strtotime（“ - 5小时”）不工作？

I thought strtotime() would convert a "string" into a timestamp. If I add on to the time, it works fine, but if I try to subtract, it doesn't. Does anyone know a workaround?

Thanks in advance.

I recommend reading Derick Rethans's excellent guide on Date and Time, http://derickrethans.nl/talks/time-zendcon9.pdf, explanatory slides start at slide 16.

He's the author of PHP's date and time functions and recommends that you use the DateTime classes if possible.

It seems to work fine for me...

echo strtotime("-5 hours");

Result:

1282061972