From: benjamin dot rich at gmail dot com
Operating system: net time incorrectly calculated?
PHP version: 4.3.10
PHP Bug Type: Date/time related
Bug description: date("B") returns wrong net time - or does it?
Description:
------------
I was hyperventilating trying to solve a seemingly phantom bug in my
script to do with net time (see bug 33082).
It appeared, when I got down to it, that when I calculated net time with
date() from the local clock, it would give me the correct net time:
date("B", time());
but when I did it from a static timestamp - adjusted to local time - it
showed the date and time correctly, but always screwed up the net time:
//6:41am 2005-5-20 GMT:
$test = date(@B", mktime(06,41,00,05,20,2005));
echo "should show @361: $test";
-> @403
I tried for some time to figure out why - it seemed - the date() function
was adding an hour to the net time for these dates - and not, as I later
found out through experimentation, the actual date or time they
represented. For example, date("r @B") for the above might give me: fri 20
may 2005 06:41am @403.
After long and painful, and unscientific, experimentation, I finally
discovered the problem: the time it was giving *was* right - just not
according to every net time calculator I entered the time into.
For example - enter the date/time 5th May 1999, 6:41pm with location
Austtralia, SYDNEY into one of the following net time calculators:
http://www.help4web.net/adds/swatch.html
and you get @361
http://www.users.bigpond.net.au/snakeman/converter.html
and you get @403
Swatch's own converter thinks different:
http://www.swatch.com/internettime/home.php
gives @361
yet PHP's date() function will give you: @403.
Something, somewhere, is not... calculating daylight savings correctly? It
would appear something is awry. I thought I should bring this to the
attention of the PHP devs.
I mean... sure, nobody *uses* net-time... but come on! That's no excuse
not to make it work properly =)
For my own money, my own calculations show 403 is the correct net time for
the above date. I worked it out as:
Australia (Sydney) is EST, and during May, which is not daylight savings
time, is GMT+10. Given that BMT, net time's meridian, is GMT+1, this means
the net time for any given time in Australia is: ((Australian time in
hours) - 9) * 41.666.
41.666 is the number of net-time 'beats' per hour. The above yields an
answer of 403 for the given date/time (18:41 EST time 2005-5-20)
--
Edit bug report at http://bugs.php.net/?id=33110&edit=1
--
Try a CVS snapshot (php4): http://bugs.php.net/fix.php?id=33110&r=trysnapshot4
Try a CVS snapshot (php5.0):
http://bugs.php.net/fix.php?id=33110&r=trysnapshot50
Try a CVS snapshot (php5.1):
http://bugs.php.net/fix.php?id=33110&r=trysnapshot51
Fixed in CVS: http://bugs.php.net/fix.php?id=33110&r=fixedcvs
Fixed in release: http://bugs.php.net/fix.php?id=33110&r=alreadyfixed
Need backtrace: http://bugs.php.net/fix.php?id=33110&r=needtrace
Need Reproduce Script: http://bugs.php.net/fix.php?id=33110&r=needscript
Try newer version: http://bugs.php.net/fix.php?id=33110&r=oldversion
Not developer issue: http://bugs.php.net/fix.php?id=33110&r=support
Expected behavior: http://bugs.php.net/fix.php?id=33110&r=notwrong
Not enough info:
http://bugs.php.net/fix.php?id=33110&r=notenoughinfo
Submitted twice:
http://bugs.php.net/fix.php?id=33110&r=submittedtwice
register_globals: http://bugs.php.net/fix.php?id=33110&r=globals
PHP 3 support discontinued: http://bugs.php.net/fix.php?id=33110&r=php3
Daylight Savings: http://bugs.php.net/fix.php?id=33110&r=dst
IIS Stability: http://bugs.php.net/fix.php?id=33110&r=isapi
Install GNU Sed: http://bugs.php.net/fix.php?id=33110&r=gnused
Floating point limitations: http://bugs.php.net/fix.php?id=33110&r=float
No Zend Extensions: http://bugs.php.net/fix.php?id=33110&r=nozend
MySQL Configuration Error: http://bugs.php.net/fix.php?id=33110&r=mysqlcfg
