This is the mail archive of the
cygwin-developers
mailing list for the Cygwin project.
Re: sem_init() fails (when used in a certain way)
On Mar 30 08:07, Eric Blake wrote:
> On 03/30/2011 02:01 AM, Corinna Vinschen wrote:
> > Thanks for clarifying. We just have to keep in mind to return EINVAL
> > rather than EFAULT.
> >
> > Btw., glibc does not test the validity of the semaphore at all. If you
> > give an invalid sem pointer to the sem functions, it just crashes:
>
> Which is allowed by POSIX. In fact, my understanding is that older
> POSIX used to require that invalid objects be identified, until Ulrich
> argued that there are pathological cases (such as reuse of heap that
> already contains contents from a prior pointer) that make such detection
> practically impossible in any reasonable amount of time, so POSIX was
> intentionally relaxed to no longer require detection of invalid objects
> (they are just as undefined as any other use of a bad pointer) in order
> to cater to glibc.
So we could not add myfault handler's *and* remove the is_good_object
tests everywhere and we would still be on the safe side of Linux and
POSIX, right? That would perhaps speed up extensive usage of the
pthread functions noticably.
Corinna
--
Corinna Vinschen Please, send mails regarding Cygwin to
Cygwin Project Co-Leader cygwin AT cygwin DOT com
Red Hat