std::span<T,Extent>::size

 

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std::span

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span::beginspan::cbegin (C++23)

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as_bytesas_writable_bytes

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dynamic_extent

Deduction guides

 

constexpr size_type size() const noexcept;		(since C++20)

Returns the number of elements in the span.

Return value

The number of elements in the span.

Note

Feature-test macro	Value	Std	Feature
__cpp_lib_ssize	201902L	(C++20)	std::ssize and unsigned std::span::size

Example

Run this code

#include <span>
 
int main()
{
    constexpr static int c_array[]{1, 2, 3, 4, 5, 6, 7, 8};
 
    constexpr std::span<const int> span{c_array};
 
    static_assert(8 == span.size();
    static_assert(7 == span.first(7).size();
    static_assert(6 == span.first<6>().size();
    static_assert(5 == span.last(5).size();
    static_assert(4 == span.last<4>().size();
    static_assert(3 == span.subspan(2, 3).size();
    static_assert(2 == span.subspan<3, 2>().size();
    static_assert(1 == span.subspan<7>().size();
}

See also

(constructor)	constructs a span (public member function)
size_bytes	returns the size of the sequence in bytes (public member function)

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