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From: S-Y. Chen on 13 Jul 2010 12:01
Dear All,

I am having a very big head about a problem. I am wondering if anyone
can help me here.


I have to constantly calling a program through "exec", for example

exec program_a.exe -input something.txt

This will be called on in a loop inside a script. The problem is, this
program_a.exe seems never close itself and return to the system. So
whenever this line is executed, I will get the result I want, but tcl
will stop with error. Then the loop is terminated.

So I use

catch {exec program_a.exe -input something.txt}

Now the loop goes on, but program_a.exe is still in the memory.
Finally there are too many program_a.exe in the memory, eating up all
the resources, and the whole system crashes.............

Is there any way that, each time I call program_a.exe, I can let tcl
wait for program_a.exe to finish the job (it can sometimes take hours
or so), kill this thread and go on ?

I know it will be better to close this program inside its own scope,
but it is just difficult to do that.

Any help will be greatly appreciated.


Regards
S-Y. Chen


Regards
S-Y. Chen





From: APN on 13 Jul 2010 12:41
On Jul 13, 9:01 pm, "S-Y. Chen" <shenyeh_c...(a)hotmail.com> wrote:
> Dear All,
>
> I am having a very big head about a problem. I am wondering if anyone
> can help me here.
>
> I have to constantly calling a program through "exec", for example
>
> exec program_a.exe -input  something.txt
>
> This will be called on in a loop inside a script. The problem is, this
> program_a.exe seems never close itself and return to the system.  So
> whenever this line is executed, I will get the result I want, but tcl
> will stop with error.  Then the loop is terminated.
>
> So I use
>
> catch {exec program_a.exe -input  something.txt}
>
> Now the loop goes on, but program_a.exe is still in the memory.
> Finally there are too many program_a.exe in the memory, eating up all
> the resources, and the whole system crashes.............
>
> Is there any way that, each time I call program_a.exe, I can let tcl
> wait for program_a.exe to finish the job (it can sometimes take hours
> or so),  kill this thread and go on ?
>
> I know it will be better to close this program inside its own scope,
> but it is just difficult to do that.
>
> Any help will be greatly appreciated.
>
> Regards
> S-Y. Chen
>
> Regards
> S-Y. Chen

Do you know why Tcl is terminating with an error ? What does
$::errorInfo show? Does the exec'ed program write to stderr ? That
would be treated as an error by Tcl unless you redirect (I think).

If you don't mind using an extension, the twapi extension (http://
twapi.magicsplat.com) has the end_process command to terminate
processes on Windows. However, the question is - how will you know
when the exec'ed program has finished doing its thing so you can
terminate it?


/Ashok
From: S-Y. Chen on 13 Jul 2010 12:54
On Jul 14, 12:41 am, APN <palm...(a)yahoo.com> wrote:
> On Jul 13, 9:01 pm, "S-Y. Chen" <shenyeh_c...(a)hotmail.com> wrote:
>
>
>
> > Dear All,
>
> > I am having a very big head about a problem. I am wondering if anyone
> > can help me here.
>
> > I have to constantly calling a program through "exec", for example
>
> > exec program_a.exe -input  something.txt
>
> > This will be called on in a loop inside a script. The problem is, this
> > program_a.exe seems never close itself and return to the system.  So
> > whenever this line is executed, I will get the result I want, but tcl
> > will stop with error.  Then the loop is terminated.
>
> > So I use
>
> > catch {exec program_a.exe -input  something.txt}
>
> > Now the loop goes on, but program_a.exe is still in the memory.
> > Finally there are too many program_a.exe in the memory, eating up all
> > the resources, and the whole system crashes.............
>
> > Is there any way that, each time I call program_a.exe, I can let tcl
> > wait for program_a.exe to finish the job (it can sometimes take hours
> > or so),  kill this thread and go on ?
>
> > I know it will be better to close this program inside its own scope,
> > but it is just difficult to do that.
>
> > Any help will be greatly appreciated.
>
> > Regards
> > S-Y. Chen
>
> > Regards
> > S-Y. Chen
>
> Do you know why Tcl is terminating with an error ? What does
> $::errorInfo show? Does the exec'ed program write to stderr ? That
> would be treated as an error by Tcl unless you redirect (I think).
>
> If you don't mind using an extension, the twapi extension (http://
> twapi.magicsplat.com) has the end_process command to terminate
> processes on Windows. However, the question is - how will you know
> when the exec'ed program has finished doing its thing so you can
> terminate it?
>
> /Ashok

No I don't think it writes to stderr. I had a similar problem before,
and tcl receives error message just because I didn't put an "exit" in
the end of that program input. Otherwise nothing is wrong.

The program just didn't return back, and I need to kill it.

Regards
S-Y. Chen


From: S-Y. Chen on 13 Jul 2010 13:02
Also, errorInfo said that

"child process exited abnormally" on this exec command

Regards
S-Y. Chen

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