软件包：libfuture-perl（0.49-1）
module for operations awaiting completion
A Future object represents an operation that is currently in progress, or has recently completed. It can be used in a variety of ways to manage the flow of control, and data, through an asynchronous program.
Some futures represent a single operation and are explicitly marked as ready by calling the done or fail methods. These are called "leaf" futures here, and are returned by the new constructor.
Other futures represent a collection sub-tasks, and are implicitly marked as ready depending on the readiness of their component futures as required. These are called "dependent" futures here, and are returned by the various wait_* and need_* constructors.
It is intended that library functions that perform asynchronous operations would use Future objects to represent outstanding operations, and allow their calling programs to control or wait for these operations to complete. The implementation and the user of such an interface would typically make use of different methods on the class. The methods below are documented in two sections; those of interest to each side of the interface.