gcc怎么知道去/include目录去找头文件的？

grt8000

如果我要把其他的一个目录也加为gcc可以自己去找，而不用 -I 参数来指定，应该如何做？

lenovo

摘自gcc4.1.0 manual

CPATH
C_INCLUDE_PATH
CPLUS_INCLUDE_PATH
OBJC_INCLUDE_PATH
    Each variable's value is a list of directories separated by a special character, much like PATH, in which to look for header files. The special character, PATH_SEPARATOR, is target-dependent and determined at GCC build time. For Microsoft Windows-based targets it is a semicolon, and for almost all other targets it is a colon.

    CPATH specifies a list of directories to be searched as if specified with -I, but after any paths given with -I options on the command line. This environment variable is used regardless of which language is being preprocessed.

    The remaining environment variables apply only when preprocessing the particular language indicated. Each specifies a list of directories to be searched as if specified with -isystem, but after any paths given with -isystem options on the command line.

    In all these variables, an empty element instructs the compiler to search its current working directory. Empty elements can appear at the beginning or end of a path. For instance, if the value of CPATH is :/special/include, that has the same effect as `-I. -I/special/include'.

albcamus

这个是写死在cpp中的。 不如就干脆在Makefile中加一句：
CC = gcc -I <pathname>

或者如果从shell调用， 用alias包裹一下。

grt8000

谢谢！