diff --git src/wmapp.cc src/wmapp.cc
index d8b0032..6a5663d 100644
--- src/wmapp.cc
+++ src/wmapp.cc
@@ -220,7 +220,7 @@ static void registerProtocols2(Window xid) {
                     PropModeReplace, (unsigned char *)win_proto, i);
 #endif
 
-    long pid = getpid();
+    XID pid = getpid();
     const char wmname[] = "IceWM "VERSION" ("HOSTOS"/"HOSTCPU")";
 
 #ifdef GNOME1_HINTS