m4/ac_have_sync_val_compare_and_swap.m4

   1 AC_DEFUN([AX_C___SYNC_VAL_COMPARE_AND_SWAP], [
   2   AC_MSG_CHECKING(for __sync_val_compare_and_swap)
   3   AC_CACHE_VAL(ac_cv___sync_val_compare_and_swap, [
   4     AC_TRY_LINK(
   5       [],
   6       [int a; if (__sync_val_compare_and_swap(&a, 0, 1)) return 1; return 0;],
   7       ac_cv___sync_val_compare_and_swap=yes,
   8       ac_cv___sync_val_compare_and_swap=no
   9     )])
  10   if test "$ac_cv___sync_val_compare_and_swap" = "yes"; then
  11     AC_DEFINE(HAVE___SYNC_VAL_COMPARE_AND_SWAP, 1, [define if your compiler has __sync_val_compare_and_swap])
  12   fi
  13   AC_MSG_RESULT($ac_cv___sync_val_compare_and_swap)
  14 ])