On Thu, 2007-12-13 at 19:38 +0200, Yitzchak Gale wrote:
Simon Marlow wrote:
It could deadlock if the script produces enough stderr to fill up its pipe buffer
If we need to worry about that, then what about this:
(_,h,e,_) <- runInteractiveCommand "script params" forkIO (hGetContents e >>= evaluate . length) output <- hGetContents h
It requires -threaded in the case of a huge amount
It does not require -threaded. GHC's single threaded rts has always been able to cope with multiple haskell threads that want to do file/network IO.
of output to both stdout and stderr; maybe that isn't good for Bulat. If that is a problem, you can read a chunk at a time and call yield - but that is getting messier.
Calling yield ends up busy waiting if there is no output available from either stdout or stderr. It also requires threads so it's not a portable solution. Something simple would be to allow attaching a pipe to just the stdout and redirecting stderr elsewhere, or connecting both stdout and stderr to the same output pipe. runProcess allows substituting any of stdin/stdout/stderr for other Handles and runInteractiveProcess substitutes them all for pipes. What we need is something in between that allows substituting some for given Handles and connecting others to pipes. Duncan