std::experimental::invocation_type, std::experimental::raw_invocation_type

Technical specifications
Filesystem library (filesystem TS)
Library fundamentals (library fundamentals TS)
Library fundamentals 2 (library fundamentals TS v2)
Library fundamentals 3 (library fundamentals TS v3)
Extensions for parallelism (parallelism TS)
Extensions for parallelism 2 (parallelism TS v2)
Extensions for concurrency (concurrency TS)
Extensions for concurrency 2 (concurrency TS v2)
Concepts (concepts TS)
Ranges (ranges TS)
Reflection (reflection TS)
Mathematical special functions (special functions TR)
Defined in header <experimental/type_traits>

struct raw_invocation_type; //undefined

template<class Fn, class... ArgTypes>

struct raw_invocation_type<Fn(ArgTypes...)>;
(1) (library fundamentals TS)

struct invocation_type; //undefined

template<class Fn, class... ArgTypes>

struct invocation_type<Fn(ArgTypes...)>;
(2) (library fundamentals TS)

Computes the invocation parameters when Fn is called with the arguments ArgTypes..., as in INVOKE(std::declval<Fn>(), std::declval<ArgTypes>()...), where INVOKE is the operation defined in Callable.

The invocation parameters of the expression INVOKE(f, t1, t2, ..., tN) is defined as follows, where T1 is the (possibly cv-qualified) type of t1 and U1 is T1& if t1 is an lvalue and T1&& otherwise:

  • If f is a pointer to a member function of a class T, then the invocation parameters are U1 followed by the parameters of f matched by t2, ..., tN.
  • If N == 1 and f is a pointer to member data of a class T, then the invocation parameter is U1.
  • If f is an object of class type, the invocation parameters are the parameters matching t1, ..., tN of the best viable function for the arguments t1, ..., tN among the function call operators and surrogate call functions of f.
  • In all other cases, the invocations parameters are the parameters of f matching t1, ..., tN.

If an argument tI matches an ellipsis in the function's parameter list, the corresponding invocation parameter is the result of applying the default argument promotions to tI.

Fn and all types in ArgTypes can be any complete type, array of unknown bound, or (possibly cv-qualified) void.

Member types

Member type Definition
raw_invocation_type<Fn(ArgTypes...)>::type R(T1, T2, ...), where:

Only defined if Fn can be called with the arguments ArgTypes... in unevaluated context.

invocation_type<Fn(ArgTypes...)>::type R(U1, U2, ...), where

Only defined if Fn can be called with the arguments ArgTypes... in unevaluated context.

Helper types

template< class T >
using raw_invocation_type_t = typename raw_invocation_type<T>::type;
(library fundamentals TS)
template< class T >
using invocation_type_t = typename invocation_type<T>::type;
(library fundamentals TS)


See also