diff --git a/slirp/tcp_timer.c b/slirp/tcp_timer.c
index 47f01bb..9215eb2 100644
--- a/slirp/tcp_timer.c
+++ b/slirp/tcp_timer.c
@@ -44,7 +44,7 @@ static struct tcpcb *tcp_timers(register struct tcpcb *tp, int timer);
  * Fast timeout routine for processing delayed acks
  */
 void
-tcp_fasttimo()
+tcp_fasttimo(void)
 {
 	register struct socket *so;
 	register struct tcpcb *tp;
@@ -69,7 +69,7 @@ tcp_fasttimo()
  * causes finite state machine actions if timers expire.
  */
 void
-tcp_slowtimo()
+tcp_slowtimo(void)
 {
 	register struct socket *ip, *ipnxt;
 	register struct tcpcb *tp;
@@ -113,8 +113,7 @@ tpgone:
  * Cancel all timers for TCP tp.
  */
 void
-tcp_canceltimers(tp)
-	struct tcpcb *tp;
+tcp_canceltimers(struct tcpcb *tp)
 {
 	register int i;
 
diff --git a/slirp/udp.c b/slirp/udp.c
index 8d3bdd2..11e78cd 100644
--- a/slirp/udp.c
+++ b/slirp/udp.c
@@ -63,7 +63,7 @@ static void udp_emu(struct socket *so, struct mbuf *m);
 struct	socket *udp_last_so = &udb;
 
 void
-udp_init()
+udp_init(void)
 {
 	udb.so_next = udb.so_prev = &udb;
 }
@@ -72,9 +72,7 @@ udp_init()
  * ip->ip_len length data (IPDU)
  */
 void
-udp_input(m, iphlen)
-	register struct mbuf *m;
-	int iphlen;
+udp_input(register struct mbuf *m, int iphlen)
 {
 	register struct ip *ip;
 	register struct udphdr *uh;
@@ -330,8 +328,7 @@ int udp_output(struct socket *so, struct mbuf *m,
 }
 
 int
-udp_attach(so)
-     struct socket *so;
+udp_attach(struct socket *so)
 {
   struct sockaddr_in addr;
 
@@ -363,8 +360,7 @@ udp_attach(so)
 }
 
 void
-udp_detach(so)
-	struct socket *so;
+udp_detach(struct socket *so)
 {
 	closesocket(so->s);
 	/* if (so->so_m) m_free(so->so_m);    done by sofree */
@@ -631,11 +627,7 @@ struct cu_header {
 }
 
 struct socket *
-udp_listen(port, laddr, lport, flags)
-	u_int port;
-	u_int32_t laddr;
-	u_int lport;
-	int flags;
+udp_listen(u_int port, u_int32_t laddr, u_int lport, int flags)
 {
 	struct sockaddr_in addr;
 	struct socket *so;