[tz] [PROPOSED PATCH 3/3] * NEWS: Reorganize recent code news clarity, and mention tzdist.
Paul Eggert
eggert at cs.ucla.edu
Wed Aug 27 01:51:47 UTC 2014
---
NEWS | 63 ++++++++++++++++++++++++++++++++-------------------------------
1 file changed, 32 insertions(+), 31 deletions(-)
diff --git a/NEWS b/NEWS
index fcb79a3..ab97918 100644
--- a/NEWS
+++ b/NEWS
@@ -42,34 +42,49 @@ Unreleased, experimental changes
Changes affecting code
- Some crashes have been fixed when zdump or the tz library is given
- invalid or outlandish input.
+ Unless NETBSD_INSPIRED is defined to 0, the tz library now
+ supplies functions for creating and using objects that represent
+ time zones. The new functions are tzalloc, tzfree, localtime_rz,
+ mktime_z, and (if STD_INSPIRED is also defined) posix2time_z and
+ time2posix_z. They are intended for performance: for example,
+ localtime_rz (unlike localtime_r) is trivially thread-safe without
+ locking. (Thanks to Christos Zoulas for proposing NetBSD-inspired
+ functions, and to Alan Barrett and Jonathan Lennox for helping to
+ debug the change.)
- The tz library no longer mishandles leap seconds on platforms with
- unsigned time_t in time zones that lack ordinary transitions after 1970.
+ zdump now builds with the tz library unless USE_LTZ is defined to 0,
+ This lets zdump use tz features even if the system library lacks them.
+ To build zdump with the system library, use 'make CFLAGS=-DUSE_LTZ=0
+ TZDOBJS=zdump.o CHECK_TIME_T_ALTERNATIVES='.
+
+ zdump now uses localtime_rz if available, as it's significantly faster,
+ and it can help zdump better diagnose invalid time zone names.
+ Define HAVE_LOCALTIME_RZ to 0 to suppress this. HAVE_LOCALTIME_TZ
+ defaults to 1 if NETBSD_INSPIRED && USE_LTZ. When localtime_rz is
+ not available, zdump now uses localtime_r and tzset if available,
+ as this is a bit cleaner and faster than plain localtime. Compile
+ with -DHAVE_LOCALTIME_R=0 and/or -DHAVE_TZSET=0 if your system
+ lacks these two functions.
- The tz library is now thread-safe if compiled with THREAD_SAFE defined.
+ If THREAD_SAFE is defined to 1, the tz library is now thread-safe.
Although not needed for tz's own applications, which are single-threaded,
this supports POSIX better if the tz library is used in multithreaded apps.
- Unless NETBSD_INSPIRED is defined to 0, the tz library now supplies
- functions that let callers create and use objects representing time zones.
- This is intended for applications that need to deal with many time
- zones simultaneously, e.g., an application where each thread may be
- in a different time zone. The new functions are tzalloc, tzfree,
- localtime_rz, mktime_z, and (if STD_INSPIRED is also defined)
- posix2time_z and time2posix_z. (Thanks to Alan Barrett and
- Jonathan Lennox for helping to debug this.)
+ Some crashes have been fixed when zdump or the tz library is given
+ invalid or outlandish input.
+
+ The tz library no longer mishandles leap seconds on platforms with
+ unsigned time_t in time zones that lack ordinary transitions after 1970.
The tz code now attempts to infer TM_GMTOFF and TM_ZONE if not
already defined, to make it easier to configure on common platforms.
Define NO_TM_GMTOFF and NO_TM_ZONE to suppress this.
- Unless the new macro UNINIT_TRAP is defined to 0, the tz code now
+ Unless the new macro UNINIT_TRAP is defined to 1, the tz code now
assumes that reading uninitialized memory yields garbage values
but does not cause other problems such as traps.
- If TM_GMTOFF is defined and UNINIT_TRAP is not 0, mktime is now
+ If TM_GMTOFF is defined and UNINIT_TRAP is 0, mktime is now
more likely to guess right for ambiguous time stamps near
transitions where tm_isdst does not change.
@@ -78,20 +93,6 @@ Unreleased, experimental changes
Only the C locale is supported, though. HAVE_STRFTIME_L defaults
to 1 on recent POSIX versions, and to 0 otherwise.
- zdump now builds with the tz library unless USE_LTZ is defined to 0,
- This lets zdump use tz features even if the system library lacks them.
- To build zdump with the system library, use 'make CFLAGS=-DUSE_LTZ=0
- TZDOBJS=zdump.o CHECK_TIME_T_ALTERNATIVES='.
-
- zdump now uses localtime_rz if available, as it's significantly faster,
- and it can help zdump better diagnose invalid time zone names.
- Define HAVE_LOCALTIME_RZ to 0 to suppress this. HAVE_LOCALTIME_TZ
- defaults to 1 if NETBSD_INSPIRED && USE_LTZ. When localtime_rz is
- not available, zdump now uses localtime_r and tzset if available,
- as this is a bit cleaner and faster than plain localtime. Compile
- with -DHAVE_LOCALTIME_R=0 and/or -DHAVE_TZSET=0 if your system
- lacks these two functions.
-
tzselect -c now uses a hybrid distance measure that works better
in Africa. (Thanks to Alan Barrett for noting the problem.)
@@ -145,8 +146,8 @@ Unreleased, experimental changes
and more like the parameters of 'ln'. LINK-FROM has become TARGET,
and LINK-TO has become LINK-NAME.
- tz-link.htm mentions Windows Runtime etc. (thanks to Matt Johnson)
- and HP-UX's tztab.
+ tz-link.htm mentions the IETF's tzdist working group; Windows
+ Runtime etc. (thanks to Matt Johnson); and HP-UX's tztab.
Some broken URLs have been fixed in the commentary. (Thanks to
Lester Caine.)
--
1.9.1
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