On Sep 9, 2010, at 6:37 AM, Simon Marlow wrote:

On 09/09/2010 10:39, Christian Maeder wrote:

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Christian Maeder schrieb:

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Hi,

we call from our haskell application the metis prover via

System.Process.readProcessWithExitCode "metis" filename ""

However, we are not able to get rid of this process if metis does not terminate by itself. In particular, wrapping this call into a System.Timeout.timeout does not work.

timeout works so far as it is possible to start another action, but the continuing metis process still blocks the whole system.

C.

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Any suggestions how we should handle this ideally portably but first of all under unix. (ghc-6.12.3)

Take a look at the timeout program in GHC's test suite:

http://darcs.haskell.org/testsuite/timeout/timeout.hs

In case it's not obvious, I believe this has to be compiled with -threaded to get the desired behavior. -David

Cheers, Simon _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users

On 09/09/2010 17:18, Christian Maeder wrote:

David Peixotto schrieb:

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On Sep 9, 2010, at 6:37 AM, Simon Marlow wrote:

...

On 09/09/2010 10:39, Christian Maeder wrote:

...

Christian Maeder schrieb:

...

Hi,

we call from our haskell application the metis prover via

System.Process.readProcessWithExitCode "metis" filename ""

However, we are not able to get rid of this process if metis does not terminate by itself. In particular, wrapping this call into a System.Timeout.timeout does not work. timeout works so far as it is possible to start another action, but the continuing metis process still blocks the whole system.

C.

...

Any suggestions how we should handle this ideally portably but first of all under unix. (ghc-6.12.3) Take a look at the timeout program in GHC's test suite:

http://darcs.haskell.org/testsuite/timeout/timeout.hs

This looks pretty complicated. Did no one else needed this? Isn't it easier to put the application into a wrapper script and call the script from haskell?

It is pretty complicated, because properly wrapping a process in a timeout is a complicated task. You have to: - kill not just the process you started, but any children it started - catch ^C, and pass it to the child process(es) - if the child process died with a signal, arrange that the wrapper dies with the same signal, so that the parent can see what happened - try to kill nicely, giving them a chance to clean up, but kill forcefully if that doesn't work. It would be a good idea to wrap this up and put it on Hackage, in fact. Cheers, Simon

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 9/10/10 04:59 , Christian Maeder wrote:

Brandon S Allbery KF8NH schrieb:

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On 9/9/10 05:35 , Christian Maeder wrote:

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System.Process.readProcessWithExitCode "metis" filename ""

If all else fails, there's:

sh -c '(sleep 120; kill -TERM $$ >/dev/null 2>&1) & exec metis'

Yes, I've considered something like this, too. It does not give metis a chance to terminate earlier, does it?

If metis exits, the backgrounded sleep will keep going, the kill will silently fail, in effect that can be ignored. It would be possible to set up something that nuked the background sleep but then getting the full exit status of metis (if needed; i.e. signals) is complex. (If your shell is too smart to let the background process deal with itself, toss in a "disown %1" before exec-ing metis. Shells that do interactive-style process management when not interactive are broken, though.) - -- brandon s. allbery [linux,solaris,freebsd,perl] allbery@kf8nh.com system administrator [openafs,heimdal,too many hats] allbery@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.10 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkyKVwwACgkQIn7hlCsL25ULkACfafrUFq15UNp8FnnfvtmtpP7E LfwAnA/8rX/k9E4nrqGB8cwB8kexId/5 =Hchn -----END PGP SIGNATURE-----

Hi, thanks for pointing this out. Am 29.09.2010 06:47, schrieb Andrés Sicard-Ramírez:

Hi Christian,

On Thu, Sep 9, 2010 at 4:35 AM, Christian Maeder wrote:

...

Hi,

we call from our haskell application the metis prover via

System.Process.readProcessWithExitCode "metis" filename ""

However, we are not able to get rid of this process if metis does not terminate by itself. In particular, wrapping this call into a System.Timeout.timeout does not work.

Maybe you want to know that the latest version of Metis has a new --time-limit command line argument

http://www.gilith.com/pipermail/metis-users/2010-September/000001.html

This message also suggest "ulimit", though. We'll try it out the choices. Christian

Best regards,