diff --git a/src/channel.c b/src/channel.c
index 46c45b6..2a75342 100644
--- a/src/channel.c
+++ b/src/channel.c
@@ -745,7 +745,7 @@
  * Return a unique ID to be used in a message.
  */
     int
-channel_get_id()
+channel_get_id(void)
 {
     static int next_id = 1;