Re: stdin charset
On Apr 29, 11:27 pm, Antimon <anti...@gmail.com> wrote:
I'm new to c/c++ and working on string stuff with visual studio 2005.
I'm trying to understand something, for example when i do this:
wstring st;
wcin >> st;
if the input is pure ascii, then everything is ok, but if there are
unicode characters like "?" (u+015f) what is the encoding of st now?
It depends on the system. Windows uses (I think) UTF-16, and
Linux UTF-32. Older systems have different conventions, which
may vary according to the compiler. (G++ and Sun CC behave
differently under Solaris, for example.)
Everything works when i use this st string, do stuff, write to cout
etc but if i want to convert this string to utf-8, what encoding am i
converting from?
It depends on the system, the compiler, and possibly even some
options of the compiler.
Btw, when i do something like this:
wsring a = L"?";
wstring b;
wcin >> b;
and write "?" into console,
(a == b) is false. i checked a and it's unicode (16), b is not
unicode, i could not manage to find what it is.
When reading from wcin (or any wide string input), how the input
is encoded depends on the locale embedded in the stream. By
default, this should be the "C" locale (although if you change
the global locale in a constructor of a static object, there may
be some issues concerning order of initialization), however, and
I can't imagine any problems with this with regards to the "C"
locale. (At least with "?", which is pure ASCII. For
historical reasons, Windows does not use the same default code
page in console windows as it uses elsewhere, so you often do
get surprises.)
FWIW: I'm unable to duplicate what you describe on my Windows
machine (with VC++ 2005). Both a and b, above, contained a
single character with the value 0x003F (which corresponds to the
UTF-16 code for '?').
--
James Kanze (GABI Software) email:james.kanze@gmail.com
Conseils en informatique orient=E9e objet/
Beratung in objektorientierter Datenverarbeitung
9 place S=E9mard, 78210 St.-Cyr-l'=C9cole, France, +33 (0)1 30 23 00 34