Stores the instant in time that this represents into
The time contained in a TimeVal is always stored in the form of seconds elapsed since 1970-01-01 00:00:00 UTC, regardless of the time zone associated with this.
On systems where 'long' is 32bit (ie: all 32bit systems and all Windows systems), a TimeVal is incapable of storing the entire range of values that DateTime is capable of expressing. On those systems, this function returns false to indicate that the time is out of range.
On systems where 'long' is 64bit, this function never fails.
a TimeVal to modify
true if successful, else false