Dear David and all,
On 21.03.2017 04:14, David Grayson wrote:
> Like I said, you should run "_wfopen(L"E:/Some/File.txt", L"rb");" so you
> narrow this down to either a problem with your C++ code or a problem with
> _wfopen.
I could narrow down the problem, and actually it seems to be mostly
a complete ignorance on my side about how unicode, utf8, utf16, wchar
etc work. I was under the (naiive?) assumption that I could convert a
std::string to std::wstring with the codecvt converter from C++11
std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>, wchar_t> and
would just get the same string in a different representation, at least
for some basic ASCII. This seems far from reality! :-( :-( :-(
In fact, it has nothing to do with Windows. Also on Linux, the following
does not do what I expect:
std::string vCharStr = "hello world";
std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>, wchar_t>
utf8_to_utf16_converter;
std::wstring vWCharStrFromCharStr =
utf8_to_utf16_converter.from_bytes(vCharStr);
std::wcout << "vWCharStrFromCharStr = '" << vWCharStrFromCharStr << "'" <<
std::endl;
// shows only unprintable characters
I tried many combinations of converters, but no luck so far. And
I can not find a reasonable description of this simple task. There
are hundreds of websites that discuss asian characters, but not one
that just explains how to convert basic ASCII between character
types. I guess I have to go to a generic C++ mailing list with this
problem, or is anybody by chance able to help?
Thanks and all the best,
Mario
> --David
>
> On Mon, Mar 20, 2017 at 4:32 PM, Mario Emmenlauer <[email protected]
> <mailto:[email protected]>> wrote:
>
>
> Sorry, here is the corrected example:
>
> std::string aFileName = "E:/Some/File.txt";
> std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>, wchar_t>
> converter;
> std::wstring vFileName = converter.from_bytes(aFileName);
> FILE *in_stream = _wfopen(vFileName.c_str(), L"rb");
> // in_stream is NULL here
>
> The same code with fopen() on the original std::string works:
> std::string aFileName = "E:/Some/File.txt";
> FILE *in_stream = fopen(aFileName.c_str(), "rb");
> // in_stream is a correctly opened file here
>
> All the best,
>
> Mario Emmenlauer
>
>
> On 21.03.2017 00 <tel:21.03.2017%2000>:27, David Grayson wrote:
> > You must be doing something wrong because aFileName is set but not used
> in the
> > first example.
> >
> > You should try doing something like _wfopen(L"E:/Some/File.txt",
> L"rb"); so that
> > you can verify that _wfopen works without strange C++ stuff.
> >
> > --David
> >
> > On Mon, Mar 20, 2017 at 4:21 PM, Mario Emmenlauer <[email protected]
> <mailto:[email protected]>
> > <mailto:[email protected] <mailto:[email protected]>>> wrote:
> >
> >
> > I have a problem with code that is using _wfopen() on Windows.
> Should it
> > work with MSYS2? I have the following code that fails:
> >
> [...]
> >
> > Is that to be expected, or am I doing something wrong?
> >
> > All the best,
> >
> > Mario Emmenlauer
>
>
>
Viele Gruesse,
Mario Emmenlauer
--
BioDataAnalysis GmbH, Mario Emmenlauer Tel. Buero: +49-89-74677203
Balanstr. 43 mailto: memmenlauer * biodataanalysis.de
D-81669 München http://www.biodataanalysis.de/
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