-#define memcached_success(X) ((X) == MEMCACHED_SUCCESS)
-#define memcached_failed(A) ((A) != MEMCACHED_SUCCESS)
+#define memcached_success(__memcached_return_t) ((__memcached_return_t) == MEMCACHED_SUCCESS or (__memcached_return_t) == MEMCACHED_END)
+#define memcached_failed(__memcached_return_t) ((__memcached_return_t) != MEMCACHED_SUCCESS and (__memcached_return_t) != MEMCACHED_END)
+#define memcached_continue(__memcached_return_t) ((__memcached_return_t) == MEMCACHED_IN_PROGRESS)