#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>
#include <err.h>
#include <errno.h>

int
main(int argc, char *argv[])
{
    int fd;

    fd = open(argv[1], O_WRONLY);
    if (fd != -1) {
        printf("[PID %ld] File \"%s\" already exists\n",
                (long) getpid(), argv[1]);
        close(fd);
    } else {
        if (errno != ENOENT) {
            err(EXIT_FAILURE, "open");
        } else {

            // -------------------------------------------------
            printf("[PID %ld] File \"%s\" doesn't exists yet\n",
                    (long) getpid(), argv[1]);
            if (argc > 2) {
                sleep(5);
                printf("[PID %ld] Done sleeping\n", (long) getpid());
            }
            // -------------------------------------------------

            fd = open(argv[1], O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR);
            if (fd == -1)
                err(EXIT_FAILURE, "open()-2");

            printf("[PID %ld] Created file \"%s\" exclusively\n",
                    (long) getpid(), argv[1]);
        }
    }
    exit(EXIT_SUCCESS);
}