Scope::Guard - lexically-scoped resource management
my $guard = guard { ... }; # or my $guard = scope_guard \&handler; # or my $guard = Scope::Guard->new(sub { ... }); $guard->dismiss(); # disable the handler
This module provides a convenient way to perform cleanup or other forms of resource management at the end of a scope. It is particularly useful when dealing with exceptions: the Scope::Guard constructor takes a reference to a subroutine that is guaranteed to be called even if the thread of execution is aborted prematurely. This effectively allows lexically-scoped "promises" to be made that are automatically honoured by perl's garbage collector.
Scope::Guard
For more information, see: http://www.drdobbs.com/cpp/184403758
my $guard = Scope::Guard->new(sub { ... }); # or my $guard = Scope::Guard->new(\&handler);
The new method creates a new Scope::Guard object which calls the supplied handler when its DESTROY method is called, typically at the end of the scope.
new
DESTROY
$guard->dismiss(); # or $guard->dismiss(1);
dismiss detaches the handler from the Scope::Guard object. This revokes the "promise" to call the handler when the object is destroyed.
dismiss
The handler can be re-enabled by calling:
$guard->dismiss(0);
guard takes a block and returns a new Scope::Guard object. It can be used as a shorthand for:
guard
Scope::Guard->new(...)
e.g.
my $guard = guard { ... };
Note: calling guard anonymously, i.e. in void context, will raise an exception. This is because anonymous guards are destroyed immediately (rather than at the end of the scope), which is unlikely to be the desired behaviour.
scope_guard is the same as guard, but it takes a code ref rather than a block. e.g.
scope_guard
my $guard = scope_guard \&handler;
or:
my $guard = scope_guard sub { ... };
my $guard = scope_guard $handler;
As with guard, calling scope_guard in void context will raise an exception.
0.21
B::Hooks::EndOfScope
End
Guard
Hook::Scope
Object::Destroyer
Perl::AtEndOfScope
ReleaseAction
Scope::local_OnExit
Scope::OnExit
Sub::ScopeFinalizer
Value::Canary
chocolateboy <chocolate@cpan.org>
Copyright (c) 2005-2015, chocolateboy.
This module is free software. It may be used, redistributed and/or modified under the same terms as Perl itself.
To install Scope::Guard, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Scope::Guard
CPAN shell
perl -MCPAN -e shell install Scope::Guard
For more information on module installation, please visit the detailed CPAN module installation guide.