Avoid file time stamp bug on MS-Windows.

* fileio.c (Fwrite_region): Don't use the heuristic on empty files,
as FAT32 doesn't update time stamps when truncating them.
Also, check that a file time stamp is not a multiple of 100 ns;
this should catch all instances of the problem on MS-Windows,
as its native file system resolution is 100 ns or worse, and
checking for a non-multiple of 100 ns should impose only a small
overhead on systems with ns resolution.

Fixes: debbugs:13149

1 files changed, 11 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index b90f18eba91..092302d6492 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,14 @@
+2013-02-02  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Avoid file time stamp bug on MS-Windows (Bug#13149).
+        * fileio.c (Fwrite_region): Don't use the heuristic on empty files,
+        as FAT32 doesn't update time stamps when truncating them.
+        Also, check that a file time stamp is not a multiple of 100 ns;
+        this should catch all instances of the problem on MS-Windows,
+        as its native file system resolution is 100 ns or worse, and
+        checking for a non-multiple of 100 ns should impose only a small
+        overhead on systems with ns resolution.
+
 2013-02-02  Eli Zaretskii  <eliz@gnu.org>
 
         Avoid encoding file names on MS-Windows when they need to be run