[Haskell-cafe] runProcess does not care about hSetBuffering?
Brandon S. Allbery KF8NH
allbery at ece.cmu.edu
Tue Jul 28 21:22:26 EDT 2009
On Jul 28, 2009, at 21:14 , Magicloud Magiclouds wrote:
> (or_, ow_) <- createPipe
> or <- fdToHandle or_
> ow <- fdToHandle ow_
> hSetBuffering ow LineBuffering
> hSetBuffering or LineBuffering
> h <- runProcess cmd  Nothing Nothing Nothing (Just ow) Nothing
> In the cmd process, the ow is not LineBuffering....
Buffering is not an attribute of a filehandle, but of the I/O
library. There is no way for you to tell cmd how you want it to
buffer, unless it has an option to do so (cat -u, tcpdump -l, etc.),
although you can hint by using a pty instead of a pipe: many programs
will switch to line buffering in that case, some will go unbuffered;
usually, a pipe, FIFO, or ordinary file will be block buffered.
brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery at kf8nh.com
system administrator [openafs,heimdal,too many hats] allbery at ece.cmu.edu
electrical and computer engineering, carnegie mellon university KF8NH
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