libstdc++-v3/testsuite/20_util/function/7.cc

   1 // { dg-do run { target c++11 } }
   2 // { dg-require-effective-target hosted }
   3
   4 // 2005-01-15 Douglas Gregor <dgregor@cs.indiana.edu>
   5 //
   6 // Copyright (C) 2005-2024 Free Software Foundation, Inc.
   7 //
   8 // This file is part of the GNU ISO C++ Library.  This library is free
   9 // software; you can redistribute it and/or modify it under the
  10 // terms of the GNU General Public License as published by the
  11 // Free Software Foundation; either version 3, or (at your option)
  12 // any later version.
  13 //
  14 // This library is distributed in the hope that it will be useful,
  15 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 // GNU General Public License for more details.
  18 //
  19 // You should have received a copy of the GNU General Public License along
  20 // with this library; see the file COPYING3.  If not see
  21 // <http://www.gnu.org/licenses/>.
  22
  23 // 20.7.15 polymorphic function object wrapper
  24 #include <functional>
  25 #include <testsuite_hooks.h>
  26 #include <testsuite_tr1.h>
  27
  28 template<typename T>
  29   const T&
  30   as_const(T& t)
  31   { return t; }
  32
  33 // Check that f's target is a reference_wrapper bound to obj.
  34 template<typename Function, typename T>
  35   bool
  36   wraps(Function& f, T& obj)
  37   {
  38     using ref_wrapper_type = std::reference_wrapper<T>;
  39     auto* p = f.template target<ref_wrapper_type>();
  40     return std::addressof(p->get()) == std::addressof(obj);
  41   }
  42
  43 // Put reference_wrappers to function pointers into function<> wrappers
  44 void test07()
  45 {
  46   using std::function;
  47   using std::ref;
  48   using std::cref;
  49   using std::reference_wrapper;
  50
  51   int (*fptr)(float) = __gnu_test::truncate_float;
  52
  53   function<int(float)> f1(ref(fptr));
  54   VERIFY( f1 );
  55   VERIFY( !!f1 );
  56   VERIFY( !(f1 == 0) );
  57   VERIFY( !(0 == f1) );
  58   VERIFY( f1 != 0 );
  59   VERIFY( 0 != f1 );
  60
  61   // Invocation
  62   VERIFY( f1(3.1f) == 3 );
  63
  64   // target_type and target() functions
  65   const function<int(float)>& f1c = f1;
  66   using ref_wrapper_type = reference_wrapper<int(*)(float)>;
  67 #if __cpp_rtti
  68   VERIFY( typeid(ref_wrapper_type) == f1.target_type() );
  69 #endif
  70   VERIFY( f1.target<ref_wrapper_type>() != nullptr );
  71   VERIFY( wraps(f1, fptr) );
  72   VERIFY( wraps(f1c, fptr) );
  73
  74   function<int(float)> f2(cref(fptr));
  75   VERIFY( f2 );
  76   VERIFY( !!f2 );
  77   VERIFY( !(f2 == 0) );
  78   VERIFY( !(0 == f2) );
  79   VERIFY( f2 != 0 );
  80   VERIFY( 0 != f2 );
  81
  82   // Invocation
  83   VERIFY( f2(3.1f) == 3 );
  84
  85   // target_type and target() functions
  86   const function<int(float)>& f2c = f2;
  87   using cref_wrapper_type = reference_wrapper<int(* const)(float)>;
  88 #if __cpp_rtti
  89   VERIFY( typeid(cref_wrapper_type) == f2.target_type() );
  90 #endif
  91   VERIFY( wraps(f2, as_const(fptr)) );
  92 #if __cpp_rtti
  93   VERIFY( f2c.target_type() == f2.target_type() );
  94 #endif
  95   VERIFY( wraps(f2c, as_const(fptr)) );
  96 }
  97
  98 int main()
  99 {
 100   test07();
 101   return 0;
 102 }