How to print a pound / hash via C preprocessor?

Question

I need help doing the following:

a preprocessor macro label(x) shall output \"#x\", e.g.,

#define label(x) ...

if I call label(anam

Answer 1

The answer is:

#define hash #
#define f(x) x
#define label(a) f(hash)a

then

label(foobar)

creates

#foobar

I found it with the help of all of you, but especially wintermute. Thanks a lot!

(Using gcc 4.3.3)