IO::Async::Loop::Select - use IO::Async with 'select(2)'

NAME  SYNOPSIS  DESCRIPTION  CONSTRUCTOR  new  METHODS  pre_select  post_select  loop_once  SEE ALSO  AUTHOR 

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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

new

$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

pre_select

$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

post_select

$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

loop_once

$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

•

IO::Select − OO interface to select system call

AUTHOR

Paul Evans <[email protected]>

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