Hi. This feature of gcc seems strange to me: Consider a directory structure of a tiny project: /main.cpp (#include "foo.hpp" ) /d1/bar.hpp /d2/foo.hpp (#include "bar.hpp") /d2/bar.hpp then compiling > g++ -I d1 -I d2 main.cpp -o main will include /d2/bar.hpp instead of /d1/bar.hpp as I expected ( I expected so because "d1/" is listed first in "-I" options). Such a behaviour of g++ limits the use of "sandboxes" in c++ projects ( consider the /d1/ directory as a sandbox of a real project). Hope I don't miss something. Thank you. Dima.