check auth_proxy return value properly
diff --git a/src/cmd/srv.c b/src/cmd/srv.c
index 01c05e6..0ae458c 100644
--- a/src/cmd/srv.c
+++ b/src/cmd/srv.c
@@ -141,7 +141,7 @@
 		return;
 	}
 
-	if(xauth_proxy(auth_getkey, "proto=p9any role=client %s", keypattern) < 0)
+	if(xauth_proxy(auth_getkey, "proto=p9any role=client %s", keypattern) == nil)
 		sysfatal("authproxy: %r");
 }