io::async::loop::select(3pm) [debian man page]

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)

IO::Async::Test(3pm)					User Contributed Perl Documentation				      IO::Async::Test(3pm)

NAME

       "IO::Async::Test" - utility functions for use in test scripts

SYNOPSIS

	use Test::More tests => 1;
	use IO::Async::Test;

	use IO::Async::Loop;
	my $loop = IO::Async::Loop->new;
	testing_loop( $loop );

	my $result;

	$loop->do_something(
	   some => args,

	   on_done => sub {
	      $result = the_outcome;
	   }
	);

	wait_for { defined $result };

	is( $result, what_we_expected, 'The event happened' );

	...

	my $buffer = "";
	my $handle = IO::Handle-> ...

	wait_for_stream { length $buffer >= 10 } $handle => $buffer;

	is( substr( $buffer, 0, 10, "" ), "0123456789", 'Buffer was correct' );

DESCRIPTION

       This module provides utility functions that may be useful when writing test scripts for code which uses "IO::Async" (as well as being used
       in the "IO::Async" test scripts themselves).

       Test scripts are often synchronous by nature; they are a linear sequence of actions to perform, interspersed with assertions which check
       for given conditions. This goes against the very nature of "IO::Async" which, being an asynchronisation framework, does not provide a
       linear stepped way of working.

       In order to write a test, the "wait_for" function provides a way of synchronising the code, so that a given condition is known to hold,
       which would typically signify that some event has occured, the outcome of which can now be tested using the usual testing primitives.

       Because the primary purpose of "IO::Async" is to provide IO operations on filehandles, a great many tests will likely be based around
       connected pipes or socket handles. The "wait_for_stream" function provides a convenient way to wait for some content to be written through
       such a connected stream.

FUNCTIONS

   testing_loop( $loop )
       Set the "IO::Async::Loop" object which the "wait_for" function will loop on.

   wait_for( $condfunc )
       Repeatedly call the "loop_once" method on the underlying loop (given to the "testing_loop" function), until the given condition function
       callback returns true.

       To guard against stalled scripts, if the loop indicates a timeout for 10 consequentive seconds, then an error is thrown.

   wait_for_stream( $condfunc, $handle, $buffer )
       As "wait_for", but will also watch the given IO handle for readability, and whenever it is readable will read bytes in from it into the
       given buffer. The buffer is NOT initialised when the function is entered, in case data remains from a previous call.

       $buffer can also be a CODE reference, in which case it will be invoked being passed data read from the handle, whenever it is readable.

AUTHOR

       Paul Evans <leonerd@leonerd.org.uk>

perl v5.14.2							    2012-10-24						      IO::Async::Test(3pm)