How Windows Notepad uses the .LOG entry in the editor.

    /* Free file mapping */
    if( lpBuf != (LPTSTR) &szNullFile )
    {
        UnmapViewOfFile( lpBuf );
    }
 
 
    if( lpch ) 
    {
 
       // Fix any NUL character that came in from the file to be spaces.
 
       for (i = 0, p = lpch; i < nChars; i++, p++)
       {
          if( *p == (TCHAR) 0 )
             *p= TEXT(' ');
       }
 
       // null terminate it.  Safe even if nChars==0 because it is 1 TCHAR bigger
 
       *(lpch+nChars)= (TCHAR) 0;      /* zero terminate the thing */
 
       // Set 'fLog' if first characters in file are ".LOG"
 
       fLog= *lpch++ == TEXT('.') && *lpch++ == TEXT('L') &&
             *lpch++ == TEXT('O') && *lpch == TEXT('G');
    }
 
    if( hNewEdit )
    {
       LocalUnlock( hNewEdit );
 
       // now it is safe to set the global edit handle
 
       hEdit= hNewEdit;
    }
 
    lstrcpy( szFileName, sz );
    SetTitle( sz );
    fUntitled= FALSE;
 
  /* Pass handle to edit control.  This is more efficient than WM_SETTEXT
   * which would require twice the buffer space.
   */
 
  /* Bug 7443: If EM_SETHANDLE doesn't have enough memory to complete things,
   * it will send the EN_ERRSPACE message.  If this happens, don't put up the
   * out of memory notification, put up the file to large message instead.
   *  17 November 1991     Clark R. Cyr
   */
    dwEmSetHandle = SETHANDLEINPROGRESS;
    SendMessage (hwndEdit, EM_SETHANDLE, (WPARAM)hEdit, (LPARAM)0);
    if (dwEmSetHandle == SETHANDLEFAILED)
    {
       SetCursor(hStdCursor);
 
       dwEmSetHandle = 0;
       AlertBox( hwndNP, szNN, szFTL, sz,MB_APPLMODAL|MB_OK|MB_ICONEXCLAMATION);
       New (FALSE);
       SendMessage (hwndEdit, WM_SETREDRAW, (WPARAM)TRUE, (LPARAM)0);
       return (FALSE);
    }
    dwEmSetHandle = 0;
 
    PostMessage (hwndEdit, EM_LIMITTEXT, (WPARAM)CCHNPMAX, 0L);
 
    /* If file starts with ".LOG" go to end and stamp date time */
    if (fLog)
    {
       SendMessage( hwndEdit, EM_SETSEL, (WPARAM)nChars, (LPARAM)nChars);
       SendMessage( hwndEdit, EM_SCROLLCARET, 0, 0);
       InsertDateTime(TRUE);
    }
 
    /* Move vertical thumb to correct position */
    SetScrollPos (hwndNP,
                  SB_VERT,
                  (int) SendMessage (hwndEdit, WM_VSCROLL, EM_GETTHUMB, 0L),
                  TRUE);
 
    /* Now display text */
    SendMessage( hwndEdit, WM_SETREDRAW, (WPARAM)TRUE, (LPARAM)0 );
    InvalidateRect( hwndEdit, (LPRECT)NULL, TRUE );
    UpdateWindow( hwndEdit );
 
    SetCursor(hStdCursor);
 
    return( TRUE );

        case M_SETFONT:
        {
            CHOOSEFONT  cf;
            HFONT       hFontNew;
            HDC         hDisplayDC;     // display DC
 
            hDisplayDC= GetDC(NULL);    // try to get display DC
            if( !hDisplayDC )
                break;
 
            // calls the font chooser (in commdlg)
            // We set lfHeight; choosefont returns ipointsize
            //
 
            cf.lStructSize = sizeof(CHOOSEFONT);
            cf.hwndOwner = hwnd;
            cf.lpLogFont = &FontStruct;         // filled in by init
            FontStruct.lfHeight= -MulDiv(iPointSize,GetDeviceCaps(hDisplayDC,LOGPIXELSY),720);
 
            // We filter out useless stuff here
            // We tried CF_NOSCRIPTSEL, but the FE had fits.
            //    Even though it looks useless, it changes the font that gets mapped on FE builds.
            //    Even though we ignore the lfCharSet that gets returned, we have the "right"
            //    font according to the FE guys.  It might make sense to use lfCharSet to
            //    convert the ansi file when it is converted to Unicode, but this might be
            //    confusing.
 
            cf.Flags = CF_INITTOLOGFONTSTRUCT |
                       CF_SCREENFONTS         | 
                       CF_NOVERTFONTS         |
                       // CF_NOSCRIPTSEL         |  // windows bug# 7770 (April 10,2001)
                       0;
            cf.rgbColors = 0;                   // only if cf_effects
            cf.lCustData = 0;                   // for hook function
            cf.lpfnHook = (LPCFHOOKPROC) NULL;
            cf.lpTemplateName = (LPTSTR) NULL;
            cf.hInstance = NULL;
            cf.lpszStyle = NULL;                // iff cf_usestyle
            cf.nFontType = SCREEN_FONTTYPE;
            cf.nSizeMin  = 0;  // iff cf_limitsize
            cf.nSizeMax  = 0;  // iff cf_limitsize
            ReleaseDC( NULL, hDisplayDC );
 
            if( ChooseFont(&cf) )
            {
                SetCursor( hWaitCursor );        // may take some time
 
                hFontNew= CreateFontIndirect(&FontStruct);
                if( hFontNew )
                {
                   DeleteObject( hFont );
                   hFont= hFontNew;
                   SendMessage( hwndEdit, WM_SETFONT,
                               (WPARAM)hFont, MAKELPARAM(TRUE, 0));
                   iPointSize= cf.iPointSize;  // remember for printer
                }
                SetCursor( hStdCursor );
            }
            break;
        }

// search forward or backward in the edit control text for the given pattern
// It is the responsibility of the caller to set the cursor
 
BOOL Search (TCHAR * szKey)
{
    BOOL      bStatus= FALSE;
    TCHAR   * pStart, *pMatch;
    DWORD     StartIndex, LineNum, EndIndex;
    DWORD     SelStart, SelEnd, i;
    HANDLE    hEText;           // handle to edit text
    UINT      uSelState;
    HMENU     hMenu;
    BOOL      bSelectAll = FALSE;
 
 
    if (!*szKey)
        return( bStatus );
 
    SendMessage(hwndEdit, EM_GETSEL, (WPARAM)&SelStart, (LPARAM)&SelEnd);
 
 
    // when we finish the search, we highlight the text found, and continue 
    // the search after the end of the highlighted position (in forward 
    // case) or from the begining of the highlighted position in the reverse
    // direction (in reverse case). this would break if the user has 
    // selected all text. this hack would take care of it. (this is consistent
    // with VC editors' search too.
 
    hMenu = GetMenu(hwndNP);
    uSelState = GetMenuState(GetSubMenu(hMenu, 1), M_SELECTALL, MF_BYCOMMAND);
    if (uSelState == MF_GRAYED)
    {
        bSelectAll = TRUE;
        SelStart = SelEnd =0;
    }
 
 
    //
    // get pointer to edit control text to search
    //
 
    hEText= (HANDLE) SendMessage( hwndEdit, EM_GETHANDLE, 0, 0 );
    if( !hEText )  // silently return if we can't get it
    {
        return( bStatus );
    }
    pStart= LocalLock( hEText );
    if( !pStart )
    {
        return( bStatus );
    }
 
    if (fReverse)
    {
        // Get current line number 
        LineNum= (DWORD)SendMessage(hwndEdit, EM_LINEFROMCHAR, SelStart, 0);
        // Get index to start of the line
        StartIndex= (DWORD)SendMessage(hwndEdit, EM_LINEINDEX, LineNum, 0);
        // Set upper limit for search text
        EndIndex= SelStart;
        pMatch= NULL;
 
        // Search line by line, from LineNum to 0
        i = LineNum;
        while (TRUE)
        {
            pMatch= ReverseScan(pStart+StartIndex,pStart+EndIndex,szKey,fCase);
            if (pMatch)
               break;
            // current StartIndex is the upper limit for the next search 
            EndIndex= StartIndex;
 
            if (i)
            {
                // Get start of the next line
                i-- ;
                StartIndex = (DWORD)SendMessage(hwndEdit, EM_LINEINDEX, i, 0);
            }
            else
               break ;
        }
    }
    else
    {
            pMatch= ForwardScan(pStart+SelEnd, szKey, fCase);
    }
 
    LocalUnlock(hEText);
 
    if (pMatch == NULL)
    {
        //
        // alert user on not finding any text unless it is replace all
        //
        if( !(FR.Flags & FR_REPLACEALL) )
        {
            HANDLE hPrevCursor= SetCursor( hStdCursor );
            AlertBox( hDlgFind ? hDlgFind : hwndNP,
                      szNN,
                      szCFS,
                      szSearch,
                      MB_APPLMODAL | MB_OK | MB_ICONINFORMATION);
            SetCursor( hPrevCursor );
        }
    }
    else
    {
        SelStart = (DWORD)(pMatch - pStart);
        SendMessage( hwndEdit, EM_SETSEL, SelStart, SelStart+lstrlen(szKey));
 
        // since we are selecting the found text, enable SelectAll again.
        if (bSelectAll)
        {
            EnableMenuItem(GetSubMenu(hMenu, 1), M_SELECTALL, MF_ENABLED);
        }
 
        //
        // show the selected text unless it is replace all
        //
 
        if( !(FR.Flags & FR_REPLACEALL) )
        {
            SendMessage(hwndEdit, EM_SCROLLCARET, 0, 0);
            UpdateStatusBar( TRUE );
        }
        bStatus= TRUE;   // found
    }
 
    return( bStatus );
}