diff --git a/common/common_func.cpp b/common/common_func.cpp
index e5a7f04..e72f3c0 100644
--- a/common/common_func.cpp
+++ b/common/common_func.cpp
@@ -35,8 +35,8 @@ char recvpacket[PACKET_SIZE];
 
 static boost::mutex s_config_mu;
 
-zlog_category_t *zct;
-zlog_category_t *zbt;
+extern zlog_category_t *zct;
+extern zlog_category_t *zbt;
 
 string GetLocalTimeWithMs(void) {
     string defaultTime = "19700101000000000";