Difference between revisions of "cpp/experimental/to array"
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< cpp | experimental
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{{example | {{example | ||
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#include <experimental/array> | #include <experimental/array> | ||
#include <unistd.h> | #include <unistd.h> | ||
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// mkstemp(3) that works | // mkstemp(3) that works | ||
| − | template <size_t N> | + | template <size_t N> |
int tempfd(char const (&tmpl)[N]) | int tempfd(char const (&tmpl)[N]) | ||
{ | { | ||
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int fd = mkstemp(s.data()); | int fd = mkstemp(s.data()); | ||
if (fd != -1) | if (fd != -1) | ||
Revision as of 07:28, 6 June 2018
| Defined in header <experimental/array>
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| 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 |
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
| (library fundamentals TS v2) |
creates a std::array object whose size and optionally element type are deduced from the arguments (function template) |
