Carbon


TXNUndo

Header: MacTextEditor.h Carbon status: Supported

Undoes the last command.

void TXNUndo (
    TXNObject iTXNObject
);
Parameter descriptions
iTXNObject

A variable of type TXNObject. Pass the text object for the document you want to examine.

DISCUSSION

The undo stack is 32 levels deep. That is, undoable actions are tracked until the total count is 32. If a user undoes two actions, the Redo command must be used twice to get back to the original state. If more than 32 actions are performed, the oldest actions are forgotten as each new action takes place.

If the user performs a new action after choosing Redo from the Edit menu, the redone action is no longer available to be undone. For example, a user performs the following actions: types some text, cuts some text, pastes some text, types some text; undoes the last typing action, and undoes the paste operation; redoes the paste; types some new text. After the new text has been typed the undo stack contains: the first text that was typed, the cut action, and the new text that was just typed. The paste action and the second block of typed text is no longer available for undo, and the new text is the only action that is undoable.

AVAILABILITY

Supported in Carbon. Available in Carbon 1.0.2 and later when running Mac OS 8.1 or later.


© 2000 Apple Computer, Inc. (Last Updated 7/17/2000)