diff --git a/ospfd/ospf_api.h b/ospfd/ospf_api.h
index e786761..77e1b23 100644
--- a/ospfd/ospf_api.h
+++ b/ospfd/ospf_api.h
@@ -205,7 +205,7 @@
 
 struct msg_reply
 {
-  char errcode;
+  signed char errcode;
 #define OSPF_API_OK                         0
 #define OSPF_API_NOSUCHINTERFACE          (-1)
 #define OSPF_API_NOSUCHAREA               (-2)