//-------------------------------------------------------------------
//-- Writing BSTR to a File C++ sample - davemoats.com
//--
//-- This sample is provided 'as-is', without any express or implied warranty.
//-- In no event will the authors be held liable for any damages arising from
//-- the use of this sample code.
//--
//-------------------------------------------------------------------

#define _UNICODE

#include <windows.h>

int wmain(int argc, wchar_t* argv[])
{
    DWORD dwRet = 0;

    // open the file
    HANDLE hUfile = CreateFile( L"test.out",
                                         GENERIC_WRITE,
                                         0,
                                         NULL,
                                         CREATE_ALWAYS,
                                         FILE_ATTRIBUTE_NORMAL,
                                         NULL );

    if( hUfile != INVALID_HANDLE_VALUE )
    {
        // allocate a BSTR
        BSTR bszVal = ::SysAllocString( L"Something to write to a file" );
        if (bszVal == NULL)
            return E_OUTOFMEMORY;
        else
        {
            // get the length of the BSTR - UNICODE so mult by 2
            DWORD dwBytes = 0;
            DWORD dwLen = ( ::SysStringLen( bszVal ) * 2 );

            if( !WriteFile( hUfile,
                                 bszVal,
                                 dwLen,
                                 &dwBytes,
                                 NULL ))
            {
                // no data written
                dwRet = GetLastError();
            }

            // free BSTR
            ::SysFreeString( bszVal );
        }

        // close file
        CloseHandle( hUfile );
    }
    else
    {
        // couldn't open the file
        dwRet = GetLastError();
    }

    return dwRet;
}