How can I tell if an executable is already running?

[pblase]

I'm writing a rather large LabWindows/CVI program, and occasionally will triple-click on the desktop icon, starting two copies of it. Is there some way to tell if a program is already running, so that the second copy can shut itself off?

[RobertoBozzolo · Accepted solution]

Look at CheckForDuplicateAppInstance () command: the help page shows also a short programming example.

[menchar]

Or if you want to do it another way create a named mutex that the application grabs when it starts, that way if it can't grab the named mutex you know that another instance of the application is already running.

[pblase]

Ok, thanks much. I thought I remembered something being in there somewhere.

[Guillaume Dargaud]

> Or if you want to do it another way create a named mutex that the
> application grabs when it starts, that way if it can't grab the named
> mutex you know that another instance of the application is already
> running.

Yet another way is to open a resource exclusively.
For instance with:
open(Filename, O_CREAT | O_EXLC | O_TEMPORARY)
The 2nd one will fail the call
--
Guillaume Dargaud
http://www.gdargaud.net/

[menchar]

Speaking of using a resource, I used a named pipe to solve this problem in grad school once.  Prof thought it was weird but he couldn't deny that it does work