这里帮助理解MinGW中，哪些是C++的头文件路径，哪些是C的头文件路径，通常C++程序设置头文件路径的话需要将C++的头文件路径设到C头文件路径的前面。

比如C头文件目录%MINGW_PATH%/include下有头文件，里面有strcpy等c函数的声明。

C++头文件目录%MINGW_PATH%/lib/gcc/mingw32/4.4.0/include/c++下有头文件，里面有std::string类的声明。

//家目录

MINGW_PATH=D:/MinGW

//C头文件目录

C_INCLUDE_PATH=%MINGW_PATH%/include;%MINGW_PATH%/lib/gcc/mingw32/3.4.5/include

//C++头文件目录

CPLUS_INCLUDE_PATH=%MINGW_PATH%/include/c++/3.4.5;%MINGW_PATH%/include/c++/3.4.5/mingw32;%MINGW_PATH%/include/c++/3.4.5/backward;%C_INCLUDE_PATH%

//在QTSDK带的MinGW中C++头文件目录均在lib文件夹下

CPLUS_INCLUDE_PATH=%MINGW_PATH%/lib/gcc/mingw32/4.4.0/include/c++;%C_INCLUDE_PATH%

//库目录

LIBRARY_PATH=%MINGW_PATH%/lib;%MINGW_PATH%/lib/gcc/mingw32/3.4.5 

//可执行程序目录

PATH=%MINGW_PATH%/bin;%MINGW_PATH%/libexec/gcc/mingw32/3.4.5