查看完整版本: IO::Select方法的作用？

IO::Select方法的作用？

IO::Select方法是什么作用？

select( readArray [, writeArray [ errorArray [ timeout ] ] ] ) -> anArray or nil  

Performs a low-level select call, which waits for data to become available from input/output devices. The first three parameters are arrays of IO objects or nil. The last is a timeout in seconds, which should be an Integer or a Float. The call waits for data to become available for any of the IO objects in readArray, for buffers to have cleared sufficiently to enable writing to any of the devices in writeArray, or for an error to occur on the devices in errorArray. If one or more of these conditions are met, the call returns a three-element array containing arrays of the IO objects that were ready. Otherwise, if there is no change in status for timeout seconds, the call returns nil. If all parameters are nil, the current thread sleeps forever.

select( [$stdin], nil, nil, 1.5 )  &raquo; [[#<IO:0x401b8090>], [], []]