[freenet-chat] Quick C Question

[David McNab]

We all know the mktime() function, which converts a *local* time in (struct tm) format into seconds since the epoch GMT.   But is there an equivalent function which converts a *GMT* time in (struct tm) format into seconds since the epoch GMT?   On windoze, I found an undocumented function hiding in library source called _mkgmtime() which does this perfectly.  But I don't want to lose portability. Is there a similar function in Linux-land?   I ask because I've been hitting all kinds of snags with handling the 'yyyymmddhhmmss'-format times in FCP. Many or most DBRs use Jan 1, 2000, 00:00:00 as the baseline. The 'fun' happens in the Southern Hemisphere, where at that time, localtime is one hour ahead with Daylight Saving. That plays havoc with the date calculation. I tried setting TZ to zero, then doing a tzset(). But then time() becomes inaccurate, because it takes the system clock to be GMT!   I'd rather not have to reinvent the wheel by writing yet another "compute the number of days between two dates" function, plus the pain of timezones, and determining whether it's daylight saving now, and was it daylight saving in the place and time of the DBR baseline.... AAARRRGGHHHH!   Cheers David