In most cases, there is no reason to test for access to functions that have been part of ANSI/ISO C since the 1989 version of the standard came out, or for availability of the standard C headers.
绝大部分情况下，没有理由去测试是否有权使用自 1989 版本标准出现以后的 ANSI/ISO C 中的函数或者标准的 C 头文件是否可用。
2
If you specify a standard older than the ISO C99 version, some of the extensions described in this article may be disabled.
如果指定比iso C99版本旧的标准，那么可能无法使用本文描述的一些扩展。
3
The XML version and encoding also must be set to "1.0" and "ISO-8859-1", respectively.