| Perl::Unsafe::Signals - Allow unsafe handling of signals in selected blocks |
Perl::Unsafe::Signals - Allow unsafe handling of signals in selected blocks
use Perl::Unsafe::Signals;
# ... some code ...
local $SIG{ALRM} = sub { ... };
alarm(60);
UNSAFE_SIGNALS {
# we want to interrupt this after one minute
call_some_long_XS_function();
};
alarm(0);
# ... continue ...
Quoting the perl581delta manpage:
In Perl 5.8.0 the so-called ``safe signals'' were introduced. This means that Perl no longer handles signals immediately but instead ``between opcodes'', when it is safe to do so. The earlier immediate handling easily could corrupt the internal state of Perl, resulting in mysterious crashes.
It's possible since perl 5.8.1 to globally disable this feature by using
the PERL_SIGNALS environment variables (as specified in
PERL_SIGNALS in the perlrun manpage); but there's no way to disable it locally, for a
short period of time. That's however something you might want to do,
if, for example, your Perl program calls a C routine that will potentially
run for a long time and for which you want to set a timeout.
This module therefore allows you to define UNSAFE_SIGNALS blocks
in which signals will be handled ``unsafely''.
Note that, no matter how short you make the unsafe block, it will still be unsafe. Use with caution.
This module used to be a source filter, but is no longer, thanks to Scott McWhirter.
Copyright (c) 2005, 2015 Rafael Garcia-Suarez. This program is free software; you may redistribute it and/or modify it under the same terms as Perl itself.
A git repository for the sources is at https://github.com/rgs/Perl-Unsafe-Signals.
the perlrun manpage, the perl581delta manpage
| Perl::Unsafe::Signals - Allow unsafe handling of signals in selected blocks |