NSDateFormatter milliseconds bug
It seems that NSDateFormatter
works only with millisecond resolution, for the
following reasons:
-
By setting a breakpoint in
CFDateFormatterCreateDateFromString
, one can see that this function is called fromdateFromString:
:(lldb) bt * thread #1: tid = 0x26d03f, 0x018f47d0 CoreFoundation`CFDateFormatterCreateDateFromString, queue = 'com.apple.main-thread', stop reason = breakpoint 3.1 frame #0: 0x018f47d0 CoreFoundation`CFDateFormatterCreateDateFromString frame #1: 0x0116e0ea Foundation`getObjectValue + 248 frame #2: 0x0116dfc7 Foundation`-[NSDateFormatter getObjectValue:forString:errorDescription:] + 206 frame #3: 0x0116879f Foundation`-[NSDateFormatter dateFromString:] + 71 * frame #4: 0x00002d56 foo`main(argc=1, argv=0xbfffee54) + 182 at main.mm:25
CFDateFormatterCreateDateFromString()
is from CFDateFormatter.c which is open source. One can see that all calendrical calculations are made using the ICU Calendar Classes.-
It is stated in calendar.h that
Calendar
usesUDate
which has a millisecond resolution:/** * <code>Calendar</code> is an abstract base class for converting between * a <code>UDate</code> object and a set of integer fields such as * <code>YEAR</code>, <code>MONTH</code>, <code>DAY</code>, <code>HOUR</code>, * and so on. (A <code>UDate</code> object represents a specific instant in * time with millisecond precision. See UDate * for information about the <code>UDate</code> class.) * ...