
|
DLGAMA(X) | REAL(8) X | REAL(8) | GNU Extension
|
LGE — Lexical greater than or equalIn general, the lexical comparison intrinsics LGE, LGT,
LLE, and LLT differ from the corresponding intrinsic
operators .GE., .GT., .LE., and .LT., in
that the latter use the processor's character ordering (which is not
ASCII on some targets), whereas the former always use the ASCII
ordering.
RESULT = LGE(STRING_A, STRING_B)
| STRING_A | Shall be of default CHARACTER type.
|
| STRING_B | Shall be of default CHARACTER type.
|
.TRUE. if STRING_A >= STRING_B, and .FALSE.
otherwise, based on the ASCII ordering.
LGT — Lexical greater thanIn general, the lexical comparison intrinsics LGE, LGT,
LLE, and LLT differ from the corresponding intrinsic
operators .GE., .GT., .LE., and .LT., in
that the latter use the processor's character ordering (which is not
ASCII on some targets), whereas the former always use the ASCII
ordering.
RESULT = LGT(STRING_A, STRING_B)
| STRING_A | Shall be of default CHARACTER type.
|
| STRING_B | Shall be of default CHARACTER type.
|
.TRUE. if STRING_A > STRING_B, and .FALSE.
otherwise, based on the ASCII ordering.
LINK — Create a hard linkCHAR(0)) can be used to mark the end of the names in
PATH1 and PATH2; otherwise, trailing blanks in the file
names are ignored. If the STATUS argument is supplied, it
contains 0 on success or a nonzero error code upon return; see
link(2).
This intrinsic is provided in both subroutine and function forms;
however, only one form can be used in any given program unit.
CALL LINK(PATH1, PATH2 [, STATUS])
|
STATUS = LINK(PATH1, PATH2)
|
| PATH1 | Shall be of default CHARACTER type.
|
| PATH2 | Shall be of default CHARACTER type.
|
| STATUS | (Optional) Shall be of default INTEGER type.
|
LLE — Lexical less than or equalIn general, the lexical comparison intrinsics LGE, LGT,
LLE, and LLT differ from the corresponding intrinsic
operators .GE., .GT., .LE., and .LT., in
that the latter use the processor's character ordering (which is not
ASCII on some targets), whereas the former always use the ASCII
ordering.
RESULT = LLE(STRING_A, STRING_B)
| STRING_A | Shall be of default CHARACTER type.
|
| STRING_B | Shall be of default CHARACTER type.
|
.TRUE. if STRING_A <= STRING_B, and .FALSE.
otherwise, based on the ASCII ordering.
LLT — Lexical less thanIn general, the lexical comparison intrinsics LGE, LGT,
LLE, and LLT differ from the corresponding intrinsic
operators .GE., .GT., .LE., and .LT., in
that the latter use the processor's character ordering (which is not
ASCII on some targets), whereas the former always use the ASCII
ordering.
RESULT = LLT(STRING_A, STRING_B)
| STRING_A | Shall be of default CHARACTER type.
|
| STRING_B | Shall be of default CHARACTER type.
|
.TRUE. if STRING_A < STRING_B, and .FALSE.
otherwise, based on the ASCII ordering.
LNBLNK — Index of the last non-blank character in a stringLEN_TRIM intrinsic, and is only
included for backwards compatibility.
RESULT = LNBLNK(STRING)
| STRING | Shall be a scalar of type CHARACTER(*),
with INTENT(IN)
|
INTEGER(kind=4) type.
LOC — Returns the address of a variableLOC(X) returns the address of X as an integer.
RESULT = LOC(X)
| X | Variable of any type.
|
INTEGER, with a KIND
corresponding to the size (in bytes) of a memory address on the target
machine.
program test_loc
integer :: i
real :: r
i = loc(r)
print *, i
end program test_loc
LOG — Logarithm functionLOG(X) computes the logarithm of X.
RESULT = LOG(X)
| X | The type shall be REAL(*) or
COMPLEX(*).
|
REAL(*) or COMPLEX(*).
The kind type parameter is the same as X.
program test_log
real(8) :: x = 1.0_8
complex :: z = (1.0, 2.0)
x = log(x)
z = log(z)
end program test_log
| Name | Argument | Return type | Standard
|
ALOG(X) | REAL(4) X | REAL(4) | f95, gnu
|
DLOG(X) | REAL(8) X | REAL(8) | f95, gnu
|
CLOG(X) | COMPLEX(4) X | COMPLEX(4) | f95, gnu
|
ZLOG(X) | COMPLEX(8) X | COMPLEX(8) | f95, gnu
|
CDLOG(X) | COMPLEX(8) X | COMPLEX(8) | f95, gnu
|
LOG10 — Base 10 logarithm functionLOG10(X) computes the base 10 logarithm of X.
RESULT = LOG10(X)
| X | The type shall be REAL(*).
|
REAL(*) or COMPLEX(*).
The kind type parameter is the same as X.
program test_log10
real(8) :: x = 10.0_8
x = log10(x)
end program test_log10
| Name | Argument | Return type | Standard
|
ALOG10(X) | REAL(4) X | REAL(4) | F95 and later
|
DLOG10(X) | REAL(8) X | REAL(8) | F95 and later
|
LOGICAL — Convert to logical typeLOGICAL variable to another.
RESULT = LOGICAL(L [, KIND])
| L | The type shall be LOGICAL(*).
|
| KIND | (Optional) An INTEGER(*) initialization
expression indicating the kind parameter of
the result.
|
LOGICAL value equal to L, with a
kind corresponding to KIND, or of the default logical kind if
KIND is not given.
LONG — Convert to integer typeKIND=4 integer type, which is the same size as a C
long integer. This is equivalent to the standard INT
intrinsic with an optional argument of KIND=4, and is only
included for backwards compatibility.
RESULT = LONG(A)
| A | Shall be of type INTEGER(*),
REAL(*), or COMPLEX(*).
|
INTEGER(4) variable.
LSHIFT — Left shift bitsLSHIFT returns a value corresponding to I with all of the
bits shifted left by SHIFT places. If the absolute value of
SHIFT is greater than BIT_SIZE(I), the value is undefined.
Bits shifted out from the left end are lost; zeros are shifted in from
the opposite end.
This function has been superseded by the ISHFT intrinsic, which
is standard in Fortran 95 and later.
RESULT = LSHIFT(I, SHIFT)
| I | The type shall be INTEGER(*).
|
| SHIFT | The type shall be INTEGER(*).
|
INTEGER(*) and of the same kind as
I.
LSTAT — Get file statusLSTAT is identical to STAT, except that if path is a symbolic link,
then the link itself is statted, not the file that it refers to.
The elements in BUFF are the same as described by STAT.
This intrinsic is provided in both subroutine and function forms; however,
only one form can be used in any given program unit.
CALL LSTAT(FILE, BUFF [, STATUS])
| FILE | The type shall be CHARACTER(*), a valid path within the file system.
|
| BUFF | The type shall be INTEGER(4), DIMENSION(13).
|
| STATUS | (Optional) status flag of type INTEGER(4). Returns 0
on success and a system specific error code otherwise.
|
LTIME — Convert time to local time infoTIME8()
intrinsic), fills TARRAY with values extracted from it appropriate
to the local time zone using localtime(3).
CALL LTIME(STIME, TARRAY)
| STIME | An INTEGER(*) scalar expression
corresponding to a system time, with
INTENT(IN).
|
| TARRAY | A default INTEGER array with 9 elements,
with INTENT(OUT).
|
MALLOC — Allocate dynamic memoryMALLOC(SIZE) allocates SIZE bytes of dynamic memory and
returns the address of the allocated memory. The MALLOC intrinsic
is an extension intended to be used with Cray pointers, and is provided
in GNU Fortran to allow the user to compile legacy code. For new code
using Fortran 95 pointers, the memory allocation intrinsic is
ALLOCATE.
PTR = MALLOC(SIZE)
| SIZE | The type shall be INTEGER(*).
|
INTEGER(K), with K such that
variables of type INTEGER(K) have the same size as
C pointers (sizeof(void *)).
MALLOC and
FREE with Cray pointers. This example is intended to run on
32-bit systems, where the default integer kind is suitable to store
pointers; on 64-bit systems, ptr_x would need to be declared as
integer(kind=8).
program test_malloc
integer i
integer ptr_x
real*8 x(*), z
pointer(ptr_x,x)
ptr_x = malloc(20*8)
do i = 1, 20
x(i) = sqrt(1.0d0 / i)
end do
z = 0
do i = 1, 20
z = z + x(i)
print *, z
end do
call free(ptr_x)
end program test_malloc
MATMUL — matrix multiplicationRESULT = MATMUL(MATRIX_A, MATRIX_B)
| MATRIX_A | An array of INTEGER(*),
REAL(*), COMPLEX(*), or
LOGICAL(*) type, with a rank of
one or two.
|
| MATRIX_B | An array of INTEGER(*),
REAL(*), or COMPLEX(*) type if
MATRIX_A is of a numeric type;
otherwise, an array of LOGICAL(*)
type. The rank shall be one or two, and the
first (or only) dimension of MATRIX_B
shall be equal to the last (or only)
dimension of MATRIX_A.
|
* or .AND. operators.
MAX — Maximum value of an argument listRESULT = MAX(A1, A2 [, A3 [, ...]])
| A1 | The type shall be INTEGER(*) or
REAL(*).
|
| A2, A3, ... | An expression of the same type and kind
as A1. (As a GNU extension,
arguments of different kinds are
permitted.)
|
| Name | Argument | Return type | Standard
|
MAX0(I) | INTEGER(4) I | INTEGER(4) | F77 and later
|
AMAX0(I) | INTEGER(4) I | REAL(MAX(X)) | F77 and later
|
MAX1(X) | REAL(*) X | INT(MAX(X)) | F77 and later
|
AMAX1(X) | REAL(4) X | REAL(4) | F77 and later
|
DMAX1(X) | REAL(8) X | REAL(8) | F77 and later
|
MAXEXPONENT — Maximum exponent of a real kindMAXEXPONENT(X) returns the maximum exponent in the model of the
type of X.
RESULT = MAXEXPONENT(X)
| X | Shall be of type REAL.
|
INTEGER and of the default integer
kind.
program exponents
real(kind=4) :: x
real(kind=8) :: y
print *, minexponent(x), maxexponent(x)
print *, minexponent(y), maxexponent(y)
end program exponents
MAXLOC — Location of the maximum value within an array.TRUE. are considered. If more than one
element in the array has the maximum value, the location returned is
that of the first such element in array element order. If the array has
zero size, or all of the elements of MASK are .FALSE., then
the result is an array of zeroes. Similarly, if DIM is supplied
and all of the elements of MASK along a given row are zero, the
result value for that row is zero.
RESULT = MAXLOC(ARRAY, DIM [, MASK])
|
RESULT = MAXLOC(ARRAY [, MASK])
|
| ARRAY | Shall be an array of type INTEGER(*),
REAL(*), or CHARACTER(*).
|
| DIM | (Optional) Shall be a scalar of type
INTEGER(*), with a value between one
and the rank of ARRAY, inclusive. It
may not be an optional dummy argument.
|
| MASK | Shall be an array of type LOGICAL(*),
and conformable with ARRAY.
|
INTEGER type.
MAXVAL — Maximum value of an array.TRUE. are
considered. If the array has zero size, or all of the elements of
MASK are .FALSE., then the result is the most negative
number of the type and kind of ARRAY if ARRAY is numeric, or
a string of nulls if ARRAY is of character type.
RESULT = MAXVAL(ARRAY, DIM [, MASK])
|
RESULT = MAXVAL(ARRAY [, MASK])
|
| ARRAY | Shall be an array of type INTEGER(*),
REAL(*), or CHARACTER(*).
|
| DIM | (Optional) Shall be a scalar of type
INTEGER(*), with a value between one
and the rank of ARRAY, inclusive. It
may not be an optional dummy argument.
|
| MASK | Shall be an array of type LOGICAL(*),
and conformable with ARRAY.
|
MCLOCK — Time functionclock(3).
This intrinsic is not fully portable, such as to systems with 32-bit
INTEGER types but supporting times wider than 32 bits. Therefore,
the values returned by this intrinsic might be, or become, negative, or
numerically less than previous values, during a single run of the
compiled program.
RESULT = MCLOCK()
INTEGER(4), equal to the
number of clock ticks since the start of the process, or -1 if
the system does not support clock(3).
MCLOCK8 — Time function (64-bit)clock(3).
Warning: this intrinsic does not increase the range of the timing
values over that returned by clock(3). On a system with a 32-bit
clock(3), MCLOCK8() will return a 32-bit value, even though
it is converted to a 64-bit INTEGER(8) value. That means
overflows of the 32-bit value can still occur. Therefore, the values
returned by this intrinsic might be or become negative or numerically
less than previous values during a single run of the compiled program.
RESULT = MCLOCK8()
INTEGER(8), equal to the
number of clock ticks since the start of the process, or -1 if
the system does not support clock(3).
MERGE — Merge variables.TRUE., or equal to
FSOURCE if it is .FALSE..
RESULT = MERGE(TSOURCE, FSOURCE, MASK)
| TSOURCE | May be of any type.
|
| FSOURCE | Shall be of the same type and type parameters
as TSOURCE.
|
| MASK | Shall be of type LOGICAL(*).
|
MIN — Minimum value of an argument listRESULT = MIN(A1, A2 [, A3, ...])
| A1 | The type shall be INTEGER(*) or
REAL(*).
|
| A2, A3, ... | An expression of the same type and kind
as A1. (As a GNU extension,
arguments of different kinds are
permitted.)
|
| Name | Argument | Return type | Standard
|
MIN0(I) | INTEGER(4) I | INTEGER(4) | F77 and later
|
AMIN0(I) | INTEGER(4) I | REAL(MIN(X)) | F77 and later
|
MIN1(X) | REAL(*) X | INT(MIN(X)) | F77 and later
|
AMIN1(X) | REAL(4) X | REAL(4) | F77 and later
|
DMIN1(X) | REAL(8) X | REAL(8) | F77 and later
|
MINEXPONENT — Minimum exponent of a real kindMINEXPONENT(X) returns the minimum exponent in the model of the
type of X.
RESULT = MINEXPONENT(X)
| X | Shall be of type REAL.
|
INTEGER and of the default integer
kind.
MAXEXPONENT for an example.
MINLOC — Location of the minimum value within an array.TRUE. are considered. If more than one
element in the array has the minimum value, the location returned is
that of the first such element in array element order. If the array has
zero size, or all of the elements of MASK are .FALSE., then
the result is an array of zeroes. Similarly, if DIM is supplied
and all of the elements of MASK along a given row are zero, the
result value for that row is zero.
RESULT = MINLOC(ARRAY, DIM [, MASK])
|
RESULT = MINLOC(ARRAY [, MASK])
|
| ARRAY | Shall be an array of type INTEGER(*),
REAL(*), or CHARACTER(*).
|
| DIM | (Optional) Shall be a scalar of type
INTEGER(*), with a value between one
and the rank of ARRAY, inclusive. It
may not be an optional dummy argument.
|
| MASK | Shall be an array of type LOGICAL(*),
and conformable with ARRAY.
|
INTEGER type.
MINVAL — Minimum value of an array.TRUE. are
considered. If the array has zero size, or all of the elements of
MASK are .FALSE., then the result is HUGE(ARRAY) if
ARRAY is numeric, or a string of CHAR(255) characters if
ARRAY is of character type.
RESULT = MINVAL(ARRAY, DIM [, MASK])
|
RESULT = MINVAL(ARRAY [, MASK])
|
| ARRAY | Shall be an array of type INTEGER(*),
REAL(*), or CHARACTER(*).
|
| DIM | (Optional) Shall be a scalar of type
INTEGER(*), with a value between one
and the rank of ARRAY, inclusive. It
may not be an optional dummy argument.
|
| MASK | Shall be an array of type LOGICAL(*),
and conformable with ARRAY.
|
MOD — Remainder functionMOD(A,P) computes the remainder of the division of A by P. It is
calculated as A - (INT(A/P) * P).
RESULT = MOD(A, P)
| A | Shall be a scalar of type INTEGER or REAL
|
| P | Shall be a scalar of the same type as A and not
equal to zero
|
program test_mod
print *, mod(17,3)
print *, mod(17.5,5.5)
print *, mod(17.5d0,5.5)
print *, mod(17.5,5.5d0)
print *, mod(-17,3)
print *, mod(-17.5,5.5)
print *, mod(-17.5d0,5.5)
print *, mod(-17.5,5.5d0)
print *, mod(17,-3)
print *, mod(17.5,-5.5)
print *, mod(17.5d0,-5.5)
print *, mod(17.5,-5.5d0)
end program test_mod
| Name | Arguments | Return type | Standard
|
AMOD(A,P) | REAL(4) | REAL(4) | F95 and later
|
DMOD(A,P) | REAL(8) | REAL(8) | F95 and later
|
MODULO — Modulo functionMODULO(A,P) computes the A modulo P.
RESULT = MODULO(A, P)
| A | Shall be a scalar of type INTEGER or REAL
|
| P | Shall be a scalar of the same type and kind as A
|
INTEGER:MODULO(A,P) has the value R such that A=Q*P+R, where
Q is an integer and R is between 0 (inclusive) and P
(exclusive).
REAL:MODULO(A,P) has the value of A - FLOOR (A / P) * P.
program test_modulo
print *, modulo(17,3)
print *, modulo(17.5,5.5)
print *, modulo(-17,3)
print *, modulo(-17.5,5.5)
print *, modulo(17,-3)
print *, modulo(17.5,-5.5)
end program
MOVE_ALLOC — Move allocation from one object to anotherMOVE_ALLOC(SRC, DEST) moves the allocation from SRC to
DEST. SRC will become deallocated in the process.
CALL MOVE_ALLOC(SRC, DEST)
| SRC | ALLOCATABLE, INTENT(INOUT), may be
of any type and kind.
|
| DEST | ALLOCATABLE, INTENT(OUT), shall be
of the same type, kind and rank as SRC
|
program test_move_alloc
integer, allocatable :: a(:), b(:)
allocate(a(3))
a = [ 1, 2, 3 ]
call move_alloc(a, b)
print *, allocated(a), allocated(b)
print *, b
end program test_move_alloc
MVBITS — Move bits from one integer to anotherFROMPOS+LEN-1 of FROM to positions TOPOS through
TOPOS+LEN-1 of TO. The portion of argument TO not
affected by the movement of bits is unchanged. The values of
FROMPOS+LEN-1 and TOPOS+LEN-1 must be less than
BIT_SIZE(FROM).
CALL MVBITS(FROM, FROMPOS, LEN, TO, TOPOS)
| FROM | The type shall be INTEGER(*).
|
| FROMPOS | The type shall be INTEGER(*).
|
| LEN | The type shall be INTEGER(*).
|
| TO | The type shall be INTEGER(*), of the
same kind as FROM.
|
| TOPOS | The type shall be INTEGER(*).
|
NEAREST — Nearest representable numberNEAREST(X, S) returns the processor-representable number nearest
to X in the direction indicated by the sign of S.
RESULT = NEAREST(X, S)
| X | Shall be of type REAL.
|
| S | (Optional) shall be of type REAL and
not equal to zero.
|
X. If S is
positive, NEAREST returns the processor-representable number
greater than X and nearest to it. If S is negative,
NEAREST returns the processor-representable number smaller than
X and nearest to it.
program test_nearest
real :: x, y
x = nearest(42.0, 1.0)
y = nearest(42.0, -1.0)
write (*,"(3(G20.15))") x, y, x - y
end program test_nearest
NEW_LINE — New line characterNEW_LINE(C) returns the new-line character.
RESULT = NEW_LINE(C)
| C | The argument shall be a scalar or array of the
type CHARACTER.
|
program newline
implicit none
write(*,'(A)') 'This is record 1.'//NEW_LINE('A')//'This is record 2.'
end program newline
NINT — Nearest whole numberNINT(X) rounds its argument to the nearest whole number.
RESULT = NINT(X)
| X | The type of the argument shall be REAL.
|
INTEGER of the default kind.
program test_nint
real(4) x4
real(8) x8
x4 = 1.234E0_4
x8 = 4.321_8
print *, nint(x4), idnint(x8)
end program test_nint
| Name | Argument | Standard
|
IDNINT(X) | REAL(8) | F95 and later
|
NOT — Logical negationNOT returns the bitwise boolean inverse of I.
RESULT = NOT(I)
| I | The type shall be INTEGER(*).
|
INTEGER(*), of the same kind as the
argument.
NULL — Function that returns an disassociated pointerIf MOLD is present, a dissassociated pointer of the same type is returned, otherwise the type is determined by context.
In Fortran 95, MOLD is optional. Please note that F2003 includes
cases where it is required.
PTR => NULL([MOLD])
| MOLD | (Optional) shall be a pointer of any association
status and of any type.
|
REAL, POINTER, DIMENSION(:) :: VEC => NULL ()
OR — Bitwise logical OROR.
This intrinsic routine is provided for backwards compatibility with
GNU Fortran 77. For integer arguments, programmers should consider
the use of the IOR intrinsic defined by the Fortran standard.
RESULT = OR(X, Y)
| X | The type shall be either INTEGER(*) or LOGICAL.
|
| Y | The type shall be either INTEGER(*) or LOGICAL.
|
INTEGER(*) or LOGICAL
after cross-promotion of the arguments.
PROGRAM test_or
LOGICAL :: T = .TRUE., F = .FALSE.
INTEGER :: a, b
DATA a / Z'F' /, b / Z'3' /
WRITE (*,*) OR(T, T), OR(T, F), OR(F, T), OR(F, F)
WRITE (*,*) OR(a, b)
END PROGRAM
PACK — Pack an array into an array of rank oneThe beginning of the resulting array is made up of elements whose MASK
equals TRUE. Afterwards, positions are filled with elements taken from
VECTOR.
RESULT = PACK(ARRAY, MASK[,VECTOR]
| ARRAY | Shall be an array of any type.
|
| MASK | Shall be an array of type LOGICAL and
of the same size as ARRAY. Alternatively, it may be a LOGICAL
scalar.
|
| VECTOR | (Optional) shall be an array of the same type
as ARRAY and of rank one. If present, the number of elements in
VECTOR shall be equal to or greater than the number of true elements
in MASK. If MASK is scalar, the number of elements in
VECTOR shall be equal to or greater than the number of elements in
ARRAY.
|
TRUE values in MASK otherwise.
PROGRAM test_pack_1
INTEGER :: m(6)
m = (/ 1, 0, 0, 0, 5, 0 /)
WRITE(*, FMT="(6(I0, ' '))") pack(m, m /= 0) ! "1 5"
END PROGRAM
Gathering nonzero elements from an array and appending elements from VECTOR:
PROGRAM test_pack_2
INTEGER :: m(4)
m = (/ 1, 0, 0, 2 /)
WRITE(*, FMT="(4(I0, ' '))") pack(m, m /= 0, (/ 0, 0, 3, 4 /)) ! "1 2 3 4"
END PROGRAM
PERROR — Print system error messagestderr stream) a newline-terminated error
message corresponding to the last system error. This is prefixed by
STRING, a colon and a space. See perror(3).
CALL PERROR(STRING)
| STRING | A scalar of default CHARACTER type.
|
PRECISION — Decimal precision of a real kindPRECISION(X) returns the decimal precision in the model of the
type of X.
RESULT = PRECISION(X)
| X | Shall be of type REAL or COMPLEX.
|
INTEGER and of the default integer
kind.
program prec_and_range
real(kind=4) :: x(2)
complex(kind=8) :: y
print *, precision(x), range(x)
print *, precision(y), range(y)
end program prec_and_range
PRESENT — Determine whether an optional dummy argument is specifiedRESULT = PRESENT(A)
| A | May be of any type and may be a pointer, scalar or array
value, or a dummy procedure. It shall be the name of an optional dummy argument
accessible within the current subroutine or function.
|
TRUE if the optional argument A is present, or
FALSE otherwise.
PROGRAM test_present
WRITE(*,*) f(), f(42) ! "F T"
CONTAINS
LOGICAL FUNCTION f(x)
INTEGER, INTENT(IN), OPTIONAL :: x
f = PRESENT(x)
END FUNCTION
END PROGRAM
PRODUCT — Product of array elementsTRUE.
RESULT = PRODUCT(ARRAY[, MASK])
RESULT = PRODUCT(ARRAY, DIM[, MASK])
| ARRAY | Shall be an array of type INTEGER(*),
REAL(*) or COMPLEX(*).
|
| DIM | (Optional) shall be a scalar of type
INTEGER with a value in the range from 1 to n, where n
equals the rank of ARRAY.
|
| MASK | (Optional) shall be of type LOGICAL
and either be a scalar or an array of the same shape as ARRAY.
|
If DIM is absent, a scalar with the product of all elements in
ARRAY is returned. Otherwise, an array of rank n-1, where n equals
the rank of ARRAY, and a shape similar to that of ARRAY with
dimension DIM dropped is returned.
PROGRAM test_product
INTEGER :: x(5) = (/ 1, 2, 3, 4 ,5 /)
print *, PRODUCT(x) ! all elements, product = 120
print *, PRODUCT(x, MASK=MOD(x, 2)==1) ! odd elements, product = 15
END PROGRAM
RADIX — Base of a model numberRADIX(X) returns the base of the model representing the entity X.
RESULT = RADIX(X)
| X | Shall be of type INTEGER or REAL
|
INTEGER and of the default
integer kind.
program test_radix
print *, "The radix for the default integer kind is", radix(0)
print *, "The radix for the default real kind is", radix(0.0)
end program test_radix
RAN — Real pseudo-random numberRAN intrinsic is
provided as an alias for RAND. See RAND for complete
documentation.
RAND — Real pseudo-random numberRAND(FLAG) returns a pseudo-random number from a uniform
distribution between 0 and 1. If FLAG is 0, the next number
in the current sequence is returned; if FLAG is 1, the generator
is restarted by CALL SRAND(0); if FLAG has any other value,
it is used as a new seed with SRAND.
This intrinsic routine is provided for backwards compatibility with
GNU Fortran 77. It implements a simple modulo generator as provided
by g77. For new code, one should consider the use of
RANDOM_NUMBER as it implements a superior algorithm.
RESULT = RAND(FLAG)
| FLAG | Shall be a scalar INTEGER of kind 4.
|
REAL type and the default kind.
program test_rand
integer,parameter :: seed = 86456
call srand(seed)
print *, rand(), rand(), rand(), rand()
print *, rand(seed), rand(), rand(), rand()
end program test_rand
RANDOM_NUMBER — Pseudo-random numberThe runtime-library implements George Marsaglia's KISS (Keep It Simple Stupid) random number generator (RNG). This RNG combines:
Please note, this RNG is thread safe if used within OpenMP directives,
i. e. its state will be consistent while called from multiple threads.
However, the KISS generator does not create random numbers in parallel
from multiple sources, but in sequence from a single source. If an
OpenMP-enabled application heavily relies on random numbers, one should
consider employing a dedicated parallel random number generator instead.
RANDOM_NUMBER(HARVEST)
| HARVEST | Shall be a scalar or an array of type REAL(*).
|
program test_random_number
REAL :: r(5,5)
CALL init_random_seed() ! see example of RANDOM_SEED
CALL RANDOM_NUMBER(r)
end program
RANDOM_SEED — Initialize a pseudo-random number sequenceRANDOM_NUMBER.
If RANDOM_SEED is called without arguments, it is initialized to
a default state. The example below shows how to initialize the random
seed based on the system's time.
CALL RANDOM_SEED(SIZE, PUT, GET)
| SIZE | (Optional) Shall be a scalar and of type default
INTEGER, with INTENT(OUT). It specifies the minimum size
of the arrays used with the PUT and GET arguments.
|
| PUT | (Optional) Shall be an array of type default
INTEGER and rank one. It is INTENT(IN) and the size of
the array must be larger than or equal to the number returned by the
SIZE argument.
|
| GET | (Optional) Shall be an array of type default
INTEGER and rank one. It is INTENT(OUT) and the size
of the array must be larger than or equal to the number returned by
the SIZE argument.
|
SUBROUTINE init_random_seed()
INTEGER :: i, n, clock
INTEGER, DIMENSION(:), ALLOCATABLE :: seed
CALL RANDOM_SEED(size = n)
ALLOCATE(seed(n))
CALL SYSTEM_CLOCK(COUNT=clock)
seed = clock + 37 * (/ (i - 1, i = 1, n) /)
CALL RANDOM_SEED(PUT = seed)
DEALLOCATE(seed)
END SUBROUTINE
RANGE — Decimal exponent range of a real kindRANGE(X) returns the decimal exponent range in the model of the
type of X.
RESULT = RANGE(X)
| X | Shall be of type REAL or COMPLEX.
|
INTEGER and of the default integer
kind.
PRECISION for an example.
REAL — Convert to real typeREAL(X [, KIND]) converts its argument X to a real type. The
REALPART(X) function is provided for compatibility with g77,
and its use is strongly discouraged.
RESULT = REAL(X [, KIND])
|
RESULT = REALPART(Z)
|
| X | Shall be INTEGER(*), REAL(*), or
COMPLEX(*).
|
| KIND | (Optional) An INTEGER(*) initialization
expression indicating the kind parameter of
the result.
|
REAL(*) variable or array under
the following rules:
REAL(X) is converted to a default real type if X is an
integer or real variable.
REAL(X) is converted to a real type with the kind type parameter
of X if X is a complex variable.
REAL(X, KIND) is converted to a real type with kind type
parameter KIND if X is a complex, integer, or real
variable.
program test_real
complex :: x = (1.0, 2.0)
print *, real(x), real(x,8), realpart(x)
end program test_real
RENAME — Rename a fileCHAR(0)) can be used to mark the end of the names in
PATH1 and PATH2; otherwise, trailing blanks in the file
names are ignored. If the STATUS argument is supplied, it
contains 0 on success or a nonzero error code upon return; see
rename(2).
This intrinsic is provided in both subroutine and function forms;
however, only one form can be used in any given program unit.
CALL RENAME(PATH1, PATH2 [, STATUS])
|
STATUS = RENAME(PATH1, PATH2)
|
| PATH1 | Shall be of default CHARACTER type.
|
| PATH2 | Shall be of default CHARACTER type.
|
| STATUS | (Optional) Shall be of default INTEGER type.
|
REPEAT — Repeated string concatenationRESULT = REPEAT(STRING, NCOPIES)
| STRING | Shall be scalar and of type CHARACTER(*).
|
| NCOPIES | Shall be scalar and of type INTEGER(*).
|
CHARACTER built up from NCOPIES copies
of STRING.
program test_repeat
write(*,*) repeat("x", 5) ! "xxxxx"
end program
RESHAPE — Function to reshape an arrayRESULT = RESHAPE(SOURCE, SHAPE[, PAD, ORDER])
| SOURCE | Shall be an array of any type.
|
| SHAPE | Shall be of type INTEGER and an
array of rank one. Its values must be positive or zero.
|
| PAD | (Optional) shall be an array of the same
type as SOURCE.
|
| ORDER | (Optional) shall be of type INTEGER
and an array of the same shape as SHAPE. Its values shall
be a permutation of the numbers from 1 to n, where n is the size of
SHAPE. If ORDER is absent, the natural ordering shall
be assumed.
|
PROGRAM test_reshape
INTEGER, DIMENSION(4) :: x
WRITE(*,*) SHAPE(x) ! prints "4"
WRITE(*,*) SHAPE(RESHAPE(x, (/2, 2/))) ! prints "2 2"
END PROGRAM
RRSPACING — Reciprocal of the relative spacingRRSPACING(X) returns the reciprocal of the relative spacing of
model numbers near X.
RESULT = RRSPACING(X)
| X | Shall be of type REAL.
|
ABS(FRACTION(X)) * FLOAT(RADIX(X))**DIGITS(X).
RSHIFT — Right shift bitsRSHIFT returns a value corresponding to I with all of the
bits shifted right by SHIFT places. If the absolute value of
SHIFT is greater than BIT_SIZE(I), the value is undefined.
Bits shifted out from the left end are lost; zeros are shifted in from
the opposite end.
This function has been superseded by the ISHFT intrinsic, which
is standard in Fortran 95 and later.
RESULT = RSHIFT(I, SHIFT)
| I | The type shall be INTEGER(*).
|
| SHIFT | The type shall be INTEGER(*).
|
INTEGER(*) and of the same kind as
I.
SCALE — Scale a real valueSCALE(X,I) returns X * RADIX(X)**I.
RESULT = SCALE(X, I)
| X | The type of the argument shall be a REAL.
|
| I | The type of the argument shall be a INTEGER.
|
X * RADIX(X)**I.
program test_scale
real :: x = 178.1387e-4
integer :: i = 5
print *, scale(x,i), x*radix(x)**i
end program test_scale
SCAN — Scan a string for the presence of a set of charactersIf BACK is either absent or equals FALSE, this function
returns the position of the leftmost character of STRING that is
in SET. If BACK equals TRUE, the rightmost position
is returned. If no character of SET is found in STRING, the
result is zero.
RESULT = SCAN(STRING, SET[, BACK [, KIND]])
| STRING | Shall be of type CHARACTER(*).
|
| SET | Shall be of type CHARACTER(*).
|
| BACK | (Optional) shall be of type LOGICAL.
|
| KIND | (Optional) An INTEGER initialization
expression indicating the kind parameter of
the result.
|
INTEGER and of kind KIND. If
KIND is absent, the return value is of default integer kind.
PROGRAM test_scan
WRITE(*,*) SCAN("FORTRAN", "AO") ! 2, found 'O'
WRITE(*,*) SCAN("FORTRAN", "AO", .TRUE.) ! 6, found 'A'
WRITE(*,*) SCAN("FORTRAN", "C++") ! 0, found none
END PROGRAM
SECNDS — Time functionSECNDS(X) gets the time in seconds from the real-time system clock.
X is a reference time, also in seconds. If this is zero, the time in
seconds from midnight is returned. This function is non-standard and its
use is discouraged.
RESULT = SECNDS (X)
| T | Shall be of type REAL(4).
|
| X | Shall be of type REAL(4).
|
program test_secnds
integer :: i
real(4) :: t1, t2
print *, secnds (0.0) ! seconds since midnight
t1 = secnds (0.0) ! reference time
do i = 1, 10000000 ! do something
end do
t2 = secnds (t1) ! elapsed time
print *, "Something took ", t2, " seconds."
end program test_secnds
SECOND — CPU time functionREAL(4) value representing the elapsed CPU time in
seconds. This provides the same functionality as the standard
CPU_TIME intrinsic, and is only included for backwards
compatibility.
This intrinsic is provided in both subroutine and function forms;
however, only one form can be used in any given program unit.
CALL SECOND(TIME)
|
TIME = SECOND()
|
| TIME | Shall be of type REAL(4).
|
SELECTED_INT_KIND — Choose integer kindSELECTED_INT_KIND(I) return the kind value of the smallest integer
type that can represent all values ranging from -10^I (exclusive)
to 10^I (exclusive). If there is no integer kind that accommodates
this range, SELECTED_INT_KIND returns -1.
RESULT = SELECTED_INT_KIND(I)
| I | Shall be a scalar and of type INTEGER.
|
program large_integers
integer,parameter :: k5 = selected_int_kind(5)
integer,parameter :: k15 = selected_int_kind(15)
integer(kind=k5) :: i5
integer(kind=k15) :: i15
print *, huge(i5), huge(i15)
! The following inequalities are always true
print *, huge(i5) >= 10_k5**5-1
print *, huge(i15) >= 10_k15**15-1
end program large_integers
SELECTED_REAL_KIND — Choose real kindSELECTED_REAL_KIND(P,R) return the kind value of a real data type
with decimal precision greater of at least P digits and exponent
range greater at least R.
RESULT = SELECTED_REAL_KIND(P, R)
| P | (Optional) shall be a scalar and of type INTEGER.
|
| R | (Optional) shall be a scalar and of type INTEGER.
|
SELECTED_REAL_KIND returns the value of the kind type parameter of
a real data type with decimal precision of at least P digits and a
decimal exponent range of at least R. If more than one real data
type meet the criteria, the kind of the data type with the smallest
decimal precision is returned. If no real data type matches the criteria,
the result is
P
R
program real_kinds
integer,parameter :: p6 = selected_real_kind(6)
integer,parameter :: p10r100 = selected_real_kind(10,100)
integer,parameter :: r400 = selected_real_kind(r=400)
real(kind=p6) :: x
real(kind=p10r100) :: y
real(kind=r400) :: z
print *, precision(x), range(x)
print *, precision(y), range(y)
print *, precision(z), range(z)
end program real_kinds
SET_EXPONENT — Set the exponent of the modelSET_EXPONENT(X, I) returns the real number whose fractional part
is that that of X and whose exponent part is I.
RESULT = SET_EXPONENT(X, I)
| X | Shall be of type REAL.
|
| I | Shall be of type INTEGER.
|
FRACTION(X) * RADIX(X)**I.
PROGRAM test_setexp
REAL :: x = 178.1387e-4
INTEGER :: i = 17
PRINT *, SET_EXPONENT(x, i), FRACTION(x) * RADIX(x)**i
END PROGRAM
SHAPE — Determine the shape of an arrayRESULT = SHAPE(SOURCE)
| SOURCE | Shall be an array or scalar of any type.
If SOURCE is a pointer it must be associated and allocatable
arrays must be allocated.
|
INTEGER array of rank one with as many elements as SOURCE
has dimensions. The elements of the resulting array correspond to the extend
of SOURCE along the respective dimensions. If SOURCE is a scalar,
the result is the rank one array of size zero.
PROGRAM test_shape
INTEGER, DIMENSION(-1:1, -1:2) :: A
WRITE(*,*) SHAPE(A) ! (/ 3, 4 /)
WRITE(*,*) SIZE(SHAPE(42)) ! (/ /)
END PROGRAM
SIGN — Sign copying functionSIGN(A,B) returns the value of A with the sign of B.
RESULT = SIGN(A, B)
| A | Shall be of type INTEGER or REAL
|
| B | Shall be of the same type and kind as A
|
ABS(A), else
it is -ABS(A).
program test_sign
print *, sign(-12,1)
print *, sign(-12,0)
print *, sign(-12,-1)
print *, sign(-12.,1.)
print *, sign(-12.,0.)
print *, sign(-12.,-1.)
end program test_sign
| Name | Arguments | Return type | Standard
|
ISIGN(A,P) | INTEGER(4) | INTEGER(4) | f95, gnu
|
DSIGN(A,P) | REAL(8) | REAL(8) | f95, gnu
|
SIGNAL — Signal handling subroutine (or function)SIGNAL(NUMBER, HANDLER [, STATUS]) causes external subroutine
HANDLER to be executed with a single integer argument when signal
NUMBER occurs. If HANDLER is an integer, it can be used to
turn off handling of signal NUMBER or revert to its default
action. See signal(2).
If SIGNAL is called as a subroutine and the STATUS argument
is supplied, it is set to the value returned by signal(2).
CALL SIGNAL(NUMBER, HANDLER [, STATUS])
|
STATUS = SIGNAL(NUMBER, HANDLER)
|
| NUMBER | Shall be a scalar integer, with INTENT(IN)
|
| HANDLER | Signal handler (INTEGER FUNCTION or
SUBROUTINE) or dummy/global INTEGER scalar.
INTEGER. It is INTENT(IN).
|
| STATUS | (Optional) STATUS shall be a scalar
integer. It has INTENT(OUT).
|
SIGNAL function returns the value returned by signal(2).
program test_signal
intrinsic signal
external handler_print
call signal (12, handler_print)
call signal (10, 1)
call sleep (30)
end program test_signal
SIN — Sine functionSIN(X) computes the sine of X.
RESULT = SIN(X)
| X | The type shall be REAL(*) or
COMPLEX(*).
|
program test_sin
real :: x = 0.0
x = sin(x)
end program test_sin
| Name | Argument | Return type | Standard
|
DSIN(X) | REAL(8) X | REAL(8) | f95, gnu
|
CSIN(X) | COMPLEX(4) X | COMPLEX(4) | f95, gnu
|
ZSIN(X) | COMPLEX(8) X | COMPLEX(8) | f95, gnu
|
CDSIN(X) | COMPLEX(8) X | COMPLEX(8) | f95, gnu
|
SINH — Hyperbolic sine functionSINH(X) computes the hyperbolic sine of X.
RESULT = SINH(X)
| X | The type shall be REAL(*).
|
REAL(*).
program test_sinh
real(8) :: x = - 1.0_8
x = sinh(x)
end program test_sinh
| Name | Argument | Return type | Standard
|
DSINH(X) | REAL(8) X | REAL(8) | F95 and later
|
SIZE — Determine the size of an arrayRESULT = SIZE(ARRAY[, DIM [, KIND]])
| ARRAY | Shall be an array of any type. If ARRAY is
a pointer it must be associated and allocatable arrays must be allocated.
|
| DIM | (Optional) shall be a scalar of type INTEGER
and its value shall be in the range from 1 to n, where n equals the rank
of ARRAY.
|
| KIND | (Optional) An INTEGER initialization
expression indicating the kind parameter of
the result.
|
INTEGER and of kind KIND. If
KIND is absent, the return value is of default integer kind.
PROGRAM test_size
WRITE(*,*) SIZE((/ 1, 2 /)) ! 2
END PROGRAM
SIZEOF — Size in bytes of an expressionSIZEOF(X) calculates the number of bytes of storage the
expression X occupies.
N = SIZEOF(X)
| X | The argument shall be of any type, rank or shape.
|
POINTER attribute, the number of bytes of the storage area pointed
to is returned. If the argument is of a derived type with POINTER
or ALLOCATABLE components, the return value doesn't account for
the sizes of the data pointed to by these components.
integer :: i
real :: r, s(5)
print *, (sizeof(s)/sizeof(r) == 5)
end
The example will print .TRUE. unless you are using a platform
where default REAL variables are unusually padded.
SLEEP — Sleep for the specified number of secondsCALL SLEEP(SECONDS)
| SECONDS | The type shall be of default INTEGER.
|
program test_sleep
call sleep(5)
end
SNGL — Convert double precision real to default realSNGL(A) converts the double precision real A
to a default real value. This is an archaic form of REAL
that is specific to one type for A.
RESULT = SNGL(A)
| A | The type shall be a double precision REAL.
|
REAL.
SPACING — Smallest distance between two numbers of a given typeRESULT = SPACING(X)
| X | Shall be of type REAL(*).
|
PROGRAM test_spacing
INTEGER, PARAMETER :: SGL = SELECTED_REAL_KIND(p=6, r=37)
INTEGER, PARAMETER :: DBL = SELECTED_REAL_KIND(p=13, r=200)
WRITE(*,*) spacing(1.0_SGL) ! "1.1920929E-07" on i686
WRITE(*,*) spacing(1.0_DBL) ! "2.220446049250313E-016" on i686
END PROGRAM
SPREAD — Add a dimension to an arrayRESULT = SPREAD(SOURCE, DIM, NCOPIES)
| SOURCE | Shall be a scalar or an array of any type and
a rank less than seven.
|
| DIM | Shall be a scalar of type INTEGER with a
value in the range from 1 to n+1, where n equals the rank of SOURCE.
|
| NCOPIES | Shall be a scalar of type INTEGER.
|
PROGRAM test_spread
INTEGER :: a = 1, b(2) = (/ 1, 2 /)
WRITE(*,*) SPREAD(A, 1, 2) ! "1 1"
WRITE(*,*) SPREAD(B, 1, 2) ! "1 1 2 2"
END PROGRAM
SQRT — Square-root functionSQRT(X) computes the square root of X.
RESULT = SQRT(X)
| X | The type shall be REAL(*) or
COMPLEX(*).
|
REAL(*) or COMPLEX(*).
The kind type parameter is the same as X.
program test_sqrt
real(8) :: x = 2.0_8
complex :: z = (1.0, 2.0)
x = sqrt(x)
z = sqrt(z)
end program test_sqrt
| Name | Argument | Return type | Standard
|
DSQRT(X) | REAL(8) X | REAL(8) | F95 and later
|
CSQRT(X) | COMPLEX(4) X | COMPLEX(4) | F95 and later
|
ZSQRT(X) | COMPLEX(8) X | COMPLEX(8) | GNU extension
|
CDSQRT(X) | COMPLEX(8) X | COMPLEX(8) | GNU extension
|
SRAND — Reinitialize the random number generatorSRAND reinitializes the pseudo-random number generator
called by RAND and IRAND. The new seed used by the
generator is specified by the required argument SEED.
CALL SRAND(SEED)
| SEED | Shall be a scalar INTEGER(kind=4).
|
RAND and IRAND for examples.
RANDOM_SEED to
initialize the pseudo-random numbers generator and RANDOM_NUMBER
to generate pseudo-random numbers. Please note that in
GNU Fortran, these two sets of intrinsics (RAND,
IRAND and SRAND on the one hand, RANDOM_NUMBER and
RANDOM_SEED on the other hand) access two independent
pseudo-random number generators.
STAT — Get file statusThe elements that are obtained and stored in the array BUFF:
buff(1) | Device ID
|
buff(2) | Inode number
|
buff(3) | File mode
|
buff(4) | Number of links
|
buff(5) | Owner's uid
|
buff(6) | Owner's gid
|
buff(7) | ID of device containing directory entry for file (0 if not available)
|
buff(8) | File size (bytes)
|
buff(9) | Last access time
|
buff(10) | Last modification time
|
buff(11) | Last file status change time
|
buff(12) | Preferred I/O block size (-1 if not available)
|
buff(13) | Number of blocks allocated (-1 if not available)
|
Not all these elements are relevant on all systems. If an element is not relevant, it is returned as 0.
This intrinsic is provided in both subroutine and function forms; however,
only one form can be used in any given program unit.
CALL STAT(FILE,BUFF[,STATUS])
| FILE | The type shall be CHARACTER(*), a valid path within the file system.
|
| BUFF | The type shall be INTEGER(4), DIMENSION(13).
|
| STATUS | (Optional) status flag of type INTEGER(4). Returns 0
on success and a system specific error code otherwise.
|
PROGRAM test_stat
INTEGER, DIMENSION(13) :: buff
INTEGER :: status
CALL STAT("/etc/passwd", buff, status)
IF (status == 0) THEN
WRITE (*, FMT="('Device ID:', T30, I19)") buff(1)
WRITE (*, FMT="('Inode number:', T30, I19)") buff(2)
WRITE (*, FMT="('File mode (octal):', T30, O19)") buff(3)
WRITE (*, FMT="('Number of links:', T30, I19)") buff(4)
WRITE (*, FMT="('Owner''s uid:', T30, I19)") buff(5)
WRITE (*, FMT="('Owner''s gid:', T30, I19)") buff(6)
WRITE (*, FMT="('Device where located:', T30, I19)") buff(7)
WRITE (*, FMT="('File size:', T30, I19)") buff(8)
WRITE (*, FMT="('Last access time:', T30, A19)") CTIME(buff(9))
WRITE (*, FMT="('Last modification time', T30, A19)") CTIME(buff(10))
WRITE (*, FMT="('Last status change time:', T30, A19)") CTIME(buff(11))
WRITE (*, FMT="('Preferred block size:', T30, I19)") buff(12)
WRITE (*, FMT="('No. of blocks allocated:', T30, I19)") buff(13)
END IF
END PROGRAM
SUM — Sum of array elementsTRUE.
RESULT = SUM(ARRAY[, MASK])
RESULT = SUM(ARRAY, DIM[, MASK])
| ARRAY | Shall be an array of type INTEGER(*),
REAL(*) or COMPLEX(*).
|
| DIM | (Optional) shall be a scalar of type
INTEGER with a value in the range from 1 to n, where n
equals the rank of ARRAY.
|
| MASK | (Optional) shall be of type LOGICAL
and either be a scalar or an array of the same shape as ARRAY.
|
If DIM is absent, a scalar with the sum of all elements in ARRAY
is returned. Otherwise, an array of rank n-1, where n equals the rank of
ARRAY,and a shape similar to that of ARRAY with dimension DIM
dropped is returned.
PROGRAM test_sum
INTEGER :: x(5) = (/ 1, 2, 3, 4 ,5 /)
print *, SUM(x) ! all elements, sum = 15
print *, SUM(x, MASK=MOD(x, 2)==1) ! odd elements, sum = 9
END PROGRAM
SYMLNK — Create a symbolic linkCHAR(0)) can be used to mark the end of the names in
PATH1 and PATH2; otherwise, trailing blanks in the file
names are ignored. If the STATUS argument is supplied, it
contains 0 on success or a nonzero error code upon return; see
symlink(2). If the system does not supply symlink(2),
ENOSYS is returned.
This intrinsic is provided in both subroutine and function forms;
however, only one form can be used in any given program unit.
CALL SYMLNK(PATH1, PATH2 [, STATUS])
|
STATUS = SYMLNK(PATH1, PATH2)
|
| PATH1 | Shall be of default CHARACTER type.
|
| PATH2 | Shall be of default CHARACTER type.
|
| STATUS | (Optional) Shall be of default INTEGER type.
|
SYSTEM — Execute a shell commandsystem(3)). If
argument STATUS is present, it contains the value returned by
system(3), which is presumably 0 if the shell command succeeded.
Note that which shell is used to invoke the command is system-dependent
and environment-dependent.
This intrinsic is provided in both subroutine and function forms;
however, only one form can be used in any given program unit.
CALL SYSTEM(COMMAND [, STATUS])
|
STATUS = SYSTEM(COMMAND)
|
| COMMAND | Shall be of default CHARACTER type.
|
| STATUS | (Optional) Shall be of default INTEGER type.
|
SYSTEM_CLOCK — Time functionIf there is no clock, COUNT is set to -HUGE(COUNT), and
COUNT_RATE and COUNT_MAX are set to zero
CALL SYSTEM_CLOCK([COUNT, COUNT_RATE, COUNT_MAX])
| COUNT | (Optional) shall be a scalar of type default
INTEGER with INTENT(OUT).
|
| COUNT_RATE | (Optional) shall be a scalar of type default
INTEGER with INTENT(OUT).
|
| COUNT_MAX | (Optional) shall be a scalar of type default
INTEGER with INTENT(OUT).
|
PROGRAM test_system_clock
INTEGER :: count, count_rate, count_max
CALL SYSTEM_CLOCK(count, count_rate, count_max)
WRITE(*,*) count, count_rate, count_max
END PROGRAM
TAN — Tangent functionTAN(X) computes the tangent of X.
RESULT = TAN(X)
| X | The type shall be REAL(*).
|
REAL(*). The kind type parameter is
the same as X.
program test_tan
real(8) :: x = 0.165_8
x = tan(x)
end program test_tan
| Name | Argument | Return type | Standard
|
DTAN(X) | REAL(8) X | REAL(8) | F95 and later
|
TANH — Hyperbolic tangent functionTANH(X) computes the hyperbolic tangent of X.
X = TANH(X)
| X | The type shall be REAL(*).
|
REAL(*) and lies in the range
- 1 \leq tanh(x) \leq 1 .
program test_tanh
real(8) :: x = 2.1_8
x = tanh(x)
end program test_tanh
| Name | Argument | Return type | Standard
|
DTANH(X) | REAL(8) X | REAL(8) | F95 and later
|
TIME — Time functiontime(3)). This value is suitable for passing to
CTIME(), GMTIME(), and LTIME().
This intrinsic is not fully portable, such as to systems with 32-bit
INTEGER types but supporting times wider than 32 bits. Therefore,
the values returned by this intrinsic might be, or become, negative, or
numerically less than previous values, during a single run of the
compiled program.
See TIME8, for information on a similar intrinsic that might be
portable to more GNU Fortran implementations, though to fewer Fortran
compilers.
RESULT = TIME()
INTEGER(4).
TIME8 — Time function (64-bit)time(3)). This value is suitable for passing to
CTIME(), GMTIME(), and LTIME().
Warning: this intrinsic does not increase the range of the timing
values over that returned by time(3). On a system with a 32-bit
time(3), TIME8() will return a 32-bit value, even though
it is converted to a 64-bit INTEGER(8) value. That means
overflows of the 32-bit value can still occur. Therefore, the values
returned by this intrinsic might be or become negative or numerically
less than previous values during a single run of the compiled program.
RESULT = TIME8()
INTEGER(8).
TINY — Smallest positive number of a real kindTINY(X) returns the smallest positive (non zero) number
in the model of the type of X.
RESULT = TINY(X)
| X | Shall be of type REAL.
|
HUGE for an example.
TRANSFER — Transfer bit patternsThis is approximately equivalent to the C concept of casting one
type to another.
RESULT = TRANSFER(SOURCE, MOLD[, SIZE])
| SOURCE | Shall be a scalar or an array of any type.
|
| MOLD | Shall be a scalar or an array of any type.
|
| SIZE | (Optional) shall be a scalar of type
INTEGER.
|
If the bitwise representation of the result is longer than that of SOURCE, then the leading bits of the result correspond to those of SOURCE and any trailing bits are filled arbitrarily.
When the resulting bit representation does not correspond to a valid
representation of a variable of the same type as MOLD, the results
are undefined, and subsequent operations on the result cannot be
guaranteed to produce sensible behavior. For example, it is possible to
create LOGICAL variables for which VAR and
.NOT.VAR both appear to be true.
PROGRAM test_transfer
integer :: x = 2143289344
print *, transfer(x, 1.0) ! prints "NaN" on i686
END PROGRAM
TRANSPOSE — Transpose an array of rank twoMATRIX(j, i), for all i, j.
RESULT = TRANSPOSE(MATRIX)
| MATRIX | Shall be an array of any type and have a rank of two.
|
(/ m, n /) if MATRIX has shape (/ n, m /).
TRIM — Remove trailing blank characters of a stringRESULT = TRIM(STRING)
| STRING | Shall be a scalar of type CHARACTER(*).
|
CHARACTER(*) which length is that of STRING
less the number of trailing blanks.
PROGRAM test_trim
CHARACTER(len=10), PARAMETER :: s = "GFORTRAN "
WRITE(*,*) LEN(s), LEN(TRIM(s)) ! "10 8", with/without trailing blanks
END PROGRAM
TTYNAM — Get the name of a terminal device.ttyname(3).
This intrinsic is provided in both subroutine and function forms;
however, only one form can be used in any given program unit.
CALL TTYNAM(UNIT, NAME)
|
NAME = TTYNAM(UNIT)
|
| UNIT | Shall be a scalar INTEGER(*).
|
| NAME | Shall be of type CHARACTER(*).
|
PROGRAM test_ttynam
INTEGER :: unit
DO unit = 1, 10
IF (isatty(unit=unit)) write(*,*) ttynam(unit)
END DO
END PROGRAM
UBOUND — Upper dimension bounds of an arrayRESULT = UBOUND(ARRAY [, DIM [, KIND]])
| ARRAY | Shall be an array, of any type.
|
| DIM | (Optional) Shall be a scalar INTEGER(*).
|
| KIND | (Optional) An INTEGER initialization
expression indicating the kind parameter of
the result.
|
INTEGER and of kind KIND. If
KIND is absent, the return value is of default integer kind.
If DIM is absent, the result is an array of the upper bounds of
ARRAY. If DIM is present, the result is a scalar
corresponding to the upper bound of the array along that dimension. If
ARRAY is an expression rather than a whole array or array
structure component, or if it has a zero extent along the relevant
dimension, the upper bound is taken to be the number of elements along
the relevant dimension.
UMASK — Set the file creation maskumask(2).
CALL UMASK(MASK [, OLD])
| MASK | Shall be a scalar of type INTEGER(*).
|
| MASK | (Optional) Shall be a scalar of type
INTEGER(*).
|
UNLINK — Remove a file from the file systemCHAR(0)) can be
used to mark the end of the name in PATH; otherwise, trailing
blanks in the file name are ignored. If the STATUS argument is
supplied, it contains 0 on success or a nonzero error code upon return;
see unlink(2).
This intrinsic is provided in both subroutine and function forms;
however, only one form can be used in any given program unit.
CALL UNLINK(PATH [, STATUS])
|
STATUS = UNLINK(PATH)
|
| PATH | Shall be of default CHARACTER type.
|
| STATUS | (Optional) Shall be of default INTEGER type.
|
UNPACK — Unpack an array of rank one into an arrayRESULT = UNPACK(VECTOR, MASK, FIELD)
| VECTOR | Shall be an array of any type and rank one. It
shall have at least as many elements as MASK has TRUE values.
|
| MASK | Shall be an array of type LOGICAL.
|
| FIELD | Shall be of the sam type as VECTOR and have
the same shape as MASK.
|
TRUE elements
of MASK replaced by values from VECTOR in array element order.
PROGRAM test_unpack
integer :: vector(2) = (/1,1/)
logical :: mask(4) = (/ .TRUE., .FALSE., .FALSE., .TRUE. /)
integer :: field(2,2) = 0, unity(2,2)
! result: unity matrix
unity = unpack(vector, reshape(mask, (/2,2/)), field)
END PROGRAM
VERIFY — Scan a string for the absence of a set of charactersIf BACK is either absent or equals FALSE, this function
returns the position of the leftmost character of STRING that is
not in SET. If BACK equals TRUE, the rightmost position
is returned. If all characters of SET are found in STRING, the
result is zero.
RESULT = VERIFY(STRING, SET[, BACK [, KIND]])
| STRING | Shall be of type CHARACTER(*).
|
| SET | Shall be of type CHARACTER(*).
|
| BACK | (Optional) shall be of type LOGICAL.
|
| KIND | (Optional) An INTEGER initialization
expression indicating the kind parameter of
the result.
|
INTEGER and of kind KIND. If
KIND is absent, the return value is of default integer kind.
PROGRAM test_verify
WRITE(*,*) VERIFY("FORTRAN", "AO") ! 1, found 'F'
WRITE(*,*) VERIFY("FORTRAN", "FOO") ! 3, found 'R'
WRITE(*,*) VERIFY("FORTRAN", "C++") ! 1, found 'F'
WRITE(*,*) VERIFY("FORTRAN", "C++", .TRUE.) ! 7, found 'N'
WRITE(*,*) VERIFY("FORTRAN", "FORTRAN") ! 0' found none
END PROGRAM
XOR — Bitwise logical exclusive ORThis intrinsic routine is provided for backwards compatibility with
GNU Fortran 77. For integer arguments, programmers should consider
the use of the IEOR intrinsic defined by the Fortran standard.
RESULT = XOR(X, Y)
| X | The type shall be either INTEGER(*) or LOGICAL.
|
| Y | The type shall be either INTEGER(*) or LOGICAL.
|
INTEGER(*) or LOGICAL
after cross-promotion of the arguments.
PROGRAM test_xor
LOGICAL :: T = .TRUE., F = .FALSE.
INTEGER :: a, b
DATA a / Z'F' /, b / Z'3' /
WRITE (*,*) XOR(T, T), XOR(T, F), XOR(F, T), XOR(F, F)
WRITE (*,*) XOR(a, b)
END PROGRAM
ISO_FORTRAN_ENVThe ISO_FORTRAN_ENV module provides the following scalar default-integer
named constants:
CHARACTER_STORAGE_SIZE:ERROR_UNIT:FILE_STORAGE_SIZE:INPUT_UNIT:*) in READ statement.
IOSTAT_END:IOSTAT_EOR:NUMERIC_STORAGE_SIZE:OUTPUT_UNIT:*) in WRITE statement.
ISO_C_BINDINGThe following intrinsic procedures are provided by the module; their definition can be found in the section Intrinsic Procedures of this manual.
C_ASSOCIATEDC_F_POINTERC_F_PROCPOINTERC_FUNLOCC_LOCThe ISO_C_BINDING module provides the following named constants of the
type integer, which can be used as KIND type parameter. Note that GNU
Fortran currently does not support the C_INT_FAST... KIND type
parameters (marked by an asterix (*) in the list below).
The C_INT_FAST... parameters have therefore the value -2
and cannot be used as KIND type parameter of the INTEGER type.
| Fortran Type | Named constant | C type
|
INTEGER | C_INT | int
|
INTEGER | C_SHORT | short int
|
INTEGER | C_LONG | long int
|
INTEGER | C_LONG_LONG | long long int
|
INTEGER | C_SIGNED_CHAR | signed char/unsigned char
|
INTEGER | C_SIZE_T | size_t
|
INTEGER | C_INT8_T | int8_t
|
INTEGER | C_INT16_T | int16_t
|
INTEGER | C_INT32_T | int32_t
|
INTEGER | C_INT64_T | int64_t
|
INTEGER | C_INT_LEAST8_T | int_least8_t
|
INTEGER | C_INT_LEAST16_T | int_least16_t
|
INTEGER | C_INT_LEAST32_T | int_least32_t
|
INTEGER | C_INT_LEAST64_T | int_least64_t
|
INTEGER | C_INT_FAST8_T* | int_fast8_t
|
INTEGER | C_INT_FAST16_T* | int_fast16_t
|
INTEGER | C_INT_FAST32_T* | int_fast32_t
|
INTEGER | C_INT_FAST64_T* | int_fast64_t
|
INTEGER | C_INTMAX_T | intmax_t
|
INTEGER | C_INTPTR_T | intptr_t
|
REAL | C_FLOAT | float
|
REAL | C_DOUBLE | double
|
REAL | C_LONG_DOUBLE | long double
|
COMPLEX | C_FLOAT_COMPLEX | float _Complex
|
COMPLEX | C_DOUBLE_COMPLEX | double _Complex
|
COMPLEX | C_LONG_DOUBLE_COMPLEX | long double _Complex
|
LOGICAL | C_BOOL | _Bool
|
CHARACTER | C_CHAR | char
|
Additionally, the following (CHARACTER(KIND=C_CHAR) are
defined.
| Name | C definition | Value
|
C_NULL_CHAR | null character | '\0'
|
C_ALERT | alert | '\a'
|
C_BACKSPACE | backspace | '\b'
|
C_FORM_FEED | form feed | '\f'
|
C_NEW_LINE | new line | '\n'
|
C_CARRIAGE_RETURN | carriage return | '\r'
|
C_HORIZONTAL_TAB | horizontal tab | '\t'
|
C_VERTICAL_TAB | vertical tab | '\v'
|
OMP_LIB and OMP_LIB_KINDSThe OpenMP Fortran runtime library routines are provided both in
a form of two Fortran 90 modules, named OMP_LIB and
OMP_LIB_KINDS, and in a form of a Fortran include file named
omp_lib.h. The procedures provided by OMP_LIB can be found
in the Introduction manual,
the named constants defined in the OMP_LIB_KINDS module are listed
below.
For details refer to the actual OpenMP Application Program Interface v2.5.
OMP_LIB_KINDS provides the following scalar default-integer
named constants:
omp_integer_kindomp_logical_kindomp_lock_kindomp_nest_lock_kindFree software is only possible if people contribute to efforts to create it. We're always in need of more people helping out with ideas and comments, writing documentation and contributing code.
If you want to contribute to GNU Fortran, have a look at the long lists of projects you can take on. Some of these projects are small, some of them are large; some are completely orthogonal to the rest of what is happening on GNU Fortran, but others are “mainstream” projects in need of enthusiastic hackers. All of these projects are important! We'll eventually get around to the things here, but they are also things doable by someone who is willing and able.
Most of the parser was hand-crafted by Andy Vaught, who is also the initiator of the whole project. Thanks Andy! Most of the interface with GCC was written by Paul Brook.
The following individuals have contributed code and/or ideas and significant help to the GNU Fortran project (in alphabetical order):
The following people have contributed bug reports, smaller or larger patches, and much needed feedback and encouragement for the GNU Fortran project:
Many other individuals have helped debug, test and improve the GNU Fortran compiler over the past few years, and we welcome you to do the same! If you already have done so, and you would like to see your name listed in the list above, please contact us.
Here's a list of proposed extensions for the GNU Fortran compiler, in no particular order. Most of these are necessary to be fully compatible with existing Fortran compilers, but they are not part of the official J3 Fortran 95 standard.
Makefile info.
Copyright © 2007 Free Software Foundation, Inc. http://fsf.org/
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If you convey a covered work, knowingly relying on a patent license, and the Corresponding Source of the work is not available for anyone to copy, free of charge and under the terms of this License, through a publicly available network server or other readily accessible means, then you must either (1) cause the Corresponding Source to be so available, or (2) arrange to deprive yourself of the benefit of the patent license for this particular work, or (3) arrange, in a manner consistent with the requirements of this License, to extend the patent license to downstream recipients. “Knowingly relying” means you have actual knowledge that, but for the patent license, your conveying the covered work in a country, or your recipient's use of the covered work in a country, would infringe one or more identifiable patents in that country that you have reason to believe are valid.
If, pursuant to or in connection with a single transaction or arrangement, you convey, or propagate by procuring conveyance of, a covered work, and grant a patent license to some of the parties receiving the covered work authorizing them to use, propagate, modify or convey a specific copy of the covered work, then the patent license you grant is automatically extended to all recipients of the covered work and works based on it.
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Nothing in this License shall be construed as excluding or limiting any implied license or other defenses to infringement that may otherwise be available to you under applicable patent law.
If conditions are imposed on you (whether by court order, agreement or otherwise) that contradict the conditions of this License, they do not excuse you from the conditions of this License. If you cannot convey a covered work so as to satisfy simultaneously your obligations under this License and any other pertinent obligations, then as a consequence you may not convey it at all. For example, if you agree to terms that obligate you to collect a royalty for further conveying from those to whom you convey the Program, the only way you could satisfy both those terms and this License would be to refrain entirely from conveying the Program.
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The Free Software Foundation may publish revised and/or new versions of the GNU General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns.
Each version is given a distinguishing version number. If the Program specifies that a certain numbered version of the GNU General Public License “or any later version” applies to it, you have the option of following the terms and conditions either of that numbered version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of the GNU General Public License, you may choose any version ever published by the Free Software Foundation.
If the Program specifies that a proxy can decide which future versions of the GNU General Public License can be used, that proxy's public statement of acceptance of a version permanently authorizes you to choose that version for the Program.
Later license versions may give you additional or different permissions. However, no additional obligations are imposed on any author or copyright holder as a result of your choosing to follow a later version.
THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
If the disclaimer of warranty and limitation of liability provided above cannot be given local legal effect according to their terms, reviewing courts shall apply local law that most closely approximates an absolute waiver of all civil liability in connection with the Program, unless a warranty or assumption of liability accompanies a copy of the Program in return for a fee.
If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms.
To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively state the exclusion of warranty; and each file should have at least the “copyright” line and a pointer to where the full notice is found.
one line to give the program's name and a brief idea of what it does.
Copyright (C) year name of author
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at
your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see http://www.gnu.org/licenses/.
Also add information on how to contact you by electronic and paper mail.
If the program does terminal interaction, make it output a short notice like this when it starts in an interactive mode:
program Copyright (C) year name of author
This program comes with ABSOLUTELY NO WARRANTY; for details type ‘show w’.
This is free software, and you are welcome to redistribute it
under certain conditions; type ‘show c’ for details.
The hypothetical commands ‘show w’ and ‘show c’ should show the appropriate parts of the General Public License. Of course, your program's commands might be different; for a GUI interface, you would use an “about box”.
You should also get your employer (if you work as a programmer) or school, if any, to sign a “copyright disclaimer” for the program, if necessary. For more information on this, and how to apply and follow the GNU GPL, see http://www.gnu.org/licenses/.
The GNU General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Lesser General Public License instead of this License. But first, please read http://www.gnu.org/philosophy/why-not-lgpl.html.
Copyright © 2000,2001,2002 Free Software Foundation, Inc.
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
The purpose of this License is to make a manual, textbook, or other functional and useful document free in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others.
This License is a kind of “copyleft”, which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software.
We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference.
This License applies to any manual or other work, in any medium, that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License. Such a notice grants a world-wide, royalty-free license, unlimited in duration, to use that work under the conditions stated herein. The “Document”, below, refers to any such manual or work. Any member of the public is a licensee, and is addressed as “you”. You accept the license if you copy, modify or distribute the work in a way requiring permission under copyright law.
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The “Cover Texts” are certain short passages of text that are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says that the Document is released under this License. A Front-Cover Text may be at most 5 words, and a Back-Cover Text may be at most 25 words.
A “Transparent” copy of the Document means a machine-readable copy, represented in a format whose specification is available to the general public, that is suitable for revising the document straightforwardly with generic text editors or (for images composed of pixels) generic paint programs or (for drawings) some widely available drawing editor, and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters. A copy made in an otherwise Transparent file format whose markup, or absence of markup, has been arranged to thwart or discourage subsequent modification by readers is not Transparent. An image format is not Transparent if used for any substantial amount of text. A copy that is not “Transparent” is called “Opaque”.
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A section “Entitled XYZ” means a named subunit of the Document whose title either is precisely XYZ or contains XYZ in parentheses following text that translates XYZ in another language. (Here XYZ stands for a specific section name mentioned below, such as “Acknowledgements”, “Dedications”, “Endorsements”, or “History”.) To “Preserve the Title” of such a section when you modify the Document means that it remains a section “Entitled XYZ” according to this definition.
The Document may include Warranty Disclaimers next to the notice which states that this License applies to the Document. These Warranty Disclaimers are considered to be included by reference in this License, but only as regards disclaiming warranties: any other implication that these Warranty Disclaimers may have is void and has no effect on the meaning of this License.
You may copy and distribute the Document in any medium, either commercially or noncommercially, provided that this License, the copyright notices, and the license notice saying this License applies to the Document are reproduced in all copies, and that you add no other conditions whatsoever to those of this License. You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in section 3.
You may also lend copies, under the same conditions stated above, and you may publicly display copies.
If you publish printed copies (or copies in media that commonly have printed covers) of the Document, numbering more than 100, and the Document's license notice requires Cover Texts, you must enclose the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects.
If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages.
If you publish or distribute Opaque copies of the Document numbering more than 100, you must either include a machine-readable Transparent copy along with each Opaque copy, or state in or with each Opaque copy a computer-network location from which the general network-using public has access to download using public-standard network protocols a complete Transparent copy of the Document, free of added material. If you use the latter option, you must take reasonably prudent steps, when you begin distribution of Opaque copies in quantity, to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public.
It is requested, but not required, that you contact the authors of the Document well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document.
You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version:
If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version's license notice. These titles must be distinct from any other section titles.
You may add a section Entitled “Endorsements”, provided it contains nothing but endorsements of your Modified Version by various parties—for example, statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard.
You may add a passage of up to five words as a Front-Cover Text, and a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one.
The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version.
You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice, and that you preserve all their Warranty Disclaimers.
The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work.
In the combination, you must combine any sections Entitled “History” in the various original documents, forming one section Entitled “History”; likewise combine any sections Entitled “Acknowledgements”, and any sections Entitled “Dedications”. You must delete all sections Entitled “Endorsements.”
You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects.
You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document.
A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, is called an “aggregate” if the copyright resulting from the compilation is not used to limit the legal rights of the compilation's users beyond what the individual works permit. When the Document is included in an aggregate, this License does not apply to the other works in the aggregate which are not themselves derivative works of the Document.
If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one half of the entire aggregate, the Document's Cover Texts may be placed on covers that bracket the Document within the aggregate, or the electronic equivalent of covers if the Document is in electronic form. Otherwise they must appear on printed covers that bracket the whole aggregate.
Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License, and all the license notices in the Document, and any Warranty Disclaimers, provided that you also include the original English version of this License and the original versions of those notices and disclaimers. In case of a disagreement between the translation and the original version of this License or a notice or disclaimer, the original version will prevail.
If a section in the Document is Entitled “Acknowledgements”, “Dedications”, or “History”, the requirement (section 4) to Preserve its Title (section 1) will typically require changing the actual title.
You may not copy, modify, sublicense, or distribute the Document except as expressly provided for under this License. Any other attempt to copy, modify, sublicense or distribute the Document is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance.
The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See http://www.gnu.org/copyleft/.
Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License “or any later version” applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation.
To use this License in a document you have written, include a copy of the License in the document and put the following copyright and license notices just after the title page:
Copyright (C) year your name.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.2
or any later version published by the Free Software Foundation;
with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
Texts. A copy of the license is included in the section entitled ``GNU
Free Documentation License''.
If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the “with...Texts.” line with this:
with the Invariant Sections being list their titles, with
the Front-Cover Texts being list, and with the Back-Cover Texts
being list.
If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation.
If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.
If you want to have more free software a few years from now, it makes sense for you to help encourage people to contribute funds for its development. The most effective approach known is to encourage commercial redistributors to donate.
Users of free software systems can boost the pace of development by encouraging for-a-fee distributors to donate part of their selling price to free software developers—the Free Software Foundation, and others.
The way to convince distributors to do this is to demand it and expect it from them. So when you compare distributors, judge them partly by how much they give to free software development. Show distributors they must compete to be the one who gives the most.
To make this approach work, you must insist on numbers that you can compare, such as, “We will donate ten dollars to the Frobnitz project for each disk sold.” Don't be satisfied with a vague promise, such as “A portion of the profits are donated,” since it doesn't give a basis for comparison.
Even a precise fraction “of the profits from this disk” is not very meaningful, since creative accounting and unrelated business decisions can greatly alter what fraction of the sales price counts as profit. If the price you pay is $50, ten percent of the profit is probably less than a dollar; it might be a few cents, or nothing at all.
Some redistributors do development work themselves. This is useful too; but to keep everyone honest, you need to inquire how much they do, and what kind. Some kinds of development make much more long-term difference than others. For example, maintaining a separate version of a program contributes very little; maintaining the standard version of a program for the whole community contributes much. Easy new ports contribute little, since someone else would surely do them; difficult ports such as adding a new CPU to the GNU Compiler Collection contribute more; major new features or packages contribute the most.
By establishing the idea that supporting further development is “the proper thing to do” when distributing free software for a fee, we can assure a steady flow of resources into making more free software.
Copyright © 1994 Free Software Foundation, Inc.
Verbatim copying and redistribution of this section is permitted
without royalty; alteration is not permitted.
gfortran's command line options are indexed here without any initial ‘-’ or ‘--’. Where an option has both positive and negative forms (such as -foption and -fno-option), relevant entries in the manual are indexed under the most appropriate form; it may sometimes be useful to look up both forms.
backslash: Fortran Dialect Optionsfall-intrinsics: Fortran Dialect Optionsfbacktrace: Debugging Optionsfblas-matmul-limit: Code Gen Optionsfbounds-check: Code Gen Optionsfconvert=conversion: Runtime Optionsfcray-pointer: Fortran Dialect Optionsfd-lines-as-code: Fortran Dialect Optionsfd-lines-as-comments: Fortran Dialect Optionsfdefault-double-8: Fortran Dialect Optionsfdefault-integer-8: Fortran Dialect Optionsfdefault-real-8: Fortran Dialect Optionsfdollar-ok: Fortran Dialect Optionsfdump-core: Debugging Optionsfdump-parse-tree: Debugging Optionsfexternal-blas: Code Gen Optionsff2c: Code Gen Optionsffixed-line-length-n: Fortran Dialect Optionsffpe-trap=list: Debugging Optionsffree-form: Fortran Dialect Optionsffree-line-length-n: Fortran Dialect Optionsfimplicit-none: Fortran Dialect Optionsfinit-character: Code Gen Optionsfinit-integer: Code Gen Optionsfinit-local-zero: Code Gen Optionsfinit-logical: Code Gen Optionsfinit-real: Code Gen Optionsfintrinsic-modules-path dir: Directory Optionsfmax-errors=n: Error and Warning Optionsfmax-identifier-length=n: Fortran Dialect Optionsfmax-stack-var-size: Code Gen Optionsfmax-subrecord-length=length: Runtime Optionsfmodule-private: Fortran Dialect Optionsfno-automatic: Code Gen Optionsfno-fixed-form: Fortran Dialect Optionsfno-underscoring: Code Gen Optionsfopenmp: Fortran Dialect Optionsfpack-derived: Code Gen Optionsfrange-check: Fortran Dialect Optionsfrecord-marker=length: Runtime Optionsfrecursive: Code Gen Optionsfrepack-arrays: Code Gen Optionsfsecond-underscore: Code Gen Optionsfshort-enums: Fortran 2003 statusfshort-enums: Code Gen Optionsfsign-zero: Runtime Optionsfsyntax-only: Error and Warning OptionsIdir: Directory OptionsJdir: Directory OptionsMdir: Directory Optionspedantic: Error and Warning Optionspedantic-errors: Error and Warning Optionsstatic-libgfortran: Link Optionsstd=std option: Fortran Dialect OptionsWaliasing: Error and Warning OptionsWall: Error and Warning OptionsWampersand: Error and Warning OptionsWcharacter-truncation: Error and Warning OptionsWconversion: Error and Warning OptionsWerror: Error and Warning OptionsWimplicit-interface: Error and Warning OptionsWnonstd-intrinsics: Error and Warning OptionsWsurprising: Error and Warning OptionsWtabs: Error and Warning OptionsWunderflow: Error and Warning OptionsWunused-parameter: Error and Warning Options%LOC: Argument list functions%REF: Argument list functions%VAL: Argument list functions[...]: Fortran 2003 statusABORT: ABORTABS: ABSACCESS: ACCESSACCESS='STREAM' I/O: Fortran 2003 statusACHAR: ACHARACOS: ACOSACOSH: ACOSHADJUSTL: ADJUSTLADJUSTR: ADJUSTRAIMAG: AIMAGAINT: AINTALARM: ALARMALGAMA: LGAMMAALL: ALLALLOCATABLE components of derived types: Fortran 2003 statusALLOCATABLE dummy arguments: Fortran 2003 statusALLOCATABLE function results: Fortran 2003 statusALLOCATED: ALLOCATEDALOG: LOGALOG10: LOG10AMAX0: MAXAMAX1: MAXAMIN0: MINAMIN1: MINAMOD: MODAND: ANDANINT: ANINTANY: ANYASIN: ASINASINH: ATANHASINH: ASINHASSOCIATED: ASSOCIATEDATAN: ATANATAN2: ATAN2BESJ0: BESJ0BESJ1: BESJ1BESJN: BESJNBESY0: BESY0BESY1: BESY1BESYN: BESYNBIT_SIZE: BIT_SIZEBTEST: BTESTC_ASSOCIATED: C_ASSOCIATEDC_F_POINTER: C_F_POINTERC_F_PROCPOINTER: C_F_PROCPOINTERC_FUNLOC: C_FUNLOCC_LOC: C_LOCCABS: ABSCCOS: COSCDABS: ABSCDCOS: COSCDEXP: EXPCDLOG: LOGCDSIN: SINCDSQRT: SQRTCEILING: CEILINGCEXP: EXPCHAR: CHARCHDIR: CHDIRCHMOD: CHMODCLOG: LOGCMPLX: CMPLXCOMMAND_ARGUMENT_COUNT: COMMAND_ARGUMENT_COUNTCOMPLEX: COMPLEXCONJG: CONJGCONVERT specifier: CONVERT specifierCOS: COSCOSH: COSHCOUNT: COUNTCPU_TIME: CPU_TIMECSHIFT: CSHIFTCSIN: SINCSQRT: SQRTCTIME: CTIMEDABS: ABSDACOS: ACOSDACOSH: ACOSHDASIN: ASINDASINH: ATANHDASINH: ASINHDATAN: ATANDATAN2: ATAN2DATE_AND_TIME: DATE_AND_TIMEDBESJ0: BESJ0DBESJ1: BESJ1DBESJN: BESJNDBESY0: BESY0DBESY1: BESY1DBESYN: BESYNDBLE: DBLEDCMPLX: DCMPLXDCONJG: CONJGDCOS: COSDCOSH: COSHDDIM: DIMDECODE: ENCODE and DECODE statementsDEXP: EXPDFLOAT: DFLOATDGAMMA: GAMMADIGITS: DIGITSDIM: DIMDIMAG: AIMAGDINT: AINTDLGAMA: LGAMMADLOG: LOGDLOG10: LOG10DMAX1: MAXDMIN1: MINDMOD: MODDNINT: ANINTDOT_PRODUCT: DOT_PRODUCTDPROD: DPRODDREAL: DREALDSIGN: SIGNDSIN: SINDSINH: SINHDSQRT: SQRTDTAN: TANDTANH: TANHDTIME: DTIMEENCODE: ENCODE and DECODE statementsENUM statement: Fortran 2003 statusENUMERATOR statement: Fortran 2003 statusEOSHIFT: EOSHIFTEPSILON: EPSILONERF: ERFERFC: ERFCETIME: ETIMEEXIT: EXITEXP: EXPEXPONENT: EXPONENTFDATE: FDATEFGET: FGETFGETC: FGETCFLOAT: FLOATFLOOR: FLOORFLUSH: FLUSHFLUSH statement: Fortran 2003 statusFNUM: FNUMFPUT: FPUTFPUTC: FPUTCFRACTION: FRACTIONFREE: FREEFSEEK: FSEEKFSTAT: FSTATFTELL: FTELLGAMMA: LGAMMAGAMMA: GAMMAGERROR: GERRORGET_COMMAND: GET_COMMANDGET_COMMAND_ARGUMENT: GET_COMMAND_ARGUMENTGET_ENVIRONMENT_VARIABLE: GET_ENVIRONMENT_VARIABLEGETARG: GETARGGETCWD: GETCWDGETENV: GETENVGETGID: GETGIDGETLOG: GETLOGGETPID: GETPIDGETUID: GETUIDGMTIME: GMTIMEHOSTNM: HOSTNMHUGE: HUGEIABS: ABSIACHAR: IACHARIAND: IANDIARGC: IARGCIBCLR: IBCLRIBITS: IBITSIBSET: IBSETICHAR: ICHARIDATE: IDATEIDIM: DIMIDINT: INTIDNINT: NINTIEOR: IEORIERRNO: IERRNOIFIX: INTIMAG: AIMAGIMAGPART: AIMAGIMPORT statement: Fortran 2003 statusINDEX: INDEX intrinsicINT: INTINT2: INT2INT8: INT8IOMSG= specifier: Fortran 2003 statusIOR: IORIRAND: IRANDIS_IOSTAT_END: IS_IOSTAT_ENDIS_IOSTAT_EOR: IS_IOSTAT_EORISATTY: ISATTYISHFT: ISHFTISHFTC: ISHFTCISIGN: SIGNISNAN: ISNANISO_FORTRAN_ENV statement: Fortran 2003 statusITIME: ITIMEKILL: KILLKIND: KINDLBOUND: LBOUNDLEN: LENLEN_TRIM: LEN_TRIMLGE: LGELGT: LGTLINK: LINKLLE: LLELLT: LLTLNBLNK: LNBLNKLOC: LOCLOG: LOGLOG10: LOG10LOGICAL: LOGICALLONG: LONGLSHIFT: LSHIFTLSTAT: LSTATLTIME: LTIMEMALLOC: MALLOCMATMUL: MATMULMAX: MAXMAX0: MAXMAX1: MAXMAXEXPONENT: MAXEXPONENTMAXLOC: MAXLOCMAXVAL: MAXVALMCLOCK: MCLOCKMCLOCK8: MCLOCK8MERGE: MERGEMIN: MINMIN0: MINMIN1: MINMINEXPONENT: MINEXPONENTMINLOC: MINLOCMINVAL: MINVALMOD: MODMODULO: MODULOMOVE_ALLOC: MOVE_ALLOCMVBITS: MVBITSNEAREST: NEARESTNEW_LINE: NEW_LINENINT: NINTNOT: NOTNULL: NULLOR: ORPACK: PACKPERROR: PERRORPRECISION: PRECISIONPRESENT: PRESENTPRODUCT: PRODUCTPROTECTED statement: Fortran 2003 statusRADIX: RADIXRAN: RANRAND: RANDRANDOM_NUMBER: RANDOM_NUMBERRANDOM_SEED: RANDOM_SEEDRANGE: RANGEREAL: REALREALPART: REALRECORD: STRUCTURE and RECORDRENAME: RENAMEREPEAT: REPEATRESHAPE: RESHAPERRSPACING: RRSPACINGRSHIFT: RSHIFTSAVE statement: Code Gen OptionsSCALE: SCALESCAN: SCANSECNDS: SECNDSSECOND: SECONDSELECTED_INT_KIND: SELECTED_INT_KINDSELECTED_REAL_KIND: SELECTED_REAL_KINDSET_EXPONENT: SET_EXPONENTSHAPE: SHAPESHORT: INT2SIGN: SIGNSIGNAL: SIGNALSIN: SINSINH: SINHSIZE: SIZESIZEOF: SIZEOFSLEEP: SLEEPSNGL: SNGLSPACING: SPACINGSPREAD: SPREADSQRT: SQRTSRAND: SRANDSTAT: STATENUM: Fortran 2003 statusENUMERATOR: Fortran 2003 statusFLUSH: Fortran 2003 statusIMPORT: Fortran 2003 statusISO_FORTRAN_ENV: Fortran 2003 statusPROTECTED: Fortran 2003 statusSAVE: Code Gen OptionsUSE, INTRINSIC: Fortran 2003 statusVALUE: Fortran 2003 statusVOLATILE: Fortran 2003 statusSTREAM I/O: Fortran 2003 statusSTRUCTURE: STRUCTURE and RECORDSUM: SUMSYMLNK: SYMLNKSYSTEM: SYSTEMSYSTEM_CLOCK: SYSTEM_CLOCKTAN: TANTANH: TANHTIME: TIMETIME8: TIME8TINY: TINYTRANSFER: TRANSFERTRANSPOSE: TRANSPOSETRIM: TRIMTTYNAM: TTYNAMUBOUND: UBOUNDUMASK: UMASKUNLINK: UNLINKUNPACK: UNPACKUSE, INTRINSIC statement: Fortran 2003 statusVALUE statement: Fortran 2003 statusVERIFY: VERIFYVOLATILE statement: Fortran 2003 statusXOR: XORZABS: ABSZCOS: COSZEXP: EXPZLOG: LOGZSIN: SINZSQRT: SQRT