Pass page orientation info to the printer.
void pdfPrintSetPaperOrientation(PDFHandle pdf, int orient)
If this function is called with orient true (non-zero), page orientation info (portrait or landscape) will be passed to the printer.

The results depend on the printer driver, but this option generally only affects finishing equipment (e.g., staplers) and PS/PCL viewers.

pdfPrintResetParams resets this to its default value, which is false.

pdfPrintSetPaperOrientation(pdf, 1);