NTPUTC

NTPUTC is a term used in several Network Time Protocol (NTP) software packages to denote a utility or interface dealing with time values in UTC. It is not a formal standard, and its exact form varies between implementations. In some open-source NTP toolchains, ntputc is a small command-line utility that can query an NTP server and display or apply the time in Coordinated Universal Time (UTC).

Functionality commonly associated with NTPUTC includes converting the 64-bit NTP timestamp format to a human-readable UTC time, and formatting times for display or logging. The NTP timestamp combines a 32-bit seconds field (count of seconds since 1900-01-01) and a 32-bit fractional field. Converting to UTC/Unix time requires subtracting 2208988800 seconds and handling sub-second precision, leap seconds, and potential wraparound.

In practice, an NTPUTC utility may offer options to query a specified NTP server, adjust the local clock, or print timestamps in UTC without changing system time. It is typically used by administrators and by other timekeeping utilities as a building block for time synchronization workflows.

Limitations and history: NTPUTC implementations have evolved with changes in NTP protocol versions and leap second handling. Some packages include a dedicated ntputc program, while other projects expose similar functionality via libraries or higher-level tools. See also: NTP, UTC, ntpdate, ntpq, ntpsec.