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
Conflicting storage orders make utter mess out of the numbers. If a
little-endian host (Intel, VAX) 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.
+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:
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
Don't open the same file more than once at a time for writing, as some
operating systems put mandatory locks on such files.
+Don't assume that write/modify permission on a directory gives the
+right to add or delete files/directories in that directory. That is
+filesystem specific: in some filesystems you need write/modify
+permission also (or even just) in the file/directory itself. In some
+filesystems (AFS, DFS) the permission to add/delete directory entries
+is a completely separate permission.
+
+Don't assume that a single C<unlink> completely gets rid of the file:
+some filesystems (most notably the ones in VMS) have versioned
+filesystems, and unlink() removes only the most recent one (it doesn't
+remove all the versions because by default the native tools on those
+platforms remove just the most recent version, too). The portable
+idiom to remove all the versions of a file is
+
+ 1 while unlink "file";
+
+This will terminate if the file is undeleteable for some reason
+(protected, not there, and so on).
+
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 or C<%SIG> for anything.
The Unix System V IPC (C<msg*(), sem*(), shm*()>) is not available
even on all Unix platforms.
+Do not use either the bare result of C<pack("N", 10, 20, 30, 40)>
+or bare v-strings (such as C<v10.20.30.40>) or to represent
+IPv4 addresses: both forms just pack the four bytes into network order.
+That this would be equal to the C language C<in_addr> struct (which is
+what the socket code internally uses) is not guaranteed. To be
+portable use the routines of the Socket extension, such as
+C<inet_aton()>, C<inet_ntoa()>, and C<sockaddr_in()>.
+
The rule of thumb for portable code is: Do it all in portable Perl, or
use a module (that may internally implement it with platform-specific
code, but expose a common interface).
Linux linux ppc-linux
HP-UX hpux PA-RISC1.1
IRIX irix irix
- Mac OS X rhapsody rhapsody
+ Mac OS X darwin darwin
MachTen PPC machten powerpc-machten
NeXT 3 next next-fat
NeXT 4 next OPENSTEP-Mach
The C<$^O> variable and the C<$Config{archname}> values for various
DOSish perls are as follows:
- OS $^O $Config{'archname'}
- --------------------------------------------
- MS-DOS dos
- PC-DOS dos
- OS/2 os2
- Windows 95 MSWin32 MSWin32-x86
- Windows 98 MSWin32 MSWin32-x86
- Windows NT MSWin32 MSWin32-x86
- Windows NT MSWin32 MSWin32-ALPHA
- Windows NT MSWin32 MSWin32-ppc
- Cygwin cygwin
+ OS $^O $Config{archname} ID Version
+ --------------------------------------------------------
+ MS-DOS dos ?
+ PC-DOS dos ?
+ OS/2 os2 ?
+ Windows 3.1 ? ? 0 3 01
+ Windows 95 MSWin32 MSWin32-x86 1 4 00
+ Windows 98 MSWin32 MSWin32-x86 1 4 10
+ Windows ME MSWin32 MSWin32-x86 1 ?
+ Windows NT MSWin32 MSWin32-x86 2 4 xx
+ Windows NT MSWin32 MSWin32-ALPHA 2 4 xx
+ Windows NT MSWin32 MSWin32-ppc 2 4 xx
+ Windows 2000 MSWin32 MSWin32-x86 2 5 xx
+ Windows XP MSWin32 MSWin32-x86 2 ?
+ Windows CE MSWin32 ? 3
+ Cygwin cygwin ?
+
+The various MSWin32 Perl's can distinguish the OS they are running on
+via the value of the fifth element of the list returned from
+Win32::GetOSVersion(). For example:
+
+ if ($^O eq 'MSWin32') {
+ my @os_version_info = Win32::GetOSVersion();
+ print +('3.1','95','NT')[$os_version_info[4]],"\n";
+ }
Also see:
=item *
The Cygwin environment for Win32; F<README.cygwin> (installed
-as L<perlcygwin>), http://sourceware.cygnus.com/cygwin/
+as L<perlcygwin>), http://www.cygwin.com/
=item *
The U/WIN environment for Win32,
-<http://www.research.att.com/sw/tools/uwin/
+http://www.research.att.com/sw/tools/uwin/
-=item Build instructions for OS/2, L<perlos2>
+=item *
+Build instructions for OS/2, L<perlos2>
=back
$is_ppc = $MacPerl::Architecture eq 'MacPPC';
$is_68k = $MacPerl::Architecture eq 'Mac68K';
-S<Mac OS X> and S<Mac OS X Server>, based on NeXT's OpenStep OS, will
-(in theory) be able to run MacPerl natively, under the "Classic"
-environment. The new "Cocoa" environment (formerly called the "Yellow Box")
-may run a slightly modified version of MacPerl, using the Carbon interfaces.
-
-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 perl 5.6.
+S<Mac OS X>, based on NeXT's OpenStep OS, runs MacPerl natively, under the
+"Classic" environment. There is no "Carbon" version of MacPerl to run
+under the primary Mac OS X environment. S<Mac OS X> and its Open Source
+version, Darwin, both run Unix perl natively.
Also see:
=item *
-The MacPerl Pages, http://www.macperl.com/ .
+MacPerl Development, http://dev.macperl.org/ .
=item *
-The MacPerl mailing lists, http://www.macperl.org/ .
+The MacPerl Pages, http://www.macperl.com/ .
=item *
-MacPerl Module Porters, http://pudge.net/mmp/ .
+The MacPerl mailing lists, http://lists.perl.org/ .
=back
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. The VMS::Stdio module
-provides access to the special fopen() requirements of files with unusual
-attributes on VMS.
+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.
=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
renamed before they can be processed by Perl. Note that VOS limits
file names to 32 or fewer characters.
-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.
+See F<README.vos> for restrictions that apply when Perl is built
+with the alpha version of VOS POSIX.1 support.
+
+Perl on VOS is built without any extensions and does not support
+dynamic loading.
The value of C<$^O> on VOS is "VOS". To determine the architecture that
you are running on without resorting to loading all of C<%Config> you
*
-L<perlos390>, F<README.os390>, F<README.posix-bc>, F<README.vmesa>
+L<perlos390>, F<README.os390>, F<perlbs2000>, F<README.vmesa>,
+L<perlebcdic>.
=item *
=item *
AS/400 Perl information at
-ttp://as400.rochester.ibm.com/
+http://as400.rochester.ibm.com/
as well as on CPAN in the F<ports/> directory.
=back
=item *
HP 300 MPE/iX, F<README.mpeix> and Mark Bixby's web page
-http://www.cccd.edu/~markb/perlix.html
+http://www.bixby.org/mark/perlix.html
=item *
precompiled binary and source code form from http://www.novell.com/
as well as from CPAN.
-=item
+=item *
Plan 9, F<README.plan9>
Not implemented. (Plan9, Win32)
+=item exit EXPR
+
+=item exit
+
+Emulates UNIX exit() (which considers C<exit 1> to indicate an error) by
+mapping the C<1> to SS$_ABORT (C<44>). This behavior may be overridden
+with the pragma C<use vmsish 'exit'>. As with the CRTL's exit()
+function, C<exit 0> is also mapped to an exit status of SS$_NORMAL
+(C<1>); this mapping cannot be overridden. Any other argument to exit()
+is used directly as Perl's exit status. (VMS)
+
=item getsockopt SOCKET,LEVEL,OPTNAME
-Not implemented. (S<Mac OS>, Plan9)
+Not implemented. (Plan9)
=item glob EXPR
=item glob
-Globbing built-in, but only C<*> and C<?> metacharacters are supported.
-(S<Mac OS>)
-
This operator is implemented via the File::Glob extension on most
platforms. See L<File::Glob> for portability information.
=item kill SIGNAL, LIST
-Not implemented, hence not useful for taint checking. (S<Mac OS>,
-S<RISC OS>)
+C<kill(0, LIST)> is implemented for the sake of taint checking;
+use with other signals is unimplemented. (S<Mac OS>)
+
+Not implemented, hence not useful for taint checking. (S<RISC OS>)
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.
=item pipe READHANDLE,WRITEHANDLE
-Not implemented. (S<Mac OS>)
-
Very limited functionality. (MiNT)
=item readlink EXPR
=item setsockopt SOCKET,LEVEL,OPTNAME,OPTVAL
-Not implemented. (S<Mac OS>, Plan9)
+Not implemented. (Plan9)
=item shmctl ID,CMD,ARG
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)
+Not implemented. (Win32, VMS, S<RISC OS>, VOS, VM/ESA)
=item stat FILEHANDLE
dev, rdev, blksize, and blocks are not available. inode is not
meaningful and will differ between stat calls on the same file. (os2)
+some versions of cygwin when doing a stat("foo") and if not finding it
+may then attempt to stat("foo.exe") (Cygwin)
+
=item symlink OLDFILE,NEWFILE
Not implemented. (Win32, VMS, S<RISC OS>)
Does not automatically flush output handles on some platforms.
(SunOS, Solaris, HP-UX)
+The return value is POSIX-like (shifted up by 8 bits), which only allows
+room for a made-up value derived from the severity bits of the native
+32-bit condition code (unless overridden by C<use vmsish 'status'>).
+For more details see L<perlvms/$?>. (VMS)
+
=item times
Only the first entry returned is nonzero. (S<Mac OS>)
=item truncate EXPR,LENGTH
-Not implemented. (VMS)
+Not implemented. (Older versions of VMS)
Truncation to zero-length only. (VOS)
If a FILEHANDLE is supplied, it must be writable and opened in append
-mode (i.e., use C<open(FH, '>>filename')>
+mode (i.e., use C<<< open(FH, '>>filename') >>>
or C<sysopen(FH,...,O_APPEND|O_RDWR)>. If a filename is supplied, it
should not be held open elsewhere. (Win32)
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
=head1 Supported Platforms
-As of early March 2000 (the Perl release 5.6.0), the following
+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 (Mac OS X)
+ DG/UX
DOS DJGPP 1)
+ DYNIX/ptx
EPOC
FreeBSD
HP-UX
IRIX
Linux
- LynxOS
MachTen
- MPE/iX
- NetBSD
+ MacOS Classic 2)
+ NonStop-UX
+ ReliantUNIX (SINIX)
OpenBSD
+ OpenVMS (VMS)
OS/2
+ OS X
QNX
- Rhapsody/Darwin 2)
- SCO SV
- SINIX
Solaris
- SVR4
- Tru64 UNIX 3)
+ Tru64 UNIX (DEC OSF/1, Digital UNIX)
UNICOS
UNICOS/mk
- Unixware
- VMS
VOS
- Windows 3.1 1)
- Windows 95 1) 4)
- Windows 98 1) 4)
- Windows NT 1) 4)
+ Win32/NT/2K 3)
1) in DOS mode either the DOS or OS/2 ports can be used
- 2) new in 5.6.0: the BSD/NeXT-based UNIX of Mac OS X
- 3) formerly known as Digital UNIX and before that DEC OSF/1
- 4) compilers: Borland, Cygwin, Mingw32 EGCS/GCC, VC++
+ 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. See the web
+ site http://dev.macperl.org/ for more information.
+ 3) compilers: Borland, Cygwin, Mingw32 EGCS/GCC, VC++
-The following platforms worked for the previous major release
-(5.005_03 being the latest maintenance release of that, as of early
-March 2000), but be did not manage to test these in time for the 5.6.0
-release of Perl. There is a very good chance that these will work
-just fine with 5.6.0.
+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.
- A/UX
- BeOS
- BSD/OS
- DG/UX
- DYNIX/ptx
DomainOS
Hurd
- NextSTEP
- OpenSTEP
+ LynxOS
+ MinGW
+ MPE/iX
+ NetBSD
PowerMAX
- SCO ODT/OSR
+ SCO SV
SunOS
- Ultrix
+ SVR4
+ Unixware
+ Windows 3.1
+ Windows 95
+ Windows 98
+ Windows Me
-The following platform worked for the previous major release (5.005_03
-being the latest maintenance release of that, as of early March 2000).
-However, standardization on UTF-8 as the internal string representation
-in 5.6.0 has introduced incompatibilities in this EBCDIC platform.
-Support for this platform may be enabled in a future release:
+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.
- OS390 1)
+ OS/390 1)
- 1) Previously known as MVS, or OpenEdition MVS.
+ 1) previously known as MVS, about to become z/OS.
-Strongly related to the OS390 platform by also being EBCDIC-based
+Strongly related to the OS/390 platform by also being EBCDIC-based
mainframe platforms are the following platforms:
- BS2000
+ POSIX-BC (BS2000)
VM/ESA
-These are also not expected to work under 5.6.0 for the same reasons
-as OS390. Contact the mailing list perl-mvs@perl.org for more details.
-
-MacOS (Classic, pre-X) is almost 5.6.0-ready; building from the source
-does work with 5.6.0, but additional MacOS specific source code is needed
-for a complete port. Contact the mailing list macperl-porters@macperl.org
-for more information.
+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, 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:
+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
- AmigaOS
+ A/UX
+ BeOS
+ BSD/OS
ConvexOS
CX/UX
DC/OSx
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:
Perl release
- AS/400 5.003
Netware 5.003_07
+ OS/400 5.005_02
Tandem Guardian 5.004
The following platforms have only binaries available via
=head1 SEE ALSO
-L<perlamiga>, L<perlcygwin>, L<perldos>, L<perlhpux>, L<perlos2>,
-L<perlos390>, L<perlwin32>, L<perlvms>, and L<Win32>.
+L<perlaix>, L<perlapollo>, L<perlamiga>, L<perlbeos>, L<perlbs200>,
+L<perlce>, L<perlcygwin>, L<perldgux>, L<perldos>, L<perlepoc>, L<perlebcdic>,
+L<perlhurd>, L<perlhpux>, L<perlmachten>, L<perlmacos>, L<perlmint>,
+L<perlmpeix>, L<perlnetware>, L<perlos2>, L<perlos390>, L<perlplan9>,
+L<perlqnx>, L<perlsolaris>, L<perltru64>, L<perlunicode>,
+L<perlvmesa>, L<perlvms>, L<perlvos>, L<perlwin32>, and L<Win32>.
=head1 AUTHORS / CONTRIBUTORS
-Abigail <abigail@fnx.com>,
+Abigail <abigail@foad.org>,
Charles Bailey <bailey@newman.upenn.edu>,
Graham Barr <gbarr@pobox.com>,
Tom Christiansen <tchrist@perl.com>,
-Nicholas Clark <Nicholas.Clark@liverpool.ac.uk>,
+Nicholas Clark <nick@ccl4.org>,
Thomas Dorner <Thomas.Dorner@start.de>,
-Andy Dougherty <doughera@lafcol.lafayette.edu>,
-Dominic Dunlop <domo@vo.lu>,
-Neale Ferguson <neale@mailbox.tabnsw.com.au>,
+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@cus.cam.ac.uk>,
-Jarkko Hietaniemi <jhi@iki.fi<gt>,
+M.J.T. Guy <mjtg@cam.ac.uk>,
+Jarkko Hietaniemi <jhi@iki.fi>,
Luther Huffman <lutherh@stratcom.com>,
-Nick Ing-Simmons <nick@ni-s.u-net.com>,
-Andreas J. KE<ouml>nig <koenig@kulturbox.de>,
+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>,
+Philip Newton <pne@cpan.org>,
Gary Ng <71564.1743@CompuServe.COM>,
Tom Phoenix <rootbeer@teleport.com>,
AndrE<eacute> Pirard <A.Pirard@ulg.ac.be>,
Gurusamy Sarathy <gsar@activestate.com>,
Paul J. Schinder <schinder@pobox.com>,
Michael G Schwern <schwern@pobox.com>,
-Dan Sugalski <sugalskd@ous.edu>,
+Dan Sugalski <dan@sidhe.org>,
Nathan Torkington <gnat@frii.com>.
-This document is maintained by Chris Nandor
-<pudge@pobox.com>.
-
=head1 VERSION
-Version 1.47, last modified 22 March 2000
+Version 1.50, last modified 10 Jul 2001
https://perl5.git.perl.org / perl5.git / blobdiff