Invoke the task associated with a std::experimental::packaged_task instance, and
store the return value or exception in the associated asynchronous result.
void operator()(ArgTypes... args);
*this
has an associated task.
Invoke the associated task func
as-if INVOKE(func,args...).
If the invocation returns normally, store the return value in the
asynchronous result associated with *this. If the invocation returns
with an exception, store the exception in the asynchronous result
associated with *this.
The asynchronous result associated with *this is ready
with a stored value or exception. Any threads blocked waiting for
the asynchronous result are unblocked.
An exception of type std::future_error
with an error code of std::future_errc::promise_already_satisfied
if the asynchronous result is already ready..
A successful call to the function call operator happens-before
a call to std::experimental::future<ResultType>::get()
or std::experimental::shared_future<ResultType>::get()
which retrieves the value or exception stored.
#include <experimental/future>