| \chapter{Generic Operating System Services} | 
 |  | 
 | The modules described in this chapter provide interfaces to operating | 
 | system features that are available on (almost) all operating systems, | 
 | such as files and a clock.  The interfaces are generally modelled | 
 | after the \UNIX{} or C interfaces but they are available on most other | 
 | systems as well.  Here's an overview: | 
 |  | 
 | \begin{description} | 
 |  | 
 | \item[os] | 
 | --- Miscellaneous OS interfaces. | 
 |  | 
 | \item[time] | 
 | --- Time access and conversions. | 
 |  | 
 | \item[getopt] | 
 | --- Parser for command line options. | 
 |  | 
 | \item[tempfile] | 
 | --- Generate temporary file names. | 
 |  | 
 | \end{description} |