Glib::Signal

Section: User Contributed Perl Documentation (3pm)
Updated: 2014-08-29
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NAME

Glib::Signal - Object customization and general purpose notification  

DESCRIPTION

This page describes some functions related to signals in Glib. Since most things you can do with signals are tied to Glib::Object instances, the majority of the signal functions are documented there.  

Thread safety

Some libraries, most notably GStreamer, sometimes invoke signal handlers from a foreign thread that has no Perl interpreter associated with it. When this happens, we have no choice but to hand the marshalling over to the main loop which in turn later wakes up the main thread and lets it handle the request. We cannot invoke the signal handler from the foreign thread since the Perl interpreter may not be used concurrently.

The downside to this approach is that the foreign thread is blocked until the main thread has finished executing the signal handler. This might lead to deadlocks. It might help in this case to wrap the crucial parts of the signal handler inside a Glib::Idle callback so that the signal handler can return directly.  

METHODS

 

integer = Glib->install_exception_handler ($func, $data=undef)

$func (subroutine)
$data (scalar)

Install a subroutine to be executed when a signal emission traps an exception (a croak or die). $func should return boolean (true if the handler should remain installed) and expect to receive a single scalar. This scalar will be a private copy of $@ which the handler can mangle to its heart's content.

Returns an identifier that may be used with "remove_exception_handler".

See "gperl_install_exception_handler()" in Glib::xsapi.  

Glib->remove_exception_handler ($tag)

$tag (integer)

Remove the exception handler identified by $tag, as returned by "install_exception_handler". If $tag cannot be found, this does nothing.

WARNING: Do not call this function from within an exception handler. If you want to remove your handler during its execution just have it return false.

See "gperl_remove_exception_handler()" in Glib::xsapi.  

ENUMS AND FLAGS

 

flags Glib::SignalFlags

'run-first' / 'G_SIGNAL_RUN_FIRST'
'run-last' / 'G_SIGNAL_RUN_LAST'
'run-cleanup' / 'G_SIGNAL_RUN_CLEANUP'
'no-recurse' / 'G_SIGNAL_NO_RECURSE'
'detailed' / 'G_SIGNAL_DETAILED'
'action' / 'G_SIGNAL_ACTION'
'no-hooks' / 'G_SIGNAL_NO_HOOKS'
 

SEE ALSO

Glib, Glib::Object  

COPYRIGHT

Copyright (C) 2003-2011 by the gtk2-perl team.

This software is licensed under the LGPL. See Glib for a full notice.


 

Index

NAME
DESCRIPTION
Thread safety
METHODS
integer = Glib->install_exception_handler ($func, $data=undef)
Glib->remove_exception_handler ($tag)
ENUMS AND FLAGS
flags Glib::SignalFlags
SEE ALSO
COPYRIGHT