libstdc++-v3/include/bits/concept_check.h

   1 // Concept-checking control -*- C++ -*-
   2
   3 // Copyright (C) 2001-2018 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