cpp/experimental/not fn

Creates a forwarding call wrapper that returns the complement of the callable object it holds.

Return value
Let be  and  be an lvalue of type  constructed from.

returns a forwarding call wrapper of unspecified type such that  is equivalent to, where  is the operation described in.

The returned call wrapper is always, and is if FD is.

Remarks
If is not, or  is not , the behavior is undefined.

Exceptions
Throws no exceptions, unless the construction of throws.