How to make G++ preprocessor output a newline in a macro?

Question

Is there a way in gcc/g++ 4.* to write a macro that expands into several lines?

The following code:

#define A X \\ Y

Expands into

Answer 1

Make the macro generate a special markup, say __CR__, then pipe the result of CPP into a script which translates the macro to a true newline, for example, sed 's/__CR__/\n/g'.

I just found this useful to generate a code pattern to be filled by hand. It is quite easier when the code is readable.