# deduction guides for `std::tuple`

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< cpp‎ | utility‎ | tuple

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

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
    }

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