transient information about idiosyncrasies of some of the ports, almost
all of which are in a state of constant evolution. Thus, this material
should be considered a perpetual work in progress
-(E<lt>IMG SRC="yellow_sign.gif" ALT="Under Construction"E<gt>).
+(<IMG SRC="yellow_sign.gif" ALT="Under Construction">).
=head1 ISSUES
logical may depend on the platform in use. In MacPerl, C<\n> always
means C<\015>. In DOSish perls, C<\n> usually means C<\012>, but
when accessing a file in "text" mode, STDIO translates it to (or
-from) C<\015\012>, depending on whether your reading or writing.
+from) C<\015\012>, depending on whether you're reading or writing.
Unix does the same thing on ttys in canonical mode. C<\015\012>
is commonly referred to as CRLF.
+A common cause of unportable programs is the misuse of chop() to trim
+newlines:
+
+ # XXX UNPORTABLE!
+ while(<FILE>) {
+ chop;
+ @array = split(/:/);
+ #...
+ }
+
+You can get away with this on Unix and MacOS (they have a single
+character end-of-line), but the same program will break under DOSish
+perls because you're only chop()ing half the end-of-line. Instead,
+chomp() should be used to trim newlines. The Dunce::Files module can
+help audit your code for misuses of chop().
+
+When dealing with binary files (or text files in binary mode) be sure
+to explicitly set $/ to the appropriate value for your file format
+before using chomp().
+
Because of the "text" mode translation, DOSish perls have limitations
in using C<seek> and C<tell> on a file accessed in "text" mode.
Stick to C<seek>-ing to locations you got from C<tell> (and no
numbers to secondary storage such as a disk file or tape.
Conflicting storage orders make utter mess out of the numbers. If a
-little-endian host (Intel, Alpha) stores 0x12345678 (305419896 in
-decimal), a big-endian host (Motorola, MIPS, Sparc, PA) reads it as
-0x78563412 (2018915346 in decimal). To avoid this problem in network
-(socket) connections use the C<pack> and C<unpack> formats C<n>
-and C<N>, the "network" orders. These are guaranteed to be portable.
+little-endian host (Intel, VAX) stores 0x12345678 (305419896 in
+decimal), a big-endian host (Motorola, Sparc, PA) reads it as
+0x78563412 (2018915346 in decimal). Alpha and MIPS can be either:
+Digital/Compaq used/uses them in little-endian mode; SGI/Cray uses
+them in big-endian mode. To avoid this problem in network (socket)
+connections use the C<pack> and C<unpack> formats C<n> and C<N>, the
+"network" orders. These are guaranteed to be portable.
+
+You can explore the endianness of your platform by unpacking a
+data structure packed in native format such as:
+
+ print unpack("h*", pack("s2", 1, 2)), "\n";
+ # '10002000' on e.g. Intel x86 or Alpha 21064 in little-endian mode
+ # '00100020' on e.g. Motorola 68040
+
+If you need to distinguish between endian architectures you could use
+either of the variables set like so:
+
+ $is_big_endian = unpack("h*", pack("s", 1)) =~ /01/;
+ $is_little_endian = unpack("h*", pack("s", 1)) =~ /^1/;
Differing widths can cause truncation even between platforms of equal
endianness. The platform of shorter width loses the upper parts of the
One can circumnavigate both these problems in two ways. Either
transfer and store numbers always in text format, instead of raw
binary, or else consider using modules like Data::Dumper (included in
-the standard distribution as of Perl 5.005) and Storable. Keeping
-all data as text significantly simplifies matters.
+the standard distribution as of Perl 5.005) and Storable (included as
+of perl 5.8). Keeping all data as text significantly simplifies matters.
=head2 Files and Filesystems
notion of a "path" to uniquely identify a file on the system. How
that path is really written, though, differs considerably.
-Atlhough similar, file path specifications differ between Unix,
+Although similar, file path specifications differ between Unix,
Windows, S<Mac OS>, OS/2, VMS, VOS, S<RISC OS>, and probably others.
Unix, for example, is one of the few OSes that has the elegant idea
of a single root directory.
$file = catfile(curdir(), 'temp', 'file.txt');
# on Unix and Win32, './temp/file.txt'
# on Mac OS, ':temp:file.txt'
+ # on VMS, '[.temp]file.txt'
File::Spec is available in the standard distribution as of version
-5.004_05.
+5.004_05. File::Spec::Functions is only in File::Spec 0.7 and later,
+and some versions of perl come with version 0.6. If File::Spec
+is not updated to 0.7 or later, you must use the object-oriented
+interface from File::Spec (or upgrade File::Spec).
In general, production code should not have file paths hardcoded.
Making them user-supplied or read from a configuration file is
Whitespace in filenames is tolerated on most systems, but not all.
Many systems (DOS, VMS) cannot have more than one C<.> in their filenames.
-Don't assume C<E<gt>> won't be the first character of a filename.
-Always use C<E<lt>> explicitly to open a file for reading,
+Don't assume C<< > >> won't be the first character of a filename.
+Always use C<< < >> explicitly to open a file for reading,
unless you want the user to be able to specify a pipe open.
open(FILE, "< $existing_file") or die $!;
If filenames might use strange characters, it is safest to open it
with C<sysopen> instead of C<open>. C<open> is magic and can
-translate characters like C<E<gt>>, C<E<lt>>, and C<|>, which may
+translate characters like C<< > >>, C<< < >>, and C<|>, which may
be the wrong thing to do. (Sometimes, though, it's the right thing.)
=head2 System Interaction
Don't count on a specific environment variable existing in C<%ENV>.
Don't count on C<%ENV> entries being case-sensitive, or even
-case-preserving.
+case-preserving. Don't try to clear %ENV by saying C<%ENV = ();>, or,
+if you really have to, make it conditional on C<$^O ne 'VMS'> since in
+VMS the C<%ENV> table is much more than a per-process key-value string
+table.
-Don't count on signals for anything.
+Don't count on signals or C<%SIG> for anything.
Don't count on filename globbing. Use C<opendir>, C<readdir>, and
C<closedir> instead.
most platforms (though many of them do not support any type of
forking). The problem with using them arises from what you invoke
them on. External tools are often named differently on different
-platforms, may not be available in the same location, migth accept
+platforms, may not be available in the same location, might accept
different arguments, can behave differently, and often present their
results in a platform-dependent way. Thus, you should seldom depend
on them to produce consistent results. (Then again, if you're calling
=item Mailing list: cpan-testers@perl.org
-=item Testing results: C<http://www.perl.org/cpan-testers/>
+=item Testing results: http://testers.cpan.org/
=back
Perl works on a bewildering variety of Unix and Unix-like platforms (see
e.g. most of the files in the F<hints/> directory in the source code kit).
On most of these systems, the value of C<$^O> (hence C<$Config{'osname'}>,
-too) is determined by lowercasing and stripping punctuation from the first
-field of the string returned by typing C<uname -a> (or a similar command)
-at the shell prompt. Here, for example, are a few of the more popular
-Unix flavors:
+too) is determined either by lowercasing and stripping punctuation from the
+first field of the string returned by typing C<uname -a> (or a similar command)
+at the shell prompt or by testing the file system for the presence of
+uniquely named files such as a kernel or header file. Here, for example,
+are a few of the more popular Unix flavors:
uname $^O $Config{'archname'}
--------------------------------------------
dgux dgux AViiON-dgux
DYNIX/ptx dynixptx i386-dynixptx
FreeBSD freebsd freebsd-i386
+ Linux linux arm-linux
Linux linux i386-linux
Linux linux i586-linux
Linux linux ppc-linux
HP-UX hpux PA-RISC1.1
IRIX irix irix
+ Mac OS X rhapsody rhapsody
+ MachTen PPC machten powerpc-machten
+ NeXT 3 next next-fat
+ NeXT 4 next OPENSTEP-Mach
openbsd openbsd i386-openbsd
OSF1 dec_osf alpha-dec_osf
reliantunix-n svr4 RM400-svr4
Windows NT MSWin32 MSWin32-x86
Windows NT MSWin32 MSWin32-ALPHA
Windows NT MSWin32 MSWin32-ppc
+ Cygwin cygwin
+
+The various MSWin32 Perl's can distinguish the OS they are running on
+via the value of the fifth element of the list returned from
+Win32::GetOSVersion(). For example:
+
+ if ($^O eq 'MSWin32') {
+ my @os_version_info = Win32::GetOSVersion();
+ print +('3.1','95','NT')[$os_version_info[4]],"\n";
+ }
Also see:
=over 4
-=item The djgpp environment for DOS, C<http://www.delorie.com/djgpp/>
+=item *
+
+The djgpp environment for DOS, http://www.delorie.com/djgpp/
+and L<perldos>.
+
+=item *
+
+The EMX environment for DOS, OS/2, etc. emx@iaehv.nl,
+http://www.leo.org/pub/comp/os/os2/leo/gnu/emx+gcc/index.html or
+ftp://hobbes.nmsu.edu/pub/os2/dev/emx. Also L<perlos2>.
+
+=item *
+
+Build instructions for Win32 in L<perlwin32>, or under the Cygnus environment
+in L<perlcygwin>.
+
+=item *
+
+The C<Win32::*> modules in L<Win32>.
+
+=item *
+
+The ActiveState Pages, http://www.activestate.com/
+
+=item *
+
+The Cygwin environment for Win32; F<README.cygwin> (installed
+as L<perlcygwin>), http://www.cygwin.com/
-=item The EMX environment for DOS, OS/2, etc. C<emx@iaehv.nl>,
-C<http://www.leo.org/pub/comp/os/os2/leo/gnu/emx+gcc/index.html> or
-C<ftp://hobbes.nmsu.edu/pub/os2/dev/emx>
+=item *
-=item Build instructions for Win32, L<perlwin32>.
+The U/WIN environment for Win32,
+http://www.research.att.com/sw/tools/uwin/
-=item The ActiveState Pages, C<http://www.activestate.com/>
+=item *
+
+Build instructions for OS/2, L<perlos2>
=back
S<Mac OS X Server> and its Open Source version, Darwin, both run Unix
perl natively (with a few patches). Full support for these
-is slated for perl5.006.
+is slated for perl 5.6.
Also see:
=over 4
-=item The MacPerl Pages, C<http://www.macperl.com/>.
+=item *
+
+The MacPerl Pages, http://www.macperl.com/ .
+
+=item *
-=item The MacPerl mailing lists, C<http://www.macperl.org/>.
+The MacPerl mailing lists, http://www.macperl.org/ .
-=item MacPerl Module Porters, C<http://pudge.net/mmp/>.
+=item *
+
+MacPerl Module Porters, http://pudge.net/mmp/ .
=back
=head2 VMS
-Perl on VMS is discussed in F<vms/perlvms.pod> in the perl distribution.
+Perl on VMS is discussed in L<perlvms> in the perl distribution.
Perl on VMS can accept either VMS- or Unix-style file
specifications as in either of the following:
$ endif
Do take care with C<$ ASSIGN/nolog/user SYS$COMMAND: SYS$INPUT> if your
-perl-in-DCL script expects to do things like C<$read = E<lt>STDINE<gt>;>.
+perl-in-DCL script expects to do things like C<< $read = <STDIN>; >>.
Filenames are in the format "name.extension;version". The maximum
length for filenames is 39 characters, and the maximum length for
non-VMS platforms and can be helpful for conversions to and from RMS
native formats.
-What C<\n> represents depends on the type of file opened. It could
-be C<\015>, C<\012>, C<\015\012>, or nothing. Reading from a file
-translates newlines to C<\012>, unless C<binmode> was executed on that
-handle, just like DOSish perls.
+What C<\n> represents depends on the type of file opened. It usually
+represents C<\012> but it could also be C<\015>, C<\012>, C<\015\012>,
+C<\000>, C<\040>, or nothing depending on the file organiztion and
+record format. The VMS::Stdio module provides access to the
+special fopen() requirements of files with unusual attributes on VMS.
TCP/IP stacks are optional on VMS, so socket routines might not be
implemented. UDP sockets may not be supported.
=over 4
-=item L<perlvms.pod>
+=item *
+
+F<README.vms> (installed as L<README_vms>), L<perlvms>
+
+=item *
-=item vmsperl list, C<majordomo@perl.org>
+vmsperl list, majordomo@perl.org
-Put the words C<subscribe vmsperl> in message body.
+(Put the words C<subscribe vmsperl> in message body.)
-=item vmsperl on the web, C<http://www.sidhe.org/vmsperl/index.html>
+=item *
+
+vmsperl on the web, http://www.sidhe.org/vmsperl/index.html
=back
=head2 VOS
-Perl on VOS is discussed in F<README.vos> in the perl distribution.
-Perl on VOS can accept either VOS- or Unix-style file
-specifications as in either of the following:
+Perl on VOS is discussed in F<README.vos> in the perl distribution
+(installed as L<perlvos>). Perl on VOS can accept either VOS- or
+Unix-style file specifications as in either of the following:
$ perl -ne "print if /perl_setup/i" >system>notices
$ perl -ne "print if /perl_setup/i" /system/notices
names, because the VOS port of Perl interprets it as a pathname
delimiting character, VOS files, directories, or links whose names
contain a slash character cannot be processed. Such files must be
-renamed before they can be processed by Perl.
+renamed before they can be processed by Perl. Note that VOS limits
+file names to 32 or fewer characters.
+
+See F<README.vos> for restrictions that apply when Perl is built
+with the alpha version of VOS POSIX.1 support.
-The following C functions are unimplemented on VOS, and any attempt by
-Perl to use them will result in a fatal error message and an immediate
-exit from Perl: dup, do_aspawn, do_spawn, fork, waitpid. Once these
-functions become available in the VOS POSIX.1 implementation, you can
-either recompile and rebind Perl, or you can download a newer port from
-ftp.stratus.com.
+Perl on VOS is built without any extensions and does not support
+dynamic loading.
The value of C<$^O> on VOS is "VOS". To determine the architecture that
you are running on without resorting to loading all of C<%Config> you
-can examine the content of the C<@INC> array like so:
+can examine the content of the @INC array like so:
- if (grep(/VOS/, @INC)) {
+ if ($^O =~ /VOS/) {
print "I'm on a Stratus box!\n";
} else {
print "I'm not on a Stratus box!\n";
print "This box is a Stratus XA/R!\n";
} elsif (grep(/7100/, @INC)) {
- print "This box is a Stratus HP 7100 or 8000!\n";
+ print "This box is a Stratus HP 7100 or 8xxx!\n";
} elsif (grep(/8000/, @INC)) {
- print "This box is a Stratus HP 8000!\n";
+ print "This box is a Stratus HP 8xxx!\n";
} else {
- print "This box is a Stratus 68K...\n";
+ print "This box is a Stratus 68K!\n";
}
Also see:
=over 4
-=item L<README.vos>
+=item *
+
+F<README.vos>
+
+=item *
-=item VOS mailing list
+The VOS mailing list.
There is no specific mailing list for Perl on VOS. You can post
comments to the comp.sys.stratus newsgroup, or subscribe to the general
Stratus mailing list. Send a letter with "Subscribe Info-Stratus" in
the message body to majordomo@list.stratagy.com.
-=item VOS Perl on the web at C<http://ftp.stratus.com/pub/vos/vos.html>
+=item *
+
+VOS Perl on the web at http://ftp.stratus.com/pub/vos/vos.html
=back
=head2 EBCDIC Platforms
Recent versions of Perl have been ported to platforms such as OS/400 on
-AS/400 minicomputers as well as OS/390 & VM/ESA for IBM Mainframes. Such
-computers use EBCDIC character sets internally (usually Character Code
-Set ID 00819 for OS/400 and IBM-1047 for OS/390 & VM/ESA). On
-the mainframe perl currently works under the "Unix system services
-for OS/390" (formerly known as OpenEdition) and VM/ESA OpenEdition.
+AS/400 minicomputers as well as OS/390, VM/ESA, and BS2000 for S/390
+Mainframes. Such computers use EBCDIC character sets internally (usually
+Character Code Set ID 0037 for OS/400 and either 1047 or POSIX-BC for S/390
+systems). On the mainframe perl currently works under the "Unix system
+services for OS/390" (formerly known as OpenEdition), VM/ESA OpenEdition, or
+the BS200 POSIX-BC system (BS2000 is supported in perl 5.6 and greater).
+See L<perlos390> for details.
As of R2.5 of USS for OS/390 and Version 2.3 of VM/ESA these Unix
sub-systems do not support the C<#!> shebang trick for script invocation.
print "Hello from perl!\n";
+OS/390 will support the C<#!> shebang trick in release 2.8 and beyond.
+Calls to C<system> and backticks can use POSIX shell syntax on all
+S/390 systems.
+
On the AS/400, if PERL5 is in your library list, you may need
to wrap your perl scripts in a CL procedure to invoke them like so:
print "Content-type: text/html\r\n\r\n";
-The value of C<$^O> on OS/390 is "os390".
+The values of C<$^O> on some of these platforms includes:
-The value of C<$^O> on VM/ESA is "vmesa".
+ uname $^O $Config{'archname'}
+ --------------------------------------------
+ OS/390 os390 os390
+ OS400 os400 os400
+ POSIX-BC posix-bc BS2000-posix-bc
+ VM/ESA vmesa vmesa
Some simple tricks for determining if you are running on an EBCDIC
platform could include any of the following (perhaps all):
=over 4
-=item perl-mvs list
+=item *
+
+*
+
+L<perlos390>, F<README.os390>, F<perlbs2000>, F<README.vmesa>,
+L<perlebcdic>.
+
+=item *
The perl-mvs@perl.org list is for discussion of porting issues as well as
general usage issues for all EBCDIC Perls. Send a message body of
"subscribe perl-mvs" to majordomo@perl.org.
-=item AS/400 Perl information at C<http://as400.rochester.ibm.com/>
+=item *
+
+AS/400 Perl information at
+http://as400.rochester.ibm.com/
+as well as on CPAN in the F<ports/> directory.
=back
Writing to a new file C<System:Modules> would be allowed only if
C<System$Path> contains a single item list. The filesystem will also
expand system variables in filenames if enclosed in angle brackets, so
-C<E<lt>System$DirE<gt>.Modules> would look for the file
+C<< <System$Dir>.Modules >> would look for the file
S<C<$ENV{'System$Dir'} . 'Modules'>>. The obvious implication of this is
-that B<fully qualified filenames can start with C<E<lt>E<gt>>> and should
+that B<fully qualified filenames can start with C<< <> >>> and should
be protected when C<open> is used for input.
Because C<.> was in use as a directory separator and filenames could not
passing C<STDIN>, C<STDOUT>, or C<STDERR> to your children.
The desire of users to express filenames of the form
-C<E<lt>Foo$DirE<gt>.Bar> on the command line unquoted causes problems,
+C<< <Foo$Dir>.Bar >> on the command line unquoted causes problems,
too: C<``> command output capture has to perform a guessing game. It
-assumes that a string C<E<lt>[^E<lt>E<gt>]+\$[^E<lt>E<gt>]E<gt>> is a
+assumes that a string C<< <[^<>]+\$[^<>]> >> is a
reference to an environment variable, whereas anything else involving
-C<E<lt>> or C<E<gt>> is redirection, and generally manages to be 99%
+C<< < >> or C<< > >> is redirection, and generally manages to be 99%
right. Of course, the problem remains that scripts cannot rely on any
Unix tools being available, or that any tools found have Unix-like command
line arguments.
Tandem Guardian, I<etc.> (Yes, we know that some of these OSes may
fall under the Unix category, but we are not a standards body.)
+Some approximate operating system names and their C<$^O> values
+in the "OTHER" category include:
+
+ OS $^O $Config{'archname'}
+ ------------------------------------------
+ Amiga DOS amigaos m68k-amigos
+ MPE/iX mpeix PA-RISC1.1
+
See also:
=over 4
-=item Atari, Guido Flohr's page C<http://stud.uni-sb.de/~gufl0000/>
+=item *
-=item HP 300 MPE/iX C<http://www.cccd.edu/~markb/perlix.html>
+Amiga, F<README.amiga> (installed as L<perlamiga>).
-=item Novell Netware
+=item *
+
+Atari, F<README.mint> and Guido Flohr's web page
+http://stud.uni-sb.de/~gufl0000/
+
+=item *
+
+Be OS, F<README.beos>
+
+=item *
+
+HP 300 MPE/iX, F<README.mpeix> and Mark Bixby's web page
+http://www.bixby.org/mark/perlix.html
+
+=item *
A free perl5-based PERL.NLM for Novell Netware is available in
-precompiled binary and source code form from C<http://www.novell.com/>
+precompiled binary and source code form from http://www.novell.com/
as well as from CPAN.
+=item *
+
+Plan 9, F<README.plan9>
+
=back
=head1 FUNCTION IMPLEMENTATIONS
C<-x> (or C<-X>) determine if a file has an executable file type.
(S<RISC OS>)
+=item alarm SECONDS
+
+=item alarm
+
+Not implemented. (Win32)
+
=item binmode FILEHANDLE
Meaningless. (S<Mac OS>, S<RISC OS>)
Implemented via Spawn. (VM/ESA)
+Does not automatically flush output handles on some platforms.
+(SunOS, Solaris, HP-UX)
+
=item fcntl FILEHANDLE,FUNCTION,SCALAR
Not implemented. (Win32, VMS)
=item fork
-Not implemented. (S<Mac OS>, Win32, AmigaOS, S<RISC OS>, VOS, VM/ESA)
+Not implemented. (S<Mac OS>, AmigaOS, S<RISC OS>, VOS, VM/ESA)
+
+Emulated using multiple interpreters. See L<perlfork>. (Win32)
+
+Does not automatically flush output handles on some platforms.
+(SunOS, Solaris, HP-UX)
=item getlogin
=item endpwent
-Not implemented. (S<Mac OS>, Win32, VM/ESA)
+Not implemented. (S<Mac OS>, MPE/iX, VM/ESA, Win32)
=item endgrent
-Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VM/ESA)
+Not implemented. (S<Mac OS>, MPE/iX, S<RISC OS>, VM/ESA, VMS, Win32)
=item endhostent
Globbing built-in, but only C<*> and C<?> metacharacters are supported.
(S<Mac OS>)
-Features depend on external perlglob.exe or perlglob.bat. May be
-overridden with something like File::DosGlob, which is recommended.
-(Win32)
-
-Globbing built-in, but only C<*> and C<?> metacharacters are supported.
-Globbing relies on operating system calls, which may return filenames
-in any order. As most filesystems are case-insensitive, even "sorted"
-filenames will not be in case-sensitive order. (S<RISC OS>)
+This operator is implemented via the File::Glob extension on most
+platforms. See L<File::Glob> for portability information.
=item ioctl FILEHANDLE,FUNCTION,SCALAR
Available only for socket handles. (S<RISC OS>)
-=item kill LIST
+=item kill SIGNAL, LIST
Not implemented, hence not useful for taint checking. (S<Mac OS>,
S<RISC OS>)
-Available only for process handles returned by the C<system(1, ...)>
-method of spawning a process. (Win32)
+C<kill()> doesn't have the semantics of C<raise()>, i.e. it doesn't send
+a signal to the identified process like it does on Unix platforms.
+Instead C<kill($sig, $pid)> terminates the process identified by $pid,
+and makes it exit immediately with exit status $sig. As in Unix, if
+$sig is 0 and the specified process exists, it returns true without
+actually terminating it. (Win32)
=item link OLDFILE,NEWFILE
-Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
+Not implemented. (S<Mac OS>, MPE/iX, VMS, S<RISC OS>)
Link count not updated because hard links are not quite that hard
(They are sort of half-way between hard and soft links). (AmigaOS)
+Hard links are implemented on Win32 (Windows NT and Windows 2000)
+under NTFS only.
+
=item lstat FILEHANDLE
=item lstat EXPR
Not implemented. (VMS, S<RISC OS>)
-Return values may be bogus. (Win32)
+Return values (especially for device and inode) may be bogus. (Win32)
=item msgctl ID,CMD,ARG
open to C<|-> and C<-|> are unsupported. (S<Mac OS>, Win32, S<RISC OS>)
+Opening a process does not automatically flush output handles on some
+platforms. (SunOS, Solaris, HP-UX)
+
=item pipe READHANDLE,WRITEHANDLE
Not implemented. (S<Mac OS>)
Only reliable on sockets. (S<RISC OS>)
+Note that the C<socket FILEHANDLE> form is generally portable.
+
=item semctl ID,SEMNUM,CMD,ARG
=item semget KEY,NSEMS,FLAGS
Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
+=item setgrent
+
+Not implemented. (MPE/iX, Win32)
+
=item setpgrp PID,PGRP
Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
+=item setpwent
+
+Not implemented. (MPE/iX, Win32)
+
=item setsockopt SOCKET,LEVEL,OPTNAME,OPTVAL
Not implemented. (S<Mac OS>, Plan9)
Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
+=item sockatmark SOCKET
+
+A relatively recent addition to socket functions, may not
+be implemented even in UNIX platforms.
+
=item socketpair SOCKET1,SOCKET2,DOMAIN,TYPE,PROTOCOL
Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
=item stat
+Platforms that do not have rdev, blksize, or blocks will return these
+as '', so numeric comparison or manipulation of these fields may cause
+'not numeric' warnings.
+
mtime and atime are the same thing, and ctime is creation time instead of
inode change time. (S<Mac OS>)
mtime, atime and ctime all return the last modification time. Device and
inode are not necessarily reliable. (S<RISC OS>)
+dev, rdev, blksize, and blocks are not available. inode is not
+meaningful and will differ between stat calls on the same file. (os2)
+
=item symlink OLDFILE,NEWFILE
Not implemented. (Win32, VMS, S<RISC OS>)
C<$ENV{PERL5SHELL}>. C<system(1, @args)> spawns an external
process and immediately returns its process designator, without
waiting for it to terminate. Return value may be used subsequently
-in C<wait> or C<waitpid>. (Win32)
+in C<wait> or C<waitpid>. Failure to spawn() a subprocess is indicated
+by setting $? to "255 << 8". C<$?> is set in a way compatible with
+Unix (i.e. the exitstatus of the subprocess is obtained by "$? >> 8",
+as described in the documentation). (Win32)
There is no shell to process metacharacters, and the native standard is
to pass a command line terminated by "\n" "\r" or "\0" to the spawned
-program. Redirection such as C<E<gt> foo> is performed (if at all) by
+program. Redirection such as C<< > foo >> is performed (if at all) by
the run time library of the spawned program. C<system> I<list> will call
the Unix emulation library's C<exec> emulation, which attempts to provide
emulation of the stdin, stdout, stderr in force in the parent, providing
Far from being POSIX compliant. Because there may be no underlying
/bin/sh tries to work around the problem by forking and execing the
first token in its argument string. Handles basic redirection
-("E<lt>" or "E<gt>") on its own behalf. (MiNT)
+("<" or ">") on its own behalf. (MiNT)
+
+Does not automatically flush output handles on some platforms.
+(SunOS, Solaris, HP-UX)
=item times
Only the first entry returned is nonzero. (S<Mac OS>)
-"cumulative" times will be bogus. On anything other than Windows NT,
-"system" time will be bogus, and "user" time is actually the time
-returned by the clock() function in the C runtime library. (Win32)
+"cumulative" times will be bogus. On anything other than Windows NT
+or Windows 2000, "system" time will be bogus, and "user" time is
+actually the time returned by the clock() function in the C runtime
+library. (Win32)
Not useful. (S<RISC OS>)
Not implemented. (S<Mac OS>, VOS)
Can only be applied to process handles returned for processes spawned
-using C<system(1, ...)>. (Win32)
+using C<system(1, ...)> or pseudo processes created with C<fork()>. (Win32)
Not useful. (S<RISC OS>)
=over 4
+=item v1.48, 02 February 2001
+
+Various updates from perl5-porters over the past year, supported
+platforms update from Jarkko Hietaniemi.
+
+=item v1.47, 22 March 2000
+
+Various cleanups from Tom Christiansen, including migration of
+long platform listings from L<perl>.
+
+=item v1.46, 12 February 2000
+
+Updates for VOS and MPE/iX. (Peter Prymmer) Other small changes.
+
+=item v1.45, 20 December 1999
+
+Small changes from 5.005_63 distribution, more changes to EBCDIC info.
+
+=item v1.44, 19 July 1999
+
+A bunch of updates from Peter Prymmer for C<$^O> values,
+endianness, File::Spec, VMS, BS2000, OS/400.
+
=item v1.43, 24 May 1999
Added a lot of cleaning up from Tom Christiansen.
Lots more little changes to formatting and content.
-Added a bunch of <$^O> and related values
+Added a bunch of C<$^O> and related values
for various platforms; fixed mail and web addresses, and added
and changed miscellaneous notes. (Peter Prymmer)
=back
+=head1 Supported Platforms
+
+As of early 2001 (the Perl releases 5.6.1 and 5.7.1), the following
+platforms are able to build Perl from the standard source code
+distribution available at http://www.perl.com/CPAN/src/index.html
+
+ AIX
+ AmigaOS
+ Darwin (Rhapsody)
+ DG/UX
+ DOS DJGPP 1)
+ DYNIX/ptx
+ EPOC
+ FreeBSD
+ HP-UX
+ IRIX
+ Linux
+ MachTen
+ MacOS Classic 2)
+ NonStop-UX
+ ReliantUNIX (SINIX)
+ OpenBSD
+ OpenVMS (VMS)
+ OS/2
+ OS X
+ QNX
+ Solaris
+ Tru64 UNIX (DEC OSF/1, Digital UNIX)
+ UNICOS
+ UNICOS/mk
+ VOS
+ Win32/NT/2K 3)
+
+ 1) in DOS mode either the DOS or OS/2 ports can be used
+ 2) Mac OS Classic (pre-X) is almost 5.6.1-ready; building from
+ the source does work with 5.6.1, but additional MacOS specific
+ source code is needed for a complete build. Contact the mailing
+ list macperl-porters@macperl.org for more information.
+ 3) compilers: Borland, Cygwin, Mingw32 EGCS/GCC, VC++
+
+The following platforms worked for the previous releases (5.6.0 and 5.7.0),
+but we did not manage to test these in time for the 5.7.1 release.
+There is a very good chance that these will work fine with the 5.7.1.
+
+ DomainOS
+ Hurd
+ LynxOS
+ MinGW
+ MPE/iX
+ NetBSD
+ PowerMAX
+ SCO SV
+ SunOS
+ SVR4
+ Unixware
+ Windows 3.1
+ Windows 95
+ Windows 98
+ Windows Me
+
+The following platform worked for the 5.005_03 major release but not
+for 5.6.0. Standardization on UTF-8 as the internal string
+representation in 5.6.0 and 5.6.1 introduced incompatibilities in this
+EBCDIC platform. While Perl 5.7.1 will build on this platform some
+regression tests may fail and the C<use utf8;> pragma typically
+introduces text handling errors.
+
+ OS/390 1)
+
+ 1) previously known as MVS, about to become z/OS.
+
+Strongly related to the OS/390 platform by also being EBCDIC-based
+mainframe platforms are the following platforms:
+
+ POSIX-BC (BS2000)
+ VM/ESA
+
+These are also expected to work, albeit with no UTF-8 support, under 5.6.1
+for the same reasons as OS/390. Contact the mailing list perl-mvs@perl.org
+for more details.
+
+The following platforms have been known to build Perl from source in
+the past (5.005_03 and earlier), but we haven't been able to verify
+their status for the current release, either because the
+hardware/software platforms are rare or because we don't have an
+active champion on these platforms--or both. They used to work,
+though, so go ahead and try compiling them, and let perlbug@perl.org
+of any trouble.
+
+ 3b1
+ A/UX
+ BeOS
+ BSD/OS
+ ConvexOS
+ CX/UX
+ DC/OSx
+ DDE SMES
+ DOS EMX
+ Dynix
+ EP/IX
+ ESIX
+ FPS
+ GENIX
+ Greenhills
+ ISC
+ MachTen 68k
+ MiNT
+ MPC
+ NEWS-OS
+ NextSTEP
+ OpenSTEP
+ Opus
+ Plan 9
+ PowerUX
+ RISC/os
+ SCO ODT/OSR
+ Stellar
+ SVR2
+ TI1500
+ TitanOS
+ Ultrix
+ Unisys Dynix
+ Unixware
+ UTS
+
+Support for the following platform is planned for a future Perl release:
+
+ Netware
+
+The following platforms have their own source code distributions and
+binaries available via http://www.perl.com/CPAN/ports/index.html:
+
+ Perl release
+
+ Netware 5.003_07
+ OS/400 5.005_02
+ Tandem Guardian 5.004
+
+The following platforms have only binaries available via
+http://www.perl.com/CPAN/ports/index.html :
+
+ Perl release
+
+ Acorn RISCOS 5.005_02
+ AOS 5.002
+ LynxOS 5.004_02
+
+Although we do suggest that you always build your own Perl from
+the source code, both for maximal configurability and for security,
+in case you are in a hurry you can check
+http://www.perl.com/CPAN/ports/index.html for binary distributions.
+
+=head1 SEE ALSO
+
+L<perlaix>, L<perlamiga>, L<perlcygwin>, L<perldos>, L<perlepoc>,
+L<perlebcdic>, L<perlhpux>, L<perlos2>, L<perlos390>, L<perlbs2000>,
+L<perlwin32>, L<perlvms>, L<perlvos>, and L<Win32>.
+
=head1 AUTHORS / CONTRIBUTORS
-Abigail E<lt>abigail@fnx.comE<gt>,
-Charles Bailey E<lt>bailey@newman.upenn.eduE<gt>,
-Graham Barr E<lt>gbarr@pobox.comE<gt>,
-Tom Christiansen E<lt>tchrist@perl.comE<gt>,
-Nicholas Clark E<lt>Nicholas.Clark@liverpool.ac.ukE<gt>,
-Andy Dougherty E<lt>doughera@lafcol.lafayette.eduE<gt>,
-Dominic Dunlop E<lt>domo@vo.luE<gt>,
-Neale Ferguson E<lt>neale@mailbox.tabnsw.com.auE<gt>
-Paul Green E<lt>Paul_Green@stratus.comE<gt>,
-M.J.T. Guy E<lt>mjtg@cus.cam.ac.ukE<gt>,
-Jarkko Hietaniemi E<lt>jhi@iki.fi<gt>,
-Luther Huffman E<lt>lutherh@stratcom.comE<gt>,
-Nick Ing-Simmons E<lt>nick@ni-s.u-net.comE<gt>,
-Andreas J. KE<ouml>nig E<lt>koenig@kulturbox.deE<gt>,
-Markus Laker E<lt>mlaker@contax.co.ukE<gt>,
-Andrew M. Langmead E<lt>aml@world.std.comE<gt>,
-Larry Moore E<lt>ljmoore@freespace.netE<gt>,
-Paul Moore E<lt>Paul.Moore@uk.origin-it.comE<gt>,
-Chris Nandor E<lt>pudge@pobox.comE<gt>,
-Matthias Neeracher E<lt>neeri@iis.ee.ethz.chE<gt>,
-Gary Ng E<lt>71564.1743@CompuServe.COME<gt>,
-Tom Phoenix E<lt>rootbeer@teleport.comE<gt>,
-Peter Prymmer E<lt>pvhp@forte.comE<gt>,
-Hugo van der Sanden E<lt>hv@crypt0.demon.co.ukE<gt>,
-Gurusamy Sarathy E<lt>gsar@umich.eduE<gt>,
-Paul J. Schinder E<lt>schinder@pobox.comE<gt>,
-Michael G Schwern E<lt>schwern@pobox.comE<gt>,
-Dan Sugalski E<lt>sugalskd@ous.eduE<gt>,
-Nathan Torkington E<lt>gnat@frii.comE<gt>.
+Abigail <abigail@foad.org>,
+Charles Bailey <bailey@newman.upenn.edu>,
+Graham Barr <gbarr@pobox.com>,
+Tom Christiansen <tchrist@perl.com>,
+Nicholas Clark <nick@ccl4.org>,
+Thomas Dorner <Thomas.Dorner@start.de>,
+Andy Dougherty <doughera@lafayette.edu>,
+Dominic Dunlop <domo@computer.org>,
+Neale Ferguson <neale@vma.tabnsw.com.au>,
+David J. Fiander <davidf@mks.com>,
+Paul Green <Paul_Green@stratus.com>,
+M.J.T. Guy <mjtg@cam.ac.uk>,
+Jarkko Hietaniemi <jhi@iki.fi>,
+Luther Huffman <lutherh@stratcom.com>,
+Nick Ing-Simmons <nick@ing-simmons.net>,
+Andreas J. KE<ouml>nig <a.koenig@mind.de>,
+Markus Laker <mlaker@contax.co.uk>,
+Andrew M. Langmead <aml@world.std.com>,
+Larry Moore <ljmoore@freespace.net>,
+Paul Moore <Paul.Moore@uk.origin-it.com>,
+Chris Nandor <pudge@pobox.com>,
+Matthias Neeracher <neeri@iis.ee.ethz.ch>,
+Gary Ng <71564.1743@CompuServe.COM>,
+Tom Phoenix <rootbeer@teleport.com>,
+AndrE<eacute> Pirard <A.Pirard@ulg.ac.be>,
+Peter Prymmer <pvhp@forte.com>,
+Hugo van der Sanden <hv@crypt0.demon.co.uk>,
+Gurusamy Sarathy <gsar@activestate.com>,
+Paul J. Schinder <schinder@pobox.com>,
+Michael G Schwern <schwern@pobox.com>,
+Dan Sugalski <dan@sidhe.org>,
+Nathan Torkington <gnat@frii.com>.
This document is maintained by Chris Nandor
-E<lt>pudge@pobox.comE<gt>.
+<pudge@pobox.com>.
=head1 VERSION
-Version 1.43, last modified 24 May 1999
+Version 1.48, last modified 24 April 2001