How to determine the standard C/C++ include paths?

[Marc Glisse]

On Wed, 12 May 2010, Alex Flint wrote:

> I was wondering how, on a given system, I can determine which include
> paths are automatically searched by gcc (and similarly for g++ when
> compiling c++ sources). That is, which paths are _not_ searched when
> using -nostdinc (and similarly for -nostdinc++)?

http://gcc.gnu.org/onlinedocs/gcc-4.5.0/gcc/Overall-Options.html#index-v-79