How to change Keyboard Layout (a X11 API solution)

Question

I want to change keyboard layout in Linux by programming, What X11's API function does this?

Answer 1

I found one good solution. It's a c++ class wrriten by Jay Bromley, that I can add to my app and using it.

source code

It's very easy to use:

#include "XKeyboard.h"

XKeyboard xkb;

std::string cGrpName=xkb.currentGroupName(); //return somethings like "USA"
std::string cGrpSymb=xkb.currentGroupSymbol(); //return somethings like "us"

xkb.setGroupByNum(0);//set keyboard layout to first layout in available ones

you can read source code and found some another useful functions. for compiling standalone version you need to un-comments "int main" function present in "XKeyboard.cpp" (or write your own main.cpp) and use somethings like this:

g++ *.cpp -o getxkblayout -L/usr/lib -lX11

Answer 2

I'm not sure what the X11 library function is but setxkbmap is the bash command I use to achieve it. Maybe searching along these lines will find what you want (or at a pinch you could just execute the bash command).

Example

setxkbmap dvorak
setxkbmap us

EDIT: After a strace of setxkbmap didn't turn up anything useful I suggest just calling:

system(“setxkbmap us”);

Answer 3

A pure X11 API solution should look something like this:

#include <stdio.h>
#include <X11/XKBlib.h>

int main() {
    Display* _display;
    char* displayName = "";
    _display = XOpenDisplay(displayName);

    XkbDescRec* _kbdDescPtr = XkbAllocKeyboard();
    XkbGetNames(_display, XkbSymbolsNameMask, _kbdDescPtr);
    Atom symName = _kbdDescPtr -> names -> symbols;
    char* layoutString = XGetAtomName(_display, symName);

    XCloseDisplay(_display);
    printf("%s\n", layoutString);
}

Compile with -lX11 flag

This will print something like pc+us+inet(evdev) for English (USA) qwerty layout, pc+ru+us:2+inet(evdev) for Russian йцукен layout, pc+us(dvorak)+us:2+inet(evdev) for English dvorak layout.

Answer 4

Yesterday I was trying to make auto layuout switcher to EN for Google's xsecurelock. I tryed to find some existing solutions for X11 api, but...

So I decided to write my own with some help from S. Razi. Here is the code: (run with gcc -lX11)

#include <stdio.h>
#include <stdlib.h>
#include <X11/XKBlib.h>

int main(){

Display* _display;
char* displayName = "";
_display = XOpenDisplay(displayName);

int _deviceId = XkbUseCoreKbd;
int i = 0;
int _groupCount = 0;

XkbDescRec* kbdDescPtr = XkbAllocKeyboard();
if (kbdDescPtr == NULL) {
printf("%s\n", "Failed to get keyboard description."); 
return False;
}

kbdDescPtr->dpy = _display;
if (_deviceId != XkbUseCoreKbd) {
    kbdDescPtr->device_spec = _deviceId;
}

XkbGetControls(_display, XkbAllControlsMask, kbdDescPtr);
XkbGetNames(_display, XkbSymbolsNameMask, kbdDescPtr);
XkbGetNames(_display, XkbGroupNamesMask, kbdDescPtr);

         /* count groups */

Atom* groupSource = kbdDescPtr->names->groups;
if (kbdDescPtr->ctrls != NULL) {
    _groupCount = kbdDescPtr->ctrls->num_groups;
} else {
    _groupCount = 0;
    while (_groupCount < XkbNumKbdGroups &&
           groupSource[_groupCount] != 0) {
        _groupCount++;
    }
}

        /* get group names */
Atom* tmpGroupSource = kbdDescPtr->names->groups;
Atom curGroupAtom;
char* groupName;
for (i = 0; i < _groupCount; i++) {
    if ((curGroupAtom = tmpGroupSource[i]) != None) {
        char* groupNameC = XGetAtomName(_display, curGroupAtom);
            if (groupNameC == NULL) {
            continue;

        } else {
            groupName =  groupNameC;
            char *temp = "English";

            if (strncmp(temp, groupName, 7) == 0){
                printf ("%s\n", groupName);
                printf ("%d\n", i);
                XkbLockGroup(_display, _deviceId, i);
                XFree(groupNameC);
                XCloseDisplay(_display);
            }
            return 0;
        }
    } 
}
}

Here you can change char* temp = "English" to name of the group of your layout (exmp: "Russian"), and this simple code will switch your current layout :)