1    	// Concept-checking control -*- C++ -*-
2    	
3    	// Copyright (C) 2001-2017 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 bits/concept_check.h
26   	 *  This is an internal header file, included by other library headers.
27   	 *  Do not attempt to use it directly. @headername{iterator}
28   	 */
29   	
30   	#ifndef _CONCEPT_CHECK_H
31   	#define _CONCEPT_CHECK_H 1
32   	
33   	#pragma GCC system_header
34   	
35   	#include <bits/c++config.h>
36   	
37   	// All places in libstdc++-v3 where these are used, or /might/ be used, or
38   	// don't need to be used, or perhaps /should/ be used, are commented with
39   	// "concept requirements" (and maybe some more text).  So grep like crazy
40   	// if you're looking for additional places to use these.
41   	
42   	// Concept-checking code is off by default unless users turn it on via
43   	// configure options or editing c++config.h.
44   	// It is not supported for freestanding implementations.
45   	
46   	#if !defined(_GLIBCXX_CONCEPT_CHECKS) || !_GLIBCXX_HOSTED
47   	
48   	#define __glibcxx_function_requires(...)
49   	#define __glibcxx_class_requires(_a,_b)
50   	#define __glibcxx_class_requires2(_a,_b,_c)
51   	#define __glibcxx_class_requires3(_a,_b,_c,_d)
52   	#define __glibcxx_class_requires4(_a,_b,_c,_d,_e)
53   	
54   	#else // the checks are on
55   	
56   	#include <bits/boost_concept_check.h>
57   	
58   	// Note that the obvious and elegant approach of
59   	//
60   	//#define glibcxx_function_requires(C) debug::function_requires< debug::C >()
61   	//
62   	// won't work due to concept templates with more than one parameter, e.g.,
63   	// BinaryPredicateConcept.  The preprocessor tries to split things up on
64   	// the commas in the template argument list.  We can't use an inner pair of
65   	// parenthesis to hide the commas, because "debug::(Temp<Foo,Bar>)" isn't
66   	// a valid instantiation pattern.  Thus, we steal a feature from C99.
67   	
68   	#define __glibcxx_function_requires(...)                                 \
69   	            __gnu_cxx::__function_requires< __gnu_cxx::__VA_ARGS__ >();
70   	#define __glibcxx_class_requires(_a,_C)                                  \
71   	            _GLIBCXX_CLASS_REQUIRES(_a, __gnu_cxx, _C);
72   	#define __glibcxx_class_requires2(_a,_b,_C)                              \
73   	            _GLIBCXX_CLASS_REQUIRES2(_a, _b, __gnu_cxx, _C);
74   	#define __glibcxx_class_requires3(_a,_b,_c,_C)                           \
75   	            _GLIBCXX_CLASS_REQUIRES3(_a, _b, _c, __gnu_cxx, _C);
76   	#define __glibcxx_class_requires4(_a,_b,_c,_d,_C)                        \
77   	            _GLIBCXX_CLASS_REQUIRES4(_a, _b, _c, _d, __gnu_cxx, _C);
78   	
79   	#endif // enable/disable
80   	
81   	#endif // _GLIBCXX_CONCEPT_CHECK
82