Linux C include路径问题

In c/c++ program, if we need include file,there are two ways:

Include <> or

Include “”

When we use include <>

The search order:

1 search “-I” target directory ifwe used in GCC command

2 search the directory defined in“CPLUS_INCLUDE_PATH”(c++) or “C_INCLUDE_PATH”(c) cenvironment variable

3 search GCC built-inpath: /usr/include /usr/local/include /usr/lib/gcc/i686-redhat-linux/<version>/include

When we use include “ ”

1 search current directory, (echo$PWD)

2 search “-I” target directory ifwe used in GCC command

3 search the directory defined in“CPLUS_INCLUDE_PATH”(c++) or “C_INCLUDE_PATH”(c) or “CPATH”(both c and c++)environment variable

4 search GCC built-inpath: /usr/include /usr/local/include /usr/lib/gcc/i686-redhat-linux/<version>/include

to verify, we can use gcc –v test.c toprint the build progress, we can find the result from the output.

Useful link:

http://www.360doc.com/content/13/0524/16/110467_287784511.shtml

http://blog.sina.com.cn/s/blog_6fe0d70d0101ep85.html

tips:

GCC built-in include path prefix(marked byred, means where GCC is installed ) can be found:

Gcc –v

Configured with:../configure --prefix=/usr--mandir=/usr/share/man --infodir=/usr/share/info