In article <[EMAIL PROTECTED]>,
Steve Hay <[EMAIL PROTECTED]> writes:
> Adding some debug, I find that $sel->can_read() is returning an empty
> list. If I change
>
> while (my @ready = $sel->can_read) {
> foreach my $fh (@ready) { # loop through buffered handles
> ...
> }
> }
>
> to
>
> foreach my $fh ($outfh, $errfh) {
> ...
> }
>
> then the output is now as expected.
>
> Presumably IO::Select->can_read() doesn't work on Win32 because it uses
> a 4-arg select(), which is only implemented for sockets on Win32. Is
> the above change safe, or did we need to call can_read() for some
> reason? Would the proposed "selectable pipes" change have any impact on
> this?
>
The case where the above type of change is dangerous is when the source
tries to write more than can be buffered in the communication channel to
err_fh and only then bothers to write to $out_fh. In that case you will
deadlock. the source will wait until enough gets drained from err_fh so it
can write again, and you will wait on $out_fh, which hasn't gotten anything
yet and now never will.
So whether that is relevant for your case depends on what you're running
(how it uses its output channels).
