Creates a marker in the buffer of type type. A marker is semantically very
similar to a GTK2.TextMark, except it has a type which is used by the
GTK2.SourceView displaying the buffer to show a pixmap on the left margin,
at the line the marker is in. Becuase of this, a marker is generally
associated to a line and not a character position. Markers are also
accessible through a position or range in the buffer.
Markers are implemented using GTK2.TextMark, so all characteristics and
restrictions to marks apply to markers too. These include life cycle
issues and "mark-set" and "mark-deleted" signal emissions.
Like a GTK2.TextMark, a GTK2.SourceMarker can be anonymous if the passed
name is 0.
Markers always have left gravity and are moved to the beginning of the line
when the users deletes the line they were in. Also, if the user deletes a
region of text which contained lines with markers, those are deleted.
Typical uses for a marker are bookmarks, breakpoints, current executing
instruction indication in a source file, etc.
GTK2.SourceBuffer()->create()