tests/test-stddef.c

   1 /* Test of <stddef.h> substitute.
   2    Copyright (C) 2009-2024 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 /* Written by Eric Blake <ebb9@byu.net>, 2009.  */
  18
  19 #include <config.h>
  20
  21 #include <stddef.h>
  22
  23 /* Check that appropriate types are defined.  */
  24 wchar_t a = 'c';
  25 ptrdiff_t b = 1;
  26 size_t c = 2;
  27 max_align_t mat;
  28
  29 /* Check that NULL can be passed through varargs as a pointer type,
  30    per POSIX 2008.  */
  31 static_assert (sizeof NULL == sizeof (void *));
  32
  33 /* Check that offsetof produces integer constants with correct type.  */
  34 struct d
  35 {
  36   char e;
  37   char f;
  38 };
  39 /* Solaris 10 has a bug where offsetof is under-parenthesized, and
  40    cannot be used as an arbitrary expression.  However, since it is
  41    unlikely to bite real code, we ignore that short-coming.  */
  42 /* static_assert (sizeof offsetof (struct d, e) == sizeof (size_t)); */
  43 static_assert (sizeof (offsetof (struct d, e)) == sizeof (size_t));
  44 static_assert (offsetof (struct d, f) == 1);
  45
  46 /* Check max_align_t's alignment.  */
  47 static_assert (alignof (double) <= alignof (max_align_t));
  48 static_assert (alignof (int) <= alignof (max_align_t));
  49 static_assert (alignof (long double) <= alignof (max_align_t));
  50 static_assert (alignof (long int) <= alignof (max_align_t));
  51 static_assert (alignof (ptrdiff_t) <= alignof (max_align_t));
  52 static_assert (alignof (size_t) <= alignof (max_align_t));
  53 static_assert (alignof (wchar_t) <= alignof (max_align_t));
  54 static_assert (alignof (struct d) <= alignof (max_align_t));
  55 #if defined __GNUC__ || defined __clang__ || defined __IBM__ALIGNOF__
  56 static_assert (__alignof__ (double) <= __alignof__ (max_align_t));
  57 static_assert (__alignof__ (int) <= __alignof__ (max_align_t));
  58 static_assert (__alignof__ (long double) <= __alignof__ (max_align_t));
  59 static_assert (__alignof__ (long int) <= __alignof__ (max_align_t));
  60 static_assert (__alignof__ (ptrdiff_t) <= __alignof__ (max_align_t));
  61 static_assert (__alignof__ (size_t) <= __alignof__ (max_align_t));
  62 static_assert (__alignof__ (wchar_t) <= __alignof__ (max_align_t));
  63 static_assert (__alignof__ (struct d) <= __alignof__ (max_align_t));
  64 #endif
  65
  66 int test_unreachable_optimization (int x);
  67 _Noreturn void test_unreachable_noreturn (void);
  68
  69 int
  70 test_unreachable_optimization (int x)
  71 {
  72   /* Check that the compiler uses 'unreachable' for optimization.
  73      This function, when compiled with optimization, should have code
  74      equivalent to
  75        return x + 3;
  76      Use 'objdump --disassemble test-stddef.o' to verify this.  */
  77   if (x < 4)
  78     unreachable ();
  79   return (x > 1 ? x + 3 : 2 * x + 10);
  80 }
  81
  82 _Noreturn void
  83 test_unreachable_noreturn (void)
  84 {
  85   /* Check that the compiler's data-flow analysis recognizes 'unreachable ()'.
  86      This function should not elicit a warning.  */
  87   unreachable ();
  88 }
  89
  90 #include <limits.h> /* INT_MAX */
  91
  92 /* offsetof promotes to an unsigned integer if and only if sizes do
  93    not fit in int.  */
  94 static_assert ((offsetof (struct d, e) < -1) == (INT_MAX < (size_t) -1));
  95
  96 int
  97 main (void)
  98 {
  99   return 0;
 100 }