On 28/12/2018 08:59, Johannes Sixt wrote:

Am 28.12.18 um 00:45 schrieb brian m. carlson:

quoted

On Thu, Dec 27, 2018 at 08:55:27PM +0100, Johannes Sixt wrote:

quoted

But why do you add another U+FEFF on the way to UTF-8? There is one 
in the
incoming UTF-16 data, and only *that* one must be converted. If 
there is no
U+FEFF in the UTF-16 data, the should not be one in UTF-8, either.
Puzzled...

So for UTF-16, there must be a BOM. For UTF-16LE and UTF-16BE, there
must not be a BOM. So if we do this:

   $ printf '\xfe\xff\x00\x0a' | iconv -f UTF-16BE -t UTF-16 | xxd -g1
   00000000: ff fe ff fe 0a 00 ......

What sort of braindamage is this? Fix iconv.

But as I said, I'm not an expert. I just vented my worries that 
widespread existing practice would be ignored under the excuse "you 
are the outlier".

-- Hannes

For ref, I dug out a Microsoft document [1] on its view of BOMs which 
can be compared to the ref [0] Brian gave

[1] 
https://docs.microsoft.com/en-us/windows/desktop/intl/using-byte-order-marks

[0] https://unicode.org/faq/utf_bom.html#bom9

Maybe the documentation patch ([PATCH 1/2] Documentation: document 
UTF-16-related behavior) should include the line ", because we encode 
into UTF-8 internally,", and a link to ref [0], and maybe [1]


Whether the various Windows programs actually follow the Microsoft 
convention is another matter altogether .

-- 

Philip