public int n_pages_to_print { get; }

The number of pages that will be printed.

Note that this value is set during print preparation phase (gtk_print_status_preparing), so this value should never be get before the data generation phase (gtk_print_status_generating_data). You can connect to the status_changed signal and call get_n_pages_to_print when print status is gtk_print_status_generating_data. This is typically used to track the progress of print operation.