| \chapter{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 \UNIX{} or C |
| interfaces but they are available on some other systems as well |
| (e.g. Windows or NT). Here's an overview: |
| |
| \begin{description} |
| |
| \item[signal] |
| --- Set handlers for asynchronous events. |
| |
| \item[socket] |
| --- Low-level networking interface. |
| |
| \item[select] |
| --- Wait for I/O completion on multiple streams. |
| |
| \item[thread] |
| --- Create multiple threads of control within one namespace. |
| |
| \end{description} |