How to wait for OS command run with $zf(-100,"/ASYNC") to finish

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Question

Timothy Leavitt · Feb 2, 2022

I'm trying to write a method that runs an OS command with $zf(-100,"/ASYNC") and then waits for it to finish before returning, but I can't figure out how to check if the child process (in $zchild) is still running. $System.Process.State($zchild) always returns "RUN" even once the child process is gone. Is there some better way to check this, short of running another OS-specific command and processing the output (which is just really annoying and unelegant)?

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Eduard Lebedyuk · Feb 2, 2022

can't figure out how to check if the child process (in $zchild) is still running.

Append 2 commands to your main command.

First one, execute before your main command to create a file with a name equal to process id.

Second one, execute after your main command. It deletes the file.

In your IRIS process check if the file exists.

Ugly but it works.

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score 0 · Answer 1 · 2022-02-02T10:53:16-05:00

Hi Tim,

That's kind of a confusing question! Isn't the point of /async so that you don't wait for the process to finish? Do you need to use /async for some other reason?

score 0 · Answer 2 · 2022-02-02T11:29:17-05:00

What I'm trying to do is manage the process spawned with $zf(-100) from ObjectScript. In short, if the ObjectScript process is killed or <INTERRUPT>ed (which you can't do while in a ZF state), I want to kill the spawned process as well.

More specifically, I have a main ObjectScript process that's monitoring an Angular build. It spawns another ObjectScript process that used to just call $zf(-100) synchronously to run a build script. This other process would then notify the parent via $System.Event when it's done. Normally this build script will run for a finite period of time, but I'm looking to run an Angular build with the --watch flag and terminate it when the user Ctrl+C's in Terminal.

score 0 · Answer 3 · 2022-02-02T11:53:22-05:00

That is an interesting idea, but I don't have too much experience with zf(-100). Hope you can find some help.

score 0 · Answer 4 · 2022-02-02T12:05:06-05:00

Timothy Leavitt · Feb 2, 2022

I think it's probably going to just come down to using a pipe/command pipe/etc. instead of $zf(-100).

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score 0 · Answer 5 · 2022-02-02T12:56:24-05:00

I was hoping to avoid something like that. It seems like I run into other issues with what I'm trying to do though around killing the spawned process anyway. I think $zf(-100) just won't do the trick.

score 0 · Answer 6 · 2022-02-03T01:04:43-05:00

Vitaliy Serdtsev · Feb 3, 2022

Perhaps the method will be useful to you: $SYSTEM.Util.CleanDeadJobs()

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score 0 · Answer 7 · 2022-02-03T15:38:57-05:00

Timothy Leavitt · Feb 3, 2022

Problem in my case is that it's a non-IRIS process, so interactions from IRIS are limited.

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