Would you explain what "$|++" meaning is in the code? Thanks

If you had put $|++ into the search box (or using super search like ?node_id=3989;HIT=%24%7C%2B%2B;re=N) you would have found: what does $|++ do here?, What the heck does $|++; do?, Perl Idioms Explained - $|++, $|++ Does What, Exactly? (was: $++ Does What, Exactly?)

Would you explain what "$|++" meaning is in the code? Thanks

Its like $foo++ except working on the variable $| , a reall shell-ish (or hack-ish) way to turn autoflush on, as in

use IO::Handle;
print 1; # doesn't print, puts 1 in the buffer
STDOUT->autoflush(1)
print 1; # prints 1 immediately (and the previously buffered 1)
print "\n2\n"; # \n forces a flush
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Tutorials: Input and Output: Suffering from Buffering?

Just think me as a kid. When i run the below script, it really print 1(not as your comment).

phillip@athens:/tmp$ perl -e 'use IO::Handle;print 1;'

And thanks for the reply(Re^3: ztk-webcam snapshot-grabber), I find "$_" mean in http://perldoc.perl.org/perlvar.html. Is its printing "1" caused by there's nothing to be flush in buffer?