1 // Iostreams base classes -*- C++ -*-
3 // Copyright (C) 1997, 1998, 1999, 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
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13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
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15 // GNU General Public License for more details.
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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
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29 // the GNU General Public License.
32 * This is an internal header file, included by other library headers.
33 * You should not attempt to use it directly.
37 #define _BASIC_IOS_H 1
39 #pragma GCC system_header
41 #include <bits/streambuf_iterator.h>
42 #include <bits/localefwd.h>
43 #include <bits/locale_classes.h>
44 #include <bits/locale_facets.h>
48 // 27.4.5 Template class basic_ios
50 * @brief Virtual base class for all stream classes.
52 * Most of the member functions called dispatched on stream objects
53 * (e.g., @c std::cout.foo(bar);) are consolidated in this class.
55 template<typename _CharT, typename _Traits>
56 class basic_ios : public ios_base
61 * These are standard types. They permit a standardized way of
62 * referring to names of (or names dependant on) the template
63 * parameters, which are specific to the implementation.
65 typedef _CharT char_type;
66 typedef typename _Traits::int_type int_type;
67 typedef typename _Traits::pos_type pos_type;
68 typedef typename _Traits::off_type off_type;
69 typedef _Traits traits_type;
75 * These are non-standard types.
78 typedef ctype<_CharT> __ctype_type;
79 typedef num_put<_CharT, ostreambuf_iterator<_CharT, _Traits> >
81 typedef num_get<_CharT, istreambuf_iterator<_CharT, _Traits> >
87 basic_ostream<_CharT, _Traits>* _M_tie;
88 mutable char_type _M_fill;
89 mutable bool _M_fill_init;
90 basic_streambuf<_CharT, _Traits>* _M_streambuf;
92 // Cached use_facet<ctype>, which is based on the current locale info.
93 const __ctype_type* _M_ctype;
95 const __num_put_type* _M_num_put;
97 const __num_get_type* _M_num_get;
102 * @brief The quick-and-easy status check.
104 * This allows you to write constructs such as
105 * "if (!a_stream) ..." and "while (a_stream) ..."
107 operator void*() const
108 { return this->fail() ? 0 : const_cast<basic_ios*>(this); }
112 { return this->fail(); }
116 * @brief Returns the error state of the stream buffer.
117 * @return A bit pattern (well, isn't everything?)
119 * See std::ios_base::iostate for the possible bit values. Most
120 * users will call one of the interpreting wrappers, e.g., good().
124 { return _M_streambuf_state; }
127 * @brief [Re]sets the error state.
128 * @param state The new state flag(s) to set.
130 * See std::ios_base::iostate for the possible bit values. Most
131 * users will not need to pass an argument.
134 clear(iostate __state = goodbit);
137 * @brief Sets additional flags in the error state.
138 * @param state The additional state flag(s) to set.
140 * See std::ios_base::iostate for the possible bit values.
143 setstate(iostate __state)
144 { this->clear(this->rdstate() | __state); }
146 // Flip the internal state on for the proper state bits, then re
147 // throws the propagated exception if bit also set in
150 _M_setstate(iostate __state)
152 // 27.6.1.2.1 Common requirements.
153 // Turn this on without causing an ios::failure to be thrown.
154 _M_streambuf_state |= __state;
155 if (this->exceptions() & __state)
156 __throw_exception_again;
160 * @brief Fast error checking.
161 * @return True if no error flags are set.
163 * A wrapper around rdstate.
167 { return this->rdstate() == 0; }
170 * @brief Fast error checking.
171 * @return True if the eofbit is set.
173 * Note that other iostate flags may also be set.
177 { return (this->rdstate() & eofbit) != 0; }
180 * @brief Fast error checking.
181 * @return True if either the badbit or the failbit is set.
183 * Checking the badbit in fail() is historical practice.
184 * Note that other iostate flags may also be set.
188 { return (this->rdstate() & (badbit | failbit)) != 0; }
191 * @brief Fast error checking.
192 * @return True if the badbit is set.
194 * Note that other iostate flags may also be set.
198 { return (this->rdstate() & badbit) != 0; }
201 * @brief Throwing exceptions on errors.
202 * @return The current exceptions mask.
204 * This changes nothing in the stream. See the one-argument version
205 * of exceptions(iostate) for the meaning of the return value.
209 { return _M_exception; }
212 * @brief Throwing exceptions on errors.
213 * @param except The new exceptions mask.
215 * By default, error flags are set silently. You can set an
216 * exceptions mask for each stream; if a bit in the mask becomes set
217 * in the error flags, then an exception of type
218 * std::ios_base::failure is thrown.
220 * If the error flage is already set when the exceptions mask is
221 * added, the exception is immediately thrown. Try running the
222 * following under GCC 3.1 or later:
224 * #include <iostream>
226 * #include <exception>
230 * std::set_terminate (__gnu_cxx::__verbose_terminate_handler);
232 * std::ifstream f ("/etc/motd");
234 * std::cerr << "Setting badbit\n";
235 * f.setstate (std::ios_base::badbit);
237 * std::cerr << "Setting exception mask\n";
238 * f.exceptions (std::ios_base::badbit);
243 exceptions(iostate __except)
245 _M_exception = __except;
246 this->clear(_M_streambuf_state);
249 // Constructor/destructor:
251 * @brief Constructor performs initialization.
253 * The parameter is passed by derived streams.
256 basic_ios(basic_streambuf<_CharT, _Traits>* __sb)
257 : ios_base(), _M_ctype(0), _M_num_put(0), _M_num_get(0)
258 { this->init(__sb); }
263 * The destructor does nothing. More specifically, it does not
264 * destroy the streambuf held by rdbuf().
271 * @brief Fetches the current @e tied stream.
272 * @return A pointer to the tied stream, or NULL if the stream is
275 * A stream may be @e tied (or synchronized) to a second output
276 * stream. When this stream performs any I/O, the tied stream is
277 * first flushed. For example, @c std::cin is tied to @c std::cout.
279 basic_ostream<_CharT, _Traits>*
284 * @brief Ties this stream to an output stream.
285 * @param tiestr The output stream.
286 * @return The previously tied output stream, or NULL if the stream
289 * This sets up a new tie; see tie() for more.
291 basic_ostream<_CharT, _Traits>*
292 tie(basic_ostream<_CharT, _Traits>* __tiestr)
294 basic_ostream<_CharT, _Traits>* __old = _M_tie;
300 * @brief Accessing the underlying buffer.
301 * @return The current stream buffer.
303 * This does not change the state of the stream.
305 basic_streambuf<_CharT, _Traits>*
307 { return _M_streambuf; }
310 * @brief Changing the underlying buffer.
311 * @param sb The new stream buffer.
312 * @return The previous stream buffer.
314 * Associates a new buffer with the current stream, and clears the
317 * Due to historical accidents which the LWG refuses to correct, the
318 * I/O library suffers from a design error: this function is hidden
319 * in derived classes by overrides of the zero-argument @c rdbuf(),
320 * which is non-virtual for hysterical raisins. As a result, you
321 * must use explicit qualifications to access this function via any
322 * derived class. For example:
325 * std::fstream foo; // or some other derived type
326 * std::streambuf* p = .....;
328 * foo.ios::rdbuf(p); // ios == basic_ios<char>
331 basic_streambuf<_CharT, _Traits>*
332 rdbuf(basic_streambuf<_CharT, _Traits>* __sb);
335 * @brief Copies fields of __rhs into this.
336 * @param __rhs The source values for the copies.
337 * @return Reference to this object.
339 * All fields of __rhs are copied into this object except that rdbuf()
340 * and rdstate() remain unchanged. All values in the pword and iword
341 * arrays are copied. Before copying, each callback is invoked with
342 * erase_event. After copying, each (new) callback is invoked with
343 * copyfmt_event. The final step is to copy exceptions().
346 copyfmt(const basic_ios& __rhs);
349 * @brief Retreives the "empty" character.
350 * @return The current fill character.
352 * It defaults to a space (' ') in the current locale.
359 _M_fill = this->widen(' ');
366 * @brief Sets a new "empty" character.
367 * @param ch The new character.
368 * @return The previous fill character.
370 * The fill character is used to fill out space when P+ characters
371 * have been requested (e.g., via setw), Q characters are actually
372 * used, and Q<P. It defaults to a space (' ') in the current locale.
377 char_type __old = this->fill();
384 * @brief Moves to a new locale.
385 * @param loc The new locale.
386 * @return The previous locale.
388 * Calls @c ios_base::imbue(loc), and if a stream buffer is associated
389 * with this stream, calls that buffer's @c pubimbue(loc).
391 * Additional l10n notes are at
392 * http://gcc.gnu.org/onlinedocs/libstdc++/22_locale/howto.html
395 imbue(const locale& __loc);
398 * @brief Squeezes characters.
399 * @param c The character to narrow.
400 * @param dfault The character to narrow.
401 * @return The narrowed character.
403 * Maps a character of @c char_type to a character of @c char,
406 * Returns the result of
408 * std::use_facet<ctype<char_type> >(getloc()).narrow(c,dfault)
411 * Additional l10n notes are at
412 * http://gcc.gnu.org/onlinedocs/libstdc++/22_locale/howto.html
415 narrow(char_type __c, char __dfault) const;
418 * @brief Widens characters.
419 * @param c The character to widen.
420 * @return The widened character.
422 * Maps a character of @c char to a character of @c char_type.
424 * Returns the result of
426 * std::use_facet<ctype<char_type> >(getloc()).widen(c)
429 * Additional l10n notes are at
430 * http://gcc.gnu.org/onlinedocs/libstdc++/22_locale/howto.html
433 widen(char __c) const;
436 // 27.4.5.1 basic_ios constructors
440 * The default constructor does nothing and is not normally
441 * accessible to users.
443 basic_ios() : ios_base(), _M_ctype(0), _M_num_put(0), _M_num_get(0)
447 * @brief All setup is performed here.
449 * This is called from the public constructor. It is not virtual and
450 * cannot be redefined.
453 init(basic_streambuf<_CharT, _Traits>* __sb);
456 _M_cache_locale(const locale& __loc);
460 #ifndef _GLIBCXX_EXPORT_TEMPLATE
461 #include <bits/basic_ios.tcc>
464 #endif /* _BASIC_IOS_H */