__STDC_LIMIT_MACROS 和 __STDC_CONSTANT_MACROS 是什么意思? [英] What do __STDC_LIMIT_MACROS and __STDC_CONSTANT_MACROS mean?

问题描述

我在系统的标准 C++ 库以及我正在使用的库中的一些头文件中看到了这一点.

I see this in the standard C++ libraries for my system, as well as some of the headers in a library I'm using.

这两个定义的语义是什么?除了源代码本身之外，是否有这样的#defines 的良好参考?

What are the semantics of these two definitions? Is there a good reference for #defines like this other than the source itself?

推荐答案

__STDC_LIMIT_MACROS 和 __STDC_CONSTANT_MACROS 是一种允许 C++ 程序使用 stdint.h C99 标准中指定但不在 C++ 标准中的宏.UINT8_MAX、INT64_MIN 和 INT32_C() 等宏可能已经以其他方式在 C++ 应用程序中定义.为了让用户决定他们是否想要像 C99 那样定义的宏，许多实现要求在 stdint.h 之前定义 __STDC_LIMIT_MACROS 和 __STDC_CONSTANT_MACROS包括在内.

__STDC_LIMIT_MACROS and __STDC_CONSTANT_MACROS are a workaround to allow C++ programs to use stdint.h macros specified in the C99 standard that aren't in the C++ standard. The macros, such as UINT8_MAX, INT64_MIN, and INT32_C() may be defined already in C++ applications in other ways. To allow the user to decide if they want the macros defined as C99 does, many implementations require that __STDC_LIMIT_MACROS and __STDC_CONSTANT_MACROS be defined before stdint.h is included.

这不是 C++ 标准的一部分，但已被多个实现采用.

This isn't part of the C++ standard, but it has been adopted by more than one implementation.

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