为什么PHP date（）在diff计算中增加+1小时？

Question

I've got kind of a tricky question, I already searched every related question on Stackoverflow and neither solved my conundrum, although I think I'm running in circles, so here's the question:

I've got this code:

$val = (strtotime('2010-03-22 10:05:00')-strtotime('2010-03-22 09:00:00'))

This returns correctly $val = 3900 (3600 seconds = 1 hour, 300 seconds = 5 mins)

But doing this:

echo date("H:i",$val)."<br>";

returns 02:05

even doing this:

echo date("H:i",3900)."<br>";

returns 02:05 (just to be naively sure)

Doing this:

echo date("H:i eTO",3900)."<br>";

returns

02:05 System/LocaltimeCET+0100

Which is correct, my timezone is CET and is +1.

What's going on? Is date() correcting the timezone for some reason? Or am I doing anything wrong?

Answer 1

This is happening because using date(, ) returns epoch (00:00:00 01 January 1970 UTC) + the number of seconds in the timestamp. It will localise itself to your timezone, so if you provided it with a timestamp of 0 it would return 01:00:00 01 January 1970 UTC+1.