[RESOLVED] error on return previous month in March

heropage

the following code return previous month, it worked fine before.
But today is March 31, the code doesn't work. I guess something to do with 28 days of Feb.

$lastmonth = mktime(0, 0, 0, date("m")-1, date("d"),   date("Y"));
$month_d=date("n",$lastmonth);
echo $month_d;

how to fix it?

NogDog

Well, the first question is: what do you when the prior month has fewer days than the current one? Since this was a leap year, would you want Mar 28 through 31 to return Feb 28, Feb 29, Feb 29, Feb 29?

heropage

date("m")-1

will return previous month, isn't it?

NogDog

Yes, but you are also specifying the current day (31), so you are trying to set the date to Feb 31. Since that is invalid, PHP interprets that as 30 days after Feb. 1, i.e. Mar 2.

heropage

NogDog wrote:
Yes, but you are also specifying the current day (31), so you are trying to set the date to Feb 31. Since that is invalid, PHP interprets that as 30 days after Feb. 1, i.e. Mar 2.

oh, I see, is it safe to use

mktime(0, 0, 0, date("m")-1, 15,   date("Y"));

I only want to return previous month.

bradgrafelman

[man]strtotime/man might be more useful here (e.g. pass it the string "-1 month").

NogDog

bradgrafelman wrote:
[man]strtotime/man might be more useful here (e.g. pass it the string "-1 month").

I believe strtotime() has the same problem: I recall seeing a discussion about it somewhere as to whether it's a feature or a bug.

Anyway, if all you want is the month, hard-coding into mktime any day less than 29 should be fine.