#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <X11/Xlib.h>

void openDisplay(char* display) 
{
    Display *d = NULL;

    printf("trying to open display %s\n", display);

    d = XOpenDisplay(display);
    if (d) {
        printf("successfully opened display %s\n", display);
        XCloseDisplay(d);
        if (d) free(d);
    }
    else {
        printf("could not open display %s\n", display);
    }
}

#define MAX_HOSTNAME_LEN 1024

int main()
{
    char* display = getenv("DISPLAY");
    if(!display){
        printf("Could not determine your current display from the DISPLAY environment "
                "variable.\nAre you running this program in X?\n");
        exit(1);
    }
    
    char* display2 = (char*) malloc(MAX_HOSTNAME_LEN + strlen(display) + 1);
    gethostname(display2, MAX_HOSTNAME_LEN);
    strncat(display2, display, strlen(display));

    openDisplay(display);
    openDisplay(display2);

    free(display2);
    exit(0);
}