Experimental Physics and
Industrial Control System

[email protected] · Tue, 26 Feb 2013 10:17:12 -0800 (PST)

Hi Ben,

Thank you for your reply. I have now disabled preemptive callback. I am
using ca_poll to process the CA client and FileDescriptorManager.process
to run the portable channel access server. These are called together in a
single loop. However, once the CA client has attached to a number of
process variables, the CA background activity that runs due to the ca_poll
seems to delay the call to FileDescriptorManager.process too much. This
results in calls to caget for process variables in the portable channel
access server timing out. Is there another way to do this? Also, is there
a way to avoid having the CA client search for process variables on the
portable channel access server, but still look for them on the localhost?

Thank you,
Patrick

> On Monday, February 25, 2013 14:58:36 [email protected] wrote:
>> I think it turns out that the problem was
>> that I actually had preemptive callback enabled and I should not have.
>
> Yes. If you use preemptive callback (i.e. multithreaded CA client) don't
> create a FileDescriptorManager. It is only needed for single-threaded
> clients
> and can be used to centralize the call to select in case the CA client is
> used
> together with other stuff that wants to call select (such as a GUI
> library).
>
> Cheers
> --
> Ben Franksen
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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System