What’s the correct way to use printf to print a clock_t?

I’m currently using a explicit cast to unsigned long long and using %llu to print it, but since size_t has the %z specifier, why doesn’t clock_t have one?

There isn’t even a macro for it. Maybe I can assume that on an x64 system (OS and CPU) size_t is 8 bytes in length (and even in this case, they have provided %z), but what about clock_t?

What’s the correct way to use printf to print a clock_t?