Tech Article: Guide to Oracle Data Guard Fast-Start Failover
This document will guide you through configuring Oracle Data Guard Fast-Start Failover (FSFO) using a physical standby database. FSFO can provide substantial gains in high availability and disaster recovery preparedness for all environments, from inexpensive Cloud-based systems to global distributed data centers.
Scope::Guard(3pm) User Contributed Perl Documentation Scope::Guard(3pm)NAME
Scope::Guard - lexically-scoped resource management
SYNOPSIS
my $guard = guard { ... };
# or
my $guard = scope_guard &handler;
# or
my $guard = Scope::Guard->new(sub { ... });
$guard->dismiss(); # disable the handler
DESCRIPTION
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.
For more information, see: <http://www.drdobbs.com/cpp/184403758>
METHODS
new
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.
dismiss
$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.
The handler can be re-enabled by calling:
$guard->dismiss(0);
EXPORTS
guard
"guard" takes a block and returns a new "Scope::Guard" object. It can be used as a shorthand for:
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
"scope_guard" is the same as "guard", but it takes a code ref rather than a block. e.g.
my $guard = scope_guard &handler;
or:
my $guard = scope_guard sub { ... };
or:
my $guard = scope_guard $handler;
As with "guard", calling "scope_guard" in void context will raise an exception.
VERSION
0.20
SEE ALSO
o B::Hooks::EndOfScope
o End
o Guard
o Hook::Scope
o Object::Destroyer
o Perl::AtEndOfScope
o ReleaseAction
o Scope::local_OnExit
o Scope::OnExit
o Sub::ScopeFinalizer
o Value::Canary
AUTHOR
chocolateboy <chocolate@cpan.org>
COPYRIGHT
Copyright (c) 2005-2010, chocolateboy.
This module is free software. It may be used, redistributed and/or modified under the same terms as Perl itself.
perl v5.10.1 2010-05-16 Scope::Guard(3pm)
