[#BloombergLP-bslstl-Function_IsInvocableWithPrototype-06]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bslstl.adoc[bslstl]::Function&lowbar;IsInvocableWithPrototype
:relfileprefix: ../../
:mrdocs:

Forward declaration of the component&hyphen;private `Function&lowbar;IsInvocableWithPrototype` `struct` template&period; The primary (unspecialized) template is not defined&period; This `struct` template implements a boolean metafunction that publicly inherits from `bsl&colon;&colon;true&lowbar;type` if an object of the specified `FUNC` type is invocable under the specified `PROTOTYPE`, and inherits from `bsl&colon;&colon;false&lowbar;type` otherwise&period; An object of `FUNC` type is invocable under the `PROTOTYPE` if it is Lvalue&hyphen;Callable with the arguments of the `PROTOTYPE`, and returns an object of type convertible to the return type of the `PROTOTYPE`&period; If the return type of the `PROTOTYPE` is `void`, then any type is considered convertible to the return type of the `PROTOTYPE`&period; In C&plus;&plus;03, `FUNC` is considered Lvalue&hyphen;Callable with the argument and return types of the `PROTOTYPE` if it is not an integral type&period; This `struct` template requires `PROTOTYPE` to be an unqualified function type&period;

== Synopsis

Declared in `&lt;bslstl&lowbar;function&period;h&gt;`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template&lt;
    class PROTOTYPE,
    class FUNC&gt;
struct Function&lowbar;IsInvocableWithPrototype;
----

== Specializations

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslstl/Function_IsInvocableWithPrototype-00.adoc[`Function&lowbar;IsInvocableWithPrototype&lt;RET(ARGS&period;&period;&period;), FUNC&gt;`] 
| This component&hyphen;private `struct` template provides a boolean metafunction that derives from `bsl&colon;&colon;true&lowbar;type` if a `bsl&colon;&colon;function` object having a prototype of `RET(ARGS&period;&period;&period;)` is constructible from an object of type `FUNC`, and derives from `bsl&colon;&colon;false&lowbar;type` otherwise&period; This metafunction is a wrapper around `bsl&colon;&colon;invoke&lowbar;result` that unwraps `FUNC` if it is a specialization of `bslalg&colon;&colon;NothrowMovableWrapper`&semi; and, if `bsl&colon;&colon;invoke&lowbar;result` provides a nested `type` typedef for `FUNC` and `RET` is non&hyphen;void, checks that the return type of the invoke operation on `FUNC` is convertible to `RET`&period;
|===



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