# HG changeset patch # User Bruno Haible # Date 1305584735 -7200 # Node ID e2175e5db8963f6a4966271e4c471f70d1313ad7 # Parent f2a4196e5eeab321d7929469033197616ea83b78 doc: List the target platforms. * doc/gnulib-intro.texi (Target Platforms): New section. * doc/gnulib.texi (Introduction): Update menu. * README (Portability guidelines): Refer to the new section. Update statement about oldest supported environment. Remove rationale why , , are assumed. Update example of an unportable C89 function. Reported by Bastien Roucariès and Charles Wilson . Feedback from Paul Eggert. diff --git a/ChangeLog b/ChangeLog --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,15 @@ +2011-05-16 Bruno Haible + + doc: List the target platforms. + * doc/gnulib-intro.texi (Target Platforms): New section. + * doc/gnulib.texi (Introduction): Update menu. + * README (Portability guidelines): Refer to the new section. Update + statement about oldest supported environment. Remove rationale why + , , are assumed. Update example of an + unportable C89 function. + Reported by Bastien Roucariès and + Charles Wilson . Feedback from Paul Eggert. + 2011-05-16 Paul Eggert * build-aux/bootstrap (gnulib_tool): Handle symlink timestamps better. diff --git a/README b/README --- a/README +++ b/README @@ -77,6 +77,7 @@ 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. @@ -201,7 +202,8 @@ ---------------------- 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 @@ -210,27 +212,17 @@ 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 environment +currently ported to are probably HP-UX 10.20 and IRIX 5.3, though we +are not testing these platform very often. Because we assume a freestanding C89 compiler, Gnulib code can include , , , and unconditionally. It can also assume the existence of , , , -, , , , , and -. Some of these headers, such as , were present in -Unix Version 7 and are thus widely available. and - 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 even though it's not -even in C99; that's OK since has been around nearly -forever. +, , , , , and . +Similarly, many modules include even though it's not even +in C99; that's OK since 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 @@ -239,10 +231,10 @@ 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 diff --git a/doc/gnulib-intro.texi b/doc/gnulib-intro.texi --- a/doc/gnulib-intro.texi +++ b/doc/gnulib-intro.texi @@ -74,6 +74,116 @@ stdout if desired, and emits an error message if the subprocess failed. +@node Target Platforms +@section Target Platforms + +Gnulib supports a number of platforms that we call the ``reasonable +portability targets''. This class consists of widespread operating systems, +for three years after their last availability, or --- for proprietary +operating systems --- as long as the vendor provides commercial support for +it. Already existing Gnulib code for older operating systems is usually +left in place for longer than these three years. So it comes that programs +that use Gnulib run pretty well also on these older operating systems. + +Some operating systems are not very widespread, but are Free Software and +are actively developed. Such platforms are also supported by Gnulib, if +that OS's developers community keeps in touch with the Gnulib developers, +by providing bug reports, analyses, or patches. For such platforms, Gnulib +will not support all versions that are at most three years old, but only +the versions of the last year or the last few months, depending on the +maturity of said OS project, the number of its users, and how often these +users upgrade. + +Niche operating systems are generally unsupported by Gnulib, unless some +people from their developers or users community contributes support to +Gnulib. + +The degree of support Gnulib guarantees for a platform depends on the +amount of testing it gets from volunteers. Platforms on which Gnulib +is frequently tested are the best supported. Then come platforms with +occasional testing, then platforms which are rarely tested. Usually, +we fix bugs when they are reported. Except that some rarely tested +platforms are also low priority; bug fixes for these platforms can +take longer. + +As of 2011, the list of supported platforms is the following: + +@itemize +@item +glibc systems. With glibc 2.8 or newer, they are frequenty tested. With +glibc 2.3 or newer, they are occasionally tested. +@item +MacOS X. In versions 10.5 and 10.6, it's frequently tested. In version +10.4, it's rarely tested. +@item +FreeBSD 6.0 or newer is occasionally tested. FreeBSD 5.x is rarely tested. +@item +NetBSD 5.0 or newer is occasionally tested. NetBSD 3.0 or newer is rarely +tested. +@item +OpenBSD 4.0 or newer is occasionally tested. OpenBSD 3.8 or newer is rarely +tested. +@item +AIX 6.1 or newer is occasionally tested. AIX 5.1 or newer is rarely tested. +@item +HP-UX 11.11 or newer is occasionally tested. HP-UX 11.00 is rarely tested. +HP-UX 10.20 is rarely tested and low priority. +@item +IRIX 6.5 is occasionally tested. IRIX 5.3 is rarely tested and low priority. +@item +OSF/1 5.1 is occasionally tested. OSF/1 4.0 is rarely tested and low +priority. +@item +Solaris 8 and newer are occasionally tested. Solaris 7 is rarely tested. +Solaris 2.6 and older is rarely tested and low priority. +@item +Cygwin 1.7.x is frequently tested. Cygwin 1.5.x is occasionally tested. +@item +mingw is frequently tested. But note that some modules are currently +unsupported on mingw: @code{mgetgroups}, @code{getugroups}, @code{idcache}, +@code{userspec}, @code{openpty}, @code{login_tty}, @code{forkpty}, +@code{pt_chown}, @code{grantpt}, @code{pty}, @code{savewd}, +@code{mkancesdirs}, @code{mkdir-p}, @code{euidaccess}, @code{faccessat}. +The versions of Windows that are supported are Windows XP and newer. +@item +Native Windows, with MSVC as compiler, is not tested and low priority. +@item +mingw in 64-bit mode is not tested and low priority so far. +@item +Interix 3.5 is not tested. +@item +Haiku is rarely tested, BeOS is not tested and low priority. +@item +uClibc on Linux is rarely tested. +@item +QNX is not tested and low priority. +@end itemize + +These operating systems are all supported in an unvirtualized environment. +When you run an OS inside a virtual machine, you have to be aware that the +virtual machine can bring in bugs of its own. For example, floating-point +operations on Solaris can behave slightly differently in QEMU than on real +hardware. And Haiku's @command{bash} program misbehaves in VirtualBox 3, +whereas it behaves fine in VirtualBox 4. + +Similarly, running native Windows binaries on GNU/Linux under WINE is +rarely tested and low priority: WINE has a set of behaviours and bugs that +is slightly different from native Windows. + +The following platforms are @emph{not} supported by Gnulib. Even correct +patches for their support will not be applied. + +@itemize +@item +Windows 95/98/ME. +@item +DJGPP and EMX (the 32-bit operating systems running in DOS). +@item +MSDOS (the 16-bit operating system). +@item +Windows Mobile, Symbian OS, iOS. +@end itemize + @node Modules @section Modules diff --git a/doc/gnulib.texi b/doc/gnulib.texi --- a/doc/gnulib.texi +++ b/doc/gnulib.texi @@ -108,6 +108,7 @@ * Benefits:: * Library vs Reusable Code:: * Portability and Application Code:: +* Target Platforms:: * Modules:: * Various Kinds of Modules:: * Collaborative Development::