Feature Test Macros |
|
|
The exact set of features available when you compile a source file is controlled
by which feature test macros you define.
If you compile your programs using `gcc -ansi', you get only the ISO C library features, unless you explicitly request additional features by defining one or more of the feature macros. See section `GNU CC Command Options' in The GNU CC Manual, for more information about GCC options.
You should define these macros by using `#define' preprocessor directives at the top of your source code files. These directives must come before any #include of a system header file. It is best to make them the very first thing in the file, preceded only by comments. You could also use the `-D' option to GCC, but it's better if you make the source files indicate their own meaning in a self-contained way.
Macro: _POSIX_SOURCE
If you define this macro, then the functionality from the POSIX.1 standard (IEEE Standard 1003.1) is available, as well as all of
< 1 > < 2 > |
|
|
在百度搜索:Feature Test Macros
|
用户登录 
新用户注册 