1 // Output streams -*- C++ -*-
3 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003
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, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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
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.
167 operator<<(long __n
);
170 operator<<(unsigned long __n
);
173 operator<<(bool __n
);
176 operator<<(short __n
)
178 ios_base::fmtflags __fmt
= this->flags() & ios_base::basefield
;
179 if (__fmt
& ios_base::oct
|| __fmt
& ios_base::hex
)
180 return this->operator<<(static_cast<unsigned long>
181 (static_cast<unsigned short>(__n
)));
183 return this->operator<<(static_cast<long>(__n
));
187 operator<<(unsigned short __n
)
188 { return this->operator<<(static_cast<unsigned long>(__n
)); }
193 ios_base::fmtflags __fmt
= this->flags() & ios_base::basefield
;
194 if (__fmt
& ios_base::oct
|| __fmt
& ios_base::hex
)
195 return this->operator<<(static_cast<unsigned long>
196 (static_cast<unsigned int>(__n
)));
198 return this->operator<<(static_cast<long>(__n
));
202 operator<<(unsigned int __n
)
203 { return this->operator<<(static_cast<unsigned long>(__n
)); }
205 #ifdef _GLIBCXX_USE_LONG_LONG
207 operator<<(long long __n
);
210 operator<<(unsigned long long __n
);
214 operator<<(double __f
);
217 operator<<(float __f
)
218 { return this->operator<<(static_cast<double>(__f
)); }
221 operator<<(long double __f
);
224 operator<<(const void* __p
);
227 * @brief Extracting from another streambuf.
228 * @param sb A pointer to a streambuf
230 * This function behaves like one of the basic arithmetic extractors,
231 * in that it also constructs a sentry object and has the same error
234 * If @a sb is NULL, the stream will set failbit in its error state.
236 * Characters are extracted from @a sb and inserted into @c *this
237 * until one of the following occurs:
239 * - the input stream reaches end-of-file,
240 * - insertion into the output sequence fails (in this case, the
241 * character that would have been inserted is not extracted), or
242 * - an exception occurs while getting a character from @a sb, which
243 * sets failbit in the error state
245 * If the function inserts no characters, failbit is set.
248 operator<<(__streambuf_type
* __sb
);
251 // [27.6.2.6] unformatted output functions
253 * @name Unformatted Output Functions
255 * All the unformatted output functions have some common behavior.
256 * Each starts by constructing a temporary object of type
257 * std::basic_ostream::sentry. This has several effects, concluding
258 * with the setting of a status flag; see the sentry documentation
261 * If the sentry status is good, the function tries to generate
262 * whatever data is appropriate for the type of the argument.
264 * If an exception is thrown during insertion, ios_base::badbit
265 * will be turned on in the stream's error state. If badbit is on in
266 * the stream's exceptions mask, the exception will be rethrown
267 * without completing its actions.
271 * @brief Simple insertion.
272 * @param c The character to insert.
275 * Tries to insert @a c.
277 * @note This function is not overloaded on signed char and
283 // Core write functionality, without sentry.
285 _M_write(const char_type
* __s
, streamsize __n
)
287 streamsize __put
= this->rdbuf()->sputn(__s
, __n
);
289 this->setstate(ios_base::badbit
);
293 * @brief Character string insertion.
294 * @param s The array to insert.
295 * @param n Maximum number of characters to insert.
298 * Characters are copied from @a s and inserted into the stream until
299 * one of the following happens:
301 * - @a n characters are inserted
302 * - inserting into the output sequence fails (in this case, badbit
303 * will be set in the stream's error state)
305 * @note This function is not overloaded on signed char and
309 write(const char_type
* __s
, streamsize __n
);
313 * @brief Synchronizing the stream buffer.
316 * If @c rdbuf() is a null pointer, changes nothing.
318 * Otherwise, calls @c rdbuf()->pubsync(), and if that returns -1,
324 // [27.6.2.4] seek members
326 * @brief Getting the current write position.
327 * @return A file position object.
329 * If @c fail() is not false, returns @c pos_type(-1) to indicate
330 * failure. Otherwise returns @c rdbuf()->pubseekoff(0,cur,out).
336 * @brief Changing the current write position.
337 * @param pos A file position object.
340 * If @c fail() is not true, calls @c rdbuf()->pubseekpos(pos). If
341 * that function fails, sets failbit.
347 * @brief Changing the current write position.
348 * @param off A file offset object.
349 * @param dir The direction in which to seek.
352 * If @c fail() is not true, calls @c rdbuf()->pubseekoff(off,dir).
353 * If that function fails, sets failbit.
356 seekp(off_type
, ios_base::seekdir
);
364 * @brief Performs setup work for output streams.
366 * Objects of this class are created before all of the standard
367 * inserters are run. It is responsible for "exception-safe prefix and
368 * suffix operations." Additional actions may be added by the
369 * implementation, and we list them in
370 * http://gcc.gnu.org/onlinedocs/libstdc++/17_intro/howto.html#5
371 * under [27.6] notes.
373 template <typename _CharT
, typename _Traits
>
374 class basic_ostream
<_CharT
, _Traits
>::sentry
378 basic_ostream
<_CharT
,_Traits
>& _M_os
;
382 * @brief The constructor performs preparatory work.
383 * @param os The output stream to guard.
385 * If the stream state is good (@a os.good() is true), then if the
386 * stream is tied to another output stream, @c is.tie()->flush()
387 * is called to synchronize the output sequences.
389 * If the stream state is still good, then the sentry state becomes
393 sentry(basic_ostream
<_CharT
,_Traits
>& __os
);
396 * @brief Possibly flushes the stream.
398 * If @c ios_base::unitbuf is set in @c os.flags(), and
399 * @c std::uncaught_exception() is true, the sentry destructor calls
400 * @c flush() on the output stream.
405 if (_M_os
.flags() & ios_base::unitbuf
&& !uncaught_exception())
407 // Can't call flush directly or else will get into recursive lock.
408 if (_M_os
.rdbuf() && _M_os
.rdbuf()->pubsync() == -1)
409 _M_os
.setstate(ios_base::badbit
);
414 * @brief Quick status checking.
415 * @return The sentry state.
417 * For ease of use, sentries may be converted to booleans. The
418 * return value is that of the sentry state (true == okay).
420 operator bool() const
424 // [27.6.2.5.4] character insertion templates
427 * @brief Character inserters
428 * @param out An output stream.
429 * @param c A character.
432 * Behaves like one of the formatted arithmetic inserters described in
433 * std::basic_ostream. After constructing a sentry object with good
434 * status, this function inserts a single character and any required
435 * padding (as determined by [22.2.2.2.2]). @c out.width(0) is then
438 * If @a c is of type @c char and the character type of the stream is not
439 * @c char, the character is widened before insertion.
441 template<typename _CharT
, typename _Traits
>
442 basic_ostream
<_CharT
, _Traits
>&
443 operator<<(basic_ostream
<_CharT
, _Traits
>& __out
, _CharT __c
);
445 template<typename _CharT
, typename _Traits
>
446 basic_ostream
<_CharT
, _Traits
>&
447 operator<<(basic_ostream
<_CharT
, _Traits
>& __out
, char __c
)
448 { return (__out
<< __out
.widen(__c
)); }
451 template <class _Traits
>
452 basic_ostream
<char, _Traits
>&
453 operator<<(basic_ostream
<char, _Traits
>& __out
, char __c
);
455 // Signed and unsigned
456 template<class _Traits
>
457 basic_ostream
<char, _Traits
>&
458 operator<<(basic_ostream
<char, _Traits
>& __out
, signed char __c
)
459 { return (__out
<< static_cast<char>(__c
)); }
461 template<class _Traits
>
462 basic_ostream
<char, _Traits
>&
463 operator<<(basic_ostream
<char, _Traits
>& __out
, unsigned char __c
)
464 { return (__out
<< static_cast<char>(__c
)); }
469 * @brief String inserters
470 * @param out An output stream.
471 * @param s A character string.
473 * @pre @a s must be a non-NULL pointer
475 * Behaves like one of the formatted arithmetic inserters described in
476 * std::basic_ostream. After constructing a sentry object with good
477 * status, this function inserts @c traits::length(s) characters starting
478 * at @a s, widened if necessary, followed by any required padding (as
479 * determined by [22.2.2.2.2]). @c out.width(0) is then called.
481 template<typename _CharT
, typename _Traits
>
482 basic_ostream
<_CharT
, _Traits
>&
483 operator<<(basic_ostream
<_CharT
, _Traits
>& __out
, const _CharT
* __s
);
485 template<typename _CharT
, typename _Traits
>
486 basic_ostream
<_CharT
, _Traits
> &
487 operator<<(basic_ostream
<_CharT
, _Traits
>& __out
, const char* __s
);
489 // Partial specializationss
490 template<class _Traits
>
491 basic_ostream
<char, _Traits
>&
492 operator<<(basic_ostream
<char, _Traits
>& __out
, const char* __s
);
494 // Signed and unsigned
495 template<class _Traits
>
496 basic_ostream
<char, _Traits
>&
497 operator<<(basic_ostream
<char, _Traits
>& __out
, const signed char* __s
)
498 { return (__out
<< reinterpret_cast<const char*>(__s
)); }
500 template<class _Traits
>
501 basic_ostream
<char, _Traits
> &
502 operator<<(basic_ostream
<char, _Traits
>& __out
, const unsigned char* __s
)
503 { return (__out
<< reinterpret_cast<const char*>(__s
)); }
506 // [27.6.2.7] standard basic_ostream manipulators
508 * @brief Write a newline and flush the stream.
510 * This manipulator is often mistakenly used when a simple newline is
511 * desired, leading to poor buffering performance. See
512 * http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html#2 for more
515 template<typename _CharT
, typename _Traits
>
516 basic_ostream
<_CharT
, _Traits
>&
517 endl(basic_ostream
<_CharT
, _Traits
>& __os
)
518 { return flush(__os
.put(__os
.widen('\n'))); }
521 * @brief Write a null character into the output sequence.
523 * "Null character" is @c CharT() by definition. For CharT of @c char,
524 * this correctly writes the ASCII @c NUL character string terminator.
526 template<typename _CharT
, typename _Traits
>
527 basic_ostream
<_CharT
, _Traits
>&
528 ends(basic_ostream
<_CharT
, _Traits
>& __os
)
529 { return __os
.put(_CharT()); }
532 * @brief Flushes the output stream.
534 * This manipulator simply calls the stream's @c flush() member function.
536 template<typename _CharT
, typename _Traits
>
537 basic_ostream
<_CharT
, _Traits
>&
538 flush(basic_ostream
<_CharT
, _Traits
>& __os
)
539 { return __os
.flush(); }
543 #ifndef _GLIBCXX_EXPORT_TEMPLATE
544 # include <bits/ostream.tcc>
547 #endif /* _GLIBCXX_OSTREAM */