bug#1501: Emacs 22 loses undo buffer

[Chong Yidong]

"Emerick Rogul" <emerick@gmail.com> writes:

> Header file attached, although the problem occurs with any header file
> (i.e., it's not specific to this particular file).  The trace below
> contains the exact key sequence that I typed.

Thanks for the clarification.

What you're encountering is the "undo-limit", which specifies the
maximum amount of undo information to keep.  The default is 20
kilobytes, but you can raise it by changing the variable `undo-limit'.
You can also find details in the Emacs manual.