Tandem time starts in 4700BC in micro seconds.

This is the whackiest time format I have ever heard of, I wonder what they were taking^Wthinking.

You want to convert to epoch seconds, then add 4700 + 1970 years worth of seconds and then multiply by 1000.

The 4700+1970 years worth of seconds is the sticky part- you have to take into account all the leap years and pretend that the calender doesn't change as you go back. I would bet they have a pre-calculated constant they cut 'n paste around.

See Time::Local and localtime() for converting to/from epoch seconds.

--
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