diff --git a/binding/c/xdb_searcher.c b/binding/c/xdb_searcher.c
index 6bcae3a..8b9f996 100644
--- a/binding/c/xdb_searcher.c
+++ b/binding/c/xdb_searcher.c
@@ -132,7 +132,7 @@ XDB_PUBLIC(int) xdb_search(xdb_searcher_t *xdb, unsigned int ip, char *region_bu
     }
 
     // buffer length checking
-    if (data_len >= length) {
+    if (data_len >= (int) length) {
         return 1;
     }