On Mar 11, 2011, at 5:30 PM, Nick Dokos wrote: > Carsten Dominik <carsten.domi...@gmail.com> wrote: > > >> THis is exactly the point, that it depends on how Emacs was compiled, and >> what kind of integer is used in the date representation. Signed or >> unsigend, 32 or 64 bits (I think). >> >> For example, Bastien can represent dates before 1970. I cannot. >> I can represent dates after 2038, Bastien cannot. >> >> The work-around is to use diary sexps for dates before 1970, that seems to >> be safe. >> And then hope that by 2038, all computers will use 64 bit integers.... >> > > But it's even more than that, no? Emacs's time implementation > (current-time, encode/decode etc) would have to change. In fact, this > might be the most significant limitation right now: the values they pass > around are (hi16 lo16 ms) so they assume that time values are 32 bits, > no matter what the underlying implementation says. I use 64-bit Linux on > an x86-64 laptop and my time_t is 64 bits (but I don't know if it's > signed or unsigned). Time for some experimentation I guess...
I believe that on your system you might get (hi48 lo16 ms) You can test if it is signed by trying a date before 1970 (encode-time 0 0 0 1 1 1960) - Carsten
