deduction guides for std::tuple

From cppreference.com
< cpp‎ | utility‎ | tuple
 
 
Utilities library
General utilities
Date and time
Function objects
Formatting library (C++20)
(C++11)
Relational operators (deprecated in C++20)
Integer comparison functions
(C++20)(C++20)(C++20)   
(C++20)
Swap and type operations
(C++14)
(C++11)
(C++11)
(C++11)
(C++17)
Common vocabulary types
(C++11)
(C++17)
(C++17)
(C++17)
(C++11)
(C++17)
(C++23)
Elementary string conversions
(C++17)
(C++17)
 
std::tuple
Member functions
Non-member functions
(until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)
Deduction guides(C++17)
Helper classes
 
Defined in header <tuple>
template<class... UTypes>
tuple(UTypes...) -> tuple<UTypes...>;
(1) (since C++17)
template<class T1, class T2>
tuple(std::pair<T1, T2>) -> tuple<T1, T2>;
(2) (since C++17)
template<class Alloc, class... UTypes>
tuple(std::allocator_arg_t, Alloc, UTypes...) -> tuple<UTypes...>;
(3) (since C++17)
template<class Alloc, class T1, class T2>
tuple(std::allocator_arg_t, Alloc, std::pair<T1, T2>) -> tuple<T1, T2>;
(4) (since C++17)
template<class Alloc, class... UTypes>
tuple(std::allocator_arg_t, Alloc, tuple<UTypes...>) -> tuple<UTypes...>;
(5) (since C++17)

These deduction guides are provided for std::tuple to account for the edge cases missed by the implicit deduction guides, in particular, non-copyable arguments and array to pointer conversion.

Example

#include <tuple>
int main()
{
    int a[2], b[3], c[4];
    std::tuple t1{a, b, c}; // explicit deduction guide is used in this case
}