After I installed OpenFOAM on Ubuntu I tried to compile some C++ codes(not a part of OpenFOAM) but the computer keeps referring it to OpenFOAM for some strange reason.
ie.
/home/shuo/OpenFOAM/linux/gcc-4.1.0/bin/../lib/gcc/i686-pc-linux-gnu/4.1.0/../.. /../../include/c++/4.1.0/istream:762: error: no type named 'off_type' in 'struct std::char_traits<wchar_t>'

Shuo

That's not referring to OpenFOAM; that's referring to the GCC installation that you installed with OpenFOAM.

Remember, when you put the OpenFOAM bashrc (or cshrc) stuff in your .bashrc (or .cshrc) file? That also tells it to add things to your path, so that the copy of GCC that you installed with OpenFOAM comes earlier in your path than the system GCC. Thus, whenever you call GCC, regardless of whether or not you're doing OpenFOAM stuff, it runs that one.

In any case, it should work perfectly fine, except for any minor bugs that have been fixed between version 4.1.0 and the current version.