_GNU_SOURCE和__USE_GNU [英] _GNU_SOURCE and __USE_GNU

问题描述

我想用 CPU_SET ，这是一个应该在 sched.h中该手册页明确指出， _GNU_SOURCE 必须定义，这样的宏定义。然而，看着头， CPU_SET 定义只有当 __ USE_GNU 定义（有一个 #IFDEF 后卫）。我似乎在几年前的 _GNU_SOURCE 需要记住。

I want to use CPU_SET, which is a glibc linux-specific macro that should be defined in sched.h The manpage clearly states that _GNU_SOURCE must be defined so that the macro is defined. However, looking at the header, CPU_SET is defined only if __USE_GNU is defined (there is an #ifdef guard). I seem to remember a few years ago that _GNU_SOURCE was needed.

问题：

1）明确的联机帮助页关闭。我如何通知维护人员的手册页是不正确的？

1) Clearly the manpage is off. How do I notify the maintainer that the manpage is incorrect?

2）什么时候从 _GNU_SOURCE __ USE_GNU过渡到 发生（无论是在版本或时间）方面

2) When did the transition from _GNU_SOURCE to __USE_GNU happen (either in terms of version or time)

3）是否有情况，其中的glibc的较新版本仍然使用 _GNU_SOURCE ？或者，我可以有把握地认为限定了 __ USE_GNU 就足够了？

3) Are there circumstances where newer versions of glibc still use _GNU_SOURCE? Or can I safely assume that defining __USE_GNU is sufficient?

推荐答案

_GNU_SOURCE 是你曾经自己定义唯一的一个。 __ USE_GNU 通过一种机制，内部定义的 features.h （这是由所有其他的glibc头在内）时， _GNU_SOURCE 的定义，并有可能在其他条件。定义或取消定义 __ USE_GNU 自己将严重打破glibc的头。

_GNU_SOURCE is the only one you should ever define yourself. __USE_GNU is defined internally through a mechanism in features.h (which is included by all other glibc headers) when _GNU_SOURCE is defined, and possibly under other conditions. Defining or undefining __USE_GNU yourself will badly break the glibc headers.

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