LabVIEW
What is the best practice for using system exec
Solved!
Does the program return data that you care about (i.e. via StdOut?).
If you set the CMD execution to be non-blocking, you can kill it using something like "taskkill", but you'd also need the Process ID using something like "tasklist".
However, setting the SysExec node to be non-blocking prevents it returning the StdOut output.
If you want to keep that, but allow cancelling the task (and you don't have some other method to cancel the task) you'd have to asynchronously launch a VI in LabVIEW to call the SysExec node, and then separately kill the task (as above) if the VI doesn't return before some timeout value.
By "some other method", I mean if the task you're calling allows interruption via something like TCP server, WCF messaging, etc.
Sure - there's an input on the top of the SysExec node that's labelled "wait until completion? (T)".
If you wire a false value to that, then the node returns immediately, which would allow you to then continue execution in the same VI, and optionally do other things (like kill the task) some time later.
However, you lose information about when the task finishes - which makes it harder to use in your situation (I suspect).
The detailed help page has the following explanation:
If wait until completion? is TRUE, standard input is available as input to the command and standard output and standard error are available when the command finishes running. If FALSE, the command runs in the background and its input and output are not available. 