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std::experimental::to_array

From cppreference.com
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.

Contents

[edit] Parameters

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

[edit] Return value

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

[edit] 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>{});
}

[edit] Example

#include <experimental/array>
#include <unistd.h>
#include <stdlib.h>
#include <assert.h>
 
// mkstemp(3) that works
template <size_t N>
int tempfd(char const (&tmpl)[N])
{
    using std::experimental::to_array;
 
    auto s = 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);
}


[edit] See also

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