[#bsl-stop_token]
= xref:bsl.adoc[bsl]::stop_token
:relfileprefix: ../
:mrdocs:

Mechanism for observing cancellation requests on a stop state.

== Synopsis

Declared in `<bslstl_stoptoken.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
class stop_token;
----

== Description

This class is a mechanism for observing cancellation requests. An object of this class either has (possibly shared) ownership of a stop state and can be used to observe whether a cancellation request has been made on that stop state, or does not own a stop state. A `stop_token` cannot be used to make a cancellation request.

== Type Aliases

[cols="1,4"]
|===
| Name| Description
| xref:bsl/stop_token/callback_type.adoc[`callback_type`] 
| Alias for `stop_callback` parameterized by `t_CALLBACK`.
|===


== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:bsl/stop_token/2constructor-06.adoc[`stop_token`]         [.small]#[constructor]#
| Constructors
| xref:bsl/stop_token/2destructor.adoc[`~stop_token`] [.small]#[destructor]#
| Destroy this object.
| xref:bsl/stop_token/operator_assign-07.adoc[`operator=`] 
| Assignment operators
| xref:bsl/stop_token/stop_possible.adoc[`stop_possible`] 
| Return whether a stop is still possible on the referred stop state.
| xref:bsl/stop_token/stop_requested.adoc[`stop_requested`] 
| Return whether a stop has been requested on the referred stop state.
| xref:bsl/stop_token/swap.adoc[`swap`] 
| Exchange the stop states referred to by `*this` and `other`.
|===


== Friends

[cols="1,4"]
|===
| Name| Description
| `xref:bsl/swap-06da.adoc[bsl::swap]`
| Exchange the stop states referred to by `lhs` and `rhs`.
| `xref:bsl/operator_eq-0c5.adoc[bsl::operator==]`
| Return whether `lhs` and `rhs` refer to the same stop state.
| `xref:bsl/stop_callback-06.adoc[bsl::stop_callback]`
| Callback invoked when a stop is requested on an associated stop state.
| `xref:bsl/stop_source.adoc[bsl::stop_source]`
| Mechanism for requesting and observing cancellation on a stop state.
|===


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