California Code, Elections Code - ELEC § 14294

(a) At all elections, a member of the precinct board shall mark, in the space provided on the voter list posted at or near the polling place, the name of each person who has voted, by drawing a line through the name of the voter, with a pen or indelible pencil.  The board member shall mark off the names at least once each hour, to and including 6 p.m. In all counties not using the voter list, the board member shall draw a line under the last name signed in the roster at 6 p.m. or at the time of discontinuation of this procedure, whichever occurs last.

(b) If an electronic poll book is used at the polling place, the elections official may use a printout or an electronic means of notification of the list of each person who has voted.  The elections official shall provide the printout or electronic notification at least once each hour, to and including 6 p.m., or at the time of discontinuation of this procedure, whichever occurs last.