libstdc++-v3/testsuite/23_containers/priority_queue/requirements/constructible.cc

   1 // { dg-do compile { target c++11 } }
   2
   3 // Copyright (C) 2017-2025 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 // You should have received a copy of the GNU General Public License
  17 // along with this library; see the file COPYING3.  If not see
  18 // <http://www.gnu.org/licenses/>.
  19
  20
  21 // This file tests explicit instantiation of library containers.
  22
  23 #include <queue>
  24
  25 using std::priority_queue;
  26 using std::vector;
  27
  28 template<typename A>
  29 constexpr bool default_constructible()
  30 { return std::is_default_constructible<A>::value; }
  31
  32 static_assert(default_constructible<priority_queue<int>>(),
  33               "priority_queue<int>");
  34
  35 struct NonDefaultConstructible : vector<int> {
  36   NonDefaultConstructible(int) { }
  37 };
  38 struct Cmp : std::less<int> {
  39   Cmp(int) { }
  40 };
  41 static_assert(
  42     !default_constructible<priority_queue<int, NonDefaultConstructible>>(),
  43     "priority_queue<int, NonDefaultConstructible>");
  44 static_assert(
  45     !default_constructible<priority_queue<int, NonDefaultConstructible, Cmp>>(),
  46     "priority_queue<int, NonDefaultConstructible, Cmp>");
  47 static_assert(
  48     !default_constructible<priority_queue<int, vector<int>, Cmp>>(),
  49     "priority_queue<int, vector<int>, Cmp>");