* progmodes/compile.el (compilation-mode-hook)

[bpt/emacs.git] / src / fileio.c

diff --git a/src/fileio.c b/src/fileio.c
index a8218fc..fb6ecfe 100644 (file)
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -5036,7 +5036,11 @@ This calls `write-region-annotate-functions' at the start, and
              && st.st_dev == st1.st_dev && st.st_ino == st1.st_ino)
            {
              EMACS_TIME modtime1 = get_stat_mtime (&st1);
-             if (EMACS_TIME_EQ (modtime, modtime1)
+             /* If neither O_EXCL nor O_TRUNC is used, and Emacs happened to
+                write nothing to the file, the file's time stamp won't change
+                so it should not be used in this heuristic.  */
+             if ((open_flags & (O_EXCL | O_TRUNC)) != 0
+                 && EMACS_TIME_EQ (modtime, modtime1)
                  && st.st_size == st1.st_size)
                {
                  timestamp_file_system = st.st_dev;