From 56fe4b85babca51dccc18ea9408efa0ea057a34b Mon Sep 17 00:00:00 2001
From: wang sheng <wangsheng1001@gmail.com>
Date: Wed, 10 Jun 2015 14:47:41 +0800
Subject: [PATCH] ensure the callback function used in ZKClusterRT.sWatchGroup
 cannot be NULL

---
 src/utils/cluster_rt.cc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/utils/cluster_rt.cc b/src/utils/cluster_rt.cc
index b60b3342e8..af6fbbc11c 100644
--- a/src/utils/cluster_rt.cc
+++ b/src/utils/cluster_rt.cc
@@ -55,6 +55,8 @@ bool ZKClusterRT::Init(){
 
 bool ZKClusterRT::sWatchSGroup(int gid, int sid, rt_callback fn, void *ctx){
 
+  CHECK_NOTNULL(fn);
+
   string path = getSGroupPath(gid);
   struct Stat stat;