Getting selected text from external appication without clipboard using ?

its nice working to select a text from external application via :

SendMessage(SomeHandle, EM_SETSEL, start, end);

but how to get selected text  without using clipboard ?
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var
THESELECTEDTEXT:string;
begin
SendMessage(SomeHandle, EM_GETSELTEXT, textlength + 1,
    lParam(integer(THESELECTEDTEXT)));
end;
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the code below, doesnt work and I dont wantto use clipboard.
is it possible like WM_GETTEXT but I know WMGETTEXT gets whole text that I
dont want.

is there a way to get selected text from an external application without
using WMclipboard and WM _COPY ?

thanks