Chung Kil Kim wrote:
> while (1)
> {
> if (-1 == fcntl (fd_no, F_GETLK, &lock_info)) /* get lock info */
> {
> perror ("fcntl()");
> exit (1);
> }
> I run this program. But end with printing following message.
> fcntl(): Invalid argument
>
> What is the wrong?
What is wrong is that you don't understand what the F_GETLK fcntl()
option is for.
You are supposed to fill in the lock_info structure with the details
of a lock that you wish to obtain.
If you could obtain the requested lock, then lock_info.l_type is set
to F_UNLCK, and the other members of lock_info are unchanged.
If there is another lock in existence which prevents you from
obtaining the requested lock, then the details of that lock are
returned in lock_info.
You haven't filled in lock_info before calling fcntl(), so the lock
that it describes is almost certainly going to be invalid, resulting
in fcntl() returning -1 and setting errno to EINVAL.
--
Glynn Clements <[EMAIL PROTECTED]>
