problem in setting cursor position in readOnly QTextEdit()

[wagmare]

hi friends ,
how can i set the cursor position of a readonly QTextEdit() after it get input to the top position ...
like this if the user click a button i am displaying a big paragraph but it showing only the tail position but i want to show the front text first ... i try

QTextCursor cursor(editor->textCursor());
    cursor.movePosition(QTextCursor::Start);

QTextCursor cursor(editor->textCursor());
    cursor.movePosition(QTextCursor::Start);

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but its not working ... i try setCursorPosition(1,1) but it says its not a member function ...
then i tried

resultTextEdit->cursorForPosition(startPos);

resultTextEdit->cursorForPosition(startPos);

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but i dont know how to set it ... please help ...
please help