PrOpen opens the printer port to prepare for writing. If useDialog is TRUE then the Page Setup and Print dialogs are shown. You should not call PrNewPage when opening a printer page using PrOpen. If useDialog is TRUE, then PrOpen returns FALSE if the Print Dialog is canceled. PrOpen returns TRUE if useDialog is TRUE or the Print Dialog is not canceled.
Also see: PrClose PrPlotData PrNewPage Print PrGetPage