span.md

title	description	ms.date	f1_keywords	helpviewer_keywords	dev_langs
<span>	API reference for the Standard Template Library (STL) span namespace, which provides a lightweight view over a contiguous sequence of objects.	05/28/2020	<span>	span header	C++

<span>

A span is a view over a contiguous sequence of objects. It provides fast and bounds-safe access. Unlike vector or array, it doesn't "own" the elements.

See span class for detailed information. Here's an example of how to use a span:

#include <span>
#include <iostream>

void Show(std::span<int> someValues)
{
    // show values in reverse
    for (auto rIt = someValues.rbegin(); rIt != someValues.rend(); ++rIt)
    {
        std::cout << *rIt;
    }

    // show a subspan
    for (auto& i : someValues.subspan(1, 2))
    {
        std::cout << i;
    }
}

int main()
{
    int numbers[]{ 0,1,2,3,4 };
    Show(numbers); // note conversion from array to span
}

Requirements

Header: <span>

Namespace: std

Compiler option: /std:c++20 or later is required.

Members

Classes

Name	Description
span	Provides a view over a contiguous sequence of objects.

Operators

Name	Description
operator=	Span assignment
operator[]	Element access

Functions

Name	Description
as_bytes	Get the underlying read-only bytes of the span.
as_writable_bytes	Get the underlying bytes of the span.

Constants

Name	Description
dynamic_extent	Indicates that the span size is determined at runtime rather than compile time. When the number of elements in the span is known at compile time, it's specified as the Extent template parameter. When the number isn't known until runtime, specify dynamic_extent instead.

See also

Header Files Reference