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Programmatically interrupt MATLAB on Windows

Asked by Szabolcs on 20 May 2013

When using MATLAB through the GUI, I can easily interrupt a computation by pressing Ctrl-C.

Is there a way to do the same programmatically when using MATLAB through the MATLAB Engine C API?

On Unix systems there is a solution: send a SIGINT signal. This will not kill MATLAB. It'll only interrupt the computation (i.e. exactly what I want). I am looking for a solution that works on Windows.

Use case: this is for a Mathematica-MATLAB interface. I want to be able to forward interrupts from Mathematica to MATLAB. The functionality is working and implemented on Linux/OSX, but I'd prefer to have it for the majority Windows platform as well.

EDIT: I'm also interested in solution that work with the MEX interface. The MEX function would be multi-threaded where the first thread is running an evalc(), and the second is watching for interrupt conditions. How would the second thread interrupt the evalc()? I have less hope for this with MEX than with Engine though.

UPDATE: I still haven't found any way to do this with the Engine interface, but I did find something which might work with MEX. The libut library has a function called utSetInterruptPending(). When running sequentially, utSetInterruptPending(1) will interrupt MATLAB (as tested with calllib()). Does anyone know utSetInterruptPending() is safe to call in a MEX function from a different thread than the main one?

7 Comments

Szabolcs on 20 May 2013

@Iain I don't understand what you are saying. What do you mean by " poll for some kind of interrupt, and break out after receiving it."? I don't have to poll, I know exactly when I receive the interrupt message (I receive it on a different thread). What do you mean by "break out", or "temporarily interrupt"? The precise problem is that I don't know how to stop MATLAB at all on Windows, either temporarily or permanently. The only thing I can do is make it quit completely.

Iain on 21 May 2013

I mean if you, in your matlab code, check to see if something has been done, say, a file being written to a known location, and if so, have the matlab code either stop execution, or, say, execute the code in that file.

Szabolcs on 21 May 2013

@Iain I have no control over the code that's being run, so I can't do that.

Szabolcs

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2 Answers

Answer by Walter Roberson on 20 May 2013

MS Windows XP SP2 and later support POSIX signals including (presumably) SIG_INT.

1 Comment

Szabolcs on 20 May 2013

How can I send such a signal? And does MATLAB actually respond to it the same way as on Unix? I did find that Windows should support these signals, but I have not found a way to actually send them to other processes. The signal.h header does not have a kill() function like on Unix.

I did find this too, but that seems to be for command line programs only, and it doesn't seem to work at all when I try (I get a permission denied error).

Walter Roberson
Answer by Jan Simon on 21 May 2013

I assume, you do not want to stop the engine temporarily, like Ctrl-C in the application, but kill the job. Then the windows command taskkill will help.

2 Comments

Szabolcs on 21 May 2013

Actually what I need is interrupting MATLAB without killing it, i.e. the equivalent of Ctrl-C. (Quoting from the question: "This will not kill MATLAB. It'll only interrupt the computation (i.e. exactly what I want).") Killing it is easy, but I'm looking for a way to interrupt it without killing it.

Jan Simon on 22 May 2013

What do you expect as internal state of an interrupted engine? When Matlab is not run as application with a GUI, I cannot imagine, what interrupting without killing can be useful for. Do you want to resume later one?

Jan Simon

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