Return t if there are markers pointing at POSITION in the current buffer.

Return a new marker pointing at the same place as MARKER.
If argument is a number, makes a new marker pointing
at that position in the current buffer.
If MARKER is not specified, the new marker does not point anywhere.
The optional argument TYPE specifies the insertion type of the new marker;
see `marker-insertion-type'.

Return the buffer that MARKER points into, or nil if none.
Returns nil if MARKER points into a dead buffer.

Return insertion type of MARKER: t if it stays after inserted text.
The value nil means the marker stays before text inserted there.

Return the position MARKER points at, as a character number.
Returns nil if MARKER points nowhere.

Position MARKER before character number POSITION in BUFFER.
BUFFER defaults to the current buffer.
If POSITION is nil, makes marker point nowhere.
Then it no longer slows down editing in any buffer.
Returns MARKER.

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.