#include <sys/file.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

int
main (int argc, char *argv[])
{
        int          fd       = -1;
        char        *filename = NULL;
        struct flock lock     = {0, };
        int          i        = 0;
        int          ret      = -1;

        if (argc != 2) {
                fprintf (stderr, "Usage: %s <filename> ", argv[0]);
                goto out;
        }

        filename = argv[1];

        fd = open (filename, O_RDWR | O_CREAT, 0);
        if (fd < 0) {
                fprintf (stderr, "open (%s) failed (%s)\n", filename,
                         strerror (errno));
                goto out;
        }

        lock.l_type = F_WRLCK;
        lock.l_whence = SEEK_SET;
        lock.l_start = 1;
        lock.l_len = 1;

        while (i < 100) {
                lock.l_type = F_WRLCK;
                ret = fcntl (fd, F_SETLK, &lock);
                if (ret < 0) {
                        fprintf (stderr, "fcntl setlk failed (%s)\n",
                                        strerror (errno));
                        goto out;
                }

                lock.l_type = F_UNLCK;
                ret = fcntl (fd, F_SETLK, &lock);
                if (ret < 0) {
                        fprintf (stderr, "fcntl setlk failed (%s)\n",
                                        strerror (errno));
                        goto out;
                }

                i++;
        }

        ret = 0;

out:
        return ret;
}