Note that this value is set during print preparation phase
(%GTK_PRINT_STATUS_PREPARING), so this function should never be
called before the data generation phase (%GTK_PRINT_STATUS_GENERATING_DATA).
You can connect to the [signal@Gtk.PrintOperation::status-changed]
signal and call gtk_print_operation_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.
Returns the number of pages that will be printed.
Note that this value is set during print preparation phase (%GTK_PRINT_STATUS_PREPARING), so this function should never be called before the data generation phase (%GTK_PRINT_STATUS_GENERATING_DATA). You can connect to the [signal@Gtk.PrintOperation::status-changed] signal and call gtk_print_operation_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.