#include <fcntl.h>
#include <err.h>
#include <stdlib.h>
#include <unistd.h>

int
main(void)
{
    int fd;

    fd = open("log", O_CREAT | O_EXCL | O_WRONLY, S_IRWXU);
    if (fd == -1)
        err(EXIT_FAILURE, "open");
    if (unlink("log") == -1)
        err(EXIT_FAILURE, "unlink");

    if (write(fd, "salam\n", 6) == -1)
        err(EXIT_FAILURE, "write");

    sleep(10);

    close(fd);

    exit(EXIT_SUCCESS);
}