pdfStartPrintJobcall is passed to the printer driver. But not all printers/drivers support printing multiple copies and/or collation. The
pdfSetPrintEmulatedMultiCopyfunction can be used to enable "emulated multi copy" mode, in which XpdfViewer will generate a print stream with multiple copies (as specified by the
pdfStartPrintJob) of each page, in collated order.
The advantage of emulated multi copy mode is that it will work on all printers. The disadvantage is that the spool file will be larger (because it contains multiple copies of each page).
pdfPrintSetEmulatedMultiCopy with a
emulated argument enables emulated multi copy mode.
Calling with a false
emulated argument disables it.