diff --git a/hw/xnest/Args.c b/hw/xnest/Args.c
index b95f70093..cdc831133 100644
--- a/hw/xnest/Args.c
+++ b/hw/xnest/Args.c
@@ -174,7 +174,7 @@ ddxProcessArgument (int argc, char *argv[], int i)
   return 0;
 }
 
-void ddxUseMsg()
+void ddxUseMsg(void)
 {
   ErrorF("-display string        display name of the real server\n");
   ErrorF("-sync                  sinchronize with the real server\n");
diff --git a/hw/xnest/Events.c b/hw/xnest/Events.c
index b3ae97284..c2c09aaa6 100644
--- a/hw/xnest/Events.c
+++ b/hw/xnest/Events.c
@@ -45,7 +45,7 @@ CARD32 lastEventTime = 0;
 extern EventList *xnestEvents;
 
 void
-ProcessInputEvents()
+ProcessInputEvents(void)
 {
   mieqProcessInputEvents();
 }
diff --git a/hw/xnest/Init.c b/hw/xnest/Init.c
index f80bbd121..2a9fc26a1 100644
--- a/hw/xnest/Init.c
+++ b/hw/xnest/Init.c
@@ -107,14 +107,14 @@ InitInput(int argc, char *argv[])
 /*
  * DDX - specific abort routine.  Called by AbortServer().
  */
-void AbortDDX()
+void AbortDDX(void)
 {
   xnestDoFullGeneration = True;
   xnestCloseDisplay();
 }
 
 /* Called by GiveUp(). */
-void ddxGiveUp()
+void ddxGiveUp(void)
 {
   AbortDDX();
 }
@@ -126,12 +126,12 @@ DarwinHandleGUI(int argc, char *argv[])
 }
 #endif
 
-void OsVendorInit()
+void OsVendorInit(void)
 {
     return;
 }
 
-void OsVendorFatalError()
+void OsVendorFatalError(void)
 {
     return;
 }