std::function

From Cppreference

C++ Standard Library
Language Utilities library Strings library Containers library Algorithms library Iterators library Numerics library Input/output library Localizations library Regular expressions library (C++11) Atomic operations library (C++11) Thread support library (C++11)
Utilities library
Function objects
std::function
Member functions function::function function::~function function::operator= function::swap function::assign function::operator bool function::operator() function::target_type function::target Non-member functions operator== operator!= std::swap(std::function) Helper classes std::uses_allocator<std::function>

Defined in header <functional>
template< class > class function; /* undefined */		(since C++11)
template< class R, class... Args > class function<R(Args...)>		(since C++11)

Class template std::function is a general-purpose polymorphic function wrapper. Instances of std::function can store, copy, and invoke any callable target -- functions, lambda expressions, bind expressions, or other function objects.

Contents 1 Member types 2 Member functions 2.1 Target access 3 Non-member functions 4 Helper classes 5 See also

[edit] Member types

Type	Definition
result_type	R
argument_type	T if sizeof...(Args)==1 and T is the first and only type in Args...
first_argument_type	T1 if sizeof...(Args)==2 and T1 is the first of the two types in Args...
second_argument_type	T2 if sizeof...(Args)==2 and T2 is the second of the two types in Args...

[edit] Member functions

(constructor)	constructs a new std::function instance (public member function)
(destructor)	destroys a std::function instance (public member function)
operator=	assigns the contents (public member function)
swap	swaps the contents (public member function)
assign	assigns a new target (public member function)
operator bool	checks if a valid target is contained (public member function)
operator()	invokes the target (public member function)
Target access
target_type	obtains the typeid of the stored target of an std::function (public member function)
target	obtains a pointer to the stored target of an std::function (public member function)

[edit] Non-member functions

std::swap(std::function) (C++11)	specializes the std::swap algorithm (function template)
operator== operator!=	compares an std::function with std::nullptr (function template)

[edit] Helper classes

std::uses_allocator<std::function> (C++11)	specializes the std::uses_allocator type trait (class template specialization)

[edit] See also

bad_function_call (C++11)	the exception thrown when invoking an empty std::function (class)
mem_fn (C++11)	binds an object to a pointer to its member function to form independent function object (function template)