From: Zac Medico <zmedico@gentoo.org>
Date: Fri, 27 Nov 2009 22:03:36 +0000 (-0000)
Subject: Add a note about lack of nanosecond precision in movefile().
X-Git-Tag: v2.2_rc53~3
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=5431b580b4ab0c231e4375bba3d414214dfaa7fd;p=portage.git

Add a note about lack of nanosecond precision in movefile().

svn path=/main/trunk/; revision=14900
---

diff --git a/pym/portage/__init__.py b/pym/portage/__init__.py
index 35ce95329..8ebcddba2 100644
--- a/pym/portage/__init__.py
+++ b/pym/portage/__init__.py
@@ -7566,6 +7566,9 @@ def movefile(src, dest, newmtime=None, sstat=None, mysettings=None,
 		if hardlinked:
 			newmtime = long(os.stat(dest).st_mtime)
 		else:
+			# Note: It is not possible to preserve nanosecond precision
+			# (supported in POSIX.1-2008 via utimensat) with the IEEE 754
+			# double precision float which only has a 53 bit significand.
 			if newmtime is not None:
 				os.utime(dest, (newmtime, newmtime))
 			else: