acet-layerp-mark

(acet-layerp-mark  [OnOff])

This function sets begin and end marker for "layer previous" tracking.

If no argument OnOff is given, this functions returns t if there is an actual "layer previous" begin marker is effective, nil otherwise.
if argument OnOff is t, a begin marker is set for layer previous" tracking, if provided as nil, an end marker is set for layer previous" tracking.

Returns : T if there is a begin marker for "layer previous" tracking present, NIL otherwise.