Adds a bookmark for the current page. Bookmarks usually appear in PDF-Viewers left of the page in a hierarchical tree. Clicking on a bookmark will jump to the given page.
The bookmark has no meaning if the document is printed or viewed but it will be used if the document is converted to pdf by either Acrobat Distiller™ or Ghostview.
The parameter parent is another bookmark which is used as the parent of the new bookmark.
If open is unequal to zero the bookmark will be shown open by the pdf viewer.