No mention of exception_ptr in clause 15

Clause / Subclause / Annex: 
15.5
Comment type: 
Ed
Comment / justification for change: 

There is no mention of the current_exception API which can extend the lifetime of an exception object. There should at least be a forward reference to the library clause 18.7.5

Recommended change: 

Add another paragraph outlining 18.7.5 and the ability of an exception_ptr to extend the lifetime of an exception object

MB: 
UK