--- pTk/mTk/unix/tkUnixXft.c
+++ pTk/mTk/unix/tkUnixXft.c
@@ -439,7 +439,7 @@
     resultPtr = Tcl_NewListObj(0, NULL);
 
     list = XftListFonts(Tk_Display(tkwin), Tk_ScreenNumber(tkwin), 0,
-	    XFT_FAMILY, 0);
+	    XFT_FAMILY, NULL);
     for (i = 0; i < list->nfont; i++) {
 	if (XftPatternGetString(list->fonts[i], XFT_FAMILY, 0,
 		&family) == XftResultMatch) {