std::copyable_function
<functional>
class copyable_function; // not defined
class copyable_function<R(Args...)>;
template< class R, class... Args >
class copyable_function<R(Args...) noexcept>;
template< class R, class... Args >
class copyable_function<R(Args...) &>;
template< class R, class... Args >
class copyable_function<R(Args...) & noexcept>;
template< class R, class... Args >
class copyable_function<R(Args...) &&>;
template< class R, class... Args >
class copyable_function<R(Args...) && noexcept>;
template< class R, class... Args >
class copyable_function<R(Args...) const>;
template< class R, class... Args >
class copyable_function<R(Args...) const noexcept>;
template< class R, class... Args >
class copyable_function<R(Args...) const &>;
template< class R, class... Args >
class copyable_function<R(Args...) const & noexcept>;
template< class R, class... Args >
class copyable_function<R(Args...) const &&>;
template< class R, class... Args >
Class template std::copyable_function is a general-purpose polymorphic function wrapper. std::copyable_function objects can store and invoke any CopyConstructible Callable target — functions, lambda expressions, bind expressions, or other function objects, as well as pointers to member functions and pointers to member objects.
The stored callable object is called the target of std::copyable_function. If a std::copyable_function contains no target, it is called empty. Unlike std::function , invoking an empty std::copyable_function results in undefined behavior.
std::copyable_functions supports every possible combination of cv-qualifiers (not including volatile), ref-qualifiers, and noexcept-specifiers provided in its template parameter. These qualifiers and specifier (if any) are added to its operator().
std::copyable_function satisfies the requirements of CopyConstructible and CopyAssignable.
[edit] Member types
result_type
R
[edit] Member functions
[edit] Non-member functions
[edit] Notes
Implementations may store a callable object of small size within the std::copyable_function object. Such small object optimization is effectively required for function pointers and std::reference_wrapper specializations, and can only be applied to types T for which std::is_nothrow_move_constructible_v <T> is true.
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_copyable_function |
202306L |
(C++26) | std::copyable_function
|
[edit] Example
Reason: no example
[edit] See also
(class template) [edit]