diff --git a/common-session.c b/common-session.c
index 5cc3a86..a3a2f17 100644
--- a/common-session.c
+++ b/common-session.c
@@ -136,7 +136,7 @@ void common_session_init(int sock_in, int sock_out) {
 	TRACE(("leave session_init"))
 }
 
-void session_loop(void(*loophandler)()) {
+void session_loop(void(*loophandler)(void)) {
 
 	fd_set readfd, writefd;
 	struct timeval timeout;
diff --git a/session.h b/session.h
index ced8ff4..0f77055 100644
--- a/session.h
+++ b/session.h
@@ -40,7 +40,7 @@
 #include "netio.h"
 
 void common_session_init(int sock_in, int sock_out);
-void session_loop(void(*loophandler)()) ATTRIB_NORETURN;
+void session_loop(void(*loophandler)(void)) ATTRIB_NORETURN;
 void session_cleanup(void);
 void send_session_identification(void);
 void send_msg_ignore(void);