See, for example, the link you gave in msg115750. It has this sample code in it (listed in the "Examples" section):

FNFCIREAD(fnFileRead)
{
    DWORD dwBytesRead = 0;

    UNREFERENCED_PARAMETER(pv);

    if( ReadFile((HANDLE)hf, memory, cb, &dwBytesRead, NULL) == FALSE )
    {
        dwBytesRead = (DWORD)-1;
        *err = GetLastError();
    }
		 
    return dwBytesRead;
}