std::experi...ocation_type(3)

Okay so this is std::experi...ocation_type(3), from the C++ Standard Libary manual — yes, that’s the manual name, and the title got truncated like it’s allergic to vowels 💀. Buckle up, bestie, because this page is about std::experimental::invocation_type and std::experimental::raw_invocation_type.

💖 NAME 💖

std::experimental::invocation_type,std::experimental::raw_invocation_type — literally the two names, no cap: std::experimental::invocation_type and std::experimental::raw_invocation_type. The dash in the original is just the manpage doing its little separator thing 🎀.

✨ Synopsis ✨

Defined in header <experimental/type_traits>

template< class >
struct raw_invocation_type; //undefined

(1) (library fundamentals TS)

template< class Fn, class... ArgTypes >
struct raw_invocation_type<Fn(ArgTypes...)>;

template< class >
struct invocation_type; //undefined

(2) (library fundamentals TS)

template< class Fn, class... ArgTypes >
struct invocation_type<Fn(ArgTypes...)>;

This 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) are 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 invocation 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 🫶

• raw_invocation_type<Fn(ArgTypes...)>::type — this one is R(T1, T2, ...), where:
  • R is std::result_of_t<Fn(ArgTypes...)>.
  • T1, T2, ... are the invocation parameters of INVOKE(std::declval<Fn>(), std::declval<ArgTypes>()...) as defined above.

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

• invocation_type<Fn(ArgTypes...)>::type — this one is R(U1, U2, ...), where:
  • R is std::result_of_t<Fn(ArgTypes...)>.
  • T1, T2, ... are the invocation parameters of INVOKE(std::declval<Fn>(), std::declval<ArgTypes>()...) as defined above.
  • A1, A2, ... denotes ArgTypes....
  • Ui is std::decay_t<Ai> if std::declval<Ai>() is an rvalue and Ti otherwise.

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)

💀 Example 💀

This section is incomplete.

Reason: no example. 🙈

👑 See also 👑

• C++ documentation for Reflection TS.

🌈 Category 🌈

• Todo no example.

---

That’s the whole std::experi...ocation_type(3) page, bestie — sourced from http://cppreference.com, dated 2024.06.10. Slay and read your templates responsibly 💅💖