Using boolean values in C

Question

C doesn't have any built-in boolean types. What's the best way to use them in C?

Answer 1

From best to worse:

Option 1 (C99 and newer)

#include <stdbool.h>

Option 2

typedef enum { false, true } bool;

Option 3

typedef int bool;
enum { false, true };

Option 4

typedef int bool;
#define true 1
#define false 0

Explanation

• Option 1 will work only if you use C99 (or newer) and it's the "standard way" to do it. Choose this if possible.
• Options 2, 3 and 4 will have in practice the same identical behavior. #2 and #3 don't use #defines though, which in my opinion is better.

If you are undecided, go with #1!