diff --git a/lib/buffer.c b/lib/buffer.c
index 0fffdfd..6fd9a2b 100644
--- a/lib/buffer.c
+++ b/lib/buffer.c
@@ -382,7 +382,7 @@
 /* Flush buffer to the file descriptor.  Mainly used from vty
    interface. */
 int
-buffer_flush_vty (struct buffer *b, int fd, int size, 
+buffer_flush_vty (struct buffer *b, int fd, unsigned int size, 
 		  int erase_flag, int no_more_flag)
 {
   int nbytes;