std::experimental::to_array
From cppreference.com
< cpp | experimental
C++
Feature test macros (C++20)
Concepts library (C++20)
Metaprogramming library (C++11)
Ranges library (C++20)
Filesystem library (C++17)
Concurrency support library (C++11)
Execution control library (C++26)
Experimental
Filesystem library (filesystem TS)
Library fundamentals (library fundamentals TS)
Library fundamentals 2 (library fundamentals TS v2)
Library fundamentals 3 (library fundamentals TS v3)
Extensions for parallelism (parallelism TS)
Extensions for parallelism 2 (parallelism TS v2)
Extensions for concurrency (concurrency TS)
Extensions for concurrency 2 (concurrency TS v2)
Concepts (concepts TS)
Ranges (ranges TS)
Reflection (reflection TS)
Mathematical special functions (special functions TR)
Library fundamentals v2
experimental::to_array
Merged into ISO C++ The functionality described on this page was merged into the mainline ISO C++ standard as of 7/2019, see std::to_array (since C++20)
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)
constexpr std::array <std::remove_cv_t <T>, N> to_array(T (&a)[N]);
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.
[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
Run this code
#include <cassert> #include <cstdlib> #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); }
[edit] See also
(library fundamentals TS v2)
(function template) [edit]