#pragma once vs包括卫兵？ [英] #pragma once vs include guards?

问题描述

我正在开发一个已知只能在Windows上运行并在Visual Studio下编译的代码库（它与excel紧密集成，所以它不会在任何地方）。我想知道我是否应该使用传统的包含守卫或使用 #pragma once 代码。我认为让编译器处理 #pragma once 将产生更快的编译，并且在处理和粘贴时不易出错。它也稍微不那么丑陋 ;）

I'm working on a codebase that is known to only run on windows and be compiled under Visual Studio (it integrates tightly with excel so it's not going anywhere). I'm wondering if I should go with the traditional include guards or use #pragma once for our code. I would think letting the compiler deal with #pragma once will yield faster compiles and is less error prone when coping and pasting. It is also slightly less ugly ;)

注意：我们可以使用冗余包含守卫，但会在所包含的文件和包含文件。通常它是确定的，因为警卫应该基于文件名，只会改变，如果你需要改变包括名称反正。

Note: to get the faster compile times we could use Redundant Include Guards but that adds a tight coupling between the included file and the including file. Usually it's ok because the guard should be based on the file name and would only change if you needed to change in the include name anyways.

推荐答案

我不认为它会在编译时间产生重大差异，但 #pragma once 在编译器中得到很好的支持，但实际上并不是标准的一部分。预处理器可能有点快，因为它更容易理解你的确切意图。

I don't think it will make a significant difference in compile time but #pragma once is very well supported across compilers but not actually part of the standard. The preprocessor may be a little faster with it as it is more simple to understand your exact intent.

#pragma once

为了加快编译时间，只要向前声明，而不是包含在.h文件中。

To speed up compile time more just forward declare instead of including in .h files when you can.

我更喜欢使用 #pragma once 。

请参阅这篇维基百科文章，了解同时使用两者的可能性。

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