Pseudo Ports

#define _XOPEN_SOURCE
#include <stdlib.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>  /* String function definitions */
#include <unistd.h>  /* UNIX standard function definitions */
#include <errno.h>   /* Error number definitions */
#include <termios.h> /* POSIX terminal control definitions */

int main()
{
    int fd, n = 0, error = 0;
    int chk1 = -1, chk2 = -1;
    char *dato;
    char *PTS;
    fd = open("/dev/ptmx", O_RDWR);
    if (fd == -1)
    {
        printf ("Error opening the serial device");
        exit(0);
    }

    PTS = ptsname(fd);
    printf("The slave port name is: %s", PTS);

    chk1 = grantpt(fd);
    chk2 = grantpt(fd);

    if (chk1 == -1 | chk2 == -1)
        printf("\nPort access denied");

    getchar();

    error = read(fd,dato,4);

    if (error = 0)
    printf("\nNothing in buffer");
    else
    printf("%s",dato);
    close(fd);
}