Retrieves the daylight saving time offset in hours.
The _get_daylight function retrieves the number of hours in daylight saving time as an integer. If daylight saving time is in effect, the default offset is one hour (although a few regions do observe a two-hour offset).
If hours is NULL, the invalid parameter handler is invoked as described in Parameter Validation. If execution is allowed to continue, this function sets errno to EINVAL and returns EINVAL.
Not applicable. To call the standard C function, use PInvoke. For more information, see Platform Invoke Examples.