It's not true that if you pass a pointer to a 'struct timezone' to gettimeofday() it just gets filled with zeroes - the tz_minuteswest field is filled with the

It's not true that if you pass a pointer to a 'struct timezone' to gettimeofday() it just gets filled with zeroes - the tz_minuteswest field is filled with the current local timezone offset (based either on the TZ environment variable or on /etc/localtime).