How to send key event to application using XCB?

Question

How can I send a key press or key release event to a window (the currently active window) from another program using XCB?

I found some tutorials using

Answer 1

You should be able to use the XTEST extension to fake input to the active window, using the xcb_test_fake_input() function.

#include 
...
xcb_test_fake_input(c, XCB_KEY_PRESS, keycode, XCB_CURRENT_TIME, XCB_NONE, 0, 0, 0);
xcb_test_fake_input(c, XCB_KEY_RELEASE, keycode, XCB_CURRENT_TIME, XCB_NONE, 0, 0, 0);

See the xte program in xcb/demos for a working example.