deductionguidesforstd::tuple (3) - Linux Manuals

deductionguidesforstd::tuple: deductionguidesforstd::tuple

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> (4) (since C++17)
tuple(std::allocator_arg_t, Alloc, std::pair<T1, T2>) -> tuple<T1, T2>;
template<class Alloc, class... UTypes> (5) (since C++17)
tuple(std::allocator_arg_t, Alloc, tuple<UTypes...>) -> 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
  }