00001 // Input streams -*- C++ -*- 00002 00003 // Copyright (C) 1997, 1998, 1999, 2001, 2002, 2003, 2004, 2005 00004 // Free Software Foundation, Inc. 00005 // 00006 // This file is part of the GNU ISO C++ Library. This library is free 00007 // software; you can redistribute it and/or modify it under the 00008 // terms of the GNU General Public License as published by the 00009 // Free Software Foundation; either version 2, or (at your option) 00010 // any later version. 00011 00012 // This library is distributed in the hope that it will be useful, 00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00015 // GNU General Public License for more details. 00016 00017 // You should have received a copy of the GNU General Public License along 00018 // with this library; see the file COPYING. If not, write to the Free 00019 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 00020 // USA. 00021 00022 // As a special exception, you may use this file as part of a free software 00023 // library without restriction. Specifically, if other files instantiate 00024 // templates or use macros or inline functions from this file, or you compile 00025 // this file and link it with other files to produce an executable, this 00026 // file does not by itself cause the resulting executable to be covered by 00027 // the GNU General Public License. This exception does not however 00028 // invalidate any other reasons why the executable file might be covered by 00029 // the GNU General Public License. 00030 00031 // 00032 // ISO C++ 14882: 27.6.1 Input streams 00033 // 00034 00035 /** @file istream 00036 * This is a Standard C++ Library header. 00037 */ 00038 00039 #ifndef _GLIBCXX_ISTREAM 00040 #define _GLIBCXX_ISTREAM 1 00041 00042 #pragma GCC system_header 00043 00044 #include <ios> 00045 #include <limits> // For numeric_limits 00046 00047 namespace std 00048 { 00049 // [27.6.1.1] Template class basic_istream 00050 /** 00051 * @brief Controlling input. 00052 * 00053 * This is the base class for all input streams. It provides text 00054 * formatting of all builtin types, and communicates with any class 00055 * derived from basic_streambuf to do the actual input. 00056 */ 00057 template<typename _CharT, typename _Traits> 00058 class basic_istream : virtual public basic_ios<_CharT, _Traits> 00059 { 00060 public: 00061 // Types (inherited from basic_ios (27.4.4)): 00062 typedef _CharT char_type; 00063 typedef typename _Traits::int_type int_type; 00064 typedef typename _Traits::pos_type pos_type; 00065 typedef typename _Traits::off_type off_type; 00066 typedef _Traits traits_type; 00067 00068 // Non-standard Types: 00069 typedef basic_streambuf<_CharT, _Traits> __streambuf_type; 00070 typedef basic_ios<_CharT, _Traits> __ios_type; 00071 typedef basic_istream<_CharT, _Traits> __istream_type; 00072 typedef num_get<_CharT, istreambuf_iterator<_CharT, _Traits> > 00073 __num_get_type; 00074 typedef ctype<_CharT> __ctype_type; 00075 00076 template<typename _CharT2, typename _Traits2> 00077 friend basic_istream<_CharT2, _Traits2>& 00078 operator>>(basic_istream<_CharT2, _Traits2>&, _CharT2&); 00079 00080 template<typename _CharT2, typename _Traits2> 00081 friend basic_istream<_CharT2, _Traits2>& 00082 operator>>(basic_istream<_CharT2, _Traits2>&, _CharT2*); 00083 00084 protected: 00085 // Data Members: 00086 /** 00087 * @if maint 00088 * The number of characters extracted in the previous unformatted 00089 * function; see gcount(). 00090 * @endif 00091 */ 00092 streamsize _M_gcount; 00093 00094 public: 00095 // [27.6.1.1.1] constructor/destructor 00096 /** 00097 * @brief Base constructor. 00098 * 00099 * This ctor is almost never called by the user directly, rather from 00100 * derived classes' initialization lists, which pass a pointer to 00101 * their own stream buffer. 00102 */ 00103 explicit 00104 basic_istream(__streambuf_type* __sb): _M_gcount(streamsize(0)) 00105 { this->init(__sb); } 00106 00107 /** 00108 * @brief Base destructor. 00109 * 00110 * This does very little apart from providing a virtual base dtor. 00111 */ 00112 virtual 00113 ~basic_istream() 00114 { _M_gcount = streamsize(0); } 00115 00116 // [27.6.1.1.2] prefix/suffix 00117 class sentry; 00118 friend class sentry; 00119 00120 // [27.6.1.2] formatted input 00121 // [27.6.1.2.3] basic_istream::operator>> 00122 //@{ 00123 /** 00124 * @brief Interface for manipulators. 00125 * 00126 * Manuipulators such as @c std::ws and @c std::dec use these 00127 * functions in constructs like "std::cin >> std::ws". For more 00128 * information, see the iomanip header. 00129 */ 00130 inline __istream_type& 00131 operator>>(__istream_type& (*__pf)(__istream_type&)); 00132 00133 inline __istream_type& 00134 operator>>(__ios_type& (*__pf)(__ios_type&)); 00135 00136 inline __istream_type& 00137 operator>>(ios_base& (*__pf)(ios_base&)); 00138 //@} 00139 00140 // [27.6.1.2.2] arithmetic extractors 00141 /** 00142 * @name Arithmetic Extractors 00143 * 00144 * All the @c operator>> functions (aka <em>formatted input 00145 * functions</em>) have some common behavior. Each starts by 00146 * constructing a temporary object of type std::basic_istream::sentry 00147 * with the second argument (noskipws) set to false. This has several 00148 * effects, concluding with the setting of a status flag; see the 00149 * sentry documentation for more. 00150 * 00151 * If the sentry status is good, the function tries to extract 00152 * whatever data is appropriate for the type of the argument. 00153 * 00154 * If an exception is thrown during extraction, ios_base::badbit 00155 * will be turned on in the stream's error state without causing an 00156 * ios_base::failure to be thrown. The original exception will then 00157 * be rethrown. 00158 */ 00159 //@{ 00160 /** 00161 * @brief Basic arithmetic extractors 00162 * @param A variable of builtin type. 00163 * @return @c *this if successful 00164 * 00165 * These functions use the stream's current locale (specifically, the 00166 * @c num_get facet) to parse the input data. 00167 */ 00168 __istream_type& 00169 operator>>(bool& __n); 00170 00171 __istream_type& 00172 operator>>(short& __n); 00173 00174 __istream_type& 00175 operator>>(unsigned short& __n); 00176 00177 __istream_type& 00178 operator>>(int& __n); 00179 00180 __istream_type& 00181 operator>>(unsigned int& __n); 00182 00183 __istream_type& 00184 operator>>(long& __n); 00185 00186 __istream_type& 00187 operator>>(unsigned long& __n); 00188 00189 #ifdef _GLIBCXX_USE_LONG_LONG 00190 __istream_type& 00191 operator>>(long long& __n); 00192 00193 __istream_type& 00194 operator>>(unsigned long long& __n); 00195 #endif 00196 00197 __istream_type& 00198 operator>>(float& __f); 00199 00200 __istream_type& 00201 operator>>(double& __f); 00202 00203 __istream_type& 00204 operator>>(long double& __f); 00205 00206 __istream_type& 00207 operator>>(void*& __p); 00208 00209 /** 00210 * @brief Extracting into another streambuf. 00211 * @param sb A pointer to a streambuf 00212 * 00213 * This function behaves like one of the basic arithmetic extractors, 00214 * in that it also constructs a sentry object and has the same error 00215 * handling behavior. 00216 * 00217 * If @a sb is NULL, the stream will set failbit in its error state. 00218 * 00219 * Characters are extracted from this stream and inserted into the 00220 * @a sb streambuf until one of the following occurs: 00221 * 00222 * - the input stream reaches end-of-file, 00223 * - insertion into the output buffer fails (in this case, the 00224 * character that would have been inserted is not extracted), or 00225 * - an exception occurs (and in this case is caught) 00226 * 00227 * If the function inserts no characters, failbit is set. 00228 */ 00229 __istream_type& 00230 operator>>(__streambuf_type* __sb); 00231 //@} 00232 00233 // [27.6.1.3] unformatted input 00234 /** 00235 * @brief Character counting 00236 * @return The number of characters extracted by the previous 00237 * unformatted input function dispatched for this stream. 00238 */ 00239 inline streamsize 00240 gcount() const 00241 { return _M_gcount; } 00242 00243 /** 00244 * @name Unformatted Input Functions 00245 * 00246 * All the unformatted input functions have some common behavior. 00247 * Each starts by constructing a temporary object of type 00248 * std::basic_istream::sentry with the second argument (noskipws) 00249 * set to true. This has several effects, concluding with the 00250 * setting of a status flag; see the sentry documentation for more. 00251 * 00252 * If the sentry status is good, the function tries to extract 00253 * whatever data is appropriate for the type of the argument. 00254 * 00255 * The number of characters extracted is stored for later retrieval 00256 * by gcount(). 00257 * 00258 * If an exception is thrown during extraction, ios_base::badbit 00259 * will be turned on in the stream's error state without causing an 00260 * ios_base::failure to be thrown. The original exception will then 00261 * be rethrown. 00262 */ 00263 //@{ 00264 /** 00265 * @brief Simple extraction. 00266 * @return A character, or eof(). 00267 * 00268 * Tries to extract a character. If none are available, sets failbit 00269 * and returns traits::eof(). 00270 */ 00271 int_type 00272 get(); 00273 00274 /** 00275 * @brief Simple extraction. 00276 * @param c The character in which to store data. 00277 * @return *this 00278 * 00279 * Tries to extract a character and store it in @a c. If none are 00280 * available, sets failbit and returns traits::eof(). 00281 * 00282 * @note This function is not overloaded on signed char and 00283 * unsigned char. 00284 */ 00285 __istream_type& 00286 get(char_type& __c); 00287 00288 /** 00289 * @brief Simple multiple-character extraction. 00290 * @param s Pointer to an array. 00291 * @param n Maximum number of characters to store in @a s. 00292 * @param delim A "stop" character. 00293 * @return *this 00294 * 00295 * Characters are extracted and stored into @a s until one of the 00296 * following happens: 00297 * 00298 * - @c n-1 characters are stored 00299 * - the input sequence reaches EOF 00300 * - the next character equals @a delim, in which case the character 00301 * is not extracted 00302 * 00303 * If no characters are stored, failbit is set in the stream's error 00304 * state. 00305 * 00306 * In any case, a null character is stored into the next location in 00307 * the array. 00308 * 00309 * @note This function is not overloaded on signed char and 00310 * unsigned char. 00311 */ 00312 __istream_type& 00313 get(char_type* __s, streamsize __n, char_type __delim); 00314 00315 /** 00316 * @brief Simple multiple-character extraction. 00317 * @param s Pointer to an array. 00318 * @param n Maximum number of characters to store in @a s. 00319 * @return *this 00320 * 00321 * Returns @c get(s,n,widen('\n')). 00322 */ 00323 inline __istream_type& 00324 get(char_type* __s, streamsize __n) 00325 { return this->get(__s, __n, this->widen('\n')); } 00326 00327 /** 00328 * @brief Extraction into another streambuf. 00329 * @param sb A streambuf in which to store data. 00330 * @param delim A "stop" character. 00331 * @return *this 00332 * 00333 * Characters are extracted and inserted into @a sb until one of the 00334 * following happens: 00335 * 00336 * - the input sequence reaches EOF 00337 * - insertion into the output buffer fails (in this case, the 00338 * character that would have been inserted is not extracted) 00339 * - the next character equals @a delim (in this case, the character 00340 * is not extracted) 00341 * - an exception occurs (and in this case is caught) 00342 * 00343 * If no characters are stored, failbit is set in the stream's error 00344 * state. 00345 */ 00346 __istream_type& 00347 get(__streambuf_type& __sb, char_type __delim); 00348 00349 /** 00350 * @brief Extraction into another streambuf. 00351 * @param sb A streambuf in which to store data. 00352 * @return *this 00353 * 00354 * Returns @c get(sb,widen('\n')). 00355 */ 00356 inline __istream_type& 00357 get(__streambuf_type& __sb) 00358 { return this->get(__sb, this->widen('\n')); } 00359 00360 /** 00361 * @brief String extraction. 00362 * @param s A character array in which to store the data. 00363 * @param n Maximum number of characters to extract. 00364 * @param delim A "stop" character. 00365 * @return *this 00366 * 00367 * Extracts and stores characters into @a s until one of the 00368 * following happens. Note that these criteria are required to be 00369 * tested in the order listed here, to allow an input line to exactly 00370 * fill the @a s array without setting failbit. 00371 * 00372 * -# the input sequence reaches end-of-file, in which case eofbit 00373 * is set in the stream error state 00374 * -# the next character equals @c delim, in which case the character 00375 * is extracted (and therefore counted in @c gcount()) but not stored 00376 * -# @c n-1 characters are stored, in which case failbit is set 00377 * in the stream error state 00378 * 00379 * If no characters are extracted, failbit is set. (An empty line of 00380 * input should therefore not cause failbit to be set.) 00381 * 00382 * In any case, a null character is stored in the next location in 00383 * the array. 00384 */ 00385 __istream_type& 00386 getline(char_type* __s, streamsize __n, char_type __delim); 00387 00388 /** 00389 * @brief String extraction. 00390 * @param s A character array in which to store the data. 00391 * @param n Maximum number of characters to extract. 00392 * @return *this 00393 * 00394 * Returns @c getline(s,n,widen('\n')). 00395 */ 00396 inline __istream_type& 00397 getline(char_type* __s, streamsize __n) 00398 { return this->getline(__s, __n, this->widen('\n')); } 00399 00400 /** 00401 * @brief Discarding characters 00402 * @param n Number of characters to discard. 00403 * @param delim A "stop" character. 00404 * @return *this 00405 * 00406 * Extracts characters and throws them away until one of the 00407 * following happens: 00408 * - if @a n @c != @c std::numeric_limits<int>::max(), @a n 00409 * characters are extracted 00410 * - the input sequence reaches end-of-file 00411 * - the next character equals @a delim (in this case, the character 00412 * is extracted); note that this condition will never occur if 00413 * @a delim equals @c traits::eof(). 00414 * 00415 * NB: Provide three overloads, instead of the single function 00416 * (with defaults) mandated by the Standard: this leads to a 00417 * better performing implementation, while still conforming to 00418 * the Standard. 00419 */ 00420 __istream_type& 00421 ignore(); 00422 00423 __istream_type& 00424 ignore(streamsize __n); 00425 00426 __istream_type& 00427 ignore(streamsize __n, int_type __delim); 00428 00429 /** 00430 * @brief Looking ahead in the stream 00431 * @return The next character, or eof(). 00432 * 00433 * If, after constructing the sentry object, @c good() is false, 00434 * returns @c traits::eof(). Otherwise reads but does not extract 00435 * the next input character. 00436 */ 00437 int_type 00438 peek(); 00439 00440 /** 00441 * @brief Extraction without delimiters. 00442 * @param s A character array. 00443 * @param n Maximum number of characters to store. 00444 * @return *this 00445 * 00446 * If the stream state is @c good(), extracts characters and stores 00447 * them into @a s until one of the following happens: 00448 * - @a n characters are stored 00449 * - the input sequence reaches end-of-file, in which case the error 00450 * state is set to @c failbit|eofbit. 00451 * 00452 * @note This function is not overloaded on signed char and 00453 * unsigned char. 00454 */ 00455 __istream_type& 00456 read(char_type* __s, streamsize __n); 00457 00458 /** 00459 * @brief Extraction until the buffer is exhausted, but no more. 00460 * @param s A character array. 00461 * @param n Maximum number of characters to store. 00462 * @return The number of characters extracted. 00463 * 00464 * Extracts characters and stores them into @a s depending on the 00465 * number of characters remaining in the streambuf's buffer, 00466 * @c rdbuf()->in_avail(), called @c A here: 00467 * - if @c A @c == @c -1, sets eofbit and extracts no characters 00468 * - if @c A @c == @c 0, extracts no characters 00469 * - if @c A @c > @c 0, extracts @c min(A,n) 00470 * 00471 * The goal is to empty the current buffer, and to not request any 00472 * more from the external input sequence controlled by the streambuf. 00473 */ 00474 streamsize 00475 readsome(char_type* __s, streamsize __n); 00476 00477 /** 00478 * @brief Unextracting a single character. 00479 * @param c The character to push back into the input stream. 00480 * @return *this 00481 * 00482 * If @c rdbuf() is not null, calls @c rdbuf()->sputbackc(c). 00483 * 00484 * If @c rdbuf() is null or if @c sputbackc() fails, sets badbit in 00485 * the error state. 00486 * 00487 * @note Since no characters are extracted, the next call to 00488 * @c gcount() will return 0, as required by DR 60. 00489 */ 00490 __istream_type& 00491 putback(char_type __c); 00492 00493 /** 00494 * @brief Unextracting the previous character. 00495 * @return *this 00496 * 00497 * If @c rdbuf() is not null, calls @c rdbuf()->sungetc(c). 00498 * 00499 * If @c rdbuf() is null or if @c sungetc() fails, sets badbit in 00500 * the error state. 00501 * 00502 * @note Since no characters are extracted, the next call to 00503 * @c gcount() will return 0, as required by DR 60. 00504 */ 00505 __istream_type& 00506 unget(); 00507 00508 /** 00509 * @brief Synchronizing the stream buffer. 00510 * @return 0 on success, -1 on failure 00511 * 00512 * If @c rdbuf() is a null pointer, returns -1. 00513 * 00514 * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1, 00515 * sets badbit and returns -1. 00516 * 00517 * Otherwise, returns 0. 00518 * 00519 * @note This function does not count the number of characters 00520 * extracted, if any, and therefore does not affect the next 00521 * call to @c gcount(). 00522 */ 00523 int 00524 sync(); 00525 00526 /** 00527 * @brief Getting the current read position. 00528 * @return A file position object. 00529 * 00530 * If @c fail() is not false, returns @c pos_type(-1) to indicate 00531 * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,in). 00532 * 00533 * @note This function does not count the number of characters 00534 * extracted, if any, and therefore does not affect the next 00535 * call to @c gcount(). 00536 */ 00537 pos_type 00538 tellg(); 00539 00540 /** 00541 * @brief Changing the current read position. 00542 * @param pos A file position object. 00543 * @return *this 00544 * 00545 * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If 00546 * that function fails, sets failbit. 00547 * 00548 * @note This function does not count the number of characters 00549 * extracted, if any, and therefore does not affect the next 00550 * call to @c gcount(). 00551 */ 00552 __istream_type& 00553 seekg(pos_type); 00554 00555 /** 00556 * @brief Changing the current read position. 00557 * @param off A file offset object. 00558 * @param dir The direction in which to seek. 00559 * @return *this 00560 * 00561 * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir). 00562 * If that function fails, sets failbit. 00563 * 00564 * @note This function does not count the number of characters 00565 * extracted, if any, and therefore does not affect the next 00566 * call to @c gcount(). 00567 */ 00568 __istream_type& 00569 seekg(off_type, ios_base::seekdir); 00570 //@} 00571 00572 protected: 00573 explicit 00574 basic_istream(): _M_gcount(streamsize(0)) { } 00575 }; 00576 00577 // Explicit specialization declarations, defined in src/istream.cc. 00578 template<> 00579 basic_istream<char>& 00580 basic_istream<char>:: 00581 getline(char_type* __s, streamsize __n, char_type __delim); 00582 00583 template<> 00584 basic_istream<char>& 00585 basic_istream<char>:: 00586 ignore(streamsize __n); 00587 00588 template<> 00589 basic_istream<char>& 00590 basic_istream<char>:: 00591 ignore(streamsize __n, int_type __delim); 00592 00593 #ifdef _GLIBCXX_USE_WCHAR_T 00594 template<> 00595 basic_istream<wchar_t>& 00596 basic_istream<wchar_t>:: 00597 getline(char_type* __s, streamsize __n, char_type __delim); 00598 00599 template<> 00600 basic_istream<wchar_t>& 00601 basic_istream<wchar_t>:: 00602 ignore(streamsize __n); 00603 00604 template<> 00605 basic_istream<wchar_t>& 00606 basic_istream<wchar_t>:: 00607 ignore(streamsize __n, int_type __delim); 00608 #endif 00609 00610 /** 00611 * @brief Performs setup work for input streams. 00612 * 00613 * Objects of this class are created before all of the standard 00614 * extractors are run. It is responsible for "exception-safe prefix and 00615 * suffix operations," although only prefix actions are currently required 00616 * by the standard. Additional actions may be added by the 00617 * implementation, and we list them in 00618 * http://gcc.gnu.org/onlinedocs/libstdc++/17_intro/howto.html#5 00619 * under [27.6] notes. 00620 */ 00621 template<typename _CharT, typename _Traits> 00622 class basic_istream<_CharT, _Traits>::sentry 00623 { 00624 public: 00625 /// Easy access to dependant types. 00626 typedef _Traits traits_type; 00627 typedef basic_streambuf<_CharT, _Traits> __streambuf_type; 00628 typedef basic_istream<_CharT, _Traits> __istream_type; 00629 typedef typename __istream_type::__ctype_type __ctype_type; 00630 typedef typename _Traits::int_type __int_type; 00631 00632 /** 00633 * @brief The constructor performs all the work. 00634 * @param is The input stream to guard. 00635 * @param noskipws Whether to consume whitespace or not. 00636 * 00637 * If the stream state is good (@a is.good() is true), then the 00638 * following actions are performed, otherwise the sentry state is 00639 * false ("not okay") and failbit is set in the stream state. 00640 * 00641 * The sentry's preparatory actions are: 00642 * 00643 * -# if the stream is tied to an output stream, @c is.tie()->flush() 00644 * is called to synchronize the output sequence 00645 * -# if @a noskipws is false, and @c ios_base::skipws is set in 00646 * @c is.flags(), the sentry extracts and discards whitespace 00647 * characters from the stream. The currently imbued locale is 00648 * used to determine whether each character is whitespace. 00649 * 00650 * If the stream state is still good, then the sentry state becomes 00651 * true ("okay"). 00652 */ 00653 explicit 00654 sentry(basic_istream<_CharT, _Traits>& __is, bool __noskipws = false); 00655 00656 /** 00657 * @brief Quick status checking. 00658 * @return The sentry state. 00659 * 00660 * For ease of use, sentries may be converted to booleans. The 00661 * return value is that of the sentry state (true == okay). 00662 */ 00663 operator bool() const { return _M_ok; } 00664 00665 private: 00666 bool _M_ok; 00667 }; 00668 00669 // [27.6.1.2.3] character extraction templates 00670 //@{ 00671 /** 00672 * @brief Character extractors 00673 * @param in An input stream. 00674 * @param c A character reference. 00675 * @return in 00676 * 00677 * Behaves like one of the formatted arithmetic extractors described in 00678 * std::basic_istream. After constructing a sentry object with good 00679 * status, this function extracts a character (if one is available) and 00680 * stores it in @a c. Otherwise, sets failbit in the input stream. 00681 */ 00682 template<typename _CharT, typename _Traits> 00683 basic_istream<_CharT, _Traits>& 00684 operator>>(basic_istream<_CharT, _Traits>& __in, _CharT& __c); 00685 00686 template<class _Traits> 00687 basic_istream<char, _Traits>& 00688 operator>>(basic_istream<char, _Traits>& __in, unsigned char& __c) 00689 { return (__in >> reinterpret_cast<char&>(__c)); } 00690 00691 template<class _Traits> 00692 basic_istream<char, _Traits>& 00693 operator>>(basic_istream<char, _Traits>& __in, signed char& __c) 00694 { return (__in >> reinterpret_cast<char&>(__c)); } 00695 //@} 00696 00697 //@{ 00698 /** 00699 * @brief Character string extractors 00700 * @param in An input stream. 00701 * @param s A pointer to a character array. 00702 * @return in 00703 * 00704 * Behaves like one of the formatted arithmetic extractors described in 00705 * std::basic_istream. After constructing a sentry object with good 00706 * status, this function extracts up to @c n characters and stores them 00707 * into the array starting at @a s. @c n is defined as: 00708 * 00709 * - if @c width() is greater than zero, @c n is width() 00710 * - otherwise @c n is "the number of elements of the largest array of 00711 * @c char_type that can store a terminating @c eos." [27.6.1.2.3]/6 00712 * 00713 * Characters are extracted and stored until one of the following happens: 00714 * - @c n-1 characters are stored 00715 * - EOF is reached 00716 * - the next character is whitespace according to the current locale 00717 * - the next character is a null byte (i.e., @c charT() ) 00718 * 00719 * @c width(0) is then called for the input stream. 00720 * 00721 * If no characters are extracted, sets failbit. 00722 */ 00723 template<typename _CharT, typename _Traits> 00724 basic_istream<_CharT, _Traits>& 00725 operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s); 00726 00727 // Explicit specialization declaration, defined in src/istream.cc. 00728 template<> 00729 basic_istream<char>& 00730 operator>>(basic_istream<char>& __in, char* __s); 00731 00732 template<class _Traits> 00733 basic_istream<char, _Traits>& 00734 operator>>(basic_istream<char, _Traits>& __in, unsigned char* __s) 00735 { return (__in >> reinterpret_cast<char*>(__s)); } 00736 00737 template<class _Traits> 00738 basic_istream<char, _Traits>& 00739 operator>>(basic_istream<char, _Traits>& __in, signed char* __s) 00740 { return (__in >> reinterpret_cast<char*>(__s)); } 00741 //@} 00742 00743 // 27.6.1.5 Template class basic_iostream 00744 /** 00745 * @brief Merging istream and ostream capabilities. 00746 * 00747 * This class multiply inherits from the input and output stream classes 00748 * simply to provide a single interface. 00749 */ 00750 template<typename _CharT, typename _Traits> 00751 class basic_iostream 00752 : public basic_istream<_CharT, _Traits>, 00753 public basic_ostream<_CharT, _Traits> 00754 { 00755 public: 00756 // _GLIBCXX_RESOLVE_LIB_DEFECTS 00757 // 271. basic_iostream missing typedefs 00758 // Types (inherited): 00759 typedef _CharT char_type; 00760 typedef typename _Traits::int_type int_type; 00761 typedef typename _Traits::pos_type pos_type; 00762 typedef typename _Traits::off_type off_type; 00763 typedef _Traits traits_type; 00764 00765 // Non-standard Types: 00766 typedef basic_istream<_CharT, _Traits> __istream_type; 00767 typedef basic_ostream<_CharT, _Traits> __ostream_type; 00768 00769 /** 00770 * @brief Constructor does nothing. 00771 * 00772 * Both of the parent classes are initialized with the same 00773 * streambuf pointer passed to this constructor. 00774 */ 00775 explicit 00776 basic_iostream(basic_streambuf<_CharT, _Traits>* __sb) 00777 : __istream_type(), __ostream_type() 00778 { this->init(__sb); } 00779 00780 /** 00781 * @brief Destructor does nothing. 00782 */ 00783 virtual 00784 ~basic_iostream() { } 00785 00786 protected: 00787 explicit 00788 basic_iostream() : __istream_type(), __ostream_type() 00789 { } 00790 }; 00791 00792 // [27.6.1.4] standard basic_istream manipulators 00793 /** 00794 * @brief Quick and easy way to eat whitespace 00795 * 00796 * This manipulator extracts whitespace characters, stopping when the 00797 * next character is non-whitespace, or when the input sequence is empty. 00798 * If the sequence is empty, @c eofbit is set in the stream, but not 00799 * @c failbit. 00800 * 00801 * The current locale is used to distinguish whitespace characters. 00802 * 00803 * Example: 00804 * @code 00805 * MyClass mc; 00806 * 00807 * std::cin >> std::ws >> mc; 00808 * @endcode 00809 * will skip leading whitespace before calling operator>> on cin and your 00810 * object. Note that the same effect can be achieved by creating a 00811 * std::basic_istream::sentry inside your definition of operator>>. 00812 */ 00813 template<typename _CharT, typename _Traits> 00814 basic_istream<_CharT, _Traits>& 00815 ws(basic_istream<_CharT, _Traits>& __is); 00816 } // namespace std 00817 00818 #ifndef _GLIBCXX_EXPORT_TEMPLATE 00819 # include <bits/istream.tcc> 00820 #endif 00821 00822 #endif /* _GLIBCXX_ISTREAM */