# std::experimental::to_array

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< cpp‎ | experimental

Defined in header `<experimental/array>` |  |
template <class T, std::size_t N> constexpr std::array < std::remove_cv_t <T>, N> to_array(T (&a)[N]); |  | (library fundamentals TS v2)

Creates a std::array from the built-in array `a`. The elements of the std::array are copy-initialized from the corresponding element of `a`.

### Parameters

a | - | the built-in array to be used to initialize the std::array

### Return value

An std::array object whose elements are copy-initialized from the corresponding element of `a`.

### Possible implementation

    namespace detail {
    template <class T, std::size_t N, std::size_t... I>
    constexpr std::array<std::remove_cv_t<T>, N>
        to_array_impl(T (&a)[N], std::index_sequence<I...>)
    {
        return { {a[I]...} };
    }
    }

    template <class T, std::size_t N>
    constexpr std::array<std::remove_cv_t<T>, N> to_array(T (&a)[N])
    {
        return detail::to_array_impl(a, std::make_index_sequence<N>{});
    }

### Example

Run this code

    #include <cstdlib>
    #include <cassert>
    #include <experimental/array>
    #include <unistd.h>

    // mkstemp(3) that works
    template <std::size_t N>
    int tempfd(char const (&tmpl)[N])
    {
        auto s = std::experimental::to_array(tmpl);
        int fd = mkstemp(s.data());
        if (fd != -1)
            unlink(s.data());

        return fd;
    }

    int main()
    {
        int fd = tempfd("/tmp/test.XXXXXX");
        int rt = close(fd);
        assert(rt == 0);
    }

### See also

make_array | Creates a std::array object whose size and optionally element type are deduced from the arguments (function template)

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