libstdc++-v3/include/std/iosfwd

// <iosfwd> Forward declarations -*- C++ -*-

// Copyright (C) 1997-2026 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
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// terms of the GNU General Public License as published by the
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// any later version.

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// 3.1, as published by the Free Software Foundation.

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/** @file include/iosfwd
 *  This is a Standard C++ Library header.
 */

//
// ISO C++ 14882: 27.2  Forward declarations
//

#ifndef _GLIBCXX_IOSFWD
#define _GLIBCXX_IOSFWD 1

#ifdef _GLIBCXX_SYSHDR
#pragma GCC system_header
#endif

#include <bits/requires_hosted.h> // iostreams

  /**
   *  @defgroup io I/O
   *
   *  Nearly all of the I/O classes are parameterized on the type of
   *  characters they read and write.  (The major exception is `ios_base` at
   *  the top of the hierarchy.)  This is a change from pre-Standard
   *  streams, which were not templates.
   *
   *  For ease of use and compatibility, all of the `basic_*` I/O-related
   *  classes are given typedef names for both of the builtin character
   *  widths (wide and narrow).  The typedefs are the same as the
   *  pre-Standard names, for example:
   *
   *  ```
   *     typedef basic_ifstream<char>  ifstream;
   *  ```
   *
   *  Because properly forward-declaring these classes can be difficult, you
   *  should not do it yourself.  Instead, include the `<iosfwd>`
   *  header, which contains only declarations of all the I/O classes as
   *  well as the typedefs.  Trying to forward-declare the typedefs
   *  themselves (e.g., `class ostream;`) is not valid ISO C++.
   *
   *  For more specific declarations, see
   *  https://gcc.gnu.org/onlinedocs/libstdc++/manual/io.html#std.io.objects
   */

#include <bits/iosfwd_file.h>
#include <bits/iosfwd_string.h>
#include <bits/iosfwd_sync.h>
#include <bits/iosfwd_span.h>

#endif /* _GLIBCXX_IOSFWD */