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.