Simulate CAPS LOCK press in Xlib

Question

How do I simulate a CAPS LOCK on and off depress using Xlib?

Answer 1

#include <X11/X.h>
#include <X11/Xlib.h>
#include <X11/keysym.h>
#include <X11/extensions/XTest.h>

// Function: Click Key (press and release key)
void click_key( Display* p_display , KeyCode keycode ) {

    XTestFakeKeyEvent( p_display , keycode , True  , 0 ); // key press event
    XTestFakeKeyEvent( p_display , keycode , False , 0 ); // key release event
    XFlush( p_display );

    return;
}

// Main
int main() {

    Display* p_display = XOpenDisplay( NULL );
    KeySym keysym = XK_VoidSymbol;
    KeyCode keycode = NoSymbol;

    keysym = XK_Caps_Lock;
    keycode = XKeysymToKeycode( p_display , keysym );

    click_key( p_display , keycode ); // activates CapsLock
    click_key( p_display , keycode ); // deactivates CapsLock

    XCloseDisplay( p_display );
    return 0;
}

• http://tronche.com/gui/x/xlib/
• http://xopendisplay.hilltopia.ca/index.html

Answer 2

#include "stdio.h"
#include "X11/Xlib.h"
#include "X11/keysym.h"
#include "time.h"

Display *display=NULL;
unsigned int keycode;

int main ()
{
display = XOpenDisplay(NULL);
keycode = XKeysymToKeycode(display, XK_Caps_Lock);

printf ("\npressed\n");
XTestFakeKeyEvent(display, keycode, True, CurrentTime);
XFlush(display);
printf ("\nreleased\n");
XTestFakeKeyEvent(display, keycode, False, CurrentTime);
XFlush(display);
sleep(3);

/* type something here */

printf ("\npressed\n");
XTestFakeKeyEvent(display, keycode, True, CurrentTime);
XFlush(display);
printf ("\nreleased\n");
XTestFakeKeyEvent(display, keycode, False, CurrentTime);
XFlush(display);
sleep(3);

return 0;
}

Replace " " -s with < > for header files. and compile using gcc main.c -lX11 -lXtst

Posted above solution in my blog