diff --git a/a8/websocketsession.cc b/a8/websocketsession.cc
index 0d96606..dcf2dd4 100644
--- a/a8/websocketsession.cc
+++ b/a8/websocketsession.cc
@@ -190,7 +190,7 @@ namespace a8
 
     void WebSocketSession::DecodeFrame(char* buf, int& offset, unsigned int buflen)
     {
-        if (offset + 2 > buflen) {
+        if (offset + 2 > (int)buflen) {
             return;
         }
         char* real_buf = buf + offset;