allow closing of help windows with WM x-button

ChangeLog

@@ -1,3 +1,6 @@
+2009-02-20 Holger Vogt
+ * x11disp.c: allow closing of help windows with WM x-button
+
 2009-02-14 Dietmar Warning
  * src/spicelib/parser/inpdomod.c: map level 10 to bsimsoi4 and map ancient 
    version 4.0 and 4.1 of bsim4 to available version 4.2

src/frontend/help/x11disp.c

@@ -25,6 +25,24 @@ static bool started = FALSE;
 static topic *topics = NULL;
 void newtopic(Widget w, caddr_t client_data, caddr_t call_data), delete(Widget w, caddr_t client_data, caddr_t call_data), quit(Widget w, caddr_t client_data, caddr_t call_data); 
 static void sputline(char *buf, char *s);
+/* atoms for catching window delet by WM x-button */
+static Atom atom_wm_delete_window;
+static Atom atom_wm_protocols;
+static Display *display;
+
+/* callback function for catching window deletion by WM x-button */
+static void handle_wm_messages(Widget w, XtPointer client_data, XEvent *event, Boolean *cont) {
+    topic *top = (topic *) client_data;
+
+    if (event->type == ClientMessage
+            && event->xclient.message_type == atom_wm_protocols
+            && event->xclient.data.l[0] == atom_wm_delete_window) 
+    {
+        hlp_killfamily(top);
+        hlp_fixchildren(top);
+    }
+}
+
 
 /* Create a new window... */
 bool
@@ -191,6 +209,14 @@ hlp_xdisplay(topic *top)
     top->winlink = topics;
     topics = top;
 
+
+    /* WM_DELETE_WINDOW protocol */
+    display = XtDisplay(top->shellwidget);
+    atom_wm_protocols = XInternAtom(display, "WM_PROTOCOLS", False);
+    atom_wm_delete_window = XInternAtom(display, "WM_DELETE_WINDOW", False);
+    XtAddEventHandler(top->shellwidget, NoEventMask, True, handle_wm_messages, top);
+    XSetWMProtocols(display, XtWindow(top->shellwidget), &atom_wm_delete_window, 1);
+
     return (TRUE);
 
 }