Writes contents of a control to a file
#include <GuiRichEdit.au3>
_GUICtrlRichEdit_StreamToFile ( $hWnd, $sFileSpec [, $bIncludeCOM = True [, $iOpts = 0 [, $iCodePage = 0 [, $iFileEncoding = Default]]]] )
| $hWnd | Handle to the control | 
| $sFileSpec | file specification | 
| $bIncludeCOM | [optional] True (default): If writing to a .rtf file, includes any COM objects (space consuming) If writing to any other file, writes a text represntation of COM objects False: Writes spaces instead of COM objects  | 
| $iOpts | [optional] additional options: (default: 0) $SFF_PLAINRTF - write only rich text keywords common to all languages $SF_UNICODE - write Unicode  | 
| $iCodePage | [optional] Generate UTF-8 and text using this code page Default: do not  | 
| $iFileEncoding | [optional] file encoding specification (See FileOpen() to more info). Default: $FO_READ.  | 
| Success: | True | 
| Failure: | False and sets the @error flag to non-zero. | 
| @error: | 101 - $hWnd is not a handle 102 - Can't create $sFileSpec 1041 - $SFF_PLAINRTF is invalid for a text file 1042 - $opts: invalid option 1043 - $SF_UNICODE is only valid for a text file 700 - internal error  | 
If text is selected, writes only the selection, else writes all text in the control.
If the extension in $sFileSpec is .rtf, RTF is written, else text.
_GUICtrlRichEdit_SetLimitOnText, _GUICtrlRichEdit_StreamFromFile, _GUICtrlRichEdit_StreamFromVar, _GUICtrlRichEdit_StreamToVar
Search EM_STREAMIN in MSDN Library.
#include <GUIConstantsEx.au3>
#include <GuiRichEdit.au3>
#include <MsgBoxConstants.au3>
#include <WindowsStylesConstants.au3>
Example()
Func Example()
    Local $hGui, $hRichEdit, $iMsg
    $hGui = GUICreate("Example (" & StringTrimRight(@ScriptName, StringLen(".exe")) & ")", 320, 350, -1, -1)
    $hRichEdit = _GUICtrlRichEdit_Create($hGui, "This is a test.", 10, 10, 300, 220, _
            BitOR($ES_MULTILINE, $WS_VSCROLL, $ES_AUTOVSCROLL))
    GUISetState(@SW_SHOW)
    _GUICtrlRichEdit_AppendText($hRichEdit, "Para with default border settings")
    MsgBox($MB_SYSTEMMODAL, "", "The default paragraph border settings are " & _GUICtrlRichEdit_GetParaBorder($hRichEdit))
    _GUICtrlRichEdit_AppendText($hRichEdit, @CRLF & "Second paragraph")
    _GUICtrlRichEdit_SetParaBorder($hRichEdit, "o", 3, "mag", 0.25)
    MsgBox($MB_SYSTEMMODAL, "", "Border settings of second paragraph are " & _GUICtrlRichEdit_GetParaBorder($hRichEdit))
    _GUICtrlRichEdit_SetSel($hRichEdit, 10, -1)
    Sleep(1000)
    MsgBox($MB_SYSTEMMODAL, "", "Border settings of first paragraph in the selection are " & _GUICtrlRichEdit_GetParaBorder($hRichEdit))
    ; Change from outside border to left border
    _GUICtrlRichEdit_SetParaBorder($hRichEdit, "l")
    ; Stream all text to the Desktop so you can look at border settings in Word
    _GUICtrlRichEdit_Deselect($hRichEdit)
    _GUICtrlRichEdit_StreamToFile($hRichEdit, @DesktopDir & "\gcre.rtf")
    While True
        $iMsg = GUIGetMsg()
        Select
            Case $iMsg = $GUI_EVENT_CLOSE
                _GUICtrlRichEdit_Destroy($hRichEdit) ; needed unless script crashes
                ; GUIDelete()   ; is OK too
                Exit
        EndSelect
    WEnd
EndFunc   ;==>Example