How to get default defines from gcc?

How to get default defines from gcc? It easy, just execute few GCC commands to show default defines:

gcc -dM -E - </dev/null
 

Or, if you C++ developer:

g++ -dM -E - </dev/null
 

If you use crosscompile, don't forget to add prefix.

arm-linux-gcc -dM -E - </dev/null