🚀 go-pugleaf

In article <8201@dog.ee.lbl.gov> kushner@ux5.lbl.gov (Gary Kushner) writes:
>Does anyone know if there are counting semaphores in OS/2 version
>1.2??  I have a resource that can have multiple users, I want to
>use a counting semaphore to control access.  I would like to be
>able to DosSemClear() the semaphore N times, and then other
>processes could DosSemRequest() the semaphore that number of times
>without being blocked.
>

private system semaphores (DosCreateSem with parameter CSEM_PRIVATE) have to be
cleared as many times as they have been set. The reason for this was that you
should be able to write recursive functions that request ownership of a
resource in each recursion level and free the resource every time they 'return'.

Bye,
-- 
Fealon, a.k.a. Frank Fuchs (Foxware), fealon@nadia.stgt.sub.org

>private system semaphores (DosCreateSem with parameter CSEM_PRIVATE) have to be
>cleared as many times as they have been set. The reason for this was that you
>should be able to write recursive functions that request ownership of a
>resource in each recursion level and free the resource every time they 'return'.

Actually what I meant was more like the traditional P and V
operations.  I wanted to be able to initialize a SEM to a count
and then have threads be able to P (request) the sem as many
times as the original count.  Used for controlling resources
that can have more than one and less than all users.

It turned out the code to implement counting semaphores in OS/2
was quite trivial.  It is just to bad that Microsoft didn't
include them in the first place.

-Gary