PROPOSAL(S): threadWaitError and threadWaitErrorSTM

Brandon Allbery allbery.b at
Sun Mar 16 15:09:14 UTC 2014

On Sun, Mar 16, 2014 at 10:25 AM, Merijn Verstraaten <merijn at
> wrote:

> threadWaitError :: Fd -> IO ()
> threadWaitErrorSTM :: Fd -> IO (STM (), IO ())
> to allow for blocking on detecting error condition on file descriptors,
> similar to what C's select() allows.

If you mean the third bitmask, it is not for errors (notwithstanding the
documentation on some systems); an "exceptional condition" is not an error,
it's MSG_OOB data. Errors show as "ready" on the appropriate mask (read or
write) since a read (resp. write) will return immediately with the error
instead of blocking.

See for more information.

brandon s allbery kf8nh                               sine nomine associates
allbery.b at                                  ballbery at
unix, openafs, kerberos, infrastructure, xmonad
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