> I had read the earlier proposal to mean that named semaphores would also
> go in globally accessible memory, which would have been a real problem.
Yes, this is true. But there is no such thing as read permission,
write permission. Only a general permission the use the semaphore.
So the use of a mapped page for semaphores might still be usable.
Or has anybody a better proposal?
> Because of the security problems, I don't believe global unnamed
> semaphores are useful.
But they have to be available. You can place the semaphore
descriptor in a shared memory segment and make it available to
other processes.
> Process local semaphores are useful for places
> where you need speed, and named semaphores for global access. But if
> you have global unnamed semaphores with no security, they really are
> pointless....
POSIX.1 always says:
>>Either the implemenation shall support the XXX function as described
above or the XXX function shall fail.<<
This means we really have to implement it.
-- Uli
--------------. drepper@cygnus.com ,-. Rubensstrasse 5
Ulrich Drepper \ ,--------------------' \ 76149 Karlsruhe/Germany
Cygnus Support `--' drepper@gnu.ai.mit.edu `------------------------