X11 Programming: receive notification if a new window appears?

Question

C programming with the X11 library, is there a way to get notified if a new window appears? I found XSetAfterFunction , but is for debugging purposes only ...

Thank you for your help!

Henry

@edit:

This code solves my problem

int main() {    
Display* display = XOpenDisplay(":2");

XSetWindowAttributes attributes;
attributes.event_mask = SubstructureNotifyMask | StructureNotifyMask;

XChangeWindowAttributes(display, 0x100, CWEventMask, &attributes);

while (true) {
    XEvent event;
    XNextEvent(display, &event);
    std::cout << "Event occured" << std::endl;
}

return 0;
}

Answer 1

From memory, you can use XChangeWindowAttributes to listen for events from the root window, and then act in XMapEvent (either XCreateWindowEvent or whateverEvent depending on your definition of “a new window has appeared”).