Function: set-marker-insertion-type
set-marker-insertion-type is a function defined in marker.c.
Signature
(set-marker-insertion-type MARKER TYPE)
Documentation
Set the insertion-type of MARKER to TYPE.
If TYPE is t, it means the marker advances when you insert text at it. If TYPE is nil, it means the marker stays behind when you insert text at it.
Probably introduced at or before Emacs version 19.30.
Source Code
// Defined in /usr/src/emacs/src/marker.c
{
CHECK_MARKER (marker);
XMARKER (marker)->insertion_type = ! NILP (type);
return type;
}