std::span<T,Extent>::span
From cppreference.com
constexpr span() noexcept; |
(1) | |
constexpr span(pointer ptr, index_type count); |
(2) | |
constexpr span(pointer first, pointer last); |
(3) | |
template <std::size_t N> constexpr span(element_type (&arr)[N]) noexcept; |
(4) | |
template <std::size_t N> constexpr span(std::array<value_type, N>& arr) noexcept; |
(5) | |
template <std::size_t N> constexpr span(const std::array<value_type, N>& arr) noexcept; |
(6) | |
template <class Container> constexpr span(Container& cont); |
(7) | |
template <class Container> constexpr span(const Container& cont); |
(8) | |
template <class U, std::size_t N> constexpr span(const std::span<U, N>& s) noexcept; |
(9) | |
constexpr span(const span& other) noexcept = default; |
(10) | |
Constructs a span
.
1) Constructs an empty span whose data() == nullptr and size() == 0. This overload only participates in overload resolution if extent == 0 || extent == std::dynamic_extent.
2) Constructs a span that is a view over the range
[ptr, ptr + count)
; the resulting span has data() == ptr and size() == count. The behavior is undefined if [ptr, ptr + count)
is not a valid range or if extent != std::dynamic_extent && count != extent.3) Constructs a span that is a view over the range
[first, last)
; equivalent to span(first, last - first).4-6) Constructs a span that is a view over the array
arr
; the resulting span has size() == N and data() == std::data(arr). These overloads only participate in overload resolution if extent == std::dynamic_extent || N == extent is true and std::remove_pointer_t<decltype(std::data(arr))>(*)[] is convertible to element_type (*)[]7-8) Constructs a span that is a view over the range [std::data(cont), std::data(cont) + std::size(cont)); the resulting span has size() == std::size(cont) and data() == std::data(cont). The behavior is undefined if that is not a valid range or if extent != std::dynamic_extent && std::size(cont) != extent.
These overloads only participate in overload resolution if
-
Container
is not a specialization ofstd::span
, a specialization of std::array, or an array type; - std::data(cont) and std::size(cont) are both well-formed; and
- std::remove_pointer_t<decltype(std::data(cont))>(*)[] is convertible to element_type (*)[]
-
9) Converting constructor from another span
s
; the resulting span has size() == s.size() and data() == s.data(). This overload only participates in overload resolution if extent == std::dynamic_extent || N == extent is true and U (*)[] is convertible to element_type (*)[].10) Defaulted copy constructor copies the size and data pointer; the resulting span has size() == other.size() and data() == other.data().
Parameters
ptr, first | - | pointer to the first element of the sequence |
count | - | number of elements in the sequence |
last | - | pointer past the last element of the sequence |
arr | - | array to construct a view for |
cont | - | container to construct a view for |
s | - | another span to convert from |
other | - | another span to copy from |
Exceptions
2-3) Throws nothing.
See also
returns a pointer to the beginning of the sequence of elements (public member function) | |
returns the number of elements in the sequence (public member function) | |
assigns a span (public member function) | |
(C++17)(C++20) |
returns the size of a container or array (function template) |
(C++17) |
obtains the pointer to the underlying array (function template) |