printf conversion specifier for _Bool?

Question

With printf(), I can use %hhu for unsigned char, %hi for a short int, %zu for a size_t

Answer 1

There is no specific conversion length modifier for _Bool type.

_Bool is an unsigned integer type large enough to store the values 0 and 1. You can print a _Bool this way:

_Bool b = 1;
printf("%d\n", b);

Because of the integer promotions rules, _Bool is guaranteed to promote to int.