libstdc++
iosfwd
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1 // <iosfwd> Forward declarations -*- C++ -*-
2 
3 // Copyright (C) 1997-2025 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 /** @file include/iosfwd
26  * This is a Standard C++ Library header.
27  */
28 
29 //
30 // ISO C++ 14882: 27.2 Forward declarations
31 //
32 
33 #ifndef _GLIBCXX_IOSFWD
34 #define _GLIBCXX_IOSFWD 1
35 
36 #ifdef _GLIBCXX_SYSHDR
37 #pragma GCC system_header
38 #endif
39 
40 #include <bits/requires_hosted.h> // iostreams
41 
42 #include <bits/c++config.h>
43 #include <bits/stringfwd.h> // For string forward declarations.
44 #include <bits/postypes.h>
45 
46 namespace std _GLIBCXX_VISIBILITY(default)
47 {
48 _GLIBCXX_BEGIN_NAMESPACE_VERSION
49 
50  /**
51  * @defgroup io I/O
52  *
53  * Nearly all of the I/O classes are parameterized on the type of
54  * characters they read and write. (The major exception is ios_base at
55  * the top of the hierarchy.) This is a change from pre-Standard
56  * streams, which were not templates.
57  *
58  * For ease of use and compatibility, all of the basic_* I/O-related
59  * classes are given typedef names for both of the builtin character
60  * widths (wide and narrow). The typedefs are the same as the
61  * pre-Standard names, for example:
62  *
63  * @code
64  * typedef basic_ifstream<char> ifstream;
65  * @endcode
66  *
67  * Because properly forward-declaring these classes can be difficult, you
68  * should not do it yourself. Instead, include the &lt;iosfwd&gt;
69  * header, which contains only declarations of all the I/O classes as
70  * well as the typedefs. Trying to forward-declare the typedefs
71  * themselves (e.g., <code>class ostream;</code>) is not valid ISO C++.
72  *
73  * For more specific declarations, see
74  * https://gcc.gnu.org/onlinedocs/libstdc++/manual/io.html#std.io.objects
75  *
76  * @{
77  */
78  class ios_base;
79 
80  template<typename _CharT, typename _Traits = char_traits<_CharT> >
81  class basic_ios;
82 
83  template<typename _CharT, typename _Traits = char_traits<_CharT> >
84  class basic_streambuf;
85 
86  template<typename _CharT, typename _Traits = char_traits<_CharT> >
87  class basic_istream;
88 
89  template<typename _CharT, typename _Traits = char_traits<_CharT> >
90  class basic_ostream;
91 
92  template<typename _CharT, typename _Traits = char_traits<_CharT> >
93  class basic_iostream;
94 
95 
96 _GLIBCXX_BEGIN_NAMESPACE_CXX11
97 
98  template<typename _CharT, typename _Traits = char_traits<_CharT>,
99  typename _Alloc = allocator<_CharT> >
100  class basic_stringbuf;
101 
102  template<typename _CharT, typename _Traits = char_traits<_CharT>,
103  typename _Alloc = allocator<_CharT> >
104  class basic_istringstream;
105 
106  template<typename _CharT, typename _Traits = char_traits<_CharT>,
107  typename _Alloc = allocator<_CharT> >
108  class basic_ostringstream;
109 
110  template<typename _CharT, typename _Traits = char_traits<_CharT>,
111  typename _Alloc = allocator<_CharT> >
112  class basic_stringstream;
113 
114 _GLIBCXX_END_NAMESPACE_CXX11
115 
116  template<typename _CharT, typename _Traits = char_traits<_CharT> >
117  class basic_filebuf;
118 
119  template<typename _CharT, typename _Traits = char_traits<_CharT> >
120  class basic_ifstream;
121 
122  template<typename _CharT, typename _Traits = char_traits<_CharT> >
123  class basic_ofstream;
124 
125  template<typename _CharT, typename _Traits = char_traits<_CharT> >
126  class basic_fstream;
127 
128  template<typename _CharT, typename _Traits = char_traits<_CharT> >
129  class istreambuf_iterator;
130 
131  template<typename _CharT, typename _Traits = char_traits<_CharT> >
132  class ostreambuf_iterator;
133 
134 
135  /// Base class for @c char streams.
136  typedef basic_ios<char> ios;
137 
138  /// Base class for @c char buffers.
139  typedef basic_streambuf<char> streambuf;
140 
141  /// Base class for @c char input streams.
142  typedef basic_istream<char> istream;
143 
144  /// Base class for @c char output streams.
145  typedef basic_ostream<char> ostream;
146 
147  /// Base class for @c char mixed input and output streams.
148  typedef basic_iostream<char> iostream;
149 
150  /// Class for @c char memory buffers.
151  typedef basic_stringbuf<char> stringbuf;
152 
153  /// Class for @c char input memory streams.
154  typedef basic_istringstream<char> istringstream;
155 
156  /// Class for @c char output memory streams.
157  typedef basic_ostringstream<char> ostringstream;
158 
159  /// Class for @c char mixed input and output memory streams.
160  typedef basic_stringstream<char> stringstream;
161 
162  /// Class for @c char file buffers.
163  typedef basic_filebuf<char> filebuf;
164 
165  /// Class for @c char input file streams.
166  typedef basic_ifstream<char> ifstream;
167 
168  /// Class for @c char output file streams.
169  typedef basic_ofstream<char> ofstream;
170 
171  /// Class for @c char mixed input and output file streams.
172  typedef basic_fstream<char> fstream;
173 
174 #ifdef _GLIBCXX_USE_WCHAR_T
175  /// Base class for @c wchar_t streams.
176  typedef basic_ios<wchar_t> wios;
177 
178  /// Base class for @c wchar_t buffers.
179  typedef basic_streambuf<wchar_t> wstreambuf;
180 
181  /// Base class for @c wchar_t input streams.
182  typedef basic_istream<wchar_t> wistream;
183 
184  /// Base class for @c wchar_t output streams.
185  typedef basic_ostream<wchar_t> wostream;
186 
187  /// Base class for @c wchar_t mixed input and output streams.
188  typedef basic_iostream<wchar_t> wiostream;
189 
190  /// Class for @c wchar_t memory buffers.
191  typedef basic_stringbuf<wchar_t> wstringbuf;
192 
193  /// Class for @c wchar_t input memory streams.
194  typedef basic_istringstream<wchar_t> wistringstream;
195 
196  /// Class for @c wchar_t output memory streams.
197  typedef basic_ostringstream<wchar_t> wostringstream;
198 
199  /// Class for @c wchar_t mixed input and output memory streams.
200  typedef basic_stringstream<wchar_t> wstringstream;
201 
202  /// Class for @c wchar_t file buffers.
203  typedef basic_filebuf<wchar_t> wfilebuf;
204 
205  /// Class for @c wchar_t input file streams.
206  typedef basic_ifstream<wchar_t> wifstream;
207 
208  /// Class for @c wchar_t output file streams.
209  typedef basic_ofstream<wchar_t> wofstream;
210 
211  /// Class for @c wchar_t mixed input and output file streams.
212  typedef basic_fstream<wchar_t> wfstream;
213 #endif
214 
215 #if __cplusplus >= 202002L && _GLIBCXX_USE_CXX11_ABI
216  template<typename _CharT, typename _Traits = char_traits<_CharT>,
217  typename _Allocator = allocator<_CharT>>
218  class basic_syncbuf;
219  template<typename _CharT, typename _Traits = char_traits<_CharT>,
220  typename _Allocator = allocator<_CharT>>
221  class basic_osyncstream;
222 
223  using syncbuf = basic_syncbuf<char>;
224  using osyncstream = basic_osyncstream<char>;
225 
226 #ifdef _GLIBCXX_USE_WCHAR_T
227  using wsyncbuf = basic_syncbuf<wchar_t>;
228  using wosyncstream = basic_osyncstream<wchar_t>;
229 #endif
230 #endif // C++20 && CXX11_ABI
231 
232 #if __cplusplus > 202002L
233  template<typename _CharT, typename _Traits = char_traits<_CharT>>
234  class basic_spanbuf;
235  template<typename _CharT, typename _Traits = char_traits<_CharT>>
236  class basic_ispanstream;
237  template<typename _CharT, typename _Traits = char_traits<_CharT>>
238  class basic_ospanstream;
239  template<typename _CharT, typename _Traits = char_traits<_CharT>>
240  class basic_spanstream;
241 
242  using spanbuf = basic_spanbuf<char>;
243  using ispanstream = basic_ispanstream<char>;
244  using ospanstream = basic_ospanstream<char>;
245  using spanstream = basic_spanstream<char>;
246 
247 #ifdef _GLIBCXX_USE_WCHAR_T
248  using wspanbuf = basic_spanbuf<wchar_t>;
249  using wispanstream = basic_ispanstream<wchar_t>;
250  using wospanstream = basic_ospanstream<wchar_t>;
251  using wspanstream = basic_spanstream<wchar_t>;
252 #endif
253 #endif // C++23
254 
255  /** @} */
256 
257 _GLIBCXX_END_NAMESPACE_VERSION
258 } // namespace
259 
260 #endif /* _GLIBCXX_IOSFWD */