XTEST example

fake_key.c

/* gcc -o fake_key fake_key.c -lXtst */
/* example usage:
 *   { sleep 1; ./fake_key l s Return; } &
*/

#include <X11/extensions/XTest.h>

int
main(int argc, char **argv)
{
    Display *dpy;
    KeySym sym;
    KeyCode code;
    int i;

    dpy = XOpenDisplay(NULL);
    if (!dpy)
	return 1;

    for (i=1; i<argc; i++) {
	sym = XStringToKeysym(argv[i]);
	if (sym == NoSymbol)
	    continue;
	code = XKeysymToKeycode(dpy, sym);
	if (code == 0)
	    continue;
	XTestFakeKeyEvent(dpy, code, True, 0);
	XTestFakeKeyEvent(dpy, code, False, 0);
	XFlush(dpy);
    }

    XCloseDisplay(dpy);

    return 0;
}