B::Hooks::EndOfScope - Execute code after a scope finished compilation
version 0.26
on_scope_end { ... };
This module allows you to execute code when perl finished compiling the
surrounding scope.
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 the Sub::Exporter manpage on how to customize it.
This caveat applies to any version of perl where the Variable::Magic manpage
is unavailable or otherwise disabled.
While the Variable::Magic manpage 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.
Due to a core interpreter bug 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 the Variable::Magic manpage is disabled
on perls prior to version 5.8.4. On such systems loading/requesting
the B::Hooks::EndOfScope::XS manpage explicitly will result in a compile-time
exception.
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.
the Sub::Exporter manpage
the Variable::Magic manpage
Bugs may be submitted through the RT bug tracker
(or bug-B-Hooks-EndOfScope@rt.cpan.org).
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.
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