cannot convert cont char* to LPCWSTR

[habbas33]

hi, I am stuck with an error in QT compiler however it works fine with VS2010. the error states that
I have seen other posts related to the same error but non has resolved my problem in QT. I have tried _T,L or TEXT but still not working

> bq. error: C2664: 'HANDLE
> LoadImageW(HINSTANCE,LPCWSTR,UINT,int,int,UINT)' : cannot convert
> argument 2 from 'const char *' to 'LPCWSTR' Types pointed to are
> unrelated; conversion requires reinterpret_cast, C-style cast or
> function-style cast

my code is as below

Bitmap::Bitmap(std::string const& file_name) {
    bitmap_ = static_cast<HBITMAP>(::LoadImage(0, file_name.c_str(), IMAGE_BITMAP,0,0,LR_LOADFROMFILE|LR_CREATEDIBSECTION));
    }

Bitmap::Bitmap(std::string const& file_name) {
    bitmap_ = static_cast<HBITMAP>(::LoadImage(0, file_name.c_str(), IMAGE_BITMAP,0,0,LR_LOADFROMFILE|LR_CREATEDIBSECTION));
    }

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please share if you have any idea to resolve this