Two instances of LabVIEW IDE

[Intaris]

I've seen on a few occasions that bogging down the LabVIEW IDE with a process (loading a large project will do the trick) and then trying to launch a VI from explorer (or from an internet browser which just downloaded a file) can cause a second instance of LabVIEW to start up (the same version as currently running).

Are there any dangers to this or should they coexist peacefully or is this (as I think) a perfect recipe for disaster?

[GerdW]

There could be a race condition when you quit both sessions at the same time and they try to save their labVIEW.ini… 😄

[JÞB]

I have seen this myself.  I immediatly close LabVIEW if it happens.  While my gut tells me that the two app instances should be fine it scares me to have multiple contexts open like that.  Not because of what LabVIEW might do but because of what misintended consequences I might make by forgetting what context I want to be in when I create things.  The VI Heirarchy view is a great place to look to see what "Co-existance" really means.  

[crossrulz]

I've never seen this as you decribe.  When I see it is in the morning when I start up LabVIEW and before it is done loading try to open up a VI from the forums.  I'm not sure of any dangers, but my first inclination is to shut down both instances and start over again.

[Intaris]

Well after running for over a week, within a minute of having two instances open, LabVIEW (both of them) crashed out on me....

I guess there's a hint int here somewhere if I could just figure it out..... 😉

[JÞB]

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@Intaris wrote:

Well after running for over a week, within a minute of having two instances open, LabVIEW (both of them) crashed out on me....

I guess there's a hint int here somewhere if I could just figure it out..... 😉

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I just have to ask if your "Recient" Lists got fouled up when you crashed? (Files>>ecient projects,Files>>recient files and browse path)

[tst]

LV does allow multiple instances in principle (you can add the line allowmultipleinstances=true to the INI file or you can create a copy of the EXE) and in my limited experience there's no major problem with it. If it's the same EXE they will share the INI file, but that shouldn't really be a problem in itself. That said, I haven't tried any single permutation. It might be possible in theory that there's some DLL function that's marked as reentrant but isn't or something else like that. If there is, I haven't run into it.

[SHowell73]

I have multiple versions of LabVIEW on my development PC at work, as we have clients with different versions, which is I am sure the normal thing. Alot of the other developers at my office are using virtual machines and have a different version of LabVIEW on each virtual machine. I am not that savvy with virtual machines, so I havent done it as of yet. I seem to remember a CLA telling me one time something about values of a certain datatype are not transported correctly when using a virtual machine? I think it was something he had to change to a string to get the value to go to an RT target, I cant really remember as it was over a year ago. 

Anywho, I sometimes have issues with multiple versions on my machine, as it always seems to launch the last version I had running when I launch from the vi itself in the folder structure instead of opening LabVIEW and opening the project in the correct version. GAH! 

[JÞB]

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@SHowell73 wrote:

I have multiple versions of LabVIEW on my development PC at work, as we have clients with different versions, which is I am sure the normal thing. Alot of the other developers at my office are using virtual machines and have a different version of LabVIEW on each virtual machine. I am not that savvy with virtual machines, so I havent done it as of yet. I seem to remember a CLA telling me one time something about values of a certain datatype are not transported correctly when using a virtual machine? I think it was something he had to change to a string to get the value to go to an RT target, I cant really remember as it was over a year ago. 

Anywho, I sometimes have issues with multiple versions on my machine, as it always seems to launch the last version I had running when I launch from the vi itself in the folder structure instead of opening LabVIEW and opening the project in the correct version. GAH! 

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Steven,  The main issue here is multiple app instances of LabVIEW (The same exe!) on the same machine.  The problem is do I have xyz.vi in context and what about the ini updates?  Again, it is frightening enough that few Champions dare tread the path.  Launching multiple versions of LabVIEW (In WIN OS's) follows a simple rule.  the vi opened from the windows explorer will open in the last version of LabVIEW to have opened a vi.  But, you should be using projects anyway!  and opening projects from the recient list or the GSW is safe.

[SHowell73]

Jeff,

I knew that you can launch from the latest projects in LabVIEW, I just sometimes take shortcuts 😃