#define _POSIX_SOURCE是什么意思? [英] What does #define _POSIX_SOURCE mean?
问题描述
如果我在C语言中使用#define _POSIX_SOURCE，那么我在程序中获得了什么好处.我可以在程序中访问更多的库，还是可以调用直接存在于C中的某些函数.我的意思是，这个神秘的宏到底意味着什么?
If I use #define _POSIX_SOURCE in C so then what advantage do i get in my program. Can I access more libraries in my program or I can call some functions which are present directly in C. I mean what does this mysterious macros means after all?
推荐答案
它允许您使用不属于标准C库但属于POSIX.1(IEEE标准1003.1)标准的函数.使用中描述的宏 feature_test_macros 允许您控制公开的定义 通过系统头文件.
It allows you to use function that are not part of the standard C library but are part of the POSIX.1 (IEEE Standard 1003.1) standard. Using the macros described in feature_test_macros allows you to control the definitions exposed by the system header files.
据我所知_POSIX_SOURCE已过时，您应该改用_POSIX_C_SOURCE.
As far as I know _POSIX_SOURCE is obsolete and you should use _POSIX_C_SOURCE instead.
例如，如果要使用 strndup ，则必须使用
For example, if you want to use strndup, you have to use
#define _POSIX_C_SOURCE 200809L
另请参见
- 1.3.4 Feature Test Macros
- 5.12 Posix Variants
- man 7 feature_test_macros
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