diff --git a/c/unpack.c b/c/unpack.c
index 6a435ba1..d5bcb2d9 100644
--- a/c/unpack.c
+++ b/c/unpack.c
@@ -152,7 +152,7 @@ static inline void init_count(void* buffer)
 static inline void decl_count(void* buffer)
 {
 	// atomic if(--*(_msgpack_atomic_counter_t*)buffer == 0) { free(buffer); }
-	if(_msgpack_sync_decr_and_fetch((volatile _msgpack_atomic_counter_t*)buffer)) {
+	if(_msgpack_sync_decr_and_fetch((volatile _msgpack_atomic_counter_t*)buffer) == 0) {
 		free(buffer);
 	}
 }