Advances to the next subpage if sub=0, performing a page advance if there are no remaining subpages on
the current page. If subpages aren't being used, pladv(3plplot)(0) will always advance the page. If
page>0, PLplot switches to the specified subpage. Note that this allows you to overwrite a plot on the
specified subpage; if this is not what you intended, use pleop(3plplot) followed by plbop(3plplot) to
first advance the page. This routine is called automatically (with page=0) by plenv(3plplot), but if
plenv(3plplot) is not used, pladv(3plplot) must be called after initializing PLplot but before defining
the viewport.
Redacted form: pladv(page)
This function is used in examples 1, 2, 4, 6-12, 14-18, 20, 21, 23-27, 29, and 31.