Re: [foxboro] Programming in C with FoxApi

This may be a long-shot but I thought I would
pass it on anyways.

I have experienced a similar situation in the past 
where my application would hang while trying to 
close a dataset.

I was then advised that I should not call clsset
from within a signal handler.

The foxapi server is using message queues (i believe)
to communicate with client applications.
It seems that the client application process can't be advised
of the arrival of a message if some particular signal is masked.
This situation may exist while the application process is executing 
in the context of a signal handler.
In that case the application would hang, waiting for a signal that
it can't receive (deadlock).
I am not sure whether this problem was particular to a specific
Solaris release or whether it is normal message queue behaviour.

Are you calling the scopen function from within a signal handler?

If that is the case because you have to open datasets in response 
to some external event,
use the signal handler to raise a flag and open the dataset
from the context of your main function.

Alain G.

-----Original Message-----
From: Johnson, Alex (Foxboro) [mailto:ajohnson@xxxxxxxxxxx]
Sent: Wednesday, August 27, 2003 9:34 PM
To: foxboro@xxxxxxxxxxxxx
Subject: Re: [foxboro] Programming in C with FoxApi


There is no reason that the list should hang. You should get error codes on
the tags and the call should return.

Alex Johnson
Invensys Systems, Inc.
10707 Haddington
Houston, TX 77043
713.722.2859 (office)
713.722.2700 (switchboard)
713.932.0222 (fax)
ajohnson@xxxxxxxxxxx
For the latest information on ArchestrA, go to
www.invensys.com/Archestra.html.

 -----Original Message-----
From:   Alexis BOUTILLIER [mailto:alexis.boutillier@xxxxxxxxxx] 
Sent:   Wednesday, August 27, 2003 3:05 AM
To:     foxboro@xxxxxxxxxxxxx
Subject:        [foxboro] Programming in C with FoxApi

Dear,

I still have a probleme to open list in read write state.
I made a program that open 612 tags for read write and about 60 for read. I
never had a problem to open the 60 tag in read state but i had problems to
open the tags in read write. 
I use the scopen fonction to open the list and the list open correctly (like
i can see in "som") but the fonction never return and hang up there when all
the tags are opens.
I tried to open the same list in read state and there were no problem.

Is there somethings special to do to open a list in read-write ?

thanks in advance
 
 
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