diff --git a/client/fdfs_append_file.c b/client/fdfs_append_file.c
index 1b1e451..b3e7998 100644
--- a/client/fdfs_append_file.c
+++ b/client/fdfs_append_file.c
@@ -24,7 +24,7 @@ int main(int argc, char *argv[])
 	int result;
 	char appender_file_id[128];
 	
-	if (argc < 4)
+	if (argc < 4 || argc < 0)
 	{
 		printf("Usage: %s <config_file> <appender_file_id> " \
 			"<local_filename>\n", argv[0]);