Re: Unicode I/O
On 13 avr, 14:36, Barry <dhb2...@gmail.com> wrote:
On Apr 13, 5:59 pm, James Kanze <james.ka...@gmail.com> wrote:
On 13 avr, 10:58, Barry <dhb2...@gmail.com> wrote:
himanshu.g...@gmail.com wrote:
The following std c++ program does not output the unicode
character.:-
%./a.out
en_US.UTF-8
Infinity:
%cat unicode.cpp
#include<iostream>
#include<string>
#include<locale>
int main()
{
std::wstring ws = L"Infinity: \u221E";
std::locale loc("");
std::cout << loc.name( ) << " " << std::endl;
std::wcout.imbue(loc);
std::wcout << ws << std::endl;
}
[...]
What I would do in his case, for starters, is do a hex dump of
the wstring's buffer, to see exactly how L"\u221E" is encoded.
Beyond that: if it's encoded as some default character indicated
a non-supported character, then he should file an error report
with the compiler, requesting a warning, otherwise, he should
file an error report for the library, indicating that locales
aren't working as specified.
I review the standard about \u and \U.
Now I'm *sure* that my assertion about the "\u" was wrong.
I run the code, realize that (Platform : Windows XP, VC8)
dumping L"\u4e00" become "0x4e 0xA1" which is exactly UTF-16,
the default Unicode transformation on Windows.
Here, you meant 0x4E 0x00, of course. Although for Windows, I'd
expect rather 0x00 0x4E---PC's are little endian (or are you
dumping wchar_t's, converted to int, rather than char's?).
dumping "\u4e00" become "0xB6 0xA1" which is GBK encoding (mbcs),
my default encoding setting.
Is it this conversion done directly by the compiler?
Yes. The standard guarantees that in L"\uxxxx", the "xxxx" is
Unicode, regardless of your platform. The compiler decides what
it will be on your platform. In a very implementation defined
manner. It then inserts the bytes into the final string,
according to what it thinks is the equivalent of the character
in what it thinks the desired encoding should be.
As you'll note, there's a lot of "what it thinks" in there.
You're very much at the compiler's mercy.
--
James Kanze (GABI Software) email:james.kanze@gmail.com
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