Is there "a better way" to judge whether select works without having to fork and without it costing (too much) runtime?

This is as much a question as a suggestion.

On an OS where select does work on pipes, if you create a pipe, write to the write handle and then immediately select on the read handle with a timeout, shouldn't you get the read handle's fileno returned immediately? On Windows, you get 0:

pipe $in, $out;;

print $out 'fred';;

$si = ''; vec $si, fileno( $in ), 1;;

print select $si, undef, undef, 0.1;;
0 0.1
[download]