Re: Native Windows, Apache Portable Runtime

Tom Lane wrote:
> 
> mlw <markw@mohawksoft.com> writes:
> > Upon doing some inspection of apache 2.x, it seems that me making a SysV
> > Windows .DLL for PostgreSQL, while a cool project, would be unnecessary.
> 
> > The APR (Apache Portable Runtime) seems to have all the necessary support.
> 
> Does it?  AFAICT they intend to provide mutexes not counting semaphores.
> Their implementation atop SysV semaphores would work the way we need
> (ie, remember multiple unlocks arriving before a lock operation), but
> I'm unclear on whether any of the other ones would.

Ok, you got me, they do not provide a semaphore, only mutexes. We should be
able to use APR in PostgreSQL, I'll implement a semaphore directory for Windows
and UNIX. Someone will have to handle the Netware, beos and OS/2.
(I may be able to do the OS/2 stuff, but it has, in fact, been 6 years since I
even looked at OS/2 in any form.)

We could provide a PGSemaphore based on an APR mutex and a counter, but I'm not
sure of the performance impact. We may want to implement a "generic" semaphore
like this and one optimized for platforms which we have development resources.