On Thu, 21 Sep 2006, George Brewster wrote:
> I'm just tried writing a function to allow convenient embedding of shell
> commands, but I'm running into behavior I don't really understand
> somewhere at the intersection of lazy evaluation, IO, and threading.
You may also find some unwelcome surprises in the area of pipes and
buffered I/O, that aren't specifically about Haskell. Are you on a
UNIX platform?
I "rewrote" your function by removing both instances of forkIO, and
it worked about like I expected. (The last one encounters an error
"broken pipe" when it tries to write "there" to the "echo hi" shell
process, because that process exits instead of reading from its input.)
I can't say whether you really need forkIO, or whether it's really going
to do what you need - not only do I not know enough about the thread
model, neither do I know what you're really trying to do.
Donn Cave, [EMAIL PROTECTED]
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