IO::Async::Routine(3) User Contributed Perl DocumentationIO::Async::Routine(3)NAME
"IO::Async::Routine" - execute code in an independent sub-process or
thread
SYNOPSIS
use IO::Async::Routine;
use IO::Async::Channel;
use IO::Async::Loop;
my $loop = IO::Async::Loop->new;
my $nums_ch = IO::Async::Channel->new;
my $ret_ch = IO::Async::Channel->new;
my $routine = IO::Async::Routine->new(
channels_in => [ $nums_ch ],
channels_out => [ $ret_ch ],
code => sub {
my @nums = @{ $nums_ch->recv };
my $ret = 0; $ret += $_ for @nums;
# Can only send references
$ret_ch->send( \$ret );
},
on_finish => sub {
say "The routine aborted early - $_[-1]";
$loop->stop;
},
);
$loop->add( $routine );
$nums_ch->send( [ 10, 20, 30 ] );
$ret_ch->recv(
on_recv => sub {
my ( $ch, $totalref ) = @_;
say "The total of 10, 20, 30 is: $$totalref";
$loop->stop;
}
);
$loop->run;
DESCRIPTION
This IO::Async::Notifier contains a body of code and executes it in a
sub-process or thread, allowing it to act independently of the main
program. Once set up, all communication with the code happens by
values passed into or out of the Routine via IO::Async::Channel
objects.
A choice of detachment model is available, with options being a
"fork()"ed child process, or a thread. In both cases the code contained
within the Routine is free to make blocking calls without stalling the
rest of the program. This makes it useful for using existing code which
has no option not to block within an "IO::Async"-based program.
Code running inside a "fork()"-based Routine runs within its own
process; it is isolated from the rest of the program in terms of
memory, CPU time, and other resources. Code running in a thread-based
Routine however, shares memory and other resources such as open
filehandles with the main thread.
To create asynchronous wrappers of functions that return a value based
only on their arguments, and do not generally maintain state within the
process it may be more convenient to use an IO::Async::Function
instead, which uses an "IO::Async::Routine" to contain the body of the
function and manages the Channels itself.
EVENTS
on_finish $exitcode
For "fork()"-based Routines, this is invoked after the process has
exited and is passed the raw exitcode status.
on_finish $type, @result
For thread-based Routines, this is invoked after the thread has
returned from its code block and is passed the "on_joined" result.
As the behaviour of these events differs per model, it may be more
convenient to use "on_return" and "on_die" instead.
on_return $result
Invoked if the code block returns normally. Note that "fork()"-based
Routines can only transport an integer result between 0 and 255, as
this is the actual "exit()" value.
on_die $exception
Invoked if the code block fails with an exception.
PARAMETERS
The following named parameters may be passed to "new" or "configure":
model => "fork" | "thread"
Optional. Defines how the routine will detach itself from the
main process. "fork" uses a child process detached using an
IO::Async::Process. "thread" uses a thread, and is only
available on threaded Perls.
If the model is not specified, the environment variable
"IO_ASYNC_ROUTINE_MODEL" is used to pick a default. If that
isn't defined, "fork" is preferred if it is available,
otherwise "thread".
channels_in => ARRAY of IO::Async::Channel
ARRAY reference of "IO::Async::Channel" objects to set up for
passing values in to the Routine.
channels_out => ARRAY of IO::Async::Channel
ARRAY reference of "IO::Async::Channel" objects to set up for
passing values out of the Routine.
code => CODE
CODE reference to the body of the Routine, to execute once the
channels are set up.
setup => ARRAY
Optional. For "fork()"-based Routines, gives a reference to an
array to pass to the underlying "Loop" "fork_child" method.
Ignored for thread-based Routines.
METHODS
$id = $routine->id
Returns an ID string that uniquely identifies the Routine out of all
the currently-running ones. (The ID of already-exited Routines may be
reused, however.)
AUTHOR
Paul Evans <leonerd@leonerd.org.uk>
perl v5.18.2 2014-05-14 IO::Async::Routine(3)