Hi I need to convert a std::wstring
to QString
and I tried the most obvious way of
std::wstring wideString;
QString qtString = QString::fromStdWString(wideString);
I got the error:
Error 2 error LNK2019: unresolved external symbol
"__declspec(dllimport) public: static class QString __cdecl QString::fromStdWString(class std::basic_string<wchar_t,struct std::char_traits<wchar_t>,class std::allocator<wchar_t> > const &)" (__imp_?fromStdWString@QString@@SA?AV1@ABV?$basic_string@_WU?$char_traits@_W@std@@V?$allocator@_W@2@@std@@@Z)
referenced in function
"public: void __thiscall FileHandler::deleteDir(class std::basic_string<wchar_t,struct std::char_traits<wchar_t>,class std::allocator<wchar_t> >&,int,unsigned int,bool,bool)" (?deleteDir@FileHandler@@QAEXAAV?$basic_string@_WU?$char_traits@_W@std@@V?$allocator@_W@2@@std@@HI_N1@Z)
filehandler.objError 3 fatal error LNK1120: 1 unresolved externals C:\Users\Documents\Visual Studio 2008\Projects\product_dev\deletefiles\Debug\FileHandler.exe
I also tried using the method QString::fromWCharArray
:
qstring temp = QString::fromWCharArray(const_cast<wchar_t*>(wideString.c_str()),wideString.size());
The error I get is
Error 2 error LNK2019: unresolved external symbol
"__declspec(dllimport) public: static class QString __cdecl QString::fromWCharArray(wchar_t const*,int)" (__imp_?fromWCharArray@QString@@SA?AV1@PB_WH@Z)
referenced in function
"public: void __thiscall FileHandler::deleteDir(class std::basic_string<wchar_t,struct std::char_traits<wchar_t>,class std::allocator<wchar_t> >&,int,unsigned int,bool,bool)" (?deleteDir@FileHandler@@QAEXAAV?$basic_string@_WU?$char_traits@_W@std@@V?$allocator@_W@2@@std@@HI_N1@Z)
filehandler.objError 3 fatal error LNK1120: 1 unresolved externals C:\Users\Documents\Visual Studio 2008\Projects\product_dev\deletefiles\Debug\FileHandler.exe 1
How do I proceed to resolve this issue?
Best solution to the problem is to set the option "Treat wchar_t was Built-in Type" to No. However in some cases this might not be possible.
For example xerces_c is compiled with wchar_t as Built-in Type. If you need to use both xerces_c then you must either recompile QT or xerces_c to match a common Built-in Type setting.
Windows uses UTF16 charset so does QT for unicode strings. Thus, the alternative solution below might be a life saver.
/*! Convert a QString to an std::wstring */
std::wstring qToStdWString(const QString &str)
{
#ifdef _MSC_VER
return std::wstring((const wchar_t *)str.utf16());
#else
return str.toStdWString();
#endif
}
/*! Convert an std::wstring to a QString */
QString stdWToQString(const std::wstring &str)
{
#ifdef _MSC_VER
return QString::fromUtf16((const ushort *)str.c_str());
#else
return QString::fromStdWString(str);
#endif
}
Edit your Visual Studio project settings and under C/C++ -> Language set the option Treat wchar_t was Built-in Type to No.
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