st.c | 2 +-

diff --git a/st.c b/st.c
index 6ba467d7cc903d90f1aa1b5aa01da592ad1b30e6..62def59f17cbf1bfd841210453ba29e5578d5610 100644
--- a/st.c
+++ b/st.c
@@ -939,7 +939,7 @@ 		fprintf(stderr, "Couldn't set window size: %s\n", strerror(errno));
 }
 
 void
-ttyhangup()
+ttyhangup(void)
 {
 	/* Send SIGHUP to shell */
 	kill(pid, SIGHUP);