* doc/gzip.texi (Overview): Mention limits of gzip format's

time stamps.  Also, gzip doesn't always preserve time stamps.

any more (the hosts it caters to are long extinct), and was
questionable anyway since the code assumes the skip= line was line 2.

diff --git a/ChangeLog b/ChangeLog
index b6d0620df22a57d7b5ad4d17bfe3985426f4ac02..8bf7830402dbd912a8ff962d6edd31dca51ef80b 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,13 +1,16 @@
 2006-12-01  Paul Eggert  <eggert@cs.ucla.edu>
 
+       * doc/gzip.texi (Overview): Mention limits of gzip format's
+       time stamps.  Also, gzip doesn't always preserve time stamps.
+
        * gzip.c (abort_gzip_signal): Don't call abort () as a "safeguard",
        since it actually causes a core dump.  Problem reported by
        Jakub Bogusz.
 
        * NEWS: Describe gzexe changes noted below.
        * Makefile.am (.in): Don't bother with SEDCMD.  This stuff isn't needed
-       any more (the hosts it caters to are long extinct), and was questionable
-       anyway since the code assumes the skip= line was line 2.
+       any more (the hosts it caters to are long extinct), and was
+       questionable anyway since the code assumes the skip= line was line 2.
        * configure.ac (AC_SYS_INTERPRETER, SEDCMD): Remove; no longer needed.
 
        * gzexe.in: Sweep the code and fix some bugs.

diff --git a/doc/gzip.texi b/doc/gzip.texi
index 2e46c023a56ed89358c03728e939f7e5d8c9b366..fd782aa8e864008d0ef8f0844beace4e926439e6 100644 (file)
--- a/doc/gzip.texi
+++ b/doc/gzip.texi
@@ -96,7 +96,13 @@ By default, @code{gzip} keeps the original file name and timestamp in
 the compressed file. These are used when decompressing the file with the
 @samp{-N} option. This is useful when the compressed file name was
 truncated or when the time stamp was not preserved after a file
-transfer.
+transfer.  However, due to limitations in the current @code{gzip} file
+format, fractional seconds are discarded.  Also, time stamps must fall
+within the range 1970-01-01 00:00:00 through 2106-02-07 06:28:15
+@acronym{UTC}, and hosts whose operating systems use 32-bit time
+stamps are further restricted to time stamps no later than 2038-01-19
+03:14:07 @acronym{UTC}.  The upper bounds assume the typical case
+where leap seconds are ignored.
 
 Compressed files can be restored to their original form using @samp{gzip -d}
 or @code{gunzip} or @code{zcat}.  If the original name saved in the
@@ -153,8 +159,8 @@ Compression is always performed, even if the compressed file is slightly
 larger than the original. The worst case expansion is a few bytes for
 the @code{gzip} file header, plus 5 bytes every 32K block, or an expansion
 ratio of 0.015% for large files. Note that the actual number of used
-disk blocks almost never increases. @code{gzip} preserves the mode,
-ownership and timestamps of files when compressing or decompressing.
+disk blocks almost never increases.  @code{gzip} normally preserves the mode,
+ownership and time stamps of files when compressing or decompressing.
 
 The @code{gzip} file format is specified in P. Deutsch, @sc{gzip} file
 format specification version 4.3,