Convert sybase datetime to time in seconds since unix epoch

FYI

I added my thoughts just for another point of view.  However, you should be mindful of Brets comments.  
In addition, this year (2007) is perfect example of potential issues relating to daylight savings time.

You might want to rethink the question.  What question(s) are you really trying to answer?

cheers
knel

Thanks guys that information is very usful, it also explains why they take the epoch from 1900 in this function:

(Taken from)
http://cvs.zope.org/Products/ZSybaseDA/src/ctsybase.c?rev=1.3

#define EPOCH_DAYS_SINCE_1900     25567
#define SYBASE_TICKS_PER_SECOND     300
#define SECONDS_PER_DAY           86400

/*****************************************************************************
 *                                                                           *
 * CS_DATETIMEToTimestamp : convert a time in CS_DATETIME format to a        *
 *                          unix timestamp                                   *
 *                                                                           *
 * Arguments:                                                                *
 *        date - the date in CS_DATETIME format                              *
 *                                                                           *
 * Remarks:                                                                  *
 *                                                                           *
 ****************************************************************************/

static time_t
CS_DATETIMEToTimestamp (CS_DATETIME date)
{
  return ((date.dtdays - EPOCH_DAYS_SINCE_1900) * SECONDS_PER_DAY) +
    (date.dttime / SYBASE_TICKS_PER_SECOND);
}

Can anyone confirm this function is correct?

Well, assuming that the CS_DATETIME is a UTC value, it is certainly close, but I'd be careful making that assumption.   It doesn't make any adjustments for leap seconds, though (but then, I don't know if UNIX time does either).

Well I got it working thanks for you help guys