World: r3wp

That could be too.

Lad, In C I tried:
#include <stdbool.h>
int main (int argc, const char * argv[]) {
    printf ("bool length %d\n", sizeof(bool));
    return 0;
}

The output was:
bool length 1

So it is usually char, at least in GNU C/C++

I haven't found any explicit type definition in the C99 though.

{"If it is a C99 _Bool, it will typically be char-sized, though." 
-- hmm, I found explicitly stated that it should be int}

Where?

A slightly better test would be:

#include <stdio.h>

int main(int argc, char *argv[]) {printf("%ld\n", sizeof(_Bool)); 
return 0;}


And then compile that in C99 mode (i.e. -std=c99 for GCC; but C89/90 
compilers will bark on the unknown _Bool keyword anyway).


Better, because there exist(ed) a few stdbool.h versions prior to 
the final C99 standard which used e.g. unsigned integers for bools. 
Should be gone/fixed by now, but one never knows :)

Under OS X using gcc, I get bool length 1 both with Cyphre and Andreas 
versions, and also with or without -std=c99 option.

Yes, I also used the C99 compiler flag. Andreas version is more correct 
test ofcourse.