Re: [PATCH] Preliminary fix for codecvt_members_unicode_wchar_t

[Paolo Carlini <pcarlini at unitus dot it>]

Benjamin Kosnik wrote:

[snip]

Thank you very much for these additional details.
In the next few days I will try to learn more myself about all of this 
starting from these notes.

>So, in summary, it looks like this is the deal, even if this directly 
>contradicts my earlier email.
>
>1) UCS4, UCS2 need a byte-order marker (bom) to indicate endianness. 
>if there is no bom, then encodings assume native byte order. This varies 
>per machine, as has been found out with the x86/powerpc divergence.
>
Ah! Ok. Now this is much more clear. Also the different kind of problem 
shown on powerpc/s390 by the wchar_t test vs the char test.

>2) UCS4-BE, UCS2-BE should not need a bom to indicate endianness, as it 
>is explicitly specified.
>
I see.

>I hope this helps explain the situation. If I'm wrong, please let me know
>and I'll try to confuse the situation some more. I realize this sounds
>really complicated at the moment. Writing docs that explain this is on my
>TODO list for May.
>
Great! At the moment, to my best knowledge, there are not many clear 
explanations available...

By the way, have you had at look at my "consistency" fix for 
collate_byname.cc? It is not strictly needed but changes those tests 
consistently with the current collate_members_xx.cc.

Ciao, Paolo.