Compares date portion of the two date-time values, first converted into the local time zone.
The returned value is like with strcmp.
| datetime1 |
a time_t-like value of the first date-time |
| datetime2 |
a time_t-like value of the second date-time |
|
0 when the dates are equal, < 0 when first is before second and > 0 when the first is after the second date |