Sets the page forwarding function to be @page_func.
This function will be used to determine what will be
the next page when the user presses the forward button.
Setting @page_func to %NULL will make the assistant to
use the default forward function, which just goes to the
next visible page.
Sets the page forwarding function to be @page_func.
This function will be used to determine what will be the next page when the user presses the forward button. Setting @page_func to %NULL will make the assistant to use the default forward function, which just goes to the next visible page.