pandora-build v0.74

[awesomized/libmemcached] / m4 / pandora_have_gcc_atomics.m4

diff --git a/m4/pandora_have_gcc_atomics.m4 b/m4/pandora_have_gcc_atomics.m4
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+dnl  Copyright (C) 2009 Sun Microsystems
+dnl This file is free software; Sun Microsystems
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+#--------------------------------------------------------------------
+# Check for GCC Atomic Support
+#--------------------------------------------------------------------
+
+
+AC_DEFUN([PANDORA_HAVE_GCC_ATOMICS],[
+       
+  AC_CACHE_CHECK(
+    [whether the compiler provides atomic builtins],
+    [ac_cv_gcc_atomic_builtins],
+    [AC_RUN_IFELSE(
+      [AC_LANG_PROGRAM([],[[
+        int foo= -10; int bar= 10;
+        if (!__sync_fetch_and_add(&foo, bar) || foo)
+          return -1;
+        bar= __sync_lock_test_and_set(&foo, bar);
+        if (bar || foo != 10)
+          return -1;
+        bar= __sync_val_compare_and_swap(&bar, foo, 15);
+        if (bar)
+          return -1;
+        return 0;
+        ]])],
+      [ac_cv_gcc_atomic_builtins=yes],
+      [ac_cv_gcc_atomic_builtins=no])])
+
+  AS_IF([test "x$ac_cv_gcc_atomic_builtins" = "xyes"],[
+    AC_DEFINE(HAVE_GCC_ATOMIC_BUILTINS, 1,
+              [Define to 1 if compiler provides atomic builtins.])
+  ])
+
+])
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