diff --git a/contrib/fb303/TClientInfo.cpp b/contrib/fb303/TClientInfo.cpp
index d093017..e07eaa8 100644
--- a/contrib/fb303/TClientInfo.cpp
+++ b/contrib/fb303/TClientInfo.cpp
@@ -160,7 +160,7 @@
 
     char buf[256];
     snprintf(buf, sizeof buf, "%d %s %s %.3f %llu", i, addrStr, callStr, secs,
-             (unsigned long long)info->getNCalls());
+             (uint64_t)info->getNCalls());
                
     result.push_back(buf);
   }