1 files changed, 1 insertions, 1 deletions
diff --git a/pkt-line.h b/pkt-line.h
index b0b4f6d495..51d0cbe219 100644
--- a/pkt-line.h
+++ b/pkt-line.h
@@ -5,7 +5,7 @@
  * Silly packetized line writing interface
  */
 void packet_flush(int fd);
-void packet_write(int fd, const char *fmt, ...);
+void packet_write(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
 
 int packet_read_line(int fd, char *buffer, unsigned size);