[#absl-FunctionRef-081]
= xref:absl.adoc[absl]::xref:absl/FunctionRef-0e3.adoc[FunctionRef]<R const(Args...)>
:relfileprefix: ../
:mrdocs:

FunctionRef

== Synopsis

Declared in `<absl/functional/function_ref.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    typename R,
    typename... Args>
class xref:absl/FunctionRef-0e3.adoc[FunctionRef]<R const(Args...)>;
----

== Description

An `absl::FunctionRef` is a lightweight wrapper to any invocable object with a compatible signature. Generally, an `absl::FunctionRef` should only be used as an argument type and should be preferred as an argument over a const reference to a `std::function`. `absl::FunctionRef` itself does not allocate, although the wrapped invocable may.

Example:

// The following function takes a function callback by const reference bool Visitor(const std::function<void(my_proto&, absl::string_view)>& callback);

// Assuming that the function is not stored or otherwise copied, it can be // replaced by an `absl::FunctionRef`: bool Visitor(absl::FunctionRef<void(my_proto&, absl::string_view)> callback);

== Type Aliases

[cols="1"]
|===
| Name
| xref:absl/FunctionRef-081/absl_internal_is_view.adoc[`absl_internal_is_view`] 
|===


== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:absl/FunctionRef-081/2constructor-059.adoc[`FunctionRef`]         [.small]#[constructor]#
| Constructors
| xref:absl/FunctionRef-081/operator_call.adoc[`operator()`] 
| 
|===


== Using Declarations

[cols="1"]
|===
| Name
| xref:absl/FunctionRef-081/operator().adoc[`operator()`] 
|===


== Protected Type Aliases

[cols="1"]
|===
| Name
| xref:absl/FunctionRef-081/EnableIfCompatible.adoc[`EnableIfCompatible`] 
|===


== Protected Member Functions

[cols="1"]
|===
| Name
| xref:absl/FunctionRef-081/2constructor-05d.adoc[`FunctionRef`]         [.small]#[constructor]#
|===



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