vc-diff-internal

vc-diff-internal is an autoloaded compiled Lisp function in `vc.el'.

(vc-diff-internal ASYNC VC-FILESET REV1 REV2 &optional VERBOSE BUFFER)

Report diffs between two revisions of a fileset.
Output goes to the buffer BUFFER, which defaults to *vc-diff*.
BUFFER, if non-nil, should be a buffer or a buffer name.
Return t if the buffer had changes, nil otherwise.