Re: light weight user level semaphores

Alan Cox
2001-04-19T19:37:00Z

> I fail to see how this works across processes. How can you generate a
> file descriptor for this pipe in a second process which simply shares
> some memory with the first one? The first process is passive: no file
> descriptor passing must be necessary.

mknod foo p. Or use sockets (although AF_UNIX sockets are higher latency)
Thats why I suggested using flock - its name based. Whether you mkstemp()
stuff and pass it around isnt something I care about

Files give you permissions for free too

> Note that semaphores need not always be shared between processes.
> This is a property the user has to choose. So the implementation can
> be easier in the normal intra-process case.

So you have unix file permissions on them ?