Determine #defined string length at compile time

Question

I have a C-program (an Apache module, i.e. the program runs often), which is going to write() a 0-terminated string over a socket, so I need to know its length.

Answer 1

sizeof works at compile time

#define POLICY "\n" \
   "\n" \
   "\n" \
   "\n" \
   "\0"

char pol[sizeof POLICY];
strcpy(pol, POLICY); /* safe, with an extra char to boot */

If you need a pre-processor symbol with the size, just count the characters and write the symbol yourself :-)

#define POLICY_LENGTH 78 /* just made that number up! */