diff --git a/usr.sbin/ppp/bundle.c b/usr.sbin/ppp/bundle.c
--- a/usr.sbin/ppp/bundle.c
+++ b/usr.sbin/ppp/bundle.c
@@ -1354,7 +1354,7 @@
 }
 
 int
-bundle_LinkSize()
+bundle_LinkSize(void)
 {
   struct iovec iov[SCATTER_SEGMENTS];
   int niov, expect, f;
diff --git a/usr.sbin/ppp/defs.c b/usr.sbin/ppp/defs.c
--- a/usr.sbin/ppp/defs.c
+++ b/usr.sbin/ppp/defs.c
@@ -384,7 +384,7 @@
 }
 
 fd_set *
-mkfdset()
+mkfdset(void)
 {
   return (fd_set *)malloc(howmany(getdtablesize(), NFDBITS) * sizeof (fd_mask));
 }
diff --git a/usr.sbin/ppp/id.c b/usr.sbin/ppp/id.c
--- a/usr.sbin/ppp/id.c
+++ b/usr.sbin/ppp/id.c
@@ -61,7 +61,7 @@
 static int euid;
 
 void
-ID0init()
+ID0init(void)
 {
   uid = getuid();
   euid = geteuid();
@@ -77,7 +77,7 @@
 }
 
 uid_t
-ID0realuid()
+ID0realuid(void)
 {
   return uid;
 }
diff --git a/usr.sbin/ppp/log.c b/usr.sbin/ppp/log.c
--- a/usr.sbin/ppp/log.c
+++ b/usr.sbin/ppp/log.c
@@ -83,7 +83,7 @@
 int log_PromptListChanged;
 
 struct prompt *
-log_PromptList()
+log_PromptList(void)
 {
   return promptlist;
 }
@@ -163,7 +163,7 @@
 }
 
 void
-log_DisplayPrompts()
+log_DisplayPrompts(void)
 {
   struct prompt *p;
 
@@ -254,7 +254,7 @@
 }
 
 void
-log_DiscardAll()
+log_DiscardAll(void)
 {
   LogMask = 0;
 }
@@ -306,7 +306,7 @@
 }
 
 void
-log_Close()
+log_Close(void)
 {
   closelog();
   LogTunno = -1;
diff --git a/usr.sbin/ppp/main.c b/usr.sbin/ppp/main.c
--- a/usr.sbin/ppp/main.c
+++ b/usr.sbin/ppp/main.c
@@ -112,7 +112,7 @@
 struct libalias *la;
 
 void
-Cleanup()
+Cleanup(void)
 {
   SignalBundle->CleaningUp = 1;
   bundle_Close(SignalBundle, NULL, CLOSE_STAYDOWN);
diff --git a/usr.sbin/ppp/physical.c b/usr.sbin/ppp/physical.c
--- a/usr.sbin/ppp/physical.c
+++ b/usr.sbin/ppp/physical.c
@@ -646,7 +646,7 @@
 }
 
 unsigned
-physical_MaxDeviceSize()
+physical_MaxDeviceSize(void)
 {
   unsigned biggest, sz, n;
 
diff --git a/usr.sbin/ppp/probe.c b/usr.sbin/ppp/probe.c
--- a/usr.sbin/ppp/probe.c
+++ b/usr.sbin/ppp/probe.c
@@ -67,7 +67,7 @@
 #endif
 
 void
-probe_Init()
+probe_Init(void)
 {
   probe.select_changes_time = select_changes_time() ? 1 : 0;
   log_Printf(LogDEBUG, "Select changes time: %s\n",
diff --git a/usr.sbin/ppp/sig.c b/usr.sbin/ppp/sig.c
--- a/usr.sbin/ppp/sig.c
+++ b/usr.sbin/ppp/sig.c
@@ -94,7 +94,7 @@
  * select() returned due to a signal being recorded by signal_recorder().
  */
 int
-sig_Handle()
+sig_Handle(void)
 {
   int sig;
   int got;