diff -ruN libmemcached-1.0.18.org/clients/memflush.cc libmemcached-1.0.18/clients/memflush.cc
--- libmemcached-1.0.18.org/clients/memflush.cc	2014-02-09 19:52:42.000000000 +0800
+++ libmemcached-1.0.18/clients/memflush.cc	2018-05-11 10:23:30.830552000 +0800
@@ -39,7 +39,7 @@
 {
   options_parse(argc, argv);
 
-  if (opt_servers == false)
+  if (!opt_servers)
   {
     char *temp;
 
@@ -48,7 +48,7 @@
       opt_servers= strdup(temp);
     }
 
-    if (opt_servers == false)
+    if (!opt_servers)
     {
       std::cerr << "No Servers provided" << std::endl;
       exit(EXIT_FAILURE);
