Long-running daemons need logs, and djb’s tools use TAI64N labels. A
label has an @, sixteen hexadecimal digits of biased TAI
seconds, and eight hexadecimal digits of nanoseconds:
@4000000037c219bf2ef02e94TAI is a continuous atomic timescale. UTC inserts leap seconds, so converting between a POSIX/UTC timestamp and TAI requires the applicable TAI−UTC offset. The offset was 10 seconds at the Unix epoch convention used here and reached 37 seconds after the 2016 leap second.
tai64n timestamps each input line at the moment its
first bytes are read. tai64nlocal recognizes a valid
leading label and replaces it with local civil time at nanosecond
precision. Invalid prefixes pass through unchanged.
multilog t uses the same label generator, ensuring
standalone filters and log files agree.
src/tai64.rs contains the complete 1972–2017
positive-leap transition table. It validates the fixed-width hexadecimal
form and nanosecond range. Both stream filters use bounded memory: the
localizer buffers only the 25-byte candidate prefix and streams the rest
of even an extremely long line. At I/O failure the command exits 111,
following the daemontools convention.
TAI64N provides sortable, unambiguous event labels. Converting to local time is a presentation step, not the archival representation.