gcc/libstdc++-v3/include/bits/stl_relops.h
Jonathan Wakely 5b965dc49a libstdc++: Update documentation comments for namespace rel_ops
The comments in <bits/stl_relops.h> describe problems that were solved
years ago (for GCC 3.1). The comparison operators in <iterator> are no
longer ambiguous with the rel_ops ones, so the linked mailing list
thread and FAQ entry aren't relevant now. The reference to std_utility.h
is also outdated as it's just called utility now, both in the source
tree and when installed.

The use of rel_ops is still frowned upon though, so replace the
discussion of ambiguities within libstdc++ headers with adminition about
using rel_ops in user code.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	* include/bits/stl_relops.h: Update documentation comments.
2021-07-23 11:22:10 +01:00

135 lines
4.5 KiB
C++

// std::rel_ops implementation -*- C++ -*-
// Copyright (C) 2001-2021 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the, 2009 Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/*
*
* Copyright (c) 1994
* Hewlett-Packard Company
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Hewlett-Packard Company makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*
* Copyright (c) 1996,1997
* Silicon Graphics
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Silicon Graphics makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*
*/
/** @file bits/stl_relops.h
* This is an internal header file, included by other library headers.
* Do not attempt to use it directly. @headername{utility}
*
* This file is only included by `<utility>`, which is required by the
* standard to define namespace `rel_ops` and its contents.
*/
#ifndef _STL_RELOPS_H
#define _STL_RELOPS_H 1
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
namespace rel_ops
{
/** @namespace std::rel_ops
* @brief The generated relational operators are sequestered here.
*
* Libstdc++ headers must not use the contents of `rel_ops`.
* User code should also avoid them, because unconstrained function
* templates are too greedy and can easily cause ambiguities.
*
* C++20 default comparisons are a better solution.
*/
/**
* @brief Defines @c != for arbitrary types, in terms of @c ==.
* @param __x A thing.
* @param __y Another thing.
* @return __x != __y
*
* This function uses @c == to determine its result.
*/
template <class _Tp>
inline bool
operator!=(const _Tp& __x, const _Tp& __y)
{ return !(__x == __y); }
/**
* @brief Defines @c > for arbitrary types, in terms of @c <.
* @param __x A thing.
* @param __y Another thing.
* @return __x > __y
*
* This function uses @c < to determine its result.
*/
template <class _Tp>
inline bool
operator>(const _Tp& __x, const _Tp& __y)
{ return __y < __x; }
/**
* @brief Defines @c <= for arbitrary types, in terms of @c <.
* @param __x A thing.
* @param __y Another thing.
* @return __x <= __y
*
* This function uses @c < to determine its result.
*/
template <class _Tp>
inline bool
operator<=(const _Tp& __x, const _Tp& __y)
{ return !(__y < __x); }
/**
* @brief Defines @c >= for arbitrary types, in terms of @c <.
* @param __x A thing.
* @param __y Another thing.
* @return __x >= __y
*
* This function uses @c < to determine its result.
*/
template <class _Tp>
inline bool
operator>=(const _Tp& __x, const _Tp& __y)
{ return !(__x < __y); }
} // namespace rel_ops
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif /* _STL_RELOPS_H */