tests/test-calloc-gnu.c

   1 /* Test of calloc function.
   2    Copyright (C) 2010-2021 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 #include <config.h>
  18
  19 #include <stdlib.h>
  20
  21 /* Return 8.
  22    Usual compilers are not able to infer something about the return value.  */
  23 static unsigned int
  24 eight (void)
  25 {
  26   unsigned int x = rand ();
  27   unsigned int y = x * x * x * x;
  28   x++; y |= x * x * x * x;
  29   x++; y |= x * x * x * x;
  30   x++; y |= x * x * x * x;
  31   y = y >> 1;
  32   return y & -y;
  33 }
  34
  35 int
  36 main ()
  37 {
  38   /* Check that calloc (0, 0) is not a NULL pointer.  */
  39   {
  40     void * volatile p = calloc (0, 0);
  41     if (p == NULL)
  42       return 1;
  43     free (p);
  44   }
  45
  46   /* Check that calloc fails when requested to allocate a block of memory
  47      larger than SIZE_MAX bytes.
  48      We use eight (), not 8, to avoid a compiler warning from GCC 7.
  49      'volatile' is needed to defeat an incorrect optimization by clang 10,
  50      see <https://bugs.llvm.org/show_bug.cgi?id=46055>.  */
  51   {
  52     void * volatile p = calloc ((size_t) -1 / 8 + 1, eight ());
  53     if (p != NULL)
  54       {
  55         free (p);
  56         return 2;
  57       }
  58   }
  59
  60   return 0;
  61 }