Template:cpp/experimental/future/future

@1@ Default constructor. Constructs an empty object that does not refer to a shared state. @2@ Constructs a object, transferring the shared state held by, if any. After construction, is. @3@ @4@ Unwrapping constructor. Constructs a object from the shared state referred to by, if any. If prior to this call, the constructed  object is empty. Otherwise, the resulting object becomes ready when one of the following happens: @@After this constructor returns, is equal to the value of  prior to this call, and.
 * and are both ready. The value or exception from  is stored in the shared state associated with the resulting  object.
 * is ready, but is invalid. An exception of type std with an error condition of std is stored in the shared state associated with the resulting  object.