glibc/timezone/leapseconds

# @(#)leapseconds	8.3

# Allowance for leapseconds added to each timezone file.

# The International Earth Rotation Service periodically uses leap seconds
# to keep UTC to within 0.9 s of UT1
# (which measures the true angular orientation of the earth in space); see
# Terry J Quinn, The BIPM and the accurate measure of time,
# Proc IEEE 79, 7 (July 1991), 894-905.
# There were no leap seconds before 1972, because the official mechanism
# accounting for the discrepancy between atomic time and the earth's rotation
# did not exist until the early 1970s.

# The correction (+ or -) is made at the given time, so lines
# will typically look like:
#	Leap	YEAR	MON	DAY	23:59:60	+	R/S
# or
#	Leap	YEAR	MON	DAY	23:59:59	-	R/S

# If the leapsecond is Rolling (R) the given time is local time
# If the leapsecond is Stationary (S) the given time is UTC

# Leap	YEAR	MONTH	DAY	HH:MM:SS	CORR	R/S
Leap	1972	Jun	30	23:59:60	+	S
Leap	1972	Dec	31	23:59:60	+	S
Leap	1973	Dec	31	23:59:60	+	S
Leap	1974	Dec	31	23:59:60	+	S
Leap	1975	Dec	31	23:59:60	+	S
Leap	1976	Dec	31	23:59:60	+	S
Leap	1977	Dec	31	23:59:60	+	S
Leap	1978	Dec	31	23:59:60	+	S
Leap	1979	Dec	31	23:59:60	+	S
Leap	1981	Jun	30	23:59:60	+	S
Leap	1982	Jun	30	23:59:60	+	S
Leap	1983	Jun	30	23:59:60	+	S
Leap	1985	Jun	30	23:59:60	+	S
Leap	1987	Dec	31	23:59:60	+	S
Leap	1989	Dec	31	23:59:60	+	S
Leap	1990	Dec	31	23:59:60	+	S
Leap	1992	Jun	30	23:59:60	+	S
Leap	1993	Jun	30	23:59:60	+	S
Leap	1994	Jun	30	23:59:60	+	S
Leap	1995	Dec	31	23:59:60	+	S
Leap	1997	Jun	30	23:59:60	+	S
Leap	1998	Dec	31	23:59:60	+	S
Leap	2005	Dec	31	23:59:60	+	S

# ...
# Sent: Thursday, February 01, 2007 9:49 AM
# ...
# Subject: Bulletin C number 33
#
# 	INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS)
#
# SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE
#
# SERVICE DE LA ROTATION TERRESTRE
# OBSERVATOIRE DE PARIS
# 61, Av. de l'Observatoire 75014 PARIS (France)
# ...
#
#                                                Paris, 1 February 2007
#                                                Bulletin C 33
#                                                To authorities responsible
#                                                for the measurement and
#                                                distribution of time
#
#                           INFORMATION ON UTC - TAI
#
# NO positive leap second will be introduced at the end of June 2007.
# The difference between Coordinated Universal Time UTC and the
# International Atomic Time TAI is:
#      from 2006 January 1, 0h UTC, until further notice : UTC-TAI = -33 s
# Leap seconds can be introduced in UTC at the end of the months of
# December  or June,  depending on the evolution of UT1-TAI. Bulletin C is
# mailed every  six months, either to announce a time step in UTC, or to
# confirm that there  will be no time step at the next possible date.
#
# 				Daniel GAMBIS
# 				Director
# 				Earth Orientation Center of IERS
# 				Observatoire de Paris, France