diff --git a/src/flow-export.c b/src/flow-export.c
index 52ae4d2..22b0330 100644
--- a/src/flow-export.c
+++ b/src/flow-export.c
@@ -961,7 +961,7 @@ #endif /* PGSQL */
 
 int fmt_xfields_type(char *buf, u_int64 xfield)
 {
-  int comma;
+  int comma = 0;
 
   buf[0] = 0;