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std::function<R(Args...)>::target_type

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<cpp‎ |utility‎ |functional‎ |function

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(C++26)

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three_way_comparablethree_way_comparable_with

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(C++20)

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compare_three_way_result

(C++20)

compare_three_way

(C++20)

(C++20)

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(C++20)

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(C++20)

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(C++20)

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(C++20)

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pair
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Partial function application
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Transparent operator wrappers

plus<> (C++14)
minus<> (C++14)
negate<> (C++14)
multiplies<> (C++14)
divides<> (C++14)
modulus<> (C++14)
bit_and<> (C++14)
bit_or<> (C++14)
bit_not<> (C++14)
bit_xor<> (C++14)

equal_to<> (C++14)
not_equal_to<> (C++14)
greater<> (C++14)
less<> (C++14)
greater_equal<> (C++14)
less_equal<> (C++14)
logical_and<> (C++14)
logical_or<> (C++14)
logical_not<> (C++14)

Negators
not_fn (C++17)
Searchers
default_searcher (C++17)
boyer_moore_searcher (C++17)
boyer_moore_horspool_searcher (C++17)

Constrained comparators
ranges::equal_to (C++20)
ranges::not_equal_to (C++20)
ranges::greater (C++20)
ranges::less (C++20)
ranges::greater_equal (C++20)
ranges::less_equal (C++20)
compare_three_way (C++20)

Old binders and adaptors

unary_function (until C++17*)
binary_function (until C++17*)
ptr_fun (until C++17*)
pointer_to_unary_function (until C++17*)
pointer_to_binary_function (until C++17*)
mem_fun (until C++17*)
mem_fun_tmem_fun1_tconst_mem_fun_tconst_mem_fun1_t (until C++17)(until C++17)(until C++17)(until C++17)
not1 (until C++20*)
not2 (until C++20*)

binder1stbinder2nd (until C++17)(until C++17)
bind1stbind2nd (until C++17)(until C++17)

mem_fun_ref (until C++17*)
mem_fun_ref_tmem_fun1_ref_tconst_mem_fun_ref_tconst_mem_fun1_ref_t (until C++17)(until C++17)(until C++17)(until C++17)
unary_negate (until C++20*)
binary_negate (until C++20*)

std::function

Member functions
function::function
function::~function
function::operator=
function::swap
function::assign (until C++17)
function::operator bool
function::operator()
function::target_type
function::target
Non-member functions
operator==operator!= (until C++20)
swap(std::function)
Helper classes
uses_allocator<std::function> (until C++17)
Deduction guides(C++17)

conststd::type_info& target_type()constnoexcept;		(since C++11)

Returns the type of the stored function.

Contents

[edit]Parameters

(none)

[edit]Return value

typeid(T) if the stored function has typeT, otherwisetypeid(void)

[edit]Example

Run this code

#include <functional>#include <iostream> int f(int a){return-a;}void g(double){}int main(){// fn1 and fn2 have the same type, but their targets do notstd::function<int(int)> fn1(f),                            fn2([](int a){return-a;});std::cout<< fn1.target_type().name()<<'\n'<< fn2.target_type().name()<<'\n'; // since C++17 deduction guides (CTAD) can availstd::cout<<std::function{g}.target_type().name()<<'\n';}

Possible output:

PFiiEZ4mainEUliE_PFvdE

[edit]See also

target	obtains a pointer to the stored target (public member function)[edit]
type_info	contains some type’s information, the class returned by the typeid operator (class)[edit]
`typeid`	queries information of a type, returning a`std::type_info` object representing the type (operator)

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