Question

I have a lot of #define‘s in my code. Now a weird problem has crept up.

I have this:

#define _ImmSign    010100

(I’m trying to simulate a binary number)

Obviously, I expect the number to become 10100. But when I use the number it has changed into 4160.

What is happening here? And how do I stop it?

ADDITIONAL

Okay, so this is due to the language interpreting this as an octal. Is there some smart way however to force the language to interpret the numbers as integers? If a leading 0 defines octal, and 0x defines hexadecimal now that I think of it…

Answer 1

If you are willing to write non-portable code and use gcc, you can use the binary constants extension:

#define _ImmSign    0b010100