Linux - Arduino key : Linux part

#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <termios.h>
#include <unistd.h>
#include <xdo.h>
#include <X11/Xlib.h>
#include <X11/keysym.h>

int open_serial(char *port);
void close_serial(int fd);

int main()
{
    sleep(1); //wait 1 second
    printf("creating xdo...\n");
    xdo_t* myXdo = xdo_new(NULL);
    printf("xdo created...\n");

    printf("getting display...\n");
    // Obtain the X11 display.
        Display *display = XOpenDisplay(0);
        if(display == NULL)
        {
            printf("could not open display, exiting...\n");
            return -1;
        }

    printf("getting root window...\n");
    // Window focus
        int revert;
        Window winFocus;

    int fd = open_serial("/dev/ttyACM0");
    if(fd == 0)
    {
        printf("serial error, exiting...\n");
        return -1;
    }
    char buff;
    unsigned int rd;


    while(1)
    {
        XGetInputFocus(display, &winFocus, &revert); //la ventana que tiene el focus
        rd = read(fd, &buff, 1);
        switch(fd)
        {
            case 1:
                xdo_keysequence_up(myXdo, winFocus, "A",  12000);
                xdo_keysequence_down(myXdo, winFocus, "A",  12000);
                break;
            case 2:
                xdo_keysequence_up(myXdo, winFocus, "B",  12000);
                xdo_keysequence_down(myXdo, winFocus, "B",  12000);
                break;
            case 3:
                xdo_keysequence_up(myXdo, winFocus, "C",  12000);
                xdo_keysequence_down(myXdo, winFocus, "C",  12000);
                break;
            default:
                break;
        }
    }

    printf("exiting...\n");
    XCloseDisplay(display);
    xdo_free(myXdo);
    close_serial(fd);
    return 0;
}

int open_serial(char *port)
{
    int fd = open(port, O_RDWR | O_NOCTTY | O_NDELAY);
    if(fd == -1)
    {
        printf("Could not open %s\n", port);
        return 0;
    }
    fcntl(fd, F_SETFL, 0);
    printf("Port %s has been sucessfully opened and %d is the file description\n", port, fd);
    return fd;
}

void close_serial(int fd)
{
    close(fd);
}