Experimental Physics and
Industrial Control System

Michael Davidsaver <[email protected]> · Thu, 6 Jul 2017 10:03:14 +0200

Which version of EPICS Base are you work with?  Also, is the source for
the CA client available?

On 07/06/2017 08:36 AM, Abdalla  Ahmad wrote:
> We started deploying Scientific Linux 7.x and one of the tools that has
> a problem is a custom Basler camera client. Every time I run the client
> I get this error message:
> 
>  
> 
> CAC: Failed to subscription request during channel connect

Seems like the message comes from nciu.cpp if "send" is omitted.

https://github.com/epics-base/epics-base/blob/3.16/src/ca/client/nciu.cpp#L533

> What does this error mean? The tool works fine on an SL6.4 machine.

Exceptions caught here are probably being thrown comes from:

https://github.com/epics-base/epics-base/blob/3.16/src/ca/client/tcpiiu.cpp#L1558

I you want to troubleshoot this further you can edit nciu::resubscribe()
in nciu.cpp and replace

>             catch ( ... ) {
>                 errlogPrintf ( "CAC: failed to send subscription request "
>                                "during channel connect\n" );
>             }

with

>             catch (cacChannel::badEventSelection& e) {
>                 errlogPrintf ( "CAC: badEventSelection send subscription request "
>                                "during channel connect\n" );
>             }
>             catch (cacChannel::msgBodyCacheTooSmall& e) {
>                 errlogPrintf ( "CAC: msgBodyCacheTooSmall send subscription request "
>                                "during channel connect\n" );
>             }
>             catch (std::exception& e) {
>                 errlogPrintf ( "CAC: \"%s\: send subscription request "
>                                "during channel connect\n", e.what() );
>             }
>             catch ( ... ) {
>                 errlogPrintf ( "CAC: failed to send subscription request "
>                                "during channel connect\n" );
>             }

which should give tell us which error condition occurs.

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System