Debugging C++ preprocessor macros

It’s possible to get clang / g++ to run only the preprocessor and to strip away all the cruft that comes in with headers.

$ g++ -std=c++11 -E -P -c main.cpp

From the documentation of g++:

 -E     Run the preprocessor stage.
 -P     Tell the preprocessor not to generate `#line' directives.
        Used with the `-E' option.
 -c     Don't run the linker

An excellent way to get online feedback on your changes is to use a service like Coliru. See an example of preprocessor output at http://coliru.stacked-crooked.com/a/ce86de4f956f9316