assert/tst-assert-c++.cc

   1 /* Tests for interactions between C++ and assert.
   2    Copyright (C) 2017-2021 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 /* Undefine NDEBUG to ensure the build system e.g. CFLAGS/CXXFLAGS
  20    does not disable the asserts we want to test.  */
  21 #undef NDEBUG
  22 #include <assert.h>
  23
  24 /* The C++ standard requires that if the assert argument is a constant
  25    subexpression, then the assert itself is one, too.  */
  26 constexpr int
  27 check_constexpr ()
  28 {
  29   return (assert (true), 1);
  30 }
  31
  32 /* Objects of this class can be contextually converted to bool, but
  33    cannot be compared to int.  */
  34 struct no_int
  35 {
  36   no_int () = default;
  37   no_int (const no_int &) = delete;
  38
  39   explicit operator bool () const
  40   {
  41     return true;
  42   }
  43
  44   bool operator! () const; /* No definition.  */
  45   template <class T> bool operator== (T) const; /* No definition.  */
  46   template <class T> bool operator!= (T) const; /* No definition.  */
  47 };
  48
  49 /* This class tests that operator== is not used by assert.  */
  50 struct bool_and_int
  51 {
  52   bool_and_int () = default;
  53   bool_and_int (const no_int &) = delete;
  54
  55   explicit operator bool () const
  56   {
  57     return true;
  58   }
  59
  60   bool operator! () const; /* No definition.  */
  61   template <class T> bool operator== (T) const; /* No definition.  */
  62   template <class T> bool operator!= (T) const; /* No definition.  */
  63 };
  64
  65 static int
  66 do_test ()
  67 {
  68   {
  69     no_int value;
  70     assert (value);
  71   }
  72
  73   {
  74     bool_and_int value;
  75     assert (value);
  76   }
  77
  78   return 0;
  79 }
  80
  81 #include <support/test-driver.c>