We all know when to use include guard, but when shall we not use it in our project?
我们都知道什么时候使用include guard，但什么时候不在我们的项目中使用它呢?
Recently, I saw a project with mix compilation (CUDA + GCC), one header file (CUDA file) is deliberately left without include guard. I am just curious about it.
最近，我看到了一个混合编译(CUDA + GCC)的项目，一个头文件(CUDA文件)被故意留下而没有包含保护。我只是好奇而已。
4 个解决方案
#1
12
There are 2 scenarios off the top of my head:
我脑海中有两种场景:
- when you want to turn on/off debugging capabilities (as how
assert.hworks) - 当您想要打开/关闭调试功能时(如如何断言)。h工作)
- for 'x-macro' type of functionality where you have the include file perform 2 parts of problem, such as defining an enum then defining an array of stringified names corresponding to the enums
- 对于包含文件的“x-macro”类型的功能，可以执行问题的两个部分，例如定义枚举，然后定义与枚举对应的字符串化名称数组
#2
2
One case in when you do want to include the same file several times with different parameters. In this case the include file would act as a sort of template. An example are the scalers on Dosbox.
有一种情况是，当您确实想要多次包含具有不同参数的相同文件时。在这种情况下，include文件将作为一种模板。Dosbox上的标量就是一个例子。
#3
2
In our projects we never use include guard. We are using include antiguard:
在我们的项目中，我们从不使用include guard。我们正在使用防护罩:
#ifndef _stdafx_h_
#define _stdafx_h_
#else
#error reinclude stdafx.h
#endif
Because if you reincluded same header - you written wrong code or worked with wrong architecture.
因为如果您重新包含了相同的标题——您编写了错误的代码或使用了错误的架构。
#4
0
Include guards are used so that the include file can be included multiple times in a single compilation unit without resulting in duplicate declarations.
使用Include保护，以便在单个编译单元中多次包含Include文件，而不会导致重复声明。
Do not use include guards when the file should be included multiple times in a single compilation unit and this does not result in duplicate declarations.
当文件应该在一个编译单元中包含多次并且不会导致重复声明时，不要使用include保护。
#1
12
There are 2 scenarios off the top of my head:
我脑海中有两种场景:
- when you want to turn on/off debugging capabilities (as how
assert.hworks) - 当您想要打开/关闭调试功能时(如如何断言)。h工作)
- for 'x-macro' type of functionality where you have the include file perform 2 parts of problem, such as defining an enum then defining an array of stringified names corresponding to the enums
- 对于包含文件的“x-macro”类型的功能，可以执行问题的两个部分，例如定义枚举，然后定义与枚举对应的字符串化名称数组
#2
2
One case in when you do want to include the same file several times with different parameters. In this case the include file would act as a sort of template. An example are the scalers on Dosbox.
有一种情况是，当您确实想要多次包含具有不同参数的相同文件时。在这种情况下，include文件将作为一种模板。Dosbox上的标量就是一个例子。
#3
2
In our projects we never use include guard. We are using include antiguard:
在我们的项目中，我们从不使用include guard。我们正在使用防护罩:
#ifndef _stdafx_h_
#define _stdafx_h_
#else
#error reinclude stdafx.h
#endif
Because if you reincluded same header - you written wrong code or worked with wrong architecture.
因为如果您重新包含了相同的标题——您编写了错误的代码或使用了错误的架构。
#4
0
Include guards are used so that the include file can be included multiple times in a single compilation unit without resulting in duplicate declarations.
使用Include保护，以便在单个编译单元中多次包含Include文件，而不会导致重复声明。
Do not use include guards when the file should be included multiple times in a single compilation unit and this does not result in duplicate declarations.
当文件应该在一个编译单元中包含多次并且不会导致重复声明时，不要使用include保护。