std::experimental::to_array

 

C++

Language

Standard library headers

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

 

Technical specifications

Filesystem library (filesystem TS)

Library fundamentals (library fundamentals TS)

Library fundamentals 2 (library fundamentals 2 TS)

Extensions for parallelism (parallelism TS)

Concepts (concepts TS)

Extensions for concurrency (concurrency TS)

Special mathematical functions (special math TR)

 

Library fundamentals v2

experimental::propagate_const

experimental::not_fn

experimental::observer_ptr

experimental::make_array

experimental::to_array

experimental::ostream_joiner

experimental::gcd

experimental::lcm

experimental::source_location

experimental::randint

detection idiom

uniform container erasure

logical operator type traits

 

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 <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);
}

See also

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