diff --git a/main/php_streams.h b/main/php_streams.h
index 81a848a3b6b..e6361c4f94d 100644
--- a/main/php_streams.h
+++ b/main/php_streams.h
@@ -413,7 +413,7 @@ END_EXTERN_C()
 /* whether or not locking is supported */
 #define PHP_STREAM_LOCK_SUPPORTED		1
 
-#define php_stream_supports_lock(stream)	_php_stream_set_option((stream), PHP_STREAM_OPTION_LOCKING, 0, (void *) PHP_STREAM_LOCK_SUPPORTED) == 0 ? 1 : 0
+#define php_stream_supports_lock(stream)	(_php_stream_set_option((stream), PHP_STREAM_OPTION_LOCKING, 0, (void *) PHP_STREAM_LOCK_SUPPORTED) == 0 ? 1 : 0)
 #define php_stream_lock(stream, mode)		_php_stream_set_option((stream), PHP_STREAM_OPTION_LOCKING, (mode), (void *) NULL)
 
 /* option code used by the php_stream_xport_XXX api */