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

   1 dnl  Copyright (C) 2009 Sun Microsystems
   2 dnl This file is free software; Sun Microsystems
   3 dnl gives unlimited permission to copy and/or distribute it,
   4 dnl with or without modifications, as long as this notice is preserved.
   5
   6 #--------------------------------------------------------------------
   7 # Check for GCC Atomic Support
   8 #--------------------------------------------------------------------
   9
  10
  11 AC_DEFUN([PANDORA_HAVE_GCC_ATOMICS],[
  12
  13   AC_CACHE_CHECK(
  14     [whether the compiler provides atomic builtins],
  15     [ac_cv_gcc_atomic_builtins],
  16     [AC_LINK_IFELSE(
  17       [AC_LANG_PROGRAM([],[[
  18         int foo= -10; int bar= 10;
  19         if (!__sync_fetch_and_add(&foo, bar) || foo)
  20           return -1;
  21         bar= __sync_lock_test_and_set(&foo, bar);
  22         if (bar || foo != 10)
  23           return -1;
  24         bar= __sync_val_compare_and_swap(&bar, foo, 15);
  25         if (bar)
  26           return -1;
  27         return 0;
  28         ]])],
  29       [ac_cv_gcc_atomic_builtins=yes],
  30       [ac_cv_gcc_atomic_builtins=no])])
  31
  32   AS_IF([test "x$ac_cv_gcc_atomic_builtins" = "xyes"],[
  33     AC_DEFINE(HAVE_GCC_ATOMIC_BUILTINS, 1,
  34               [Define to 1 if compiler provides atomic builtins.])
  35   ])
  36
  37 ])