Optional Operating System Services

The modules described in this chapter provide interfaces to operating system features that are available on selected operating systems only. The interfaces are generally modelled after the or C interfaces but they are available on some other systems as well (e.g. Windows or NT). Here's an overview:
signal
— Set handlers for asynchronous events.
socket
— Low-level networking interface.
select
— Wait for I/O completion on multiple streams.
thread
— Create multiple threads of control within one namespace.