1 // Output streams -*- C++ -*-
3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2005, 2006
4 // Free Software Foundation, Inc.
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)
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.
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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
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.
32 // ISO C++ 14882: 27.6.2 Output streams
36 * This is a Standard C++ Library header.
39 #ifndef _GLIBCXX_OSTREAM
40 #define _GLIBCXX_OSTREAM 1
42 #pragma GCC system_header
46 _GLIBCXX_BEGIN_NAMESPACE(std
)
48 // [27.6.2.1] Template class basic_ostream
50 * @brief Controlling output.
52 * This is the base class for all output streams. It provides text
53 * formatting of all builtin types, and communicates with any class
54 * derived from basic_streambuf to do the actual output.
56 template<typename _CharT
, typename _Traits
>
57 class basic_ostream
: virtual public basic_ios
<_CharT
, _Traits
>
60 // Types (inherited from basic_ios (27.4.4)):
61 typedef _CharT char_type
;
62 typedef typename
_Traits::int_type int_type
;
63 typedef typename
_Traits::pos_type pos_type
;
64 typedef typename
_Traits::off_type off_type
;
65 typedef _Traits traits_type
;
67 // Non-standard Types:
68 typedef basic_streambuf
<_CharT
, _Traits
> __streambuf_type
;
69 typedef basic_ios
<_CharT
, _Traits
> __ios_type
;
70 typedef basic_ostream
<_CharT
, _Traits
> __ostream_type
;
71 typedef num_put
<_CharT
, ostreambuf_iterator
<_CharT
, _Traits
> >
73 typedef ctype
<_CharT
> __ctype_type
;
75 template<typename _CharT2
, typename _Traits2
>
76 friend basic_ostream
<_CharT2
, _Traits2
>&
77 operator<<(basic_ostream
<_CharT2
, _Traits2
>&, _CharT2
);
79 template<typename _Traits2
>
80 friend basic_ostream
<char, _Traits2
>&
81 operator<<(basic_ostream
<char, _Traits2
>&, char);
83 template<typename _CharT2
, typename _Traits2
>
84 friend basic_ostream
<_CharT2
, _Traits2
>&
85 operator<<(basic_ostream
<_CharT2
, _Traits2
>&, const _CharT2
*);
87 template<typename _Traits2
>
88 friend basic_ostream
<char, _Traits2
>&
89 operator<<(basic_ostream
<char, _Traits2
>&, const char*);
91 template<typename _CharT2
, typename _Traits2
>
92 friend basic_ostream
<_CharT2
, _Traits2
>&
93 operator<<(basic_ostream
<_CharT2
, _Traits2
>&, const char*);
95 // [27.6.2.2] constructor/destructor
97 * @brief Base constructor.
99 * This ctor is almost never called by the user directly, rather from
100 * derived classes' initialization lists, which pass a pointer to
101 * their own stream buffer.
104 basic_ostream(__streambuf_type
* __sb
)
105 { this->init(__sb
); }
108 * @brief Base destructor.
110 * This does very little apart from providing a virtual base dtor.
115 // [27.6.2.3] prefix/suffix
119 // [27.6.2.5] formatted output
120 // [27.6.2.5.3] basic_ostream::operator<<
123 * @brief Interface for manipulators.
125 * Manuipulators such as @c std::endl and @c std::hex use these
126 * functions in constructs like "std::cout << std::endl". For more
127 * information, see the iomanip header.
129 inline __ostream_type
&
130 operator<<(__ostream_type
& (*__pf
)(__ostream_type
&));
132 inline __ostream_type
&
133 operator<<(__ios_type
& (*__pf
)(__ios_type
&));
135 inline __ostream_type
&
136 operator<<(ios_base
& (*__pf
) (ios_base
&));
139 // [27.6.2.5.2] arithmetic inserters
141 * @name Arithmetic Inserters
143 * All the @c operator<< functions (aka <em>formatted output
144 * functions</em>) have some common behavior. Each starts by
145 * constructing a temporary object of type std::basic_ostream::sentry.
146 * This can have several effects, concluding with the setting of a
147 * status flag; see the sentry documentation for more.
149 * If the sentry status is good, the function tries to generate
150 * whatever data is appropriate for the type of the argument.
152 * If an exception is thrown during insertion, ios_base::badbit
153 * will be turned on in the stream's error state without causing an
154 * ios_base::failure to be thrown. The original exception will then
159 * @brief Basic arithmetic inserters
160 * @param A variable of builtin type.
161 * @return @c *this if successful
163 * These functions use the stream's current locale (specifically, the
164 * @c num_get facet) to perform numeric formatting.
168 { return _M_insert(__n
); }
171 operator<<(unsigned long __n
)
172 { return _M_insert(__n
); }
176 { return _M_insert(__n
); }
179 operator<<(short __n
);
182 operator<<(unsigned short __n
)
184 // _GLIBCXX_RESOLVE_LIB_DEFECTS
185 // 117. basic_ostream uses nonexistent num_put member functions.
186 return _M_insert(static_cast<unsigned long>(__n
));
193 operator<<(unsigned int __n
)
195 // _GLIBCXX_RESOLVE_LIB_DEFECTS
196 // 117. basic_ostream uses nonexistent num_put member functions.
197 return _M_insert(static_cast<unsigned long>(__n
));
200 #ifdef _GLIBCXX_USE_LONG_LONG
202 operator<<(long long __n
)
203 { return _M_insert(__n
); }
206 operator<<(unsigned long long __n
)
207 { return _M_insert(__n
); }
211 operator<<(double __f
)
212 { return _M_insert(__f
); }
215 operator<<(float __f
)
217 // _GLIBCXX_RESOLVE_LIB_DEFECTS
218 // 117. basic_ostream uses nonexistent num_put member functions.
219 return _M_insert(static_cast<double>(__f
));
223 operator<<(long double __f
)
224 { return _M_insert(__f
); }
227 operator<<(const void* __p
)
228 { return _M_insert(__p
); }
231 * @brief Extracting from another streambuf.
232 * @param sb A pointer to a streambuf
234 * This function behaves like one of the basic arithmetic extractors,
235 * in that it also constructs a sentry object and has the same error
238 * If @a sb is NULL, the stream will set failbit in its error state.
240 * Characters are extracted from @a sb and inserted into @c *this
241 * until one of the following occurs:
243 * - the input stream reaches end-of-file,
244 * - insertion into the output sequence fails (in this case, the
245 * character that would have been inserted is not extracted), or
246 * - an exception occurs while getting a character from @a sb, which
247 * sets failbit in the error state
249 * If the function inserts no characters, failbit is set.
252 operator<<(__streambuf_type
* __sb
);
255 // [27.6.2.6] unformatted output functions
257 * @name Unformatted Output Functions
259 * All the unformatted output functions have some common behavior.
260 * Each starts by constructing a temporary object of type
261 * std::basic_ostream::sentry. This has several effects, concluding
262 * with the setting of a status flag; see the sentry documentation
265 * If the sentry status is good, the function tries to generate
266 * whatever data is appropriate for the type of the argument.
268 * If an exception is thrown during insertion, ios_base::badbit
269 * will be turned on in the stream's error state. If badbit is on in
270 * the stream's exceptions mask, the exception will be rethrown
271 * without completing its actions.
275 * @brief Simple insertion.
276 * @param c The character to insert.
279 * Tries to insert @a c.
281 * @note This function is not overloaded on signed char and
287 // Core write functionality, without sentry.
289 _M_write(const char_type
* __s
, streamsize __n
)
291 streamsize __put
= this->rdbuf()->sputn(__s
, __n
);
293 this->setstate(ios_base::badbit
);
297 * @brief Character string insertion.
298 * @param s The array to insert.
299 * @param n Maximum number of characters to insert.
302 * Characters are copied from @a s and inserted into the stream until
303 * one of the following happens:
305 * - @a n characters are inserted
306 * - inserting into the output sequence fails (in this case, badbit
307 * will be set in the stream's error state)
309 * @note This function is not overloaded on signed char and
313 write(const char_type
* __s
, streamsize __n
);
317 * @brief Synchronizing the stream buffer.
320 * If @c rdbuf() is a null pointer, changes nothing.
322 * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1,
328 // [27.6.2.4] seek members
330 * @brief Getting the current write position.
331 * @return A file position object.
333 * If @c fail() is not false, returns @c pos_type(-1) to indicate
334 * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,out).
340 * @brief Changing the current write position.
341 * @param pos A file position object.
344 * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If
345 * that function fails, sets failbit.
351 * @brief Changing the current write position.
352 * @param off A file offset object.
353 * @param dir The direction in which to seek.
356 * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir).
357 * If that function fails, sets failbit.
360 seekp(off_type
, ios_base::seekdir
);
366 template<typename _ValueT
>
368 _M_insert(_ValueT __v
);
372 * @brief Performs setup work for output streams.
374 * Objects of this class are created before all of the standard
375 * inserters are run. It is responsible for "exception-safe prefix and
376 * suffix operations." Additional actions may be added by the
377 * implementation, and we list them in
378 * http://gcc.gnu.org/onlinedocs/libstdc++/17_intro/howto.html#5
379 * under [27.6] notes.
381 template <typename _CharT
, typename _Traits
>
382 class basic_ostream
<_CharT
, _Traits
>::sentry
386 basic_ostream
<_CharT
,_Traits
>& _M_os
;
390 * @brief The constructor performs preparatory work.
391 * @param os The output stream to guard.
393 * If the stream state is good (@a os.good() is true), then if the
394 * stream is tied to another output stream, @c is.tie()->flush()
395 * is called to synchronize the output sequences.
397 * If the stream state is still good, then the sentry state becomes
401 sentry(basic_ostream
<_CharT
,_Traits
>& __os
);
404 * @brief Possibly flushes the stream.
406 * If @c ios_base::unitbuf is set in @c os.flags(), and
407 * @c std::uncaught_exception() is true, the sentry destructor calls
408 * @c flush() on the output stream.
413 if (_M_os
.flags() & ios_base::unitbuf
&& !uncaught_exception())
415 // Can't call flush directly or else will get into recursive lock.
416 if (_M_os
.rdbuf() && _M_os
.rdbuf()->pubsync() == -1)
417 _M_os
.setstate(ios_base::badbit
);
422 * @brief Quick status checking.
423 * @return The sentry state.
425 * For ease of use, sentries may be converted to booleans. The
426 * return value is that of the sentry state (true == okay).
428 operator bool() const
432 // [27.6.2.5.4] character insertion templates
435 * @brief Character inserters
436 * @param out An output stream.
437 * @param c A character.
440 * Behaves like one of the formatted arithmetic inserters described in
441 * std::basic_ostream. After constructing a sentry object with good
442 * status, this function inserts a single character and any required
443 * padding (as determined by [22.2.2.2.2]). @c out.width(0) is then
446 * If @a c is of type @c char and the character type of the stream is not
447 * @c char, the character is widened before insertion.
449 template<typename _CharT
, typename _Traits
>
450 basic_ostream
<_CharT
, _Traits
>&
451 operator<<(basic_ostream
<_CharT
, _Traits
>& __out
, _CharT __c
);
453 template<typename _CharT
, typename _Traits
>
454 basic_ostream
<_CharT
, _Traits
>&
455 operator<<(basic_ostream
<_CharT
, _Traits
>& __out
, char __c
)
456 { return (__out
<< __out
.widen(__c
)); }
459 template <class _Traits
>
460 basic_ostream
<char, _Traits
>&
461 operator<<(basic_ostream
<char, _Traits
>& __out
, char __c
);
463 // Signed and unsigned
464 template<class _Traits
>
465 basic_ostream
<char, _Traits
>&
466 operator<<(basic_ostream
<char, _Traits
>& __out
, signed char __c
)
467 { return (__out
<< static_cast<char>(__c
)); }
469 template<class _Traits
>
470 basic_ostream
<char, _Traits
>&
471 operator<<(basic_ostream
<char, _Traits
>& __out
, unsigned char __c
)
472 { return (__out
<< static_cast<char>(__c
)); }
477 * @brief String inserters
478 * @param out An output stream.
479 * @param s A character string.
481 * @pre @a s must be a non-NULL pointer
483 * Behaves like one of the formatted arithmetic inserters described in
484 * std::basic_ostream. After constructing a sentry object with good
485 * status, this function inserts @c traits::length(s) characters starting
486 * at @a s, widened if necessary, followed by any required padding (as
487 * determined by [22.2.2.2.2]). @c out.width(0) is then called.
489 template<typename _CharT
, typename _Traits
>
490 basic_ostream
<_CharT
, _Traits
>&
491 operator<<(basic_ostream
<_CharT
, _Traits
>& __out
, const _CharT
* __s
);
493 template<typename _CharT
, typename _Traits
>
494 basic_ostream
<_CharT
, _Traits
> &
495 operator<<(basic_ostream
<_CharT
, _Traits
>& __out
, const char* __s
);
497 // Partial specializationss
498 template<class _Traits
>
499 basic_ostream
<char, _Traits
>&
500 operator<<(basic_ostream
<char, _Traits
>& __out
, const char* __s
);
502 // Signed and unsigned
503 template<class _Traits
>
504 basic_ostream
<char, _Traits
>&
505 operator<<(basic_ostream
<char, _Traits
>& __out
, const signed char* __s
)
506 { return (__out
<< reinterpret_cast<const char*>(__s
)); }
508 template<class _Traits
>
509 basic_ostream
<char, _Traits
> &
510 operator<<(basic_ostream
<char, _Traits
>& __out
, const unsigned char* __s
)
511 { return (__out
<< reinterpret_cast<const char*>(__s
)); }
514 // [27.6.2.7] standard basic_ostream manipulators
516 * @brief Write a newline and flush the stream.
518 * This manipulator is often mistakenly used when a simple newline is
519 * desired, leading to poor buffering performance. See
520 * http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#2 for more
523 template<typename _CharT
, typename _Traits
>
524 basic_ostream
<_CharT
, _Traits
>&
525 endl(basic_ostream
<_CharT
, _Traits
>& __os
)
526 { return flush(__os
.put(__os
.widen('\n'))); }
529 * @brief Write a null character into the output sequence.
531 * "Null character" is @c CharT() by definition. For CharT of @c char,
532 * this correctly writes the ASCII @c NUL character string terminator.
534 template<typename _CharT
, typename _Traits
>
535 basic_ostream
<_CharT
, _Traits
>&
536 ends(basic_ostream
<_CharT
, _Traits
>& __os
)
537 { return __os
.put(_CharT()); }
540 * @brief Flushes the output stream.
542 * This manipulator simply calls the stream's @c flush() member function.
544 template<typename _CharT
, typename _Traits
>
545 basic_ostream
<_CharT
, _Traits
>&
546 flush(basic_ostream
<_CharT
, _Traits
>& __os
)
547 { return __os
.flush(); }
549 _GLIBCXX_END_NAMESPACE
551 #ifndef _GLIBCXX_EXPORT_TEMPLATE
552 # include <bits/ostream.tcc>
555 #endif /* _GLIBCXX_OSTREAM */