Experimental Physics and
Industrial Control System

Michael Davidsaver <[email protected]> · Sun, 9 Oct 2016 14:37:51 -0400

Mark,

First, the *Requester classes are somewhat "transient", so it's probably
not a good idea to combine this with ADDriver, which isn't.  You may
also get into trouble should you wish to have one ADDriver associated
with more than on PVA channel (as you have inadvertently done).

Disconnecting is done with Channel::destory(), not the ChannelRequester.
 For various annoying reasons it is *not* sufficient to let a connected
Channel be destroyed (as in c++ destructor).  Calling Channel::destory()
is mandatory.

You may (or not) find the following test code useful in understanding
the Channel/Monitor lifecycle.

https://github.com/mdavidsaver/pva2pva/blob/master/testApp/testtest.cpp

Michael

On 10/09/2016 01:24 PM, Mark Rivers wrote:
> I have some EPICS V4 client code that basically does the following:
> 
>  
> 
> class epicsShareClass pvaDriver : public ADDriver,
> 
>         public virtual epics::pvAccess::ChannelRequester,
> 
>         public virtual epics::pvData::MonitorRequester
> 
>  
> 
> …
> 
>  
> 
>     try
> 
>     {
> 
>         ClientFactory::start();
> 
>         m_provider = getChannelProviderRegistry()->getProvider("pva");
> 
>         m_channel = m_provider->createChannel(m_pvName, m_thisPtr,
> m_priority);
> 
>         m_pvRequest = CreateRequest::create()->createRequest(m_request);
> 
>         m_monitor = m_channel->createMonitor(m_thisPtr, m_pvRequest);
> 
>     }
> 
>     catch (exception &ex)
> 
>     {
> 
> …
> 
>     }
> 
>  
> 
> The monitorConnect() and monitorEvent() methods are being called as
> expected, and everything is working.
> 
>  
> 
> Now I want to extend the code to allow the current channel to be
> disconnected, and call m_provider->createChannel() to a different
> channel.  What do I need to do for this?  I found that if I just call
> m_provider->createChannel with a different p_pvName it does not throw an
> exception, but it appears to simply stay connected to the existing channel.
> 
>  
> 
> Thanks,
> 
> Mark
> 
>  
> 

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System