Variable: org-pre-cycle-hook
org-pre-cycle-hook is an alias and customizable for
org-cycle-pre-hook, defined in org-cycle.el.gz.
Value
nil
Documentation
Hook that is run before visibility cycling is happening.
The function(s) in this hook must accept a single argument which indicates
the new state that will be set right after running this hook. The
argument is a symbol. Before a global state change, it can have the values
overview, content, or all. Before a local state change, it can have
the values folded, children, or subtree.