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Reflex-0.100
River stage one • 7 direct dependents • 7 total dependents
13 ++
/ Reflex::Signal

NAME

Reflex::Signal - receive callbacks when signals arrive

VERSION

This document describes version 0.100, released on April 02, 2017.

SYNOPSIS

eg/eg-39-signals.pl

        use warnings;
        use strict;

        use Reflex::Signal;
        use Reflex::Callbacks qw(cb_coderef);
        use ExampleHelpers qw(eg_say);

        eg_say("Process $$ is waiting for SIGUSR1 and SIGUSR2.");

        my $usr1 = Reflex::Signal->new(
                signal    => "USR1",
                on_signal => cb_coderef { eg_say("Got SIGUSR1.") },
        );

        my $usr2 = Reflex::Signal->new( signal => "USR2" );
        while ($usr2->next()) {
                eg_say("Got SIGUSR2.");
        }

DESCRIPTION

Reflex::Signal waits for signals from the operating system. It may invoke callback functions and/or be used as a promise of new signals depending on the application's needs.

Reflex::Signal is almost entirely implemented in Reflex::Role::SigCatcher. That role's documentation contains important details that won't be covered here.

Reflex::Signal is not suitable for SIGCHLD use. The specialized Reflex::PID class is used for that, and it will automatically wait() for processes and return their exit statuses.

Public Attributes

signal

Reflex:Signal's signal attribute defines the name of the signal to catch. Names are as those in %SIG, namely with the leading "SIG" scraped off.

active

The active attribute controls whether the signal catcher will be started in an actively catching state. It defaults to true; set it to false if you'd like to activate the signal catcher later.

Public Methods

start

Reflex::Signal's start() method may be used to initialize signal catchers and start them watching for signals. start() will be called automatically if the signal catcher is started in the active state, which it is by default.

Signal catchers may not be stopped, paused or resumed until they have been started.

stop

The stop() method stops and finalizes the signal catcher. It's automatically called at DEMOLISH time, just in case it hasn't already been.

pause

pause() pauses the signal catcher without finalizing it. This is a lighter-weight, non-final version of stop().

resume

resume() resumes a paused signal catcher without re-initializing it. This is a lighter-weight, non-initial version of start().

Callbacks

on_signal

The on_signal() callback notifies the user when the watched signal has been caught. It includes no parameters of note.

on_data

on_data() will be called whenever Reflex::Stream receives data. It will include one named parameter in $_[1], "data", containing raw octets received from the stream.

        sub on_data {
                my ($self, $param) = @_;
                print "Got data: $param->{data}\n";
        }

The default on_data() callback will emit a "data" event.

on_error

on_error() will be called if an error occurs reading from or writing to the stream's handle. Its parameters are the usual for Reflex:

        sub on_error {
                my ($self, $param) = @_;
                print "$param->{errfun} error $param->{errnum}: $param->{errstr}\n";
        }

The default on_error() callback will emit a "error" event. It will also call stopped().

When overriding this callback, please be sure to call stopped(), which is provided by Reflex::Role::Collectible. Calling stopped() is vital for collectible objects to be released from memory when managed by Reflex::Collection.

Public Events

Reflex::Stream emits stream-related events, naturally.

closed

The "closed" event indicates that the stream is closed. This is most often caused by the remote end of a socket closing their connection.

See "on_closed" for more details.

data

The "data" event is emitted when a stream produces data to work with. It includes a single parameter, also "data", containing the raw octets read from the handle.

See "on_data" for more details.

error

Reflex::Stream emits "error" when any of a number of calls fails.

See "on_error" for more details.

EXAMPLES

eg/EchoStream.pm in the distribution is the same EchoStream that appears in the SYNOPSIS.

eg/eg-38-promise-client.pl shows a lengthy inline usage of Reflex::Stream and a few other classes.

SEE ALSO

Please see those modules/websites for more information related to this module.

BUGS AND LIMITATIONS

You can make new bug reports, and view existing ones, through the web interface at http://rt.cpan.org/Public/Dist/Display.html?Name=Reflex.

AUTHOR

Rocco Caputo <rcaputo@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2017 by Rocco Caputo.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

AVAILABILITY

The latest version of this module is available from the Comprehensive Perl Archive Network (CPAN). Visit http://www.perl.com/CPAN/ to find a CPAN site near you, or see https://metacpan.org/module/Reflex/.

DISCLAIMER OF WARRANTY

BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR, OR CORRECTION.

IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENCE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE SOFTWARE TO OPERATE WITH ANY OTHER SOFTWARE), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.