Thanks for this PR!

I think that it is a net benefit over what we have today, but I do think it's probably pretty inefficient, and considering we're already in C-land, maybe we can just directly call the C functions underlying timedelta addition instead of constructing a timedelta for this?

I think what you need to do to accomplish that is basically convert thetimestamp parameter to an integer number of seconds and microseconds, then do something like:

intyear=1970;intmonth=1;intday=1;inthour=0;intminute=0;intsecond=seconds;intmicrosecond=microseconds;normalize_datetime(&year,&month,&day,&hour,&minute,&second,&microsecond);

Then construct adatetime object with the results.

Callingnormalize_datetime() doesn't work sinceseconds hastime_t time, whereas the function only acceptsint.

Callingnormalize_datetime() doesn't work sinceseconds hastime_t time, whereas the function only acceptsint.

I am suggesting that we make the proper conversions, which will be almost certainly be dramatically more efficient than converting everything totimedelta and constructing at least 2datetime objects.

In the end it's not abig deal to be inefficient here, because it's a pretty rare situation that wasn't evenpossible before, but we might as well do it now rather than wait for someone to notice and show up with a new issue "negative timestamps on windows are dramatically slower than positive ones!"

Actually it occurs to me that if we just split into seconds and microseconds we will overflow in the late 19th century. I think it is best to convert to (hours, seconds, microseconds), then normalize the datetime. That will give 244k years, which is well outside the range supported by datetime.