You could buy yourself another 68 years by just treating it as an unsigned 32 bit value, assuming that you don't care about dates before 1January 1970. Otherwise, you'll need to adopt the 64 bit "version" of the time_t data type. On Wed, Feb 27, 2019, 10:34 Harold Hallikainen Thanks for the comments! The IETF RFC below is interesting. I currently > log stuff with a 32 bit Unix time stamp and convert it to a string > representing the date and time in the appropriate time zone when > displaying. The 32 bit counter is updated by a 1 Hz interrupt and now and > then set using NTP. When NTP adjusts by more than one second, the period > register is adjusted one click in the appropriate direction to speed up o= r > slow down the interrupt rate. > > The 1 Hz interrupt just increments a counter, which is very simple and > speedy in the interrupt. Using the below RFC method, I'd have to figure > out year, month, day, hour, minute, second, etc. during the interrupt. It > seems much easier to do this at display time. > > The simplest thing seems to be to increase the 32 bit time stamp to 64 > bits. That would resolve the issue for a LONG time. Making my interrupt d= o > that is, of course, easy. But, I need time.c to accept the 64 bit time > stamp and figure out the year, month, date, hour, minute, second. Also, > NTP would need to return the 64 bit time stamp. At this point, I'm not > sure what an NTP server returns after 2038 (probably otta look into that)= .. > > THANKS! > > Harold > > > Hi Harold, you could try RFC2550: > > https://tools.ietf.org/html/rfc2550 > > > > Regards, > > Ryan > > > > > > On Wed, 27 Feb 2019 at 16:13, Harold Hallikainen > > > > wrote: > > > >> I had to deal with Y2k in my firmware way back. I suspect some of my > >> stuff > >> will still be running in 2038 when the 32 bit Unix timestamp rolls ove= r. > >> Is there a 64 bit version of time.c? Or what is the best way to deal > >> with > >> this? > >> > >> Thanks! > >> > >> Harold > >> > >> > >> -- > >> FCC Rules Updated Daily at http://www.hallikainen.com > >> Not sent from an iPhone. > >> -- > >> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > >> View/change your membership options at > >> http://mailman.mit.edu/mailman/listinfo/piclist > >> > > -- > > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > > View/change your membership options at > > http://mailman.mit.edu/mailman/listinfo/piclist > > > > > -- > FCC Rules Updated Daily at http://www.hallikainen.com > Not sent from an iPhone. > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .