Re: [Haskell-cafe] Standard output of exec

Hi Michael, Thank you for your answer. Conduits certainly are the best approach, but the output I am going to read is very short and the external program will only be called once or twice per execution so I think Lazy IO won't be problematic here. Best regards, Ernesto On Thu, Dec 11, 2014 at 10:18 AM, Michael Snoyman wrote:

You can use readProcess[1], but it has some downsides:

1. Can't specify all options to CreateProcess, e.g., working directory and environment variables. 2. Relies on lazy I/O

I use Data.Conduit.Process[2] for this kind of thing, which has a full tutorial[3]. However, it *does* involve non-base dependencies.

[1] http://www.stackage.org/haddock/2014-12-10-ghc78-exc/process-1.2.0.0/System-... [2] http://www.stackage.org/haddock/2014-12-10-ghc78-exc/conduit-extra-1.1.4.2/D... [3] https://www.fpcomplete.com/user/snoyberg/library-documentation/data-conduit-...

On Thu Dec 11 2014 at 11:11:12 AM Ernesto Rodriguez wrote:

...

Dear All,

I have a program which invokes an external program via exec. I wish to capture the standard output of the program without using external (temporary) files. Is it possible to create an in memory handle which I can tell exec to use as standard output of the invoked program. It would be great if it can be done without any extra dependencies.

Best,

-- Ernesto Rodriguez

Masters Student Computer Science Utrecht University

www.netowork.me github.com/netogallo

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-- Ernesto Rodriguez Masters Student Computer Science Utrecht University www.netowork.me github.com/netogallo