Returns %TRUE if @iter could be moved; i.e. if @iter was at
character offset 0, this function returns %FALSE. Therefore,
if @iter was already on line 0, but not at the start of the line,
@iter is snapped to the start of the line and the function returns
%TRUE. (Note that this implies that
in a loop calling this function, the line number may not change on
every iteration, if your first iteration is on line 0.)
Moves @iter to the start of the previous line.
Returns %TRUE if @iter could be moved; i.e. if @iter was at character offset 0, this function returns %FALSE. Therefore, if @iter was already on line 0, but not at the start of the line, @iter is snapped to the start of the line and the function returns %TRUE. (Note that this implies that in a loop calling this function, the line number may not change on every iteration, if your first iteration is on line 0.)