Schedule a function to be invoked when *this becomes ready.
template<typename Func> see below then( Func&& func); template<typename Func> see below then( std::launch policy,Func&& func);
this->valid()
would return true.
func(this->get())
is valid. Func
is MoveConstructible.
If the asynchronous result associated with *this contains a deferred function
that has not yet started execution, invokes the deferred function.
Copies func to
internal storage.
If *this
is ready, schedules func
immediately. Otherwise, func
is scheduled when the asynchronous result associated with *this
becomes ready.
When func is scheduled,
it is scheduled as-if std::async(policy,func,this->get()). If policy
is not specified in the call to then,
the policy is given
the value used when creating the asynchronous result associated
with *this,
if any, or std::launch::deferred
| std::launch::async
if the asynchronous result associated with *this does not have an associated
launch policy.
If std::result_of<Func(ResultType)>::type is an instance of either
std::experimental::future or std::experimental::shared_future, then returns
std::result_of<Func(ResultType)>::type; the resulting future will
become ready when the continuation function
has completed, and the future returned from the continuation is
ready, as per the std::experimental::shared_future Unwrapping constructor.
Otherwise, returns a new instance of std::experimental::future<std::result_of<Func(ResultType)>::type> associated with a newly-created
asynchronous result to be populated with the return value or any
exception thrown by the invocation of func.
std::bad_alloc if the required internal
storage cannot be allocated, otherwise std::future_error
when the effects cannot be achieved, or any exception thrown during
the copy of func
to internal storage.
#include <experimental/future>