deductionguidesforstd::tuple(3)

NAME
deductionguidesforstd::tuple - deductionguidesforstd::tuple

Synopsis
   Defined in header <tuple>
   template<class... UTypes> (1) (since C++17)
   tuple(UTypes...) -> tuple<UTypes...>;
   template<class T1, class T2> (2) (since C++17)
   tuple(std::pair<T1, T2>) -> tuple<T1, T2>;
   template<class Alloc, class... UTypes> (3) (since C++17)
   tuple(std::allocator_arg_t, Alloc, UTypes...) -> tuple<UTypes...>;
   template<class Alloc, class T1, class T2>
   tuple(std::allocator_arg_t, Alloc, std::pair<T1, T2>) -> tuple<T1, (4) (since C++17)
   T2>;
   template<class Alloc, class... UTypes>
   tuple(std::allocator_arg_t, Alloc, tuple<UTypes...>) -> (5) (since C++17)
   tuple<UTypes...>;
   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
// Run this code
 #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
 }