cpp/thread/packaged task/reset

Resets the state abandoning the results of previous executions. New shared state is constructed.

Equivalent to, where is the stored task.

Parameters
(none)

Return value
(none)

Exceptions

 * std if has no shared state. The error condition is set to.
 * std if there was not enough memory for a new shared state.
 * any exception thrown by the move constructor of the new