rx: Add atomic operations code
[openafs.git] / acinclude.m4
index 98c6771..276cace 100644 (file)
@@ -981,6 +981,16 @@ dnl Linux-only, but just enable always.
                AC_DEFINE(AFS_CACHE_BYPASS, 1, [define to activate cache bypassing Unix client])
 esac
 
+AC_CACHE_CHECK([if compiler has __sync_add_and_fetch],
+    [ac_cv_sync_fetch_and_add],
+    [AC_TRY_LINK(, [int var; return __sync_add_and_fetch(&var, 1);],
+                   [ac_cv_sync_fetch_and_add=yes],
+                   [ac_cv_sync_fetch_and_add=no])
+])
+AS_IF([test "$ac_cv_sync_fetch_and_add" = "yes"],
+      [AC_DEFINE(HAVE_SYNC_FETCH_AND_ADD, 1,
+               [define if your C compiler has __sync_add_and_fetch])])
+
 AC_CACHE_CHECK([if struct sockaddr has sa_len field],
     [ac_cv_sockaddr_len],
     [AC_TRY_COMPILE( [#include <sys/types.h>