I've seen this a few times and yes, it is explained as "fancy" but will someone help me understand exactly what it's doing?

select( (select(STDERR), $|++)[0] );

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I will take a stab at it. Select() simply select a filehandle to read and write to for the current process, right? But what exactly is the embedded select() doing??

It looks like the inside select() is returning element 0 of an array which the external select() is selecting.

So, I ran a couple of tests:

$ perl -e '
open(F,"/etc/passwd");
print select(F),"\n";
print select(STDOUT),"\n";
close(F);
'
main::F

$ perl -e '
open(F,"/etc/passwd");
print select((select(F),$|++)[0]),"\n";
print select(STDOUT),"\n";close(F);
'
main::F
main::STDOUT

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It looks like I now have select()'ed two filehandles to play with at the same time. Is that right? TIA, - Jim

_ _ _ _ _ _ _ _ _ _
- Jim
Insert clever comment here...

In reply to Tear it apart...select() by snafu

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