How to change Keyboard Layout (a X11 API solution) - c

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 :)