Experimental Physics and Industrial Control System

Hi Andrew:

> .. "field(value)" seems to have always been the default...
> What does your older pvget show for its help text?

Same as the new one:

  -r <pv request>:   Request, specifies what fields to return and options, default is 'field(value)'

> this change in behavior looks like a regression now that you point it out.

Yes, it is a change. In the old code, I find this in EPICS-CPP-4.6.0/pvAccessCPP/pvtoolsSrc/pvget.cpp:

               // probe for value field
...
                        if (structure.get() == 0 || structure->getField("value").get() == 0)
                        {
                            // fallback to structure
                            mode = StructureMode;
                            pvRequest = CreateRequest::create()->createRequest("field()");
                        }

That must be what made it tolerant to a missing "value" field, falling back to getting everything.

The new pvget code doesn't update the pvRequest. In the printout section, it's prepared to say "no value field" if there is none, but then it's already too late, because it forced the "field(value)" request and failed, instead of falling back to "field()".

If this was a democracy, I'd vote for putting the more tolerant code back in.

Thanks,
-Kay

Replies:

Re: "Invalid request" for simply "pvget ThePV" when all other requests seem fine Michael Davidsaver

References:

"Invalid request" for simply "pvget ThePV" when all other requests seem fine Kasemir, Kay

Re: "Invalid request" for simply "pvget ThePV" when all other requests seem fine Andrew Johnson

Re: "Invalid request" for simply "pvget ThePV" when all other requests seem fine Kasemir, Kay

Re: "Invalid request" for simply "pvget ThePV" when all other requests seem fine Andrew Johnson

Navigate by Date:

Prev: Re: "Invalid request" for simply "pvget ThePV" when all other requests seem fine Andrew Johnson

Next: Re: "Invalid request" for simply "pvget ThePV" when all other requests seem fine Michael Davidsaver

Index: 2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  <2018>  2019  2020  2021  2022  2023  2024 

Navigate by Thread:

Prev: Re: "Invalid request" for simply "pvget ThePV" when all other requests seem fine Andrew Johnson

Next: Re: "Invalid request" for simply "pvget ThePV" when all other requests seem fine Michael Davidsaver

Index: 2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  <2018>  2019  2020  2021  2022  2023  2024