On 2015-08-25 11:10+0100 Phil Rosenberg wrote:
> Hi Alan
> It seems that this character is a BOM -
> https://en.wikipedia.org/wiki/Byte_order_mark. I think it is there so
> that if a system with different endianness tries to read the file it
> will see that character as FFFE instead of FEFF and knows to swap the
> byte order. However given that the file was (auto detected to be?)
> UTF8, I'm not sure why this was added. UTF8 has a different BOM which
> isn't really needed.
>
> There is a setting to turn the BOM off on my editor so I have done so
> and resaved the file. In git status -v I could see that the first line
> had changed, however the new and old lines looked Identical. I guess
> this is because my console is rendering the BOM as a utf16 character -
> it's representation being a zero width nonbreaking space.
>
> If you could confirm it is gone then that would be great.
Hi Phil (and others here who use Windows editors):
Now that you have identified that character as a BOM added by your
windows editor, I looked that up with google, and it appears that is a
character that is allowed but definitely not required by the UTF-8
standard. Since not all software recognizes such BOM characters for
best results it is good to remove BOM characters from UTF-8 files.
Also, from google searching I found a method (using the file command
on POSIX systems) to detect whether your editor had added a BOM to any
other file in our source tree:
Here is the overall check for that before fetching your change:
software@raven> pwd
/home/software/plplot/HEAD/plplot.git
software@raven> (find . -type f |grep -v .git |xargs file) |grep BOM
./doc/docbook/src/api.xml: HTML document, UTF-8 Unicode (with BOM) text
So that file was the only one in our source tree that contained a BOM,
and after fetching your change here are the git diff results:
software@raven> git diff 246eea0..68c0256
diff --git a/doc/docbook/src/api.xml b/doc/docbook/src/api.xml
index 706aece..f31a0cc 100644
--- a/doc/docbook/src/api.xml
+++ b/doc/docbook/src/api.xml
@@ -1,4 +1,4 @@
-<U+FEFF><!-- -*- mode: nxml -*- -->
+<!-- -*- mode: nxml -*- -->
<!--
api.xml: "The Common API for PLplot" chapter
which confirms your commit removed that BOM. I also retried the above
find command, and this time it reported (as expected) no BOM results.
Therefore, we now have a BOM-free source tree again. Thanks for this
cleanup!
Alan
__________________________
Alan W. Irwin
Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).
Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.sf.net); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
__________________________
Linux-powered Science
__________________________
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