IO::Async::Loop::SelecUsermContributed Perl DocumeIO::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 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 <leonerd@leonerd.org.uk> perl v5.34.0 2022-08-19 IO::Async::Loop::Select(3pm)
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