[#absl-Cleanup-0a]
= xref:absl.adoc[absl]::Cleanup
:relfileprefix: ../
:mrdocs:

Scope guard that invokes a callback on scope exit.

== Synopsis

Declared in `<absl/cleanup/cleanup.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    typename Arg,
    typename Callback = void()>
class [[nodiscard]] Cleanup final
----

== Description

`absl::Cleanup` implements the scope guard idiom, invoking the contained callback's `operator()() &&` on scope exit.

This class doesn't allocate or take any locks, and is safe to use in a signal handler. Of course the callback with which it is constructed also must be signal safe in order for this to be useful.

== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:absl/Cleanup-0a/2constructor-0e.adoc[`Cleanup`]         [.small]#[constructor]#
| Constructors
| xref:absl/Cleanup-0a/2destructor.adoc[`~Cleanup`] [.small]#[destructor]#
| Invoke the callback, if still engaged, on scope exit.
| xref:absl/Cleanup-0a/Cancel.adoc[`Cancel`] 
| Prevent the callback from executing.
| xref:absl/Cleanup-0a/Invoke.adoc[`Invoke`] 
| Execute the callback early and prevent it from running on destruction.
|===


== Deduction Guides

[cols="1,4"]
|===
| Name| Description
| xref:absl/Cleanup-03.adoc[`Cleanup<cleanup_internal::Tag, Callback>`] 
| Deduction guide for creating an `absl::Cleanup` from a callback.
|===


== Non-Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:absl/MakeCleanup.adoc[`MakeCleanup`]
| Create an `absl::Cleanup` from a callback.
|===

== Return Value

[NOTE]
====
The return value https://en.cppreference.com/cpp/language/attributes/nodiscard[should not be discarded^].
====

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