select.select()

select.select(rlist, wlist, xlist[, timeout]) -> (rlist, wlist, xlist)

Wait until one or more file descriptors are ready for some kind of I/O. The first three arguments are sequences of file descriptors to be waited for: rlist – wait until ready for reading wlist – wait until ready for writing xlist – wait for an ``exceptional condition’’ If only one kind of condition is required, pass [] for the other lists. A file descriptor is either a socket or file object, or a small integer gotten from a fileno() method call on one of those.

The optional 4th argument specifies a timeout in seconds; it may be a floating point number to specify fractions of seconds. If it is absent or None, the call will never time out.

The return value is a tuple of three lists corresponding to the first three arguments; each contains the subset of the corresponding file descriptors that are ready.

* IMPORTANT NOTICE * On Windows and OpenVMS, only sockets are supported; on Unix, all file descriptors can be used.