Ahh... you want a named semaphore... There is such a thing in POSIX but it
is only portable if their names begin with "/" (which tells OS to put it
where appropriate). I believe without leading slash they end up in current
directory, but we can't rely on that... too bad. Glad UDS it is getting
supported on my platform, lol ;)
This will however leave QNX4 in the dust, if anyone cares. And most likely
BeOS, MP/X and half dozen other platforms. Which prompts me to think if it
would not be better to come up with a platform independent 'namespace sync'
mechanism. Can't we use fcntl()-based lock for that purpose? That's what
apache is doing apparently (one of variants).
-- igor
> On Wed, 8 May 2002, Igor Kovalenko wrote:
>
> > Can you be more specific? What required syntax? I was talking about
> > named pipe vs UDS socket...
>
> Sorry, I meant semantics.
>
> A pipe can have multiple readers and multiple writers. This is
> no use for us.
>
> A listening SOCK_STREAM Unix domain socket can have no readers or
> writers, but only one listener (well, except that other processes
> can inherit or be passed the socket). You have to connect() (and
> the server must accept()) before read and write do anything. But
> we have no use for that here. It's just an exclusive-only mutex
> whose namespace is the filesystem.
>
> It really is like a TCP socket, except that the address namespace
> is the filesystem, and thus it's not available remotely.
>
> Think of it as a TCP socket without the "which address and port
> do I use, and how do I keep it secure" issues.
>
> Matthew.
>