diff --git a/include/nfsc/libnfs-zdr.h b/include/nfsc/libnfs-zdr.h
index a2b372b..dac5b76 100644
--- a/include/nfsc/libnfs-zdr.h
+++ b/include/nfsc/libnfs-zdr.h
@@ -96,7 +96,7 @@ typedef uint32_t u_int;
 typedef uint32_t enum_t;
 typedef uint32_t bool_t;
 
-typedef int (*zdrproc_t) (ZDR *, void *,...);
+typedef uint32_t (*zdrproc_t) (ZDR *, void *,...);
 
 #define AUTH_NONE 0
 #define AUTH_NULL 0