1 : // File based streams -*- C++ -*-
2 :
3 : // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
4 : // Free Software Foundation, Inc.
5 : //
6 : // This file is part of the GNU ISO C++ Library. This library is free
7 : // software; you can redistribute it and/or modify it under the
8 : // terms of the GNU General Public License as published by the
9 : // Free Software Foundation; either version 2, or (at your option)
10 : // any later version.
11 :
12 : // This library is distributed in the hope that it will be useful,
13 : // but WITHOUT ANY WARRANTY; without even the implied warranty of
14 : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 : // GNU General Public License for more details.
16 :
17 : // You should have received a copy of the GNU General Public License along
18 : // with this library; see the file COPYING. If not, write to the Free
19 : // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
20 : // USA.
21 :
22 : // As a special exception, you may use this file as part of a free software
23 : // library without restriction. Specifically, if other files instantiate
24 : // templates or use macros or inline functions from this file, or you compile
25 : // this file and link it with other files to produce an executable, this
26 : // file does not by itself cause the resulting executable to be covered by
27 : // the GNU General Public License. This exception does not however
28 : // invalidate any other reasons why the executable file might be covered by
29 : // the GNU General Public License.
30 :
31 : //
32 : // ISO C++ 14882: 27.8 File-based streams
33 : //
34 :
35 : /** @file fstream
36 : * This is a Standard C++ Library header.
37 : */
38 :
39 : #ifndef _GLIBCXX_FSTREAM
40 : #define _GLIBCXX_FSTREAM 1
41 :
42 : #pragma GCC system_header
43 :
44 : #include <istream>
45 : #include <ostream>
46 : #include <locale> // For codecvt
47 : #include <cstdio> // For SEEK_SET, SEEK_CUR, SEEK_END, BUFSIZ
48 : #include <bits/basic_file.h>
49 : #include <bits/gthr.h>
50 :
51 : namespace std
52 : {
53 : // [27.8.1.1] template class basic_filebuf
54 : /**
55 : * @brief The actual work of input and output (for files).
56 : *
57 : * This class associates both its input and output sequence with an
58 : * external disk file, and maintains a joint file position for both
59 : * sequences. Many of its sematics are described in terms of similar
60 : * behavior in the Standard C Library's @c FILE streams.
61 : */
62 : // Requirements on traits_type, specific to this class:
63 : // traits_type::pos_type must be fpos<traits_type::state_type>
64 : // traits_type::off_type must be streamoff
65 : // traits_type::state_type must be Assignable and DefaultConstructable,
66 : // and traits_type::state_type() must be the initial state for codecvt.
67 : template<typename _CharT, typename _Traits>
68 : class basic_filebuf : public basic_streambuf<_CharT, _Traits>
69 : {
70 : public:
71 : // Types:
72 : typedef _CharT char_type;
73 : typedef _Traits traits_type;
74 : typedef typename traits_type::int_type int_type;
75 : typedef typename traits_type::pos_type pos_type;
76 : typedef typename traits_type::off_type off_type;
77 :
78 : typedef basic_streambuf<char_type, traits_type> __streambuf_type;
79 : typedef basic_filebuf<char_type, traits_type> __filebuf_type;
80 : typedef __basic_file<char> __file_type;
81 : typedef typename traits_type::state_type __state_type;
82 : typedef codecvt<char_type, char, __state_type> __codecvt_type;
83 :
84 : friend class ios_base; // For sync_with_stdio.
85 :
86 : protected:
87 : // Data Members:
88 : // MT lock inherited from libio or other low-level io library.
89 : __c_lock _M_lock;
90 :
91 : // External buffer.
92 : __file_type _M_file;
93 :
94 : /**
95 : * @if maint
96 : * Place to stash in || out || in | out settings for current filebuf.
97 : * @endif
98 : */
99 : ios_base::openmode _M_mode;
100 :
101 : // Beginning state type for codecvt.
102 : __state_type _M_state_beg;
103 :
104 : // During output, the state that corresponds to pptr(),
105 : // during input, the state that corresponds to egptr() and
106 : // _M_ext_next.
107 : __state_type _M_state_cur;
108 :
109 : // Not used for output. During input, the state that corresponds
110 : // to eback() and _M_ext_buf.
111 : __state_type _M_state_last;
112 :
113 : /**
114 : * @if maint
115 : * Pointer to the beginning of internal buffer.
116 : * @endif
117 : */
118 : char_type* _M_buf;
119 :
120 : /**
121 : * @if maint
122 : * Actual size of internal buffer. This number is equal to the size
123 : * of the put area + 1 position, reserved for the overflow char of
124 : * a full area.
125 : * @endif
126 : */
127 : size_t _M_buf_size;
128 :
129 : // Set iff _M_buf is allocated memory from _M_allocate_internal_buffer.
130 : bool _M_buf_allocated;
131 :
132 : /**
133 : * @if maint
134 : * _M_reading == false && _M_writing == false for 'uncommitted' mode;
135 : * _M_reading == true for 'read' mode;
136 : * _M_writing == true for 'write' mode;
137 : *
138 : * NB: _M_reading == true && _M_writing == true is unused.
139 : * @endif
140 : */
141 : bool _M_reading;
142 : bool _M_writing;
143 :
144 : //@{
145 : /**
146 : * @if maint
147 : * Necessary bits for putback buffer management.
148 : *
149 : * @note pbacks of over one character are not currently supported.
150 : * @endif
151 : */
152 : char_type _M_pback;
153 : char_type* _M_pback_cur_save;
154 : char_type* _M_pback_end_save;
155 : bool _M_pback_init;
156 : //@}
157 :
158 : // Cached codecvt facet.
159 : const __codecvt_type* _M_codecvt;
160 :
161 : /**
162 : * @if maint
163 : * Buffer for external characters. Used for input when
164 : * codecvt::always_noconv() == false. When valid, this corresponds
165 : * to eback().
166 : * @endif
167 : */
168 : char* _M_ext_buf;
169 :
170 : /**
171 : * @if maint
172 : * Size of buffer held by _M_ext_buf.
173 : * @endif
174 : */
175 : streamsize _M_ext_buf_size;
176 :
177 : /**
178 : * @if maint
179 : * Pointers into the buffer held by _M_ext_buf that delimit a
180 : * subsequence of bytes that have been read but not yet converted.
181 : * When valid, _M_ext_next corresponds to egptr().
182 : * @endif
183 : */
184 : const char* _M_ext_next;
185 : char* _M_ext_end;
186 :
187 : /**
188 : * @if maint
189 : * Initializes pback buffers, and moves normal buffers to safety.
190 : * Assumptions:
191 : * _M_in_cur has already been moved back
192 : * @endif
193 : */
194 : void
195 : _M_create_pback()
196 : {
197 : if (!_M_pback_init)
198 : {
199 : _M_pback_cur_save = this->gptr();
200 : _M_pback_end_save = this->egptr();
201 : this->setg(&_M_pback, &_M_pback, &_M_pback + 1);
202 : _M_pback_init = true;
203 : }
204 : }
205 :
206 : /**
207 : * @if maint
208 : * Deactivates pback buffer contents, and restores normal buffer.
209 : * Assumptions:
210 : * The pback buffer has only moved forward.
211 : * @endif
212 : */
213 : void
214 : _M_destroy_pback() throw()
215 : {
216 : if (_M_pback_init)
217 : {
218 : // Length _M_in_cur moved in the pback buffer.
219 : _M_pback_cur_save += this->gptr() != this->eback();
220 : this->setg(_M_buf, _M_pback_cur_save, _M_pback_end_save);
221 : _M_pback_init = false;
222 : }
223 : }
224 :
225 : public:
226 : // Constructors/destructor:
227 : /**
228 : * @brief Does not open any files.
229 : *
230 : * The default constructor initializes the parent class using its
231 : * own default ctor.
232 : */
233 : basic_filebuf();
234 :
235 : /**
236 : * @brief The destructor closes the file first.
237 : */
238 : virtual
239 : ~basic_filebuf()
240 74 : { this->close(); }
241 :
242 : // Members:
243 : /**
244 : * @brief Returns true if the external file is open.
245 : */
246 : bool
247 : is_open() const throw()
248 : { return _M_file.is_open(); }
249 :
250 : /**
251 : * @brief Opens an external file.
252 : * @param s The name of the file.
253 : * @param mode The open mode flags.
254 : * @return @c this on success, NULL on failure
255 : *
256 : * If a file is already open, this function immediately fails.
257 : * Otherwise it tries to open the file named @a s using the flags
258 : * given in @a mode.
259 : *
260 : * [Table 92 gives the relation between openmode combinations and the
261 : * equivalent fopen() flags, but the table has not been copied yet.]
262 : */
263 : __filebuf_type*
264 : open(const char* __s, ios_base::openmode __mode);
265 :
266 : /**
267 : * @brief Closes the currently associated file.
268 : * @return @c this on success, NULL on failure
269 : *
270 : * If no file is currently open, this function immediately fails.
271 : *
272 : * If a "put buffer area" exists, @c overflow(eof) is called to flush
273 : * all the characters. The file is then closed.
274 : *
275 : * If any operations fail, this function also fails.
276 : */
277 : __filebuf_type*
278 : close() throw();
279 :
280 : protected:
281 : void
282 : _M_allocate_internal_buffer();
283 :
284 : void
285 : _M_destroy_internal_buffer() throw();
286 :
287 : // [27.8.1.4] overridden virtual functions
288 : virtual streamsize
289 : showmanyc();
290 :
291 : // Stroustrup, 1998, p. 628
292 : // underflow() and uflow() functions are called to get the next
293 : // charater from the real input source when the buffer is empty.
294 : // Buffered input uses underflow()
295 :
296 : virtual int_type
297 : underflow();
298 :
299 : virtual int_type
300 : pbackfail(int_type __c = _Traits::eof());
301 :
302 : // Stroustrup, 1998, p 648
303 : // The overflow() function is called to transfer characters to the
304 : // real output destination when the buffer is full. A call to
305 : // overflow(c) outputs the contents of the buffer plus the
306 : // character c.
307 : // 27.5.2.4.5
308 : // Consume some sequence of the characters in the pending sequence.
309 : virtual int_type
310 : overflow(int_type __c = _Traits::eof());
311 :
312 : // Convert internal byte sequence to external, char-based
313 : // sequence via codecvt.
314 : bool
315 : _M_convert_to_external(char_type*, streamsize);
316 :
317 : /**
318 : * @brief Manipulates the buffer.
319 : * @param s Pointer to a buffer area.
320 : * @param n Size of @a s.
321 : * @return @c this
322 : *
323 : * If no file has been opened, and both @a s and @a n are zero, then
324 : * the stream becomes unbuffered. Otherwise, @c s is used as a
325 : * buffer; see
326 : * http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#2
327 : * for more.
328 : */
329 : virtual __streambuf_type*
330 : setbuf(char_type* __s, streamsize __n);
331 :
332 : virtual pos_type
333 : seekoff(off_type __off, ios_base::seekdir __way,
334 : ios_base::openmode __mode = ios_base::in | ios_base::out);
335 :
336 : virtual pos_type
337 : seekpos(pos_type __pos,
338 : ios_base::openmode __mode = ios_base::in | ios_base::out);
339 :
340 : // Common code for seekoff and seekpos
341 : pos_type
342 : _M_seek(off_type __off, ios_base::seekdir __way, __state_type __state);
343 :
344 : virtual int
345 : sync();
346 :
347 : virtual void
348 : imbue(const locale& __loc);
349 :
350 : virtual streamsize
351 : xsgetn(char_type* __s, streamsize __n);
352 :
353 : virtual streamsize
354 : xsputn(const char_type* __s, streamsize __n);
355 :
356 : // Flushes output buffer, then writes unshift sequence.
357 : bool
358 : _M_terminate_output();
359 :
360 : /**
361 : * @if maint
362 : * This function sets the pointers of the internal buffer, both get
363 : * and put areas. Typically:
364 : *
365 : * __off == egptr() - eback() upon underflow/uflow ('read' mode);
366 : * __off == 0 upon overflow ('write' mode);
367 : * __off == -1 upon open, setbuf, seekoff/pos ('uncommitted' mode).
368 : *
369 : * NB: epptr() - pbase() == _M_buf_size - 1, since _M_buf_size
370 : * reflects the actual allocated memory and the last cell is reserved
371 : * for the overflow char of a full put area.
372 : * @endif
373 : */
374 : void
375 : _M_set_buffer(streamsize __off)
376 : {
377 : const bool __testin = _M_mode & ios_base::in;
378 : const bool __testout = _M_mode & ios_base::out;
379 :
380 : if (__testin && __off > 0)
381 : this->setg(_M_buf, _M_buf, _M_buf + __off);
382 : else
383 : this->setg(_M_buf, _M_buf, _M_buf);
384 :
385 : if (__testout && __off == 0 && _M_buf_size > 1 )
386 : this->setp(_M_buf, _M_buf + _M_buf_size - 1);
387 : else
388 : this->setp(NULL, NULL);
389 : }
390 : };
391 :
392 : // [27.8.1.5] Template class basic_ifstream
393 : /**
394 : * @brief Controlling input for files.
395 : *
396 : * This class supports reading from named files, using the inherited
397 : * functions from std::basic_istream. To control the associated
398 : * sequence, an instance of std::basic_filebuf is used, which this page
399 : * refers to as @c sb.
400 : */
401 : template<typename _CharT, typename _Traits>
402 : class basic_ifstream : public basic_istream<_CharT, _Traits>
403 : {
404 : public:
405 : // Types:
406 : typedef _CharT char_type;
407 : typedef _Traits traits_type;
408 : typedef typename traits_type::int_type int_type;
409 : typedef typename traits_type::pos_type pos_type;
410 : typedef typename traits_type::off_type off_type;
411 :
412 : // Non-standard types:
413 : typedef basic_filebuf<char_type, traits_type> __filebuf_type;
414 : typedef basic_istream<char_type, traits_type> __istream_type;
415 :
416 : private:
417 : __filebuf_type _M_filebuf;
418 :
419 : public:
420 : // Constructors/Destructors:
421 : /**
422 : * @brief Default constructor.
423 : *
424 : * Initializes @c sb using its default constructor, and passes
425 : * @c &sb to the base class initializer. Does not open any files
426 : * (you haven't given it a filename to open).
427 : */
428 : basic_ifstream() : __istream_type(), _M_filebuf()
429 : { this->init(&_M_filebuf); }
430 :
431 : /**
432 : * @brief Create an input file stream.
433 : * @param s Null terminated string specifying the filename.
434 : * @param mode Open file in specified mode (see std::ios_base).
435 : *
436 : * @c ios_base::in is automatically included in @a mode.
437 : *
438 : * Tip: When using std::string to hold the filename, you must use
439 : * .c_str() before passing it to this constructor.
440 : */
441 : explicit
442 : basic_ifstream(const char* __s, ios_base::openmode __mode = ios_base::in)
443 : : __istream_type(), _M_filebuf()
444 : {
445 : this->init(&_M_filebuf);
446 : this->open(__s, __mode);
447 : }
448 :
449 : /**
450 : * @brief The destructor does nothing.
451 : *
452 : * The file is closed by the filebuf object, not the formatting
453 : * stream.
454 : */
455 : ~basic_ifstream()
456 : { }
457 :
458 : // Members:
459 : /**
460 : * @brief Accessing the underlying buffer.
461 : * @return The current basic_filebuf buffer.
462 : *
463 : * This hides both signatures of std::basic_ios::rdbuf().
464 : */
465 : __filebuf_type*
466 : rdbuf() const
467 : { return const_cast<__filebuf_type*>(&_M_filebuf); }
468 :
469 : /**
470 : * @brief Wrapper to test for an open file.
471 : * @return @c rdbuf()->is_open()
472 : */
473 : bool
474 : is_open()
475 : { return _M_filebuf.is_open(); }
476 :
477 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
478 : // 365. Lack of const-qualification in clause 27
479 : bool
480 : is_open() const
481 : { return _M_filebuf.is_open(); }
482 :
483 : /**
484 : * @brief Opens an external file.
485 : * @param s The name of the file.
486 : * @param mode The open mode flags.
487 : *
488 : * Calls @c std::basic_filebuf::open(s,mode|in). If that function
489 : * fails, @c failbit is set in the stream's error state.
490 : *
491 : * Tip: When using std::string to hold the filename, you must use
492 : * .c_str() before passing it to this constructor.
493 : */
494 : void
495 : open(const char* __s, ios_base::openmode __mode = ios_base::in)
496 : {
497 : if (!_M_filebuf.open(__s, __mode | ios_base::in))
498 : this->setstate(ios_base::failbit);
499 : else
500 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
501 : // 409. Closing an fstream should clear error state
502 : this->clear();
503 : }
504 :
505 : /**
506 : * @brief Close the file.
507 : *
508 : * Calls @c std::basic_filebuf::close(). If that function
509 : * fails, @c failbit is set in the stream's error state.
510 : */
511 : void
512 : close()
513 : {
514 : if (!_M_filebuf.close())
515 : this->setstate(ios_base::failbit);
516 : }
517 : };
518 :
519 :
520 : // [27.8.1.8] Template class basic_ofstream
521 : /**
522 : * @brief Controlling output for files.
523 : *
524 : * This class supports reading from named files, using the inherited
525 : * functions from std::basic_ostream. To control the associated
526 : * sequence, an instance of std::basic_filebuf is used, which this page
527 : * refers to as @c sb.
528 : */
529 : template<typename _CharT, typename _Traits>
530 : class basic_ofstream : public basic_ostream<_CharT,_Traits>
531 : {
532 : public:
533 : // Types:
534 : typedef _CharT char_type;
535 : typedef _Traits traits_type;
536 : typedef typename traits_type::int_type int_type;
537 : typedef typename traits_type::pos_type pos_type;
538 : typedef typename traits_type::off_type off_type;
539 :
540 : // Non-standard types:
541 : typedef basic_filebuf<char_type, traits_type> __filebuf_type;
542 : typedef basic_ostream<char_type, traits_type> __ostream_type;
543 :
544 : private:
545 : __filebuf_type _M_filebuf;
546 :
547 : public:
548 : // Constructors:
549 : /**
550 : * @brief Default constructor.
551 : *
552 : * Initializes @c sb using its default constructor, and passes
553 : * @c &sb to the base class initializer. Does not open any files
554 : * (you haven't given it a filename to open).
555 : */
556 674 : basic_ofstream(): __ostream_type(), _M_filebuf()
557 233 : { this->init(&_M_filebuf); }
558 :
559 : /**
560 : * @brief Create an output file stream.
561 : * @param s Null terminated string specifying the filename.
562 : * @param mode Open file in specified mode (see std::ios_base).
563 : *
564 : * @c ios_base::out|ios_base::trunc is automatically included in
565 : * @a mode.
566 : *
567 : * Tip: When using std::string to hold the filename, you must use
568 : * .c_str() before passing it to this constructor.
569 : */
570 : explicit
571 : basic_ofstream(const char* __s,
572 : ios_base::openmode __mode = ios_base::out|ios_base::trunc)
573 : : __ostream_type(), _M_filebuf()
574 : {
575 : this->init(&_M_filebuf);
576 : this->open(__s, __mode);
577 : }
578 :
579 : /**
580 : * @brief The destructor does nothing.
581 : *
582 : * The file is closed by the filebuf object, not the formatting
583 : * stream.
584 : */
585 : ~basic_ofstream()
586 115 : { }
587 :
588 : // Members:
589 : /**
590 : * @brief Accessing the underlying buffer.
591 : * @return The current basic_filebuf buffer.
592 : *
593 : * This hides both signatures of std::basic_ios::rdbuf().
594 : */
595 : __filebuf_type*
596 : rdbuf() const
597 : { return const_cast<__filebuf_type*>(&_M_filebuf); }
598 :
599 : /**
600 : * @brief Wrapper to test for an open file.
601 : * @return @c rdbuf()->is_open()
602 : */
603 : bool
604 : is_open()
605 : { return _M_filebuf.is_open(); }
606 :
607 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
608 : // 365. Lack of const-qualification in clause 27
609 : bool
610 : is_open() const
611 : { return _M_filebuf.is_open(); }
612 :
613 : /**
614 : * @brief Opens an external file.
615 : * @param s The name of the file.
616 : * @param mode The open mode flags.
617 : *
618 : * Calls @c std::basic_filebuf::open(s,mode|out|trunc). If that
619 : * function fails, @c failbit is set in the stream's error state.
620 : *
621 : * Tip: When using std::string to hold the filename, you must use
622 : * .c_str() before passing it to this constructor.
623 : */
624 : void
625 : open(const char* __s,
626 : ios_base::openmode __mode = ios_base::out | ios_base::trunc)
627 : {
628 233 : if (!_M_filebuf.open(__s, __mode | ios_base::out))
629 0 : this->setstate(ios_base::failbit);
630 : else
631 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
632 : // 409. Closing an fstream should clear error state
633 233 : this->clear();
634 : }
635 :
636 : /**
637 : * @brief Close the file.
638 : *
639 : * Calls @c std::basic_filebuf::close(). If that function
640 : * fails, @c failbit is set in the stream's error state.
641 : */
642 : void
643 : close()
644 : {
645 233 : if (!_M_filebuf.close())
646 0 : this->setstate(ios_base::failbit);
647 : }
648 : };
649 :
650 :
651 : // [27.8.1.11] Template class basic_fstream
652 : /**
653 : * @brief Controlling intput and output for files.
654 : *
655 : * This class supports reading from and writing to named files, using
656 : * the inherited functions from std::basic_iostream. To control the
657 : * associated sequence, an instance of std::basic_filebuf is used, which
658 : * this page refers to as @c sb.
659 : */
660 : template<typename _CharT, typename _Traits>
661 : class basic_fstream : public basic_iostream<_CharT, _Traits>
662 : {
663 : public:
664 : // Types:
665 : typedef _CharT char_type;
666 : typedef _Traits traits_type;
667 : typedef typename traits_type::int_type int_type;
668 : typedef typename traits_type::pos_type pos_type;
669 : typedef typename traits_type::off_type off_type;
670 :
671 : // Non-standard types:
672 : typedef basic_filebuf<char_type, traits_type> __filebuf_type;
673 : typedef basic_ios<char_type, traits_type> __ios_type;
674 : typedef basic_iostream<char_type, traits_type> __iostream_type;
675 :
676 : private:
677 : __filebuf_type _M_filebuf;
678 :
679 : public:
680 : // Constructors/destructor:
681 : /**
682 : * @brief Default constructor.
683 : *
684 : * Initializes @c sb using its default constructor, and passes
685 : * @c &sb to the base class initializer. Does not open any files
686 : * (you haven't given it a filename to open).
687 : */
688 : basic_fstream()
689 : : __iostream_type(), _M_filebuf()
690 : { this->init(&_M_filebuf); }
691 :
692 : /**
693 : * @brief Create an input/output file stream.
694 : * @param s Null terminated string specifying the filename.
695 : * @param mode Open file in specified mode (see std::ios_base).
696 : *
697 : * Tip: When using std::string to hold the filename, you must use
698 : * .c_str() before passing it to this constructor.
699 : */
700 : explicit
701 : basic_fstream(const char* __s,
702 : ios_base::openmode __mode = ios_base::in | ios_base::out)
703 : : __iostream_type(NULL), _M_filebuf()
704 : {
705 : this->init(&_M_filebuf);
706 : this->open(__s, __mode);
707 : }
708 :
709 : /**
710 : * @brief The destructor does nothing.
711 : *
712 : * The file is closed by the filebuf object, not the formatting
713 : * stream.
714 : */
715 : ~basic_fstream()
716 : { }
717 :
718 : // Members:
719 : /**
720 : * @brief Accessing the underlying buffer.
721 : * @return The current basic_filebuf buffer.
722 : *
723 : * This hides both signatures of std::basic_ios::rdbuf().
724 : */
725 : __filebuf_type*
726 : rdbuf() const
727 : { return const_cast<__filebuf_type*>(&_M_filebuf); }
728 :
729 : /**
730 : * @brief Wrapper to test for an open file.
731 : * @return @c rdbuf()->is_open()
732 : */
733 : bool
734 : is_open()
735 : { return _M_filebuf.is_open(); }
736 :
737 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
738 : // 365. Lack of const-qualification in clause 27
739 : bool
740 : is_open() const
741 : { return _M_filebuf.is_open(); }
742 :
743 : /**
744 : * @brief Opens an external file.
745 : * @param s The name of the file.
746 : * @param mode The open mode flags.
747 : *
748 : * Calls @c std::basic_filebuf::open(s,mode). If that
749 : * function fails, @c failbit is set in the stream's error state.
750 : *
751 : * Tip: When using std::string to hold the filename, you must use
752 : * .c_str() before passing it to this constructor.
753 : */
754 : void
755 : open(const char* __s,
756 : ios_base::openmode __mode = ios_base::in | ios_base::out)
757 : {
758 : if (!_M_filebuf.open(__s, __mode))
759 : this->setstate(ios_base::failbit);
760 : else
761 : // _GLIBCXX_RESOLVE_LIB_DEFECTS
762 : // 409. Closing an fstream should clear error state
763 : this->clear();
764 : }
765 :
766 : /**
767 : * @brief Close the file.
768 : *
769 : * Calls @c std::basic_filebuf::close(). If that function
770 : * fails, @c failbit is set in the stream's error state.
771 : */
772 : void
773 : close()
774 : {
775 : if (!_M_filebuf.close())
776 : this->setstate(ios_base::failbit);
777 : }
778 : };
779 : } // namespace std
780 :
781 : #ifndef _GLIBCXX_EXPORT_TEMPLATE
782 : # include <bits/fstream.tcc>
783 : #endif
784 :
785 : #endif /* _GLIBCXX_FSTREAM */
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