std::span::first

 

C++

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Concepts library (C++20)

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Technical Specifications

 

Containers library

array (C++11)

vector

deque

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list

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span (C++20)

 

std::span

Member functions

span::span

span::operator=

Element access

span::operator[]span::operator()

span::data

Iterators

span::beginspan::cbegin

span::endspan::cend

span::rbeginspan::crbegin

span::rendspan::crend

Observers

span::empty

span::size

span::size_bytes

Subviews

span::first

span::last

span::subspan

Non-member functions

as_bytesas_writable_bytes

Non-member constant

dynamic_extent

Deduction guides

 

template< std::ptrdiff_t Count > constexpr std::span<element_type, Count> first() const;
constexpr std::span<element_type, std::dynamic_extent> first( std::ptrdiff_t Count ) const;

Obtains a span that is a view over the first Count elements of this span. The behavior is undefined if Count < 0 || Count > size().

Return value

A span r that is a view over the first Count elements of *this, such that r.data() == this->data() && r.size() == Count.

See also

last	obtains a subspan consisting of the last N elements of the sequence (public member function)
subspan	obtains a subspan (public member function)