Contributing to Gnulib
======================
+
All software here is copyrighted by the Free Software Foundation - you need
to have filled out an assignment form for a project that uses the
module for that contribution to be accepted here.
----------------------
Gnulib code is intended to be portable to a wide variety of platforms,
-not just GNU platforms.
+not just GNU platforms. See the documentation section "Target Platforms"
+for details.
Many Gnulib modules exist so that applications need not worry about
undesirable variability in implementations. For example, an
need not worry about localtime_r returning int (not char *) on some
platforms that predate POSIX 1003.1-2001.
-Originally much of the Gnulib code was portable to ancient hosts like
-4.2BSD, but it is a maintenance hassle to maintain compatibility with
-unused hosts, so currently we assume at least a freestanding C89
-compiler, possibly operating with a C library that predates C89. The
-oldest environment currently ported to is probably SunOS 4 + GCC 1.x,
-though we haven't tested this exact combination. SunOS 4 last shipped
-on 1998-09-30, and Sun dropped support for it on 2003-10-01, so at
-some point we may start assuming a C89 library as well.
+Currently we assume at least a freestanding C89 compiler, possibly
+operating with a C library that predates C89. The oldest environments
+currently ported to are probably HP-UX 10.20 and IRIX 5.3, though we
+are not testing these platforms very often.
Because we assume a freestanding C89 compiler, Gnulib code can include
<float.h>, <limits.h>, <stdarg.h>, and <stddef.h> unconditionally. It
can also assume the existence of <ctime.h>, <errno.h>, <fcntl.h>,
-<locale.h>, <signal.h>, <stdio.h>, <stdlib.h>, <string.h>, and
-<time.h>. Some of these headers, such as <errno.h>, were present in
-Unix Version 7 and are thus widely available. <string.h> and
-<stdlib.h> were not in Unix Version 7, so they weren't universally
-available on ancient hosts, but they are both in SunOS 4 (the oldest
-platform still in relatively-common use) so Gnulib assumes them now.
-Similarly, many modules include <sys/types.h> even though it's not
-even in C99; that's OK since <sys/types.h> has been around nearly
-forever.
+<locale.h>, <signal.h>, <stdio.h>, <stdlib.h>, <string.h>, and <time.h>.
+Similarly, many modules include <sys/types.h> even though it's not even
+in C99; that's OK since <sys/types.h> has been around nearly forever.
Even if the include files exist, they may not conform to C89.
However, GCC has a "fixincludes" script that attempts to fix most
should use fixincludes or fix their include files manually.
Even if the include files conform to C89, the library itself may not.
-For example, SunOS 4's (free (NULL)) can dump core, so Gnulib code
-must avoid freeing a null pointer, even though C89 allows it.
+For example, strtod and mktime have some bugs on some platforms.
You can work around some of these problems by requiring the relevant
-modules, e.g., the Gnulib 'free' module supplies a conforming 'free'.
+modules, e.g., the Gnulib 'mktime' module supplies a working and
+conforming 'mktime'.
The GNU coding standards allow one departure from strict C99: Gnulib
code can assume that standard internal types like size_t are no wider
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