gsl :: multi_span可以用来做什么? [英] What is gsl::multi_span to be used for?

问题描述

C ++核心准则提到跨度，而不是多跨度".但是-我看到Microsoft的GSL实现具有 multi_span类

The C++ core guidelines mention spans, not "multi-spans". But - I see that Microsoft's GSL implementation has a multi_span class

template <
    typename ValueType,
    std::ptrdiff_t FirstDimension,
    std::ptrdiff_t... RestDimensions
>
class multi_span { ... };

因此，很明显，这是gsl::span的某种多维版本.但是那是什么意思呢?为什么我们需要这个多维范围，或者更确切地说-我们什么时候使用它?我似乎找不到关于此的任何文档.

So, obviously this is some sort of a multi-dimensional version of gsl::span. But what is that supposed to mean? Why do we need this multi-dimensional span, or rather - when would we use it? I can't seem to find any documentation on this.

推荐答案

简而言之，它是跨连续内存的跨度，代表多维数组.

In short, it is a span over contiguous piece of memory, which represents multidimensional array.

以下是使用示例:

int data[6] = {0, 1, 2, 3, 4, 5};
multi_span<int, 2, 3> span{data, 6};
std::cout << span[1][1] << '\n'; //Outputs 4

从链接的来源看，它似乎也支持运行时范围，但是我不确定这些范围的正确语法.

From the linked source, it seems, that it also supports runtime bounds, but I am not sure about proper syntax for those.

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