selection-owner.c

#include <stdio.h>
#include <stdlib.h>

#include <X11/Xlib.h>
#include <X11/Xatom.h>
#include <X11/Xmu/Atoms.h>

#define die(fmt, args...)\
    fprintf(stderr, fmt "\n", ##args);\
    exit(1)

int
main(void)
{
    Display *dsp;
    Window selection;

    dsp = XOpenDisplay(NULL);
    if(!dsp) {
        die("Couldn't connect to X");
    }

    selection = XGetSelectionOwner(dsp, XA_PRIMARY);

    if(selection == None) {
        fprintf(stderr, "no selection owner\n");
    } else {
        printf("0x%x\n", selection);
    }

    XCloseDisplay(dsp);
    return 0;
}