On 06/02/2014 08:31 AM, Theodore Ts'o wrote: > > I wonder if it would make sense to try to promulgate via the Austin > group, and possibly the C standards committee the concept of a bit > pattern (that might commonly be INT_MAX or UINT_MAX) that means "time > unknown", or "time indefinite" or "we couldn't encode the time". > (time_t)-1 already has this meaning for some calls (e.g. time(2)). However, this also means Wed Dec 31 23:59:59 UTC 1969, and unfortunately something similar applies to all possible bit patterns, certainly within the range of an int. > We would then teach gmtime(3) and asctime(3) to print some appropriate > message, and we could teach programs like find (with the -mtime) > option, make, tmpwatch, et. al., that they can't make any presumption > about the comparibility of any timestamp which has a value of > TIME_UNDEFINIED. > > It would be problematic for time(2) or gettimeofday(2) to return > TIME_UNDEFINED, since there are programs that care about time ticking > forward, but I could imagine a new interface which would be permitted > to return a flag indicating that we don't know the current time > (because the CMOS battery had run down, etc.) so instead we're going > to be counting the number of seconds since the system was booted. This assumes that we actually know that that is the case, which may be an aggressive assumption. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
