LabView hangs when clearcase view is disconnected

[kmc]

I am using clearcase for source control and I am having a problem where LabView hangs when I open a VI which contains subVIs that are located on my clearcase view drive and that drive is disconnected.  I would expect that LabView wouldn't be able to find the subVI and ask me for the location but it just hangs there until I reconnect my clearcase view drive.  I am able to reproduce this problem by disconnecting my machine from the network, (thus disconnecting from teh clearcase virtual drive/view) and trying to open a VI.  This causes LabView to hang and if I reconnect my machine to the network, LabView will come back and I see it searching my clearcase drive for the subVI which it finds and then everything is fine.  I've tried changing the search path, which was set to point to my clearcase drive, to a local drive but that doesn't seem to work.  Has anyone seen or heard of this happening?  Any feedback would be appreciated.

Thanks. 

[gmart]

When you open a VI and source control is configured, LabVIEW queries the provider (i.e. Clearcase) to get the status of the file (is it checked out, in, etc) and its hierarchy. So what you are seeing is expected. 95% of the time when network connections and traffic are operating at full steam, you don't notice the communication. But when network traffic is loaded or the connection to the provider's server is lost, you see the behavior of LabVIEW "hanging" waiting for a response from the provider.

There is currently no mechanism to prompt during user operations for new connection information. If the configuration changed, you need to update the settings in the Source Control options page (via Tools>>Source Control>>Configure Source Control).

[kmc]

Thanks for the reply.

I am using LabView 7.1 which from what I understand does not have built in support for ClearCase, therefore I do not have source control configured with regards to LabView.  What I have done is set up my VI search path to point at the my ClearCase view/vob.  Thus what I would expect is that when it tries to find the subVI using that search path which is no longer there, it would prompt me for a new location.   Something else I have done was to remove the clearcase view from the VI search path and replace it with a local drive search path.  This didn't seem to work either, LabView still hung until I restored my network connection at which point it woke up and started looking for subVIs.  Note that while it was "hung" I couldn't even kill the process thru windows task manager, it remained in the process list until the connection was restored at which point it ended.  I understand that LabView 8 does support ClearCase as a source control provider.  From what you have explained there is no timeout in the wait for response from a source control provider? 

[gmart]

My post assumed that you were using LabVIEW 8.0 since you correctly noted that Clearcase was not supported in LabVIEW 7.1. While Clearcase works in LabVIEW 8.0, there is currently no timeout while waiting for a response from the provider (hence the tone of my post).

Regarding the search path and loading of your VI. LabVIEW typically stores the linkage information of subVIs in a relative format. There are occasions where the linkages are stored as absolute paths (ex. network drives). When a top-level VI is loaded, LabVIEW makes calls to the OS to search for the files. Typically, if the file is not found, you will get the prompt asking you to find the file. What I am guessing is happening is that Clearcase may be involved during the OS call and intercept the standard LabVIEW operation such that the hang occurs at the "Clearcase" level (since the volume is not mounted anymore) and doesn't allow LabVIEW to prompt you. What you could try is to see if the same behavior happens on a machine that does not have Clearcase installed. I don't think changing search paths will work since the linkage is stored in the VIs. What you would need to do is open the VI and all the subVIs and relink the hierarchy such that the VIs no longer point to the network drive. This would mean copying everything local and manually pointing to the new path. This unfortunately will be tedious but I believe that is what would need to be done.

As an aside, from my experience with Clearcase, it seems that it can couple itself with the OS such that you can do things such as compare VIs from "Tools>>Compare VIs" if you provide the right file syntax (see http://digital.ni.com/public.nsf/allkb/55E773AAA636C69D862570D600728434).

[kmc]

Yeah, I should have stated that I was using 7.1 sorry about that.  However, I have since upgraded to 8.0.1, and still have the same problem.  Note that I have not configured source control in version 8 either (from your post not sure that it would matter).  I had my suspicions about clearcases involvment as well and I have actually gone off already and done what you said to try, that is load the VIs on a machine which doesn't have clearcase installed, and its seem to be OK (I am prompted for the location of the subVIs).  I am going to talke to our clearcase admin to get some insight into what might be going on.

Thanks again for the reply.

[Kips]

Can you guys throw some light on how to add labview files in Clearcase View?