Re: file-locking and postmaster.pid

[korry <korry(at)appx(dot)com>]

> Certainly on all platforms there must be *some* locking primitive.  We
> just need to figure out the appropiate parameters to fcntl() or flock()
> or lockf() on each.
Right.

> The Win32 API for locking seems mighty strange to me.

Linux/Unix byte locking is advisory (meaning that one lock can block another lock, but it can't block a read).  Win32 locking is mandatory (at least in the most portable form) so a lock blocks a reader.  To avoid that problem, youlock a byte that you never intend to read (that is, you lock a byte past the end of the file).  Locking past the end-of-file is portable to all Unix/Linux systems that I've seen (that way, you can lock a region of a file before you grow the file).

        -- Korry