"\n", and "\n" on output becomes CRLF.
These are just the most common definitions of C<\n> and C<\r> in Perl.
-There may well be others. For example, on an EBCDIC implementation such
-as z/OS or OS/400 the above material is similar to "Unix" but the code
-numbers change:
+There may well be others. For example, on an EBCDIC implementation
+such as z/OS (OS/390) or OS/400 (using the ILE, the PASE is ASCII-based)
+the above material is similar to "Unix" but the code numbers change:
- LF eq \025 eq \x15 eq chr(21) eq CP-1047 21
- LF eq \045 eq \x25 eq \cU eq chr(37) eq CP-0037 37
+ LF eq \025 eq \x15 eq \cU eq chr(21) eq CP-1047 21
+ LF eq \045 eq \x25 eq chr(37) eq CP-0037 37
CR eq \015 eq \x0D eq \cM eq chr(13) eq CP-1047 13
CR eq \015 eq \x0D eq \cM eq chr(13) eq CP-0037 13
not work everywhere. This is probably for the user of the program
to deal with, so don't stay up late worrying about it.
-Some platforms can't delete or rename files held open by the system.
-Remember to C<close> files when you are done with them. Don't
-C<unlink> or C<rename> an open file. Don't C<tie> or C<open> a
-file already tied or opened; C<untie> or C<close> it first.
+Some platforms can't delete or rename files held open by the system,
+this limitation may also apply to changing filesystem metainformation
+like file permissions or owners. Remember to C<close> files when you
+are done with them. Don't C<unlink> or C<rename> an open file. Don't
+C<tie> or C<open> a file already tied or opened; C<untie> or C<close>
+it first.
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 count on per-program environment variables, or per-program current
directories.
-Don't count on specific values of C<$!>.
+Don't count on specific values of C<$!>, neither numeric nor
+especially the strings values-- users may switch their locales causing
+error messages to be translated into their languages. If you can
+trust a POSIXish environment, you can portably use the symbols defined
+by the Errno module, like ENOENT. And don't trust on the values of C<$!>
+at all except immediately after a failed system call.
=head2 Command names versus file pathnames
if ($^O ne 'VMS')
{$thisperl .= $Config{_exe} unless $thisperl =~ m/$Config{_exe}$/i;}
+=head2 Networking
+
+Don't assume that you can reach the public Internet.
+
+Don't assume that there is only one way to get through firewalls
+to the public Internet.
+
+Don't assume that you can reach outside world through any other port
+than 80, or some web proxy. ftp is blocked by many firewalls.
+
+Don't assume that you can send email by connecting to the local SMTP port.
+
+Don't assume that you can reach yourself or any node by the name
+'localhost'. The same goes for '127.0.0.1'. You will have to try both.
+
+Don't assume that the host has only one network card, or that it
+can't bind to many virtual IP addresses.
+
+Don't assume a particular network device name.
+
+Don't assume a particular set of ioctl()s will work.
+
+Don't assume that you can ping hosts and get replies.
+
+Don't assume that any particular port (service) will respond.
+
+Don't assume that Sys::Hostname() (or any other API or command)
+returns either a fully qualified hostname or a non-qualified hostname:
+it all depends on how the system had been configured. Also remember
+things like DHCP and NAT-- the hostname you get back might not be very
+useful.
+
+All the above "don't":s may look daunting, and they are -- but the key
+is to degrade gracefully if one cannot reach the particular network
+service one wants. Croaking or hanging do not look very professional.
+
=head2 Interprocess Communication (IPC)
In general, don't directly access the system in code meant to be
The system's notion of time of day and calendar date is controlled in
widely different ways. Don't assume the timezone is stored in C<$ENV{TZ}>,
and even if it is, don't assume that you can control the timezone through
-that variable.
+that variable. Don't assume anything about the three-letter timezone
+abbreviations (for example that MST would be the Mountain Standard Time,
+it's been known to stand for Moscow Standard Time). If you need to
+use timezones, express them in some unambiguous format like the
+exact number of minutes offset from UTC, or the POSIX timezone
+format.
Don't assume that the epoch starts at 00:00:00, January 1, 1970,
-because that is OS- and implementation-specific. It is better to store a date
-in an unambiguous representation. The ISO-8601 standard defines
-"YYYY-MM-DD" as the date format. A text representation (like "1987-12-18")
-can be easily converted into an OS-specific value using a module like
-Date::Parse. An array of values, such as those returned by
-C<localtime>, can be converted to an OS-specific representation using
-Time::Local.
+because that is OS- and implementation-specific. It is better to
+store a date in an unambiguous representation. The ISO 8601 standard
+defines YYYY-MM-DD as the date format, or YYYY-MM-DDTHH-MM-SS
+(that's a literal "T" separating the date from the time).
+Please do use the ISO 8601 instead of making us to guess what
+date 02/03/04 might be. ISO 8601 even sorts nicely as-is.
+A text representation (like "1987-12-18") can be easily converted
+into an OS-specific value using a module like Date::Parse.
+An array of values, such as those returned by C<localtime>, can be
+converted to an OS-specific representation using Time::Local.
When calculating specific times, such as for tests in time or date modules,
it may be appropriate to calculate an offset for the epoch.
some large number. C<$offset> can then be added to a Unix time value
to get what should be the proper value on any system.
+On Windows (at least), you shouldn't pass a negative value to C<gmtime> or
+C<localtime>.
+
=head2 Character sets and character encoding
Assume very little about character sets.
users. The system affects character sets and encoding, and date
and time formatting--amongst other things.
+If you really want to be international, you should consider Unicode.
+See L<perluniintro> and L<perlunicode> for more information.
+
+If you want to use non-ASCII bytes (outside the bytes 0x00..0x7f) in
+the "source code" of your code, to be portable you have to be explicit
+about what bytes they are. Someone might for example be using your
+code under a UTF-8 locale, in which case random native bytes might be
+illegal ("Malformed UTF-8 ...") This means that for example embedding
+ISO 8859-1 bytes beyond 0x7f into your strings might cause trouble
+later. If the bytes are native 8-bit bytes, you can use the C<bytes>
+pragma. If the bytes are in a string (regular expression being a
+curious string), you can often also use the C<\xHH> notation instead
+of embedding the bytes as-is. If they are in some particular legacy
+encoding (ether single-byte or something more complicated), you can
+use the C<encoding> pragma. (If you want to write your code in UTF-8,
+you can use either the C<utf8> pragma, or the C<encoding> pragma.)
+The C<bytes> and C<utf8> pragmata are available since Perl 5.6.0, and
+the C<encoding> pragma since Perl 5.8.0.
+
=head2 System Resources
If your code is destined for systems with severely constrained (or
Module code may be fully portable, but its tests might not be. This
often happens when tests spawn off other processes or call external
programs to aid in the testing, or when (as noted above) the tests
-assume certain things about the filesystem and paths. Be careful
-not to depend on a specific output style for errors, such as when
-checking C<$!> after a system call. Some platforms expect a certain
-output format, and perl on those platforms may have been adjusted
-accordingly. Most specifically, don't anchor a regex when testing
-an error value.
+assume certain things about the filesystem and paths. Be careful not
+to depend on a specific output style for errors, such as when checking
+C<$!> after a failed system call. Using C<$!> for anything else than
+displaying it as output is doubtful (though see the Errno module for
+testing reasonably portably for error value). Some platforms expect
+a certain output format, and Perl on those platforms may have been
+adjusted accordingly. Most specifically, don't anchor a regex when
+testing an error value.
=head1 CPAN Testers
print +('3.1','95','NT')[$os_version_info[4]],"\n";
}
-There are also Win32::IsWinNT()and Win32::IsWin95().,
-try C<perldoc Win32>.
+There are also Win32::IsWinNT() and Win32::IsWin95(), try C<perldoc Win32>,
+and as of libwin32 0.19 (not part of the core Perl distribution)
+Win32::GetOSName(). The very portable POSIX::uname() will work too:
+
+ c:\> perl -MPOSIX -we "print join '|', uname"
+ Windows NT|moonru|5.0|Build 2195 (Service Pack 2)|x86
Also see:
renamed before they can be processed by Perl. Note that VOS limits
file names to 32 or fewer characters.
-Perl on VOS can be built using two different compilers and two different
-versions of the POSIX runtime. The recommended method for building full
-Perl is with the GNU C compiler and the generally-available version of
-VOS POSIX support. See F<README.vos> (installed as L<perlvos>) for
-restrictions that apply when Perl is built using the VOS Standard C
-compiler or the alpha version of VOS POSIX support.
-
The value of C<$^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 @INC array like so:
die;
}
- if (grep(/860/, @INC)) {
- print "This box is a Stratus XA/R!\n";
-
- } elsif (grep(/7100/, @INC)) {
- print "This box is a Stratus HP 7100 or 8xxx!\n";
-
- } elsif (grep(/8000/, @INC)) {
- print "This box is a Stratus HP 8xxx!\n";
-
- } else {
- print "This box is a Stratus 68K!\n";
- }
-
Also see:
=over 4
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.
+See L<perlos390> for details. Note that for OS/400 there is also a port of
+Perl 5.8.1/5.9.0 or later to the PASE which is ASCII-based (as opposed to
+ILE which is EBCDIC-based), see L<perlos400>.
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.
=item *
-Plan 9, F<README.plan9>
+S<Plan 9>, F<README.plan9>
=back
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>)
=item chown LIST
-Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>, VOS)
+Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
Does nothing, but won't fail. (Win32)
+A little funky, because VOS's notion of ownership is a little funky (VOS).
+
=item chroot FILENAME
=item chroot
-Not implemented. (S<Mac OS>, Win32, VMS, Plan9, S<RISC OS>, VOS, VM/ESA)
+Not implemented. (S<Mac OS>, Win32, VMS, S<Plan 9>, S<RISC OS>, VOS, VM/ESA)
=item crypt PLAINTEXT,SALT
May not be available if library or source was not provided when building
perl. (Win32)
-Not implemented. (VOS)
-
=item dbmclose HASH
-Not implemented. (VMS, Plan9, VOS)
+Not implemented. (VMS, S<Plan 9>, VOS)
=item dbmopen HASH,DBNAME,MODE
-Not implemented. (VMS, Plan9, VOS)
+Not implemented. (VMS, S<Plan 9>, VOS)
=item dump LABEL
=item fork
-Not implemented. (S<Mac OS>, AmigaOS, S<RISC OS>, VOS, VM/ESA)
+Not implemented. (S<Mac OS>, AmigaOS, S<RISC OS>, VM/ESA, VMS)
Emulated using multiple interpreters. See L<perlfork>. (Win32)
=item getpgrp PID
-Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
+Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
=item getppid
-Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
+Not implemented. (S<Mac OS>, Win32, S<RISC OS>)
=item getpriority WHICH,WHO
=item getnetbyname NAME
-Not implemented. (S<Mac OS>, Win32, Plan9)
+Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
=item getpwuid UID
=item getnetbyaddr ADDR,ADDRTYPE
-Not implemented. (S<Mac OS>, Win32, Plan9)
+Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
=item getprotobynumber NUMBER
Not implemented. (S<Mac OS>, Win32, VMS, VM/ESA)
+=item gethostbyname
+
+C<gethostbyname('localhost')> does not work everywhere: you may have
+to use C<gethostbyname('127.0.0.1')>. (S<Mac OS>, S<Irix 5>)
+
=item gethostent
Not implemented. (S<Mac OS>, Win32)
=item getnetent
-Not implemented. (S<Mac OS>, Win32, Plan9)
+Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
=item getprotoent
-Not implemented. (S<Mac OS>, Win32, Plan9)
+Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
=item getservent
-Not implemented. (Win32, Plan9)
+Not implemented. (Win32, S<Plan 9>)
=item sethostent STAYOPEN
-Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>)
+Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
=item setnetent STAYOPEN
-Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>)
+Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
=item setprotoent STAYOPEN
-Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>)
+Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
=item setservent STAYOPEN
-Not implemented. (Plan9, Win32, S<RISC OS>)
+Not implemented. (S<Plan 9>, Win32, S<RISC OS>)
=item endpwent
=item endnetent
-Not implemented. (S<Mac OS>, Win32, Plan9)
+Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
=item endprotoent
-Not implemented. (S<Mac OS>, Win32, Plan9)
+Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
=item endservent
-Not implemented. (Plan9, Win32)
+Not implemented. (S<Plan 9>, Win32)
=item getsockopt SOCKET,LEVEL,OPTNAME
-Not implemented. (Plan9)
+Not implemented. (S<Plan 9>)
=item glob EXPR
=item msgrcv ID,VAR,SIZE,TYPE,FLAGS
-Not implemented. (S<Mac OS>, Win32, VMS, Plan9, S<RISC OS>, VOS)
+Not implemented. (S<Mac OS>, Win32, VMS, S<Plan 9>, S<RISC OS>, VOS)
=item open FILEHANDLE,EXPR
=item setgrent
-Not implemented. (S<Mac OS>, MPE/iX, VMS, Win32, VMS, S<RISC OS>)
+Not implemented. (S<Mac OS>, MPE/iX, VMS, Win32, S<RISC OS>, VOS)
=item setpgrp PID,PGRP
=item setpwent
-Not implemented. (S<Mac OS>, MPE/iX, Win32, S<RISC OS>)
+Not implemented. (S<Mac OS>, MPE/iX, Win32, S<RISC OS>, VOS)
=item setsockopt SOCKET,LEVEL,OPTNAME,OPTVAL
-Not implemented. (Plan9)
+Not implemented. (S<Plan 9>)
=item shmctl ID,CMD,ARG
Not implemented. (Older versions of VMS)
-Truncation to zero-length only. (VOS)
+Truncation to same-or-shorter lengths only. (VOS)
If a FILEHANDLE is supplied, it must be writable and opened in append
mode (i.e., use C<<< open(FH, '>>filename') >>>
=item waitpid PID,FLAGS
-Not implemented. (S<Mac OS>, VOS)
+Not implemented. (S<Mac OS>)
Can only be applied to process handles returned for processes spawned
using C<system(1, ...)> or pseudo processes created with C<fork()>. (Win32)
=over 4
+=item v1.49, 12 August 2002
+
+Updates for VOS from Paul Green.
+
=item v1.48, 02 February 2001
Various updates from perl5-porters over the past year, supported
=head1 Supported Platforms
-As of June 2002 (the Perl release 5.8.0), the following platforms are
+As of July 2002 (the Perl release 5.8.0), the following platforms are
able to build Perl from the standard source code distribution
available at http://www.cpan.org/src/index.html
AIX
BeOS
+ BSD/OS (BSDi)
Cygwin
DG/UX
DOS DJGPP 1)
DYNIX/ptx
EPOC R5
FreeBSD
+ HI-UXMPP (Hitachi) (5.8.0 worked but we didn't know it)
HP-UX
IRIX
Linux
Mac OS Classic
- Mac OS X (Darwin)
+ Mac OS X (Darwin)
MPE/iX
NetBSD
NetWare
NonStop-UX
- ReliantUNIX (SINIX)
+ ReliantUNIX (formerly SINIX)
OpenBSD
- OpenVMS (VMS)
+ OpenVMS (formerly VMS)
+ Open UNIX (Unixware) (since Perl 5.8.1/5.9.0)
OS/2
- POSIX-BC (BS2000)
+ OS/400 (using the PASE) (since Perl 5.8.1/5.9.0)
+ PowerUX
+ POSIX-BC (formerly BS2000)
QNX
Solaris
- SUPER-UX
- Tru64 UNIX (DEC OSF/1, Digital UNIX)
+ SunOS 4
+ SUPER-UX (NEC)
+ Tru64 UNIX (formerly DEC OSF/1, Digital UNIX)
UNICOS
UNICOS/mk
UTS
VOS
Win95/98/ME/2K/XP 2)
WinCE
- z/OS (OS/390)
+ z/OS (formerly OS/390)
VM/ESA
1) in DOS mode either the DOS or OS/2 ports can be used
- 2) compilers: Borland, Cygwin (GCC), MinGW (GCC), VC6
+ 2) compilers: Borland, MinGW (GCC), VC6
The following platforms worked with the previous releases (5.6 and
5.7), but we did not manage either to fix or to test these in time
for the 5.8.0 release. There is a very good chance that many of these
-will work fine with the 5.8.0. The only one known for certain to be
-broken for 5.8.0 is the AmigaOS.
+will work fine with the 5.8.0.
- AmigaOS
+ BSD/OS
DomainOS
Hurd
LynxOS
MachTen
PowerMAX
SCO SV
- SunOS 4
SVR4
Unixware
Windows 3.1
+Known to be broken for 5.8.0 (but 5.6.1 and 5.7.2 can be used):
+
+ AmigaOS
+
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
3b1
A/UX
- BSD/OS
ConvexOS
CX/UX
DC/OSx
OpenSTEP
Opus
Plan 9
- PowerUX
RISC/os
- SCO ODT/OSR
+ SCO ODT/OSR
Stellar
SVR2
TI1500
TitanOS
Ultrix
Unisys Dynix
- Unixware
The following platforms have their own source code distributions and
binaries available via http://www.cpan.org/ports/
Perl release
- OS/400 5.005_02
+ OS/400 (ILE) 5.005_02
Tandem Guardian 5.004
The following platforms have only binaries available via
=head1 SEE ALSO
L<perlaix>, L<perlamiga>, L<perlapollo>, L<perlbeos>, L<perlbs2000>,
-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>.
+L<perlce>, L<perlcygwin>, L<perldgux>, L<perldos>, L<perlepoc>,
+L<perlebcdic>, L<perlfreebsd>, L<perlhurd>, L<perlhpux>, L<perlirix>,
+L<perlmachten>, L<perlmacos>, L<perlmacosx>, L<perlmint>, L<perlmpeix>,
+L<perlnetware>, L<perlos2>, L<perlos390>, L<perlos400>,
+L<perlplan9>, L<perlqnx>, L<perlsolaris>, L<perltru64>,
+L<perlunicode>, L<perlvmesa>, L<perlvms>, L<perlvos>,
+L<perlwin32>, and L<Win32>.
=head1 AUTHORS / CONTRIBUTORS
Dominic Dunlop <domo@computer.org>,
Neale Ferguson <neale@vma.tabnsw.com.au>,
David J. Fiander <davidf@mks.com>,
-Paul Green <Paul_Green@stratus.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>,
https://perl5.git.perl.org / perl5.git / blobdiff