Re: Filenames in Ada

["Björn Persson" <spam-away@nowhere.nil>]

Martin Krischik wrote:
> But I take it that on a Russian system the Windows-1251 code
> page is active and all filenames are expressed using that and not Latin 1.

Speaking of that, do you know how to find out which code page is active? 
Can I get it from C's nl_langinfo like in Unix?

> It is sad that XML/Ada has no UCS-2 and UCS-4 convertion available - but
> AdaCL allready has that - so not problem for you really.

My main problem is lack of time. I found a job a year ago. Darn! ;-)

>>It seems that the right thing to do would be to tap into the Gnat
>>library and make UTF-16 (or UCS-2) versions of the file operations. It
>>could be as easy as changing the parameter type and replacing calls to
>>the Windows functions with their -W equivalents, or it could be very
>>hairy.
> 
> I had that idea as well and did take a look. Lots of "pragma Import" there.

I take it you mean that's a complication. You can't just import other 
functions?

> Well there seems an better article:
> 
> http://msdn.microsoft.com/library/default.asp?url=/library/en-us/fileio/fs/naming_a_file.asp

Well, it says "Windows stores the long file names on disk in Unicode", 
so now we have to guess which encoding it is they call "Unicode". I'm 
guessing UTF-16, because UTF-16 was defined by Unicode while I think 
UCS-2 was defined by ISO.

Maybe you can do an experiment? Create a file with a surrogate pair in 
the name and see how it's shown in the file manager. You may get boxes 
or something if Windows doesn't have the glyphs, but if you see only one 
box it's obviusly been interpreted as UTF-16. If you see two boxes or 
you get some error then Windows seems to expect UCS-2.

> I wonder about that \\?\ stuff and what it really means

It looks like a crude hack to allow longer paths by bypassing parts of 
the library. Anyway it's not relevant to the question of character 
encodings.

-- 
Bjï¿œrn Persson                              PGP key A88682FD
                    omb jor ers @sv ge.
                    r o.b n.p son eri nu