connections use the C<pack> and C<unpack> formats C<n> and C<N>, the
"network" orders. These are guaranteed to be portable.
-As of perl 5.9.2, you can also use the C<E<gt>> and C<E<lt>> modifiers
+As of perl 5.10.0, you can also use the C<E<gt>> and C<E<lt>> modifiers
to force big- or little-endian byte-order. This is useful if you want
to store signed integers or 64-bit integers, for example.
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 (included as
-of perl 5.8). Keeping all data as text significantly simplifies matters.
+binary, or else consider using modules like Data::Dumper and Storable
+(included as of perl 5.8). Keeping all data as text significantly
+simplifies matters.
The v-strings are portable only up to v2147483647 (0x7FFFFFFF), that's
how far EBCDIC, or more precisely UTF-EBCDIC will go.
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, or YYYY-MM-DDTHH-MM-SS
+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 guess what
date 02/03/04 might be. ISO 8601 even sorts nicely as-is.
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 you want to write your code in UTF-8,
-you can use the C<utf8>.) The C<bytes> and C<utf8> pragmata are
-available since Perl 5.6.0.
+of embedding the bytes as-is. If you want to write your code in UTF-8,
+you can use the C<utf8>.
=head2 System Resources
missing!) virtual memory systems then you want to be I<especially> mindful
of avoiding wasteful constructs such as:
- # NOTE: this is no longer "bad" in perl5.005
- for (0..10000000) {} # bad
- for (my $x = 0; $x <= 10000000; ++$x) {} # good
-
my @lines = <$very_large_file>; # bad
while (<$fh>) {$file .= $_} # sometimes bad
=item *
-Testing results: http://www.cpantesters.org/
+Testing results: L<http://www.cpantesters.org/>
=back
=head1 PLATFORMS
-As of version 5.002, Perl is built with a C<$^O> variable that
-indicates the operating system it was built on. This was implemented
+Perl is built with a C<$^O> variable that indicates the operating
+system it was built on. This was implemented
to help speed up code that would otherwise have to C<use Config>
and use the value of C<$Config{osname}>. Of course, to get more
detailed information about the system, looking into C<%Config> is
Windows Vista MSWin32 MSWin32-x86 2 6 00
Windows 7 MSWin32 MSWin32-x86 2 6 01
Windows 7 MSWin32 MSWin32-x64 2 6 01
+ Windows 2008 MSWin32 MSWin32-x86 2 6 01
+ Windows 2008 MSWin32 MSWin32-x64 2 6 01
Windows CE MSWin32 ? 3
Cygwin cygwin cygwin
=item *
-The djgpp environment for DOS, http://www.delorie.com/djgpp/
+The djgpp environment for DOS, L<http://www.delorie.com/djgpp/>
and L<perldos>.
=item *
The EMX environment for DOS, OS/2, etc. emx@iaehv.nl,
-
ftp://hobbes.nmsu.edu/pub/os2/dev/emx/ Also L<perlos2>.
+
L<ftp://hobbes.nmsu.edu/pub/os2/dev/emx/> Also L<perlos2>.
=item *
=item *
-The ActiveState Pages, http://www.activestate.com/
+The ActiveState Pages, L<http://www.activestate.com/>
=item *
The Cygwin environment for Win32; F<README.cygwin> (installed
-as L<perlcygwin>), http://www.cygwin.com/
+as L<perlcygwin>), L<http://www.cygwin.com/>
=item *
The U/WIN environment for Win32,
-http://www.research.att.com/sw/tools/uwin/
+L<http://www.research.att.com/sw/tools/uwin/>
=item *
=item *
-F<README.vms> (installed as
L<README_vms>), L<perlvms>
+F<README.vms> (installed as
F<README_vms>), L<perlvms>
=item *
=item *
-vmsperl on the web, http://www.sidhe.org/vmsperl/index.html
+vmsperl on the web, L<http://www.sidhe.org/vmsperl/index.html>
=back
can contain up to 255 characters, are prohibited from starting
with a C<-> character, and the set of prohibited characters is
reduced to any character matching C<< tr/#%*<>?// >>. There are
-restrictions involving spaces and apostrophies: these characters
+restrictions involving spaces and apostrophes: these characters
must not begin or end a name, nor can they immediately precede or
follow a period. Additionally, a space must not immediately
precede another space or hyphen. Specifically, the following
=item *
-VOS Perl on the web at http://ftp.stratus.com/pub/vos/posix/posix.html
+VOS Perl on the web at L<http://ftp.stratus.com/pub/vos/posix/posix.html>
=back
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. 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
+Perl 5.8.1/5.10.0 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
=item *
AS/400 Perl information at
-http://as400.rochester.ibm.com/
+L<http://as400.rochester.ibm.com/>
as well as on CPAN in the F<ports/> directory.
=back
The Unix emulation library's translation of filenames to native assumes
that this sort of translation is required, and it allows a user-defined list
of known suffixes that it will transpose in this fashion. This may
-seem transparent, but consider that with these rules C<foo/bar/baz.h>
-and C<foo/bar/h/baz> both map to C<foo.bar.h.baz>, and that C<readdir> and
+seem transparent, but consider that with these rules F<foo/bar/baz.h>
+and F<foo/bar/h/baz> both map to F<foo.bar.h.baz>, and that C<readdir> and
C<glob> cannot and do not attempt to emulate the reverse mapping. Other
C<.>'s in filenames are translated to C</>.
=item *
HP 300 MPE/iX, F<README.mpeix> and Mark Bixby's web page
-http://www.bixby.org/mark/porting.html
+L<http://www.bixby.org/mark/porting.html>
=item *
A free perl5-based PERL.NLM for Novell Netware is available in
-precompiled binary and source code form from http://www.novell.com/
+precompiled binary and source code form from L<http://www.novell.com/>
as well as from CPAN.
=item *
Does not automatically flush output handles on some platforms.
(SunOS, Solaris, HP-UX)
+Not supported. (Symbian OS)
+
=item exit
Emulates Unix exit() (which considers C<exit 1> to indicate an error) by
the C library _POSIX_EXIT macro so that it can be decoded by other
programs, particularly ones written in C, like the GNV package. (VMS)
+C<exit()> resets file pointers, which is a problem when called
+from a child process (created by C<fork()>) in C<BEGIN>.
+A workaround is to use C<POSIX::_exit>. (Solaris)
+
+ exit unless $Config{archname} =~ /\bsolaris\b/;
+ require POSIX and POSIX::_exit(0);
+
=item fcntl
Not implemented. (Win32)
+
Some functions available based on the version of VMS. (VMS)
=item flock
=item umask
-Returns undef where unavailable, as of version 5.005.
+Returns undef where unavailable.
C<umask> works but the correct permissions are set only when the file
is finally closed. (AmigaOS)
The following platforms are known to build Perl 5.12 (as of April 2010,
its release date) from the standard source code distribution available
-at http://www.cpan.org/src
+at L<http://www.cpan.org/src>
=over
=item FreeBSD
+=item Debian GNU/kFreeBSD
+
=item Haiku
=item Irix (6.5. What else?)
=back
-
=item Symbian (Series 60 v3, 3.2 and 5 - what else?)
=item Stratus VOS / OpenVOS
As of July 2002 (the Perl release 5.8.0), the following platforms were
able to build Perl from the standard source code distribution
-available at http://www.cpan.org/src/
+available at L<http://www.cpan.org/src/>
AIX
BeOS
Unisys Dynix
The following platforms have their own source code distributions and
-binaries available via http://www.cpan.org/ports/
+binaries available via L<http://www.cpan.org/ports/>
Perl release
Tandem Guardian 5.004
The following platforms have only binaries available via
-http://www.cpan.org/ports/index.html :
+L<http://www.cpan.org/ports/index.html> :
Perl release
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.cpan.org/ports/index.html for binary distributions.
+L<http://www.cpan.org/ports/index.html> for binary distributions.
=head1 SEE ALSO
-L<perlaix>, L<perlamiga>, L<perl
apollo>, L<perlbeos>, L<perlbs2000>,
+L<perlaix>, L<perlamiga>, L<perlbeos>, L<perlbs2000>,
L<perlce>, L<perlcygwin>, L<perldgux>, L<perldos>, L<perlepoc>,
L<perlebcdic>, L<perlfreebsd>, L<perlhurd>, L<perlhpux>, L<perlirix>,
L<perlmacos>, L<perlmacosx>, L<perlmpeix>,
Paul J. Schinder <schinder@pobox.com>,
Michael G Schwern <schwern@pobox.com>,
Dan Sugalski <dan@sidhe.org>,
-Nathan Torkington <gnat@frii.com>.
+Nathan Torkington <gnat@frii.com>,
John Malmberg <wb8tyw@qsl.net>
https://perl5.git.perl.org / perl5.git / blobdiff