On Mon, Dec 15, 2014 at 9:11 AM, Henk-Jan van Tuyl <hjgtuyl@chello.nl> wrote:

I am experimenting with the createProcess function from the package "process"; this function does not return any handle, on both Ubuntu and Windows. I am doing something wrong, or is this a bug? (I am using GHC 7.8.3 on both platforms.)

Not a bug; you need to tell it which ones to create handles for.

createProcess returns (mb_stdin_hdl, mb_stdout_hdl, mb_stderr_hdl, p), where
if std_in == CreatePipe, then mb_stdin_hdl will be Just h, where h is the write end of the pipe connected to the child process's stdin.
otherwise, mb_stdin_hdl == Nothing
Similarly for mb_stdout_hdl and mb_stderr_hdl.

The default action is to inherit the existing handles for stdin/out/err in the subprocess and provide no handles to the caller; this mirrors the default behavior of creating a new process on Windows and POSIX.

brandon s allbery kf8nh sine nomine associates

allbery.b@gmail.com ballbery@sinenomine.net

unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net