C / C++ / MFC

// Convert a Latin-1 string to UTF-8.
// from xterm sources.
// t: output, s: input, len: input length.
// returns length of output.
static int Latin1toUTF8(TCHAR *t, const TCHAR *s, int len)
{
    const TCHAR *p = s;
    TCHAR *q = t;
    while (p < s + len) {
        if ((*p & 0x80) == 0) {
            *q++ = *p++;
        } else {
            *q++ = 0xC0 | ((*p >> 6) & 0x3);
            *q++ = 0x80 | (*p & 0x3F);
            p++;
        }
    }
    return q - t;
}

// MFC-wrapper for Latin1toUTF8.
void StringToUTF8( const CString& input, CByteArray& output )
{
	output.RemoveAll();

	if ( input.IsEmpty() )
		return;

	output.SetSize(input.GetLength()*6);	// prepare for worst-case.
	const int new_length = Latin1toUTF8( (TCHAR*)output.GetData(), input, input.GetLength() );

	ASSERT(new_length<=output.GetLength());
	output.SetSize(new_length);
}

CString filename;
CFileDialog opendlg(TRUE, NULL, NULL, OFN_HIDEREADONLY,
    _T("Text files|*.txt;*.doc|Images|*.bmp;*.gif||"));
if (opendlg.DoModal() == IDOK)
    filename = opendlg.GetPathName()