git.m6w6.name Git - awesomized/libmemcached/blob - m4/ax_gcc_atomic_builtins.m4

   1 # serial 1
   2 #
   3 AC_DEFUN([HAVE_GCC_ATOMICS],
   4     [AC_CACHE_CHECK([whether the compiler provides atomic builtins],
   5       [ax_cv_gcc_atomic_builtins],
   6       [AX_SAVE_FLAGS
   7       AC_LANG_PUSH([C])
   8       AC_RUN_IFELSE([AC_LANG_PROGRAM([],
   9           [[
  10           int foo= -10; int bar= 10;
  11           if (!__sync_fetch_and_add(&foo, bar) || foo)
  12           {
  13           return -1;
  14           }
  15           bar= __sync_lock_test_and_set(&foo, bar);
  16           if (bar || foo != 10)
  17           {
  18           return -1;
  19           }
  20           bar= __sync_val_compare_and_swap(&bar, foo, 15);
  21           if (bar)
  22           {
  23           return -1;
  24           }
  25           ]])],
  26         [ax_cv_gcc_atomic_builtins=yes],
  27         [ax_cv_gcc_atomic_builtins=no],
  28         [AC_MSG_WARN([test program execution failed])])
  29       AC_LANG_POP
  30       AX_RESTORE_FLAGS
  31       ])
  32
  33       AS_IF([test "x$ax_cv_gcc_atomic_builtins" = "xyes"],
  34           [AC_DEFINE([HAVE_GCC_ATOMIC_BUILTINS],[1],
  35             [Define to 1 if compiler provides atomic builtins.])
  36           ])
  37       ])