Re: Difference between can_read() and select() in IO::Select

I have also had confusions like this in the earlier stages, but now if I have confusion I will just open the module code and understand it.
For example, if I want to know what can_read is doing in IO::Select, I will just do this on my system

my system details
OS:Debian GNU/Linux 4.0
Kernel:2.6.18-4-686 GNU/Linux
Perl: 5.8.8
[download]

steps I will follow

$ locate Select.pm
/usr/lib/perl/5.8.8/IO/Select.pm
/usr/share/perl/5.8.8/Pod/Select.pm
/usr/share/perl5/Debconf/AutoSelect.pm
/usr/share/perl5/Debconf/Element/Dialog/Select.pm
/usr/share/perl5/Debconf/Element/Editor/Select.pm
/usr/share/perl5/Debconf/Element/Gnome/Select.pm
/usr/share/perl5/Debconf/Element/Kde/Select.pm
/usr/share/perl5/Debconf/Element/Noninteractive/Select.pm
/usr/share/perl5/Debconf/Element/Select.pm
/usr/share/perl5/Debconf/Element/Teletype/Select.pm
/usr/share/perl5/Debconf/Element/Web/Select.pm
/usr/share/perl5/HTML/Widget/Element/Select.pm

I will open the below module in vim editor


$vim /usr/lib/perl/5.8.8/IO/Select.pm

just search the pattern /b can_read
I have got this
sub can_read
{
 my $vec = shift;
 my $timeout = shift;
 my $r = $vec->[VEC_BITS];

 defined($r) && (select($r,undef,undef,$timeout) > 0)
    ? handles($vec, $r)
    : ();
}
after seeing this I will know what can_read can do.
I have done this for lot of perl modules and I have learnt some effici
+ent techniques in this process, I am still learning, this is just my 
+tips to you.
[download]

Vivek
-- In accordance with the prarabdha of each, the One whose function it is to ordain makes each to act. What will not happen will never happen, whatever effort one may put forth. And what will happen will not fail to happen, however much one may seek to prevent it. This is certain. The part of wisdom therefore is to stay quiet.

Comment on Re: Difference between can_read() and select() in IO::Select Select or Download Code

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Re^2: Difference between can_read() and select() in IO::Select by chromatic (Archbishop) on Feb 25, 2009 at 19:24 UTC
If you don't mind using a pager instead of an editor, `perldoc -m IO::Select` is easier.	[reply] [d/l]
Re^2: Difference between can_read() and select() in IO::Select by zentara (Cardinal) on Feb 25, 2009 at 16:57 UTC
Sometimes reading the actual code is more confusing.:-) So you are trying to understand Perl's select, and you get code using select on vec? Simplifies things for sure. !! :-) I'm not really a human, but I play one on earth My Petition to the Great Cosmic Conciousness	[reply]