#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>

int main(int argc, char **argv) {
    int ptm;
    char ptsname[64];

    if ((ptm = open("/dev/ptmx", O_RDWR)) < 0) {
        fprintf(stderr, "%s: %s: %s: %s\n", argv[0], "open()", "/dev/ptmx", strerror(errno));

        goto error_open_ptmx;
    }

    if (grantpt(ptm) < 0) {
        fprintf(stderr, "%s: %s: %s\n", argv[0], "grantpt()", strerror(errno));

        goto error_grantpt_ptm;
    }

    if (unlockpt(ptm) < 0) {
        fprintf(stderr, "%s: %s: %s\n", argv[0], "unlockpt()", strerror(errno));

        goto error_unlockpt_ptm;
    }

    if (ptsname_r(ptm, ptsname, sizeof(ptsname)) < 0) {
        fprintf(stderr, "%s: %s: %s: %s\n", argv[0], "ptsname_r()", "/dev/ptmx", strerror(errno));

        goto error_ptsname_r_ptm;
    }

    printf("pts %s\n", ptsname);

    close(ptm);

    return 0;

error_unlockpt_ptm:
error_grantpt_ptm:
error_ptsname_r_ptm:
    close(ptm);

error_open_ptmx:
    return 127;
}