1// Concept-checking control -*- C++ -*-
2
3// Copyright (C) 2001 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 2, 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// You should have received a copy of the GNU General Public License along
17// with this library; see the file COPYING.  If not, write to the Free
18// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
19// USA.
20
21// As a special exception, you may use this file as part of a free software
22// library without restriction.  Specifically, if other files instantiate
23// templates or use macros or inline functions from this file, or you compile
24// this file and link it with other files to produce an executable, this
25// file does not by itself cause the resulting executable to be covered by
26// the GNU General Public License.  This exception does not however
27// invalidate any other reasons why the executable file might be covered by
28// the GNU General Public License.
29
30/** @file concept_check.h
31 *  This is an internal header file, included by other library headers.
32 *  You should not attempt to use it directly.
33 */
34
35#ifndef _CONCEPT_CHECK_H
36#define _CONCEPT_CHECK_H 1
37
38#pragma GCC system_header
39
40#include <bits/c++config.h>
41
42// All places in libstdc++-v3 where these are used, or /might/ be used, or
43// don't need to be used, or perhaps /should/ be used, are commented with
44// "concept requirements" (and maybe some more text).  So grep like crazy
45// if you're looking for additional places to use these.
46
47// Concept-checking code is off by default unless users turn it on via
48// configure options or editing c++config.h.
49
50#ifndef _GLIBCXX_CONCEPT_CHECKS
51
52#define __glibcxx_function_requires(...)
53#define __glibcxx_class_requires(_a,_b)
54#define __glibcxx_class_requires2(_a,_b,_c)
55#define __glibcxx_class_requires3(_a,_b,_c,_d)
56#define __glibcxx_class_requires4(_a,_b,_c,_d,_e)
57
58#else // the checks are on
59
60#include <bits/boost_concept_check.h>
61
62// Note that the obvious and elegant approach of
63//
64//#define glibcxx_function_requires(C) boost::function_requires< boost::C >()
65//
66// won't work due to concept templates with more than one parameter, e.g.,
67// BinaryPredicateConcept.  The preprocessor tries to split things up on
68// the commas in the template argument list.  We can't use an inner pair of
69// parenthesis to hide the commas, because "boost::(Temp<Foo,Bar>)" isn't
70// a valid instantiation pattern.  Thus, we steal a feature from C99.
71
72#define __glibcxx_function_requires(...)                                 \
73            __gnu_cxx::__function_requires< __gnu_cxx::__VA_ARGS__ >();
74#define __glibcxx_class_requires(_a,_C)                                  \
75            _GLIBCXX_CLASS_REQUIRES(_a, __gnu_cxx, _C);
76#define __glibcxx_class_requires2(_a,_b,_C)                              \
77            _GLIBCXX_CLASS_REQUIRES2(_a, _b, __gnu_cxx, _C);
78#define __glibcxx_class_requires3(_a,_b,_c,_C)                           \
79            _GLIBCXX_CLASS_REQUIRES3(_a, _b, _c, __gnu_cxx, _C);
80#define __glibcxx_class_requires4(_a,_b,_c,_d,_C)                        \
81            _GLIBCXX_CLASS_REQUIRES4(_a, _b, _c, _d, __gnu_cxx, _C);
82
83#endif // enable/disable
84
85#endif // _GLIBCXX_CONCEPT_CHECK
86