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.)
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.)