B::Hooks::EndOfScope(3User Contributed Perl DocumentaB::Hooks::EndOfScope(3pm)
NAME
B::Hooks::EndOfScope - Execute code after a scope finished compilation
VERSION
version 0.26
SYNOPSIS
on_scope_end { ... };
DESCRIPTION
This module allows you to execute code when perl finished compiling the
surrounding scope.
FUNCTIONS
on_scope_end
on_scope_end { ... };
on_scope_end $code;
Registers $code to be executed after the surrounding scope has been
compiled.
This is exported by default. See Sub::Exporter on how to customize it.
LIMITATIONS
Pure-perl mode caveat
This caveat applies to any version of perl where Variable::Magic is
unavailable or otherwise disabled.
While Variable::Magic has access to some very dark sorcery to make it
possible to throw an exception from within a callback, the pure-perl
implementation does not have access to these hacks. Therefore, what
would have been a compile-time exception is instead converted to a
warning, and your execution will continue as if the exception never
happened.
To explicitly request an XS (or PP) implementation one has two choices.
Either to import from the desired implementation explicitly:
use B::Hooks::EndOfScope::XS
or
use B::Hooks::EndOfScope::PP
or by setting $ENV{B_HOOKS_ENDOFSCOPE_IMPLEMENTATION} to either "XS" or
"PP".
Perl 5.8.0 ~ 5.8.3
Due to a core interpreter bug
<https://rt.perl.org/Public/Bug/Display.html?id=27040#txn-82797>
present in older perl versions, the implementation of
B::Hooks::EndOfScope deliberately leaks a single empty hash for every
scope being cleaned. This is done to avoid the memory corruption
associated with the bug mentioned above.
In order to stabilize this workaround use of Variable::Magic is
disabled on perls prior to version 5.8.4. On such systems
loading/requesting B::Hooks::EndOfScope::XS explicitly will result in a
compile-time exception.
Perl versions 5.6.x
Versions of perl before 5.8.0 lack a feature allowing changing the
visibility of "%^H" via setting bit 17 within $^H. As such the only way
to achieve the effect necessary for this module to work, is to use the
"local" operator explicitly on these platforms. This might lead to
unexpected interference with other scope-driven libraries relying on
the same mechanism. On the flip side there are no such known
incompatibilities at the time this note was written.
For further details on the unavailable behavior please refer to the
test file t/02-localise.t included with the distribution.
SEE ALSO
Sub::Exporter
Variable::Magic
SUPPORT
Bugs may be submitted through the RT bug tracker
<https://rt.cpan.org/Public/Dist/Display.html?Name=B-Hooks-EndOfScope>
(or bug-B-Hooks-EndOfScope@rt.cpan.org <mailto:bug-B-Hooks-
EndOfScope@rt.cpan.org>).
AUTHORS
• Florian Ragwitz <rafl@debian.org>
• Peter Rabbitson <ribasushi@leporine.io>
CONTRIBUTORS
• Karen Etheridge <ether@cpan.org>
• Christian Walde <walde.christian@googlemail.com>
• Graham Knop <haarg@haarg.org>
• Simon Wilper <sxw@chronowerks.de>
• Tatsuhiko Miyagawa <miyagawa@bulknews.net>
• Tomas Doran <bobtfish@bobtfish.net>
COPYRIGHT AND LICENCE
This software is copyright (c) 2008 by Florian Ragwitz.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
perl v5.34.0 2022-02-25 B::Hooks::EndOfScope(3pm)
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