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

   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, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  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 #ifndef _GLIBCPP_CONCEPT_CHECK
  31 #define _GLIBCPP_CONCEPT_CHECK 1
  32
  33 #pragma GCC system_header
  34 #include <bits/c++config.h>
  35
  36
  37 // Concept-checking code is on by default unless users turn it off via any
  38 // of these methods:
  39 //  -  _GLIBCPP_NO_CONCEPT_CHECKS is a user hook; defining it disables the
  40 //     checks.
  41 //  -  _STL_NO_CONCEPT_CHECKS is a user hook from the old STL implementation
  42 //     specifically for this purpose; defining it disables the checks, in
  43 //     case the user is expecting the old version.
  44 //  -  NDEBUG is the usual macro that kills assert().  Defining it will also
  45 //     disable the checks, by the reasoning that if the user doesn't want
  46 //     any runtime assertion code, then no space penalty for the checks
  47 //     is desired either.
  48
  49 // All places in libstdc++-v3 where these are used, or /might/ be used, or
  50 // don't need to be used, or perhaps /should/ be used, are commented with
  51 // "concept requirements" (and maybe some more text).  So grep like crazy
  52 // if you're looking for additional places to use these.
  53
  54
  55 #if defined(_GLIBCPP_NO_CONCEPT_CHECKS) || defined(_STL_NO_CONCEPT_CHECKS) \
  56     || defined(NDEBUG)
  57
  58 #define glibcpp_function_requires(...)
  59 #define glibcpp_class_requires(a,b)
  60 #define glibcpp_class_requires2(a,b,c)
  61 #define glibcpp_class_requires3(a,b,c,d)
  62 #define glibcpp_class_requires4(a,b,c,d,e)
  63
  64 #else // the checks are on
  65
  66 #include <bits/boost_concept_check.h>
  67
  68 // Note that the obvious and elegant approach of
  69 //
  70 //#define glibcpp_function_requires(C)      \
  71 //            boost::function_requires< boost::C >()
  72 //
  73 // won't work due to concept templates with more than one parameter, e.g.,
  74 // BinaryPredicateConcept.  The preprocessor tries to split things up on
  75 // the commas in the template argument list.  We can't use an inner pair of
  76 // parenthesis to hide the commas, because "boost::(Temp<Foo,Bar>)" isn't
  77 // a valid instantiation pattern.
  78
  79 #define glibcpp_function_requires(...)                         \
  80             boost::function_requires< boost::__VA_ARGS__ >()
  81 #define glibcpp_class_requires(a,C)                            \
  82             BOOST_CLASS_REQUIRES(a, boost, C)
  83 #define glibcpp_class_requires2(a,b,C)                         \
  84             BOOST_CLASS_REQUIRES2(a, b, boost, C)
  85 #define glibcpp_class_requires3(a,b,c,C)                       \
  86             BOOST_CLASS_REQUIRES3(a, b, c, boost, C)
  87 #define glibcpp_class_requires4(a,b,c,d,C)                     \
  88             BOOST_CLASS_REQUIRES4(a, b, c, d, boost, C)
  89
  90 #endif // enable/disable
  91
  92 #endif // _GLIBCPP_CONCEPT_CHECK
  93