The code is using the function `snprintf` to format a...

The code is using the function snprintf to format a string and store it in the character array address_format.

The first argument of snprintf is the destination buffer (address_format) where the formatted string will be stored. The second argument is the maximum number of characters that can be written to the buffer, which is calculated as the size of address_format multiplied by 8.

The third argument is the format string specifying how the output should be formatted. In this case, the format string is "address = %%%zus \n".

The % character signals that a format specifier follows, and %% means to print a literal %. %zu is a format specifier for an unsigned integer of type size_t, and %zus means to print a string with a field width equal to the value of address_size.

So the final formatted string will look something like this:

address = %1234s

Where 1234 is the value of address_size.