monitor background process

[clkanski]

I want to launch a process is the background and monitor it in a polling routine. The process is variable in length and may or may not be killed by the user. Is there a way to assign a variable to the stdout? Can I "see" the process ID? Here is what I was thinking. Is this possible?

exec $somescript &

while {!$done} {
#monitor the process of $somescript
#possibley with a vwait statement?
set done 1
}

#process output from $somescript

 

[marsd]

Sure. Use threads for monitored proc + fork() for
the process and some passed variables.
You can go lower than this, but I'm getting the
impression that you don't want to.
C is it. Tcl would work as well except you would have
to parse a ps - ? and hope it's right.

The shell has been used for stuff like this for years
also. The code is often horribly lame, but works.

 

[clkanski]

I was hoping to stay within tcl. This is art of an script, that for the most part, is already written and works pretty good. I use to wait till the process was done, but more and more often, the process got killed by the user of the machine. So, the script died, and I had to go clean up manually. I would like the polling script to tell the difference of a natuaral stop and a forced stop. I don't know which tcl commands allow for this branch/unite mechanism.

 

[marsd]

You need to include signal handlers. Catch the
termination and cleanup. That's the easiest and best
way IMHO.
TclX and Expect both have the desired
capability. For windows, have a look at
twapi, which is very cool too.


HTH