.. index:: single: time_scales_data .. _time_scales_data/0:

.. rst-class:: right

object

`time_scales_data`

Bundled and override data plus constants for UTC/TAI/TT/UT1/TDB/TCG/TCB conversions.

| Availability: | logtalk_load(time_scales(loader))

| Author: Paulo Moura | Version: 0:2:0 | Date: 2026-02-26

| Compilation flags: | static, context_switching_calls

| Uses: | :ref:`logtalk <logtalk/0>`

| Remarks: | (none)

| Inherited public predicates: | (none)

.. contents:: :local: :backlinks: top

Public predicates

.. index:: load_leap_seconds_override/1 .. _time_scales_data/0::load_leap_seconds_override/1:

load_leap_seconds_override/1 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Loads leap-second override data from a file containing leap(UnixSeconds,OffsetSeconds). terms.

| Compilation flags: | static

| Template: | load_leap_seconds_override(File) | Mode and number of proofs: | load_leap_seconds_override(+atom) - one

| Remarks:

Term format: Each term must be of the form leap(UnixSeconds,OffsetSeconds)..
Term ordering: Terms must be sorted by increasing UnixSeconds.
Value constraints: UnixSeconds must be an integer greater than or equal to 63072000 and OffsetSeconds must be a non-decreasing integer sequence.

.. index:: clear_leap_seconds_override/0 .. _time_scales_data/0::clear_leap_seconds_override/0:

clear_leap_seconds_override/0 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Clears leap-second override data and reverts to bundled data.

| Compilation flags: | static

| Mode and number of proofs: | clear_leap_seconds_override - one

.. index:: leap_seconds_source/1 .. _time_scales_data/0::leap_seconds_source/1:

leap_seconds_source/1 ^^^^^^^^^^^^^^^^^^^^^^^^^

Returns the active leap-seconds data source as bundled or override.

| Compilation flags: | static

| Template: | leap_seconds_source(Source) | Mode and number of proofs: | leap_seconds_source(-atom) - one

.. index:: leap_seconds_entries/1 .. _time_scales_data/0::leap_seconds_entries/1:

leap_seconds_entries/1 ^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns the active leap-seconds data as an ordered list of leap(UnixSeconds,OffsetSeconds) terms.

| Compilation flags: | static

| Template: | leap_seconds_entries(Entries) | Mode and number of proofs: | leap_seconds_entries(-list) - one

.. index:: save_leap_seconds_entries/1 .. _time_scales_data/0::save_leap_seconds_entries/1:

save_leap_seconds_entries/1 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Saves the active leap-seconds data to a file using leap(UnixSeconds,OffsetSeconds). terms.

| Compilation flags: | static

| Template: | save_leap_seconds_entries(File) | Mode and number of proofs: | save_leap_seconds_entries(+atom) - one

.. index:: load_dut1_override/1 .. _time_scales_data/0::load_dut1_override/1:

load_dut1_override/1 ^^^^^^^^^^^^^^^^^^^^^^^^

Loads DUT1 override data from a file containing dut1(UnixSeconds,Numerator,Denominator). terms.

| Compilation flags: | static

| Template: | load_dut1_override(File) | Mode and number of proofs: | load_dut1_override(+atom) - one

| Remarks:

Term format: Each term must be of the form dut1(UnixSeconds,Numerator,Denominator)..
Term ordering: Terms must be sorted by increasing UnixSeconds.
Value constraints: UnixSeconds and Numerator must be integers; Denominator must be a positive integer; UnixSeconds must be greater than or equal to 63072000.

.. index:: clear_dut1_override/0 .. _time_scales_data/0::clear_dut1_override/0:

clear_dut1_override/0 ^^^^^^^^^^^^^^^^^^^^^^^^^

Clears DUT1 override data and reverts to bundled data.

| Compilation flags: | static

| Mode and number of proofs: | clear_dut1_override - one

.. index:: dut1_source/1 .. _time_scales_data/0::dut1_source/1:

dut1_source/1 ^^^^^^^^^^^^^^^^^

Returns the active DUT1 data source as bundled or override.

| Compilation flags: | static

| Template: | dut1_source(Source) | Mode and number of proofs: | dut1_source(-atom) - one

.. index:: dut1_entries/1 .. _time_scales_data/0::dut1_entries/1:

dut1_entries/1 ^^^^^^^^^^^^^^^^^^

Returns the active DUT1 data as an ordered list of dut1(UnixSeconds,Numerator,Denominator) terms.

| Compilation flags: | static

| Template: | dut1_entries(Entries) | Mode and number of proofs: | dut1_entries(-list) - one

.. index:: save_dut1_entries/1 .. _time_scales_data/0::save_dut1_entries/1:

save_dut1_entries/1 ^^^^^^^^^^^^^^^^^^^^^^^

Saves the active DUT1 data to a file using dut1(UnixSeconds,Numerator,Denominator). terms.

| Compilation flags: | static

| Template: | save_dut1_entries(File) | Mode and number of proofs: | save_dut1_entries(+atom) - one

.. index:: leap_offset_at_utc_unix/2 .. _time_scales_data/0::leap_offset_at_utc_unix/2:

leap_offset_at_utc_unix/2 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns the TAI-UTC offset in SI seconds for a given UTC Unix epoch second within the supported range.

| Compilation flags: | static

| Template: | leap_offset_at_utc_unix(UnixSeconds,OffsetSeconds) | Mode and number of proofs: | leap_offset_at_utc_unix(+integer,-integer) - zero_or_one

.. index:: leap_effective_date/2 .. _time_scales_data/0::leap_effective_date/2:

leap_effective_date/2 ^^^^^^^^^^^^^^^^^^^^^^^^^

Enumerates UTC effective dates for TAI-UTC offset changes and their resulting offset in SI seconds.

| Compilation flags: | static

| Template: | leap_effective_date(UTCDateTime,OffsetSeconds) | Mode and number of proofs: | leap_effective_date(?compound,?integer) - zero_or_more

.. index:: tt_minus_tai/2 .. _time_scales_data/0::tt_minus_tai/2:

tt_minus_tai/2 ^^^^^^^^^^^^^^^^^^

Returns the constant TT minus TAI offset as a rational value Numerator/Denominator seconds.

| Compilation flags: | static

| Template: | tt_minus_tai(Numerator,Denominator) | Mode and number of proofs: | tt_minus_tai(-integer,-integer) - one

.. index:: dut1_offset_at_utc_unix/3 .. _time_scales_data/0::dut1_offset_at_utc_unix/3:

dut1_offset_at_utc_unix/3 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns DUT1 (UT1-UTC) at a UTC Unix epoch second as a rational value Numerator/Denominator.

| Compilation flags: | static

| Template: | dut1_offset_at_utc_unix(UnixSeconds,Numerator,Denominator) | Mode and number of proofs: | dut1_offset_at_utc_unix(+integer,-integer,-integer) - zero_or_one

.. index:: tdb_minus_tt_approx/3 .. _time_scales_data/0::tdb_minus_tt_approx/3:

tdb_minus_tt_approx/3 ^^^^^^^^^^^^^^^^^^^^^^^^^

Returns an approximate TDB-TT offset in seconds for a TT instant represented by integer seconds and normalized fraction.

| Compilation flags: | static

| Template: | tdb_minus_tt_approx(TTSeconds,Fraction,OffsetSeconds) | Mode and number of proofs: | tdb_minus_tt_approx(+integer,+compound,-float) - one

.. index:: tcg_minus_tt_approx/3 .. _time_scales_data/0::tcg_minus_tt_approx/3:

tcg_minus_tt_approx/3 ^^^^^^^^^^^^^^^^^^^^^^^^^

Returns an approximate TCG-TT offset in seconds for a TT instant represented by integer seconds and normalized fraction.

| Compilation flags: | static

| Template: | tcg_minus_tt_approx(TTSeconds,Fraction,OffsetSeconds) | Mode and number of proofs: | tcg_minus_tt_approx(+integer,+compound,-float) - one

.. index:: tcb_minus_tdb_approx/3 .. _time_scales_data/0::tcb_minus_tdb_approx/3:

tcb_minus_tdb_approx/3 ^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns an approximate TCB-TDB offset in seconds for a TDB instant represented by integer seconds and normalized fraction.

| Compilation flags: | static

| Template: | tcb_minus_tdb_approx(TDBSeconds,Fraction,OffsetSeconds) | Mode and number of proofs: | tcb_minus_tdb_approx(+integer,+compound,-float) - one

.. index:: tai_minus_utc_for_tai_unix/2 .. _time_scales_data/0::tai_minus_utc_for_tai_unix/2:

tai_minus_utc_for_tai_unix/2 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns the TAI-UTC offset in SI seconds for a given TAI instant represented as Unix-like integer seconds.

| Compilation flags: | static

| Template: | tai_minus_utc_for_tai_unix(TAISeconds,OffsetSeconds) | Mode and number of proofs: | tai_minus_utc_for_tai_unix(+integer,-integer) - zero_or_one

Protected predicates

(no local declarations; see entity ancestors if any)

Private predicates

(no local declarations; see entity ancestors if any)

Operators

(none)