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:
-- Miscellaneous OS interfaces.
-- Time access and conversions.
-- Parser for command line options.
-- Generate temporary file names.
-- Standard errno system symbols.
-- Unix shell style pathname pattern expansion.
-- Unix shell style pathname pattern matching.
-- Internationalization services.