These macros will let you use binary constants straight in your code.  C normally only allows you to use base 8, 10, and 16.  Base 2 is extreamely useful when you're dealing with individual bits in a bitfield.

Code:

 binconst.h

Usage:

#include "binconst.h"

unsigned char bitfield = B8(01010101); // 85

unsigned int bigbitfield = B32(10000000,11111111,10101010,01010101); // 2164238933

Extensions:

If you needed, it would be pretty trivial to create a 64 bit binary macro as well.  I'll leave that as an exercise for the reader.

Sources:

http://cprog.tomsweb.net/binconst.txt