diff --git a/appl/gssmask/common.h b/appl/gssmask/common.h
index eb92d286a..8b2ab6c83 100644
--- a/appl/gssmask/common.h
+++ b/appl/gssmask/common.h
@@ -42,6 +42,7 @@
 #include <sys/utsname.h>
 #endif
 
+#include <assert.h>
 #include <krb5.h>
 #include <gssapi.h>
 #include <unistd.h>
@@ -54,6 +55,12 @@
 krb5_error_code store_string(krb5_storage *, const char *);
 
 
+#define ret16(_client, num)					\
+    do {							\
+        if (krb5_ret_int16((_client)->sock, &(num)) != 0)	\
+	    errx(1, "krb5_ret_int16 " #num);		\
+    } while(0)
+
 #define ret32(_client, num)					\
     do {							\
         if (krb5_ret_int32((_client)->sock, &(num)) != 0)	\