问当调用单个字符行时，CRichEditCtrl::GetLine()添加的伪'\r‘？

EN

CString GetLine(CRichEditCtrl& richEdit, const int lineNum)
{
    int lineLength = richEdit.LineLength(richEdit.LineIndex(lineNum));
    if (lineLength == 0)
    {
        // Empty line
        return CString();
    }

    const int kMinBufferLength = sizeof(int) / sizeof(wchar_t);
    const int bufferLength = max(kMinBufferLength, lineLength);

    CString line;
    wchar_t* buffer = line.GetBuffer(bufferLength);   
    lineLength = richEdit.GetLine(lineNum, buffer, bufferLength);      
    line.ReleaseBuffer(lineLength);

    return line;
}

// Code inserted after the richEdit.GetLine() call, before the line.ReleaseBuffer() call:    

// *** Special Case ***
// It seems that when there's only one character (e.g. 'C') in the line,
// CRichEditCtrl::GetLine() returns 2, and appends a '\r' after 
// the read character in the output buffer.
if ((lineLength == 2) && (buffer[1] == L'\r'))
{
    // Chop off the spurious '\r'
    lineLength = 1;
}

int CRichEditCtrl::GetLine(_In_ int nIndex, _Out_writes_to_(nMaxLength, return) LPTSTR lpszBuffer, _In_ int nMaxLength) const
{
    ASSERT(::IsWindow(m_hWnd));
    ENSURE(sizeof(nMaxLength)<=nMaxLength*sizeof(TCHAR)&&nMaxLength>0);
    *(LPINT)lpszBuffer = nMaxLength;
    return (int)::SendMessage(m_hWnd, EM_GETLINE, nIndex, (LPARAM)lpszBuffer);
}