# tag: Tom Lord Tue Dec  4 15:06:35 2001 (os/=README)
#

		   Gateway to System Include Files

A Hackerlab coding convention is that every include file should:

	1. Be idempotent.  Including an already included file
	   must have no effect.

	2. Be self-sufficient.  No include file may require that
	   a second file be included first.

System header files generally do not have those properties.
Therefore, Hackerlab code doesn't use those header files directly.
Instead, they use the `os' header files.

Whenever you would normally have a sequence of system includes such
as:

	#include <A.h>
	#include <B.h>

where `A.h' is required to be included before `B.h', in Hackerlab
code, write:

	#include "hackerlab/os/B.h"


The set of files here isn't yet ``complete'' -- files are being added
as-needed.  Still, the most commonly needed files for file system
access, time values, and network programming are all here.

There are also a few C functions here which simply call equivalent
functions in libc (e.g. `errno_to_string' which calls `strerror').  In
some cases, there is a tentative plan to later replace these with new
implementations for various obscure reasons (e.g., because some
popular libc implementation or other is absurd).  In other cases, I
simply wanted a function name that was consistent with other names in
`libhackerlab'.