使用哪一个 - memmove与（）或memcpy的（） - 当缓冲区不重叠？ [英] Which one to use - memmove() or memcpy() - when buffers don't overlap?

问题描述

使用的memcpy（）当源和目的地的重叠可能会导致不确定的行为 - 在这种情况下只有 memmove与（）可以使用。

Using memcpy() when source and destination overlap can lead to undefined behaviour - in those cases only memmove() can be used.

但如果我知道肯定缓冲区不重叠 - 有没有理由使用专门的memcpy（）或专的memmove（） ？我应该使用，为什么？

But what if I know for sure buffers don't overlap - is there a reason to use specifically memcpy() or specifically memmove()? Which should I use and why?

推荐答案

假设一个健全的库实现者，的memcpy 将永远在至少一样快 memmove与。然而，在大多数平台上的差别将是最小的，而且在许多平台的memcpy 只是一个别名 memmove与来支持传统code，它（错误地）调用的memcpy 上重叠的缓冲区。

Assuming a sane library implementor, memcpy will always be at least as fast as memmove. However, on most platforms the difference will be minimal, and on many platforms memcpy is just an alias for memmove to support legacy code that (incorrectly) calls memcpy on overlapping buffers.

两者的memcpy 和 memmove与应写入充分利用该平台上最快的载入和存储的。

Both memcpy and memmove should be written to take advantage of the fastest loads and stores available on the platform.

要回答你的问题：你应该使用一个是语义正确的。如果你能保证缓冲区不重叠，你应该使用的memcpy 。如果你不能保证缓冲区不重叠，你应该使用 memmove与。

To answer your question: you should use the one that is semantically correct. If you can guarantee that the buffers do not overlap, you should use memcpy. If you cannot guarantee that the buffers don't overlap, you should use memmove.

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