gcc默认include路径
1 2 | `gcc -print-prog-name=cc1` -v `g++ -print-prog-name=cc1` -v |
优先级由大到小对应下表中的从上到下
1 2 3 4 5 | 命令行-I指定，前面的大于后面的 CPATH CPLUS_INCLUDE_PATH #只对c++文件起作用 C_INCLUDE_PATH #只对c文件起作用，即C_INCLUDE_PATH和CPLUS_INCLUDE_PATH不会同时起作用 gcc默认include路径 |
refer to:
http://www.3scard.com/index.php?m=blog&f=view&id=42