std::span::first

C++

Language

Headers

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Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

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

Containers library

array (C++11)

vector

deque

forward_list (C++11)

list

set

multiset

map

multimap

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

stack

queue

priority_queue

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

operator==operator!=operator<operator<=operator>operator>=

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)