John's Blog

In my X11 Intercept Window Close Event post I left out one very important piece of information. How to actually close the embedded window after intercepting the WM_DELETE_WINDOW message. The best thing to do is send our own WM_DELETE_WINDOW message to the embedded window. This will keep the embedded window embedded until it actually closes. Meaning any question dialogs that might stop the window from closing (Gedit asking to save for instance) can be answered and it keeps the window embedded if the user decides not to close.

In the previous post we overrode the WM_DELETE_WINDOW message. All we need to do is send it on to the embedded window. This will keep it embedded until it actually closes. Sending a this message entails setting the type to ClinetMessage, message type to the WM_PROTOCOLS Atom, the first l data value to the WM_DELETE_WINDOW Atom, and the second l data value to CurrentTime. The format of course if 32. Send the message to the embedded window and it will try to close.

#include <QX11Info>
#include <X11/XLib.h>
 
Display *display = QX11Info::display();
XEvent ev;
 
memset(&ev, 0, sizeof (ev));
 
ev.xclient.type = ClientMessage;
ev.xclient.window = window;
ev.xclient.message_type = XInternAtom(display, "WM_PROTOCOLS", true);
ev.xclient.format = 32;
ev.xclient.data.l[0] = XInternAtom(display, "WM_DELETE_WINDOW", false);
ev.xclient.data.l[1] = CurrentTime;
XSendEvent(display, window, False, NoEventMask, &ev);

Tags: c++, KDocker, x11, xlib