Experimental Physics and
Industrial Control System

"Wang Xiaoqiang (PSI)" <[email protected]> · Wed, 4 Mar 2015 10:11:28 +0000

Hi Jamie, Kay,

The problem is indeed with empty strings. That causes an invalid zero sized gdd value.
The fix is to ensure it is null terminated.
See my comment at https://code.google.com/p/pcaspy/issues/detail?id=14

It is a one-liner fix, which you can apply on your installation easily.

Best
Xiaoqiang

> On 03 Mar 2015, at 22:40, Jameson Graef Rollins <[email protected]> wrote:
> 
> On Tue, Mar 03 2015, "Wang Xiaoqiang (PSI)" <[email protected]> wrote:
>> Since this is a pcaspy only bug, I created the report in the project issue tracker.
>> https://code.google.com/p/pcaspy/issues/detail?id=14
>> 
>> Thanks for the detective work to reveal the bug.
> 
> Hey, Xiaoqiang.  I think the problem might actually be more insidious
> than I originally thought.  It seems that if the value for a char array
> is every set to an array of null bytes this described error will be
> thrown when a monitoring clients connects to the channel.  Clients that
> are already connected to the channel will also throw an error and not
> update their values if the value is set to an array of null bytes.
> 
> I thought before that this problem was relatively innocuous, since it
> would have only been a startup problem.  But now I see that whenever my
> pcaspy application clears the char array PV, all connected clients show
> the bad behavior.
> 
> I haven't had any luck tracking down where in the pcaspy the problem may
> be coming from.
> 
> jamie.

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System