RE: ffi : use of wchar_t, size_t
- From: Alain Meunier <deco33@xxxxxxxxxx>
- To: "luajit@xxxxxxxxxxxxx" <luajit@xxxxxxxxxxxxx>
- Date: Fri, 11 Apr 2014 11:42:12 +0200
ok,
How do you handle unicode (utf8) strings then ?
thanks
> Date: Fri, 11 Apr 2014 10:03:17 +0100
> Subject: Re: ffi : use of wchar_t, size_t
> From: justin@xxxxxxxxxxxxxxxxxxxxx
> To: luajit@xxxxxxxxxxxxx
>
> On Fri, Apr 11, 2014 at 9:25 AM, Alain Meunier <deco33@xxxxxxxxxx> wrote:
> > Hello,
> >
> > I have this useless - but meaningful and working - code in c :
> >
> > #include <stdio.h>
> > #include <wchar.h>
> > #include <locale.h>
> >
> > int main(int argc, char **argv)
> > {
> > setlocale(LC_ALL, "");
> >
> > wchar_t po[] = L"sé";
> >
> > wprintf(L"%lc\n",po[1]);
> > wprintf(L"%ls \n", L"éáèï");
> >
> > size_t s1 = 5;
> >
> > wprintf(L"%zd",s1);
> >
> >
> > return 0;
> > }
> >
> > Using luajit + ffi, I would like to be able to use wchar to manipulate the
> > accents and so on.
> > The following code leads to errors :
> > bad argument #1 to 'cast' (invalid C type) or bad argument #1 to 'string'
> > (cannot convert 'int' to 'const char *')..
> >
> > The only thing I understand is that I do things wrong.
> >
> > ffi.cdef[[
> > wchar_t so[10];
> > int wprintf (const wchar_t* format, ...);
> > ]]
> >
> > --[[
> > local a = ffi.new("char[4]","sae")
> > local gou = ffi.new("so",a)
> > ]]
> > local gou = ffi.cast("wchar_t","joé")
> > ffi.C.wprintf(gou[1])
>
> You want to do ffi.new("wchar_t[10]") or similar, you are casting to a
> wchar_t not an array.
>
> But there is no built in conversion from strings to wchar_t, wchar_t
> is just an integer, would will have to parse them with something like
> mbrtowc, the luajit program text is UTF-8.
>
> Basically wchar is obsolete unless you need to talk to Windows system
> calls, I don't recommend using it.
>
> Justin
>
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