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Full Discussion: Bash : While Loop behavior
Top Forums UNIX for Advanced & Expert Users Bash : While Loop behavior Post 302935048 by popeye on Thursday 12th of February 2015 01:13:11 PM
Old 02-12-2015
VERY INTERESTING !

Ive tried this on a VM at school, a Ubuntu VM on my latptop and a Centos VM on my laptop.

What happens on all is that as I run through and test each option, at one point it seems that the read doesnt except input. It really behave like a backspace, but what I suspect is happening is that read is executing again. Kind of ignores input.

PS Stumped the instructor too !!!

---------- Post updated at 01:13 PM ---------- Previous update was at 01:05 PM ----------

I just tried to execute it on a work VM ... shhh dont tell the boss. Its running on that vserver. What the heck ? Only difference is that Im using VMPLAYER on my laptop and at school. .... scratching my head. Technical problem between chair and keyboard ??
 

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IO::Async::Loop::Select(3pm)				User Contributed Perl Documentation			      IO::Async::Loop::Select(3pm)

NAME
"IO::Async::Loop::Select" - use "IO::Async" with "select(2)" SYNOPSIS
Normally an instance of this class would not be directly constructed by a program. It may however, be useful for runinng IO::Async with an existing program already using a "select" call. use IO::Async::Loop::Select; my $loop = IO::Async::Loop::Select->new; $loop->add( ... ); while(1) { my ( $rvec, $wvec, $evec ) = ('') x 3; my $timeout; $loop->pre_select( $rvec, $wvec, $evec, $timeout ); ... my $ret = select( $rvec, $wvec, $evec, $timeout ); ... $loop->post_select( $rvec, $evec, $wvec ); } DESCRIPTION
This subclass of "IO::Async::Loop" uses the select(2) syscall to perform read-ready and write-ready tests. To integrate with an existing "select"-based event loop, a pair of methods "pre_select" and "post_select" can be called immediately before and after a "select" call. The relevant bits in the read-ready, write-ready and exceptional-state bitvectors are set by the "pre_select" method, and tested by the "post_select" method to pick which event callbacks to invoke. CONSTRUCTOR
$loop = IO::Async::Loop::Select->new This function returns a new instance of a "IO::Async::Loop::Select" object. It takes no special arguments. METHODS
$loop->pre_select( $readvec, $writevec, $exceptvec, $timeout ) This method prepares the bitvectors for a "select" call, setting the bits that the Loop is interested in. It will also adjust the $timeout value if appropriate, reducing it if the next event timeout the Loop requires is sooner than the current value. $readvec $writevec $exceptvec Scalar references to the reading, writing and exception bitvectors $timeout Scalar reference to the timeout value $loop->post_select( $readvec, $writevec, $exceptvec ) This method checks the returned bitvectors from a "select" call, and calls any of the callbacks that are appropriate. $readvec $writevec $exceptvec Scalars containing the read-ready, write-ready and exception bitvectors $count = $loop->loop_once( $timeout ) This method calls the "pre_select" method to prepare the bitvectors for a "select" syscall, performs it, then calls "post_select" to process the result. It returns the total number of callbacks invoked by the "post_select" method, or "undef" if the underlying select(2) syscall returned an error. SEE ALSO
o IO::Select - OO interface to select system call AUTHOR
Paul Evans <leonerd@leonerd.org.uk> perl v5.14.2 2012-10-24 IO::Async::Loop::Select(3pm)
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