Calculates the length of the text in the rich edit control.
UINT uCodePage = -1
Value specifying the method to be used in determining the text length. This member can be one or more of the values listed in the flags member of GETTEXTLENGTHEX described in the Windows SDK.
Code page for translation (CP_ACP for ANSI Code Page, 1200 for Unicode).
The number of characters or bytes in the edit control. If incompatible flags were set in dwFlags, this member function returns E_INVALIDARG.
GetTextLengthEx provides additional ways of determining the length of the text. It supports the Rich Edit 2.0 functionality. See About Rich Edit Controls in the Windows SDK for more information.