mktime, how do I override limitations

The last time i try to attempt this problem, i get rid of the detail of the system calls from PHP to OS. i worked with datetime in a MySQL server which supports 1000-01-01 to 9999-12-31 and whole lots of datetime manipulation functions there.  I wanna know how if it's solely on PHP and the local OS.

Apart from system calls from PHP, what i can think of in programming aspect is a simple mapping.  Basically, days r running in a 4 year cycle. Thus, it's not difficult to just count on the year and map the datetime to a corresponding pt within 1970 and 2037...
what's left is to count on the exception... that's no leap year every 100 years(just as ordinary years) but leap year again every 400 years....
btw, it's very lucky that 2000 is the every 400 year exception...

Anyway, I wanna know how ppl usually do it, too.


$Spud->Regards();

Usually with builtin or library functions, but yeah, 2037 is coming close. This is a C thing, not just UNIX. C time library functions use a 32 bit integer to represent the number:

- Data Type: time_t
This is the data type used to represent calendar time.  In the GNU C library and other POSIX-compliant implementations, time_t is equivalent to long int.  When interpreted as an absolute time value, it represents the number of seconds elapsed since 00:00:00 on January 1, 1970, Coordinated Universal Time.  (This date is sometimes referred to as the "epoch".)

In other systems, time_t might be either an integer or floating-point type.

There used to be some time calcultaion functions (C/C++) on www.programmersheaven.com and www.snippets.org

I tested potatotsang's theory of the four year cycle, unfortunatly with bad results,

1st jan 2001 = Monday
1st jan 2005 = Saturday
1st jan 2009 = Thursday

therefor there must be more to it in date calculations (which I am also very bad in)

As for KangaRoo, I searched for the function time_t, also without success, my guess is that this is used in C but not in PHP.

Thx anyway, hope I find a way round it.

time_t is the /type/ of the object the C library uses to represent time with. This is (at least) a 32 bit integer.

Given the similarity in the limitation of mktime at the year 2037 in both PHP and C my bet is that PHP simply uses the C functions (PHP is written using C).
In a couple of years, when 64 bit processors are the standard, the C library will likely start using 64 bit integers for time_t, eliminating the year 2037 boundary.

I am looking for code, but :(
There used to exist some usefull date/functions on www.snippets.org but the site is undergoing major maintenance and only yhe entire snippets.zip (~1Mb) is available.

thx 4 all, I guess I can use potatosang's input very well.

I'll just make all calculations using the first 28 Years after the epoch, then extract the year as a number, then add the needed amount of years to it.

This will keep my (faked) date calculation script working correctly until the next 100 Year exception, which is 2100. Luckily I'll be dead by then :)