How to Break Text Based on Locale

Different languages might have different rules for hyphenation, spacing, and where a line should be broken on a page. For this reason, the MLang IMLangLineBreakConsole interface provides a locale-aware line-breaking functionality for console-based applications.

To use this feature to break a Unicode string for output:

  1. Make sure the Component Object Library has been initialized.

    Before you can use any of the functionality provided by MLang, you must first initialize the Component Object Library through a call to CoInitialize. Every call to CoInitialize must be accompanied by a call to CoUninitialize when the application terminates. CoUninitialize ensures that the application does not quit until it has received all of its pending messages.

  2. Obtain a pointer to an IMLangLineBreakConsole interface.

    The IMLangLineBreakConsole interface is part of the MultiLanguage. If no such object exists, you must create one and obtain a pointer to the corresponding IMultiLanguage interface through a call to CoCreateInstance. Once this has been accomplished, call QueryInterface through IMultiLanguage for a pointer to an IMLangLineBreakConsole interface.

  3. Use the IMLangLineBreakConsole methods to break the string into the proper number of columns for output.

    For Unicode strings, use IMLangLineBreakConsole::BreakLineW. For multibyte strings, use IMLangLineBreakConsole::BreakLineA. The following code sample breaks the null-terminated Unicode string pwszStr, based on the constant NUMCOLUMNS and the given locale, and prints it to the screen.

    // pwszStr - null-terminated Unicode string of cchMax characters or less.
    // locale - locale identifier of the output string.
    // pMLLBC - pointer to an IMLangLineBreakConsole interface.
    size_t cchMax = STRSAFE_MAX_CCH;
    size_t cchLength;
    WCHAR pwszSrc[cchMax] = L("some source string");
    HRESULT lengthHr = StringCchLengthW(pwszSrc, cchMax, &cchLength);
    long cchSize = cchLength;
        // Size of pwszStr in characters.
    int MaxColumns = NUMCOLUMNS;
        // Desired number of columns for output.
    long cchLine;
        // Number of characters to output in the current line.
    long cchSkip;
        // Number of characters to skip before starting the next line.
    long totalLine = 0;
       // Total number of characters processed.
        WCHAR wStr[NUMCOLUMNS] = "";
        HRESULT hr = S_OK;
        while((totalLine < cchSize) && SUCCEEDED(hr))
            // Process the entire string unless an error occurs.
            hr = pMLLBC->BreakLineW(locale, pwszStr + totalLine,
                cchSize - totalLine, MaxColumns, &cchLine, &cchSkip);
            HRESULT copyHr = StringCchCopyW(wStr,  cchLine + 1, pwszStr + cchSkip + totalLine);
                // Copy characters of pwszStr for output.
                totalLine = totalLine + cchLine + cchSkip;
                    // Increase the total number of characters processed. 
                wprintf(L"%s\n", wStr);
                    // Output the string to the console-based application.
       //  TODO: Add error handling code here.
  4. Remember to release the interfaces and uninitialize the Component Object Library before your program terminates.

MLang Reference