pipe through external process?

John Meacham john@repetae.net
Tue, 17 Jul 2001 15:25:23 -0700

It is not time-critical, but it would be nice to know how to do it
properly :). is this a part of the whole IO system rewrite?  also, is
withStdin broken? every time i try to call it the program aborts with an
hFlush - cannot flush, Handle is not writeable error.

On Tue, Jul 17, 2001 at 10:39:08PM +1000, Manuel M. T. Chakravarty wrote:
> John Meacham <john@repetae.net> wrote,
> > I am trying to implement a function which takes a string, pipes it
> > through an external command and returns the stdout of teh command
> > utilizing the Posix library and ghc. 
> > 
> > first of all, if someone has this handy code tidbit already written then
> > feel free to send it to me. the other thing is that I cannot figure out
> > how to get data into and out of the process. I can create a pipe which
> > returns a pair of Fd's but then i cannot pass these into runProcess
> > since it expects handles. also I have no ability to wait for the
> > termination of the command that runProcess starts... 
> I have all this stuff ready to use in a library in my CVS
> repository (but it is not very heavily tested yet).  I plan
> to release it soon, but just returned from a trip and so may
> take a couple of more days.  Is it very urgent for you?
> Manuel
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John Meacham - California Institute of Technology, Alum. - john@repetae.net