Replace of XKeycodeToKeysym

Question

When I try to build my code with the X11 headers in Ubuntu 12.04

    case KeyPress:
        xcommon_update_server_time( event.xkey.time );
        /* if( event.xkey.state & ShiftMask ) arg |= I_SHIFT; */
        /* this alternate approach allows handling of keys like '<' and '>' -- mrallen */
        if( event.xkey.state & ShiftMask ) {
            mykey = XKeycodeToKeysym( display, event.xkey.keycode, 1 );
        } else {
            mykey = XKeycodeToKeysym( display, event.xkey.keycode, 0 );
        }

What is the expected result? Compiles.

What happens instead?

warning: 'XKeycodeToKeysym' is deprecated (declared at /usr/include/X11/Xlib.h:1695) [-Wdeprecated-declarations]

As a result of https://bugs.freedesktop.org/show_bug.cgi?id=5349 XKeycodeToKeysym is now properly marked as being deprecated.

How to fix my code for warning free and correct build?

Thanks

Solution 1

Provided XKB is available then the simplest replacement for XKeycodeToKeysym is:

#include <X11/XKBlib.h>
/* which declares:
     KeySym XkbKeycodeToKeysym(Display *dpy, KeyCode kc,
                               unsigned int group, unsigned int level); */

... and then the original question's code could become:

    mykey = XkbKeycodeToKeysym( display, event.xkey.keycode, 
                                0, event.xkey.state & ShiftMask ? 1 : 0);

notes:

• this chromium bug report discusses both the XGetKeyboardMapping and the XKB replacement solutions.
• XkbKeyCodeToKeysym man page on X.org

Solution 2

Show you an example and you can do the same on your source.

Replace

keysym = XKeycodeToKeysym(dpy,xe->xkey.keycode,0)

with

{
    int keysyms_per_keycode_return;
    KeySym *keysym = XGetKeyboardMapping(dpy,
        xe->xkey.keycode,
        1,
        &keysyms_per_keycode_return);

    /* do something with keysym[0] */

    XFree(keysym);
}

Not forgetting to free the return value.

Comments

[AlwaysLearning]

This should be the accepted answer. It takes care of ShiftMask as well, which saves a lot of headache. Only why does it say "provided XKB is available"? Does it happen that X11 comes without XKB?

[Noitidart]

I am also curious @AlwaysLearning , is it possible for XKB to not be there ? In all the X11 systems I tested it was there.

[Brent Baccala]

XKB isn't there in the Ubuntu 16 tightvnc server.