This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
Update Changes.
[perl5.git] / pod / perlport.pod
CommitLineData
e41182b5
GS
1=head1 NAME
2
3perlport - Writing portable Perl
4
e41182b5
GS
5=head1 DESCRIPTION
6
b7df3edc
GS
7Perl runs on numerous operating systems. While most of them share
8much in common, they also have their own unique features.
e41182b5
GS
9
10This document is meant to help you to find out what constitutes portable
b7df3edc 11Perl code. That way once you make a decision to write portably,
e41182b5
GS
12you know where the lines are drawn, and you can stay within them.
13
b7df3edc
GS
14There is a tradeoff between taking full advantage of one particular
15type of computer and taking advantage of a full range of them.
16Naturally, as you broaden your range and become more diverse, the
17common factors drop, and you are left with an increasingly smaller
18area of common ground in which you can operate to accomplish a
19particular task. Thus, when you begin attacking a problem, it is
20important to consider under which part of the tradeoff curve you
21want to operate. Specifically, you must decide whether it is
22important that the task that you are coding have the full generality
23of being portable, or whether to just get the job done right now.
24This is the hardest choice to be made. The rest is easy, because
25Perl provides many choices, whichever way you want to approach your
0a47030a
GS
26problem.
27
28Looking at it another way, writing portable code is usually about
b7df3edc
GS
29willfully limiting your available choices. Naturally, it takes
30discipline and sacrifice to do that. The product of portability
31and convenience may be a constant. You have been warned.
e41182b5
GS
32
33Be aware of two important points:
34
35=over 4
36
37=item Not all Perl programs have to be portable
38
b7df3edc 39There is no reason you should not use Perl as a language to glue Unix
e41182b5
GS
40tools together, or to prototype a Macintosh application, or to manage the
41Windows registry. If it makes no sense to aim for portability for one
42reason or another in a given program, then don't bother.
43
b7df3edc 44=item Nearly all of Perl already I<is> portable
e41182b5
GS
45
46Don't be fooled into thinking that it is hard to create portable Perl
47code. It isn't. Perl tries its level-best to bridge the gaps between
48what's available on different platforms, and all the means available to
49use those features. Thus almost all Perl code runs on any machine
6ab3f9cb 50without modification. But there are some significant issues in
e41182b5
GS
51writing portable code, and this document is entirely about those issues.
52
53=back
54
b7df3edc
GS
55Here's the general rule: When you approach a task commonly done
56using a whole range of platforms, think about writing portable
e41182b5
GS
57code. That way, you don't sacrifice much by way of the implementation
58choices you can avail yourself of, and at the same time you can give
59your users lots of platform choices. On the other hand, when you have to
60take advantage of some unique feature of a particular platform, as is
61often the case with systems programming (whether for Unix, Windows,
62S<Mac OS>, VMS, etc.), consider writing platform-specific code.
63
b7df3edc
GS
64When the code will run on only two or three operating systems, you
65may need to consider only the differences of those particular systems.
66The important thing is to decide where the code will run and to be
0a47030a
GS
67deliberate in your decision.
68
69The material below is separated into three main sections: main issues of
70portability (L<"ISSUES">, platform-specific issues (L<"PLATFORMS">, and
b7df3edc 71built-in perl functions that behave differently on various ports
0a47030a 72(L<"FUNCTION IMPLEMENTATIONS">.
e41182b5
GS
73
74This information should not be considered complete; it includes possibly
b8099c3d 75transient information about idiosyncrasies of some of the ports, almost
b7df3edc 76all of which are in a state of constant evolution. Thus, this material
e41182b5 77should be considered a perpetual work in progress
cc07ed0b 78(C<< <IMG SRC="yellow_sign.gif" ALT="Under Construction"> >>).
e41182b5 79
e41182b5
GS
80=head1 ISSUES
81
82=head2 Newlines
83
638bc118 84In most operating systems, lines in files are terminated by newlines.
e41182b5 85Just what is used as a newline may vary from OS to OS. Unix
b7df3edc 86traditionally uses C<\012>, one type of DOSish I/O uses C<\015\012>,
e41182b5
GS
87and S<Mac OS> uses C<\015>.
88
b7df3edc
GS
89Perl uses C<\n> to represent the "logical" newline, where what is
90logical may depend on the platform in use. In MacPerl, C<\n> always
91means C<\015>. In DOSish perls, C<\n> usually means C<\012>, but
92when accessing a file in "text" mode, STDIO translates it to (or
56d7751a 93from) C<\015\012>, depending on whether you're reading or writing.
b7df3edc
GS
94Unix does the same thing on ttys in canonical mode. C<\015\012>
95is commonly referred to as CRLF.
96
5b3eff12
MS
97A common cause of unportable programs is the misuse of chop() to trim
98newlines:
99
100 # XXX UNPORTABLE!
101 while(<FILE>) {
102 chop;
103 @array = split(/:/);
104 #...
105 }
106
107You can get away with this on Unix and MacOS (they have a single
108character end-of-line), but the same program will break under DOSish
109perls because you're only chop()ing half the end-of-line. Instead,
110chomp() should be used to trim newlines. The Dunce::Files module can
111help audit your code for misuses of chop().
112
113When dealing with binary files (or text files in binary mode) be sure
114to explicitly set $/ to the appropriate value for your file format
115before using chomp().
116
b7df3edc
GS
117Because of the "text" mode translation, DOSish perls have limitations
118in using C<seek> and C<tell> on a file accessed in "text" mode.
119Stick to C<seek>-ing to locations you got from C<tell> (and no
120others), and you are usually free to use C<seek> and C<tell> even
121in "text" mode. Using C<seek> or C<tell> or other file operations
122may be non-portable. If you use C<binmode> on a file, however, you
123can usually C<seek> and C<tell> with arbitrary values in safety.
e41182b5
GS
124
125A common misconception in socket programming is that C<\n> eq C<\012>
0a47030a 126everywhere. When using protocols such as common Internet protocols,
e41182b5
GS
127C<\012> and C<\015> are called for specifically, and the values of
128the logical C<\n> and C<\r> (carriage return) are not reliable.
129
130 print SOCKET "Hi there, client!\r\n"; # WRONG
131 print SOCKET "Hi there, client!\015\012"; # RIGHT
132
0a47030a
GS
133However, using C<\015\012> (or C<\cM\cJ>, or C<\x0D\x0A>) can be tedious
134and unsightly, as well as confusing to those maintaining the code. As
6ab3f9cb 135such, the Socket module supplies the Right Thing for those who want it.
e41182b5
GS
136
137 use Socket qw(:DEFAULT :crlf);
138 print SOCKET "Hi there, client!$CRLF" # RIGHT
139
6ab3f9cb 140When reading from a socket, remember that the default input record
b7df3edc
GS
141separator C<$/> is C<\n>, but robust socket code will recognize as
142either C<\012> or C<\015\012> as end of line:
e41182b5
GS
143
144 while (<SOCKET>) {
145 # ...
146 }
147
b7df3edc
GS
148Because both CRLF and LF end in LF, the input record separator can
149be set to LF and any CR stripped later. Better to write:
e41182b5
GS
150
151 use Socket qw(:DEFAULT :crlf);
152 local($/) = LF; # not needed if $/ is already \012
153
154 while (<SOCKET>) {
155 s/$CR?$LF/\n/; # not sure if socket uses LF or CRLF, OK
156 # s/\015?\012/\n/; # same thing
157 }
158
b7df3edc
GS
159This example is preferred over the previous one--even for Unix
160platforms--because now any C<\015>'s (C<\cM>'s) are stripped out
e41182b5
GS
161(and there was much rejoicing).
162
6ab3f9cb 163Similarly, functions that return text data--such as a function that
b7df3edc
GS
164fetches a web page--should sometimes translate newlines before
165returning the data, if they've not yet been translated to the local
166newline representation. A single line of code will often suffice:
2ee0eb3c 167
b7df3edc
GS
168 $data =~ s/\015?\012/\n/g;
169 return $data;
2ee0eb3c 170
6ab3f9cb
GS
171Some of this may be confusing. Here's a handy reference to the ASCII CR
172and LF characters. You can print it out and stick it in your wallet.
173
74555b7a
PP
174 LF eq \012 eq \x0A eq \cJ eq chr(10) eq ASCII 10
175 CR eq \015 eq \x0D eq \cM eq chr(13) eq ASCII 13
6ab3f9cb
GS
176
177 | Unix | DOS | Mac |
178 ---------------------------
179 \n | LF | LF | CR |
180 \r | CR | CR | LF |
181 \n * | LF | CRLF | CR |
182 \r * | CR | CR | LF |
183 ---------------------------
184 * text-mode STDIO
185
b7df3edc
GS
186The Unix column assumes that you are not accessing a serial line
187(like a tty) in canonical mode. If you are, then CR on input becomes
188"\n", and "\n" on output becomes CRLF.
189
6ab3f9cb 190These are just the most common definitions of C<\n> and C<\r> in Perl.
aa7f90d3 191There may well be others. For example, on an EBCDIC implementation such
74555b7a
PP
192as z/OS or OS/400 the above material is similar to "Unix" but the code
193numbers change:
194
195 LF eq \025 eq \x15 eq chr(21) eq CP-1047 21
196 LF eq \045 eq \x25 eq \cU eq chr(37) eq CP-0037 37
197 CR eq \015 eq \x0D eq \cM eq chr(13) eq CP-1047 13
198 CR eq \015 eq \x0D eq \cM eq chr(13) eq CP-0037 13
199
200 | z/OS | OS/400 |
201 ----------------------
202 \n | LF | LF |
203 \r | CR | CR |
204 \n * | LF | LF |
205 \r * | CR | CR |
206 ----------------------
207 * text-mode STDIO
6ab3f9cb 208
322422de
GS
209=head2 Numbers endianness and Width
210
211Different CPUs store integers and floating point numbers in different
212orders (called I<endianness>) and widths (32-bit and 64-bit being the
b7df3edc
GS
213most common today). This affects your programs when they attempt to transfer
214numbers in binary format from one CPU architecture to another,
215usually either "live" via network connection, or by storing the
216numbers to secondary storage such as a disk file or tape.
322422de 217
b7df3edc 218Conflicting storage orders make utter mess out of the numbers. If a
d1e3b762 219little-endian host (Intel, VAX) stores 0x12345678 (305419896 in
b84d4f81
JH
220decimal), a big-endian host (Motorola, Sparc, PA) reads it as
2210x78563412 (2018915346 in decimal). Alpha and MIPS can be either:
222Digital/Compaq used/uses them in little-endian mode; SGI/Cray uses
223them in big-endian mode. To avoid this problem in network (socket)
224connections use the C<pack> and C<unpack> formats C<n> and C<N>, the
225"network" orders. These are guaranteed to be portable.
322422de 226
d1e3b762
GS
227You can explore the endianness of your platform by unpacking a
228data structure packed in native format such as:
229
230 print unpack("h*", pack("s2", 1, 2)), "\n";
231 # '10002000' on e.g. Intel x86 or Alpha 21064 in little-endian mode
232 # '00100020' on e.g. Motorola 68040
233
234If you need to distinguish between endian architectures you could use
235either of the variables set like so:
236
237 $is_big_endian = unpack("h*", pack("s", 1)) =~ /01/;
4375e838 238 $is_little_endian = unpack("h*", pack("s", 1)) =~ /^1/;
d1e3b762 239
b7df3edc
GS
240Differing widths can cause truncation even between platforms of equal
241endianness. The platform of shorter width loses the upper parts of the
322422de
GS
242number. There is no good solution for this problem except to avoid
243transferring or storing raw binary numbers.
244
b7df3edc 245One can circumnavigate both these problems in two ways. Either
322422de 246transfer and store numbers always in text format, instead of raw
b7df3edc 247binary, or else consider using modules like Data::Dumper (included in
83df6a1d
JH
248the standard distribution as of Perl 5.005) and Storable (included as
249of perl 5.8). Keeping all data as text significantly simplifies matters.
322422de 250
979699d9
JH
251The v-strings are portable only up to v2147483647 (0x7FFFFFFF), that's
252how far EBCDIC, or more precisely UTF-EBCDIC will go.
253
433acd8a 254=head2 Files and Filesystems
e41182b5
GS
255
256Most platforms these days structure files in a hierarchical fashion.
b7df3edc 257So, it is reasonably safe to assume that all platforms support the
6ab3f9cb 258notion of a "path" to uniquely identify a file on the system. How
b7df3edc 259that path is really written, though, differs considerably.
e41182b5 260
4375e838 261Although similar, file path specifications differ between Unix,
b7df3edc
GS
262Windows, S<Mac OS>, OS/2, VMS, VOS, S<RISC OS>, and probably others.
263Unix, for example, is one of the few OSes that has the elegant idea
264of a single root directory.
322422de 265
6ab3f9cb
GS
266DOS, OS/2, VMS, VOS, and Windows can work similarly to Unix with C</>
267as path separator, or in their own idiosyncratic ways (such as having
268several root directories and various "unrooted" device files such NIL:
269and LPT:).
322422de
GS
270
271S<Mac OS> uses C<:> as a path separator instead of C</>.
272
6ab3f9cb
GS
273The filesystem may support neither hard links (C<link>) nor
274symbolic links (C<symlink>, C<readlink>, C<lstat>).
433acd8a 275
6ab3f9cb 276The filesystem may support neither access timestamp nor change
433acd8a
JH
277timestamp (meaning that about the only portable timestamp is the
278modification timestamp), or one second granularity of any timestamps
279(e.g. the FAT filesystem limits the time granularity to two seconds).
280
74555b7a 281The "inode change timestamp" (the C<-C> filetest) may really be the
95a3fe12
MS
282"creation timestamp" (which it is not in UNIX).
283
495c5fdc
GP
284VOS perl can emulate Unix filenames with C</> as path separator. The
285native pathname characters greater-than, less-than, number-sign, and
286percent-sign are always accepted.
287
6ab3f9cb 288S<RISC OS> perl can emulate Unix filenames with C</> as path
322422de 289separator, or go native and use C<.> for path separator and C<:> to
6ab3f9cb 290signal filesystems and disk names.
e41182b5 291
a1667ba3
JH
292Don't assume UNIX filesystem access semantics: that read, write,
293and execute are all the permissions there are, and even if they exist,
294that their semantics (for example what do r, w, and x mean on
295a directory) are the UNIX ones. The various UNIX/POSIX compatibility
296layers usually try to make interfaces like chmod() work, but sometimes
297there simply is no good mapping.
298
b7df3edc
GS
299If all this is intimidating, have no (well, maybe only a little)
300fear. There are modules that can help. The File::Spec modules
301provide methods to do the Right Thing on whatever platform happens
302to be running the program.
e41182b5 303
6ab3f9cb
GS
304 use File::Spec::Functions;
305 chdir(updir()); # go up one directory
306 $file = catfile(curdir(), 'temp', 'file.txt');
e41182b5
GS
307 # on Unix and Win32, './temp/file.txt'
308 # on Mac OS, ':temp:file.txt'
d1e3b762 309 # on VMS, '[.temp]file.txt'
e41182b5 310
b7df3edc 311File::Spec is available in the standard distribution as of version
d1e3b762
GS
3125.004_05. File::Spec::Functions is only in File::Spec 0.7 and later,
313and some versions of perl come with version 0.6. If File::Spec
314is not updated to 0.7 or later, you must use the object-oriented
315interface from File::Spec (or upgrade File::Spec).
e41182b5 316
b7df3edc
GS
317In general, production code should not have file paths hardcoded.
318Making them user-supplied or read from a configuration file is
319better, keeping in mind that file path syntax varies on different
320machines.
e41182b5
GS
321
322This is especially noticeable in scripts like Makefiles and test suites,
323which often assume C</> as a path separator for subdirectories.
324
b7df3edc 325Also of use is File::Basename from the standard distribution, which
e41182b5
GS
326splits a pathname into pieces (base filename, full path to directory,
327and file suffix).
328
19799a22 329Even when on a single platform (if you can call Unix a single platform),
b7df3edc 330remember not to count on the existence or the contents of particular
3c075c7d 331system-specific files or directories, like F</etc/passwd>,
b7df3edc
GS
332F</etc/sendmail.conf>, F</etc/resolv.conf>, or even F</tmp/>. For
333example, F</etc/passwd> may exist but not contain the encrypted
334passwords, because the system is using some form of enhanced security.
335Or it may not contain all the accounts, because the system is using NIS.
3c075c7d 336If code does need to rely on such a file, include a description of the
b7df3edc 337file and its format in the code's documentation, then make it easy for
3c075c7d
CN
338the user to override the default location of the file.
339
b7df3edc
GS
340Don't assume a text file will end with a newline. They should,
341but people forget.
e41182b5 342
ec481373
JH
343Do not have two files or directories of the same name with different
344case, like F<test.pl> and F<Test.pl>, as many platforms have
345case-insensitive (or at least case-forgiving) filenames. Also, try
346not to have non-word characters (except for C<.>) in the names, and
347keep them to the 8.3 convention, for maximum portability, onerous a
348burden though this may appear.
dd9f0070 349
b7df3edc
GS
350Likewise, when using the AutoSplit module, try to keep your functions to
3518.3 naming and case-insensitive conventions; or, at the least,
dd9f0070
CN
352make it so the resulting files have a unique (case-insensitively)
353first 8 characters.
354
ec481373
JH
355Whitespace in filenames is tolerated on most systems, but not all,
356and even on systems where it might be tolerated, some utilities
fe829689 357might become confused by such whitespace.
ec481373 358
b7df3edc 359Many systems (DOS, VMS) cannot have more than one C<.> in their filenames.
433acd8a 360
c47ff5f1 361Don't assume C<< > >> won't be the first character of a filename.
fe829689
PN
362Always use C<< < >> explicitly to open a file for reading, or even
363better, use the three-arg version of open, unless you want the user to
364be able to specify a pipe open.
0a47030a 365
fe829689 366 open(FILE, '<', $existing_file) or die $!;
0a47030a 367
6ab3f9cb
GS
368If filenames might use strange characters, it is safest to open it
369with C<sysopen> instead of C<open>. C<open> is magic and can
c47ff5f1 370translate characters like C<< > >>, C<< < >>, and C<|>, which may
b7df3edc 371be the wrong thing to do. (Sometimes, though, it's the right thing.)
fe829689
PN
372Three-arg open can also help protect against this translation in cases
373where it is undesirable.
e41182b5 374
ec481373
JH
375Don't use C<:> as a part of a filename since many systems use that for
376their own semantics (MacOS Classic for separating pathname components,
377many networking schemes and utilities for separating the nodename and
08fef530
JH
378the pathname, and so on). For the same reasons, avoid C<@>, C<;> and
379C<|>.
ec481373 380
e1516da7
JH
381Don't assume that in pathnames you can collapse two leading slashes
382C<//> into one: some networking and clustering filesystems have special
383semantics for that. Let the operating system to sort it out.
384
ec481373
JH
385The I<portable filename characters> as defined by ANSI C are
386
387 a b c d e f g h i j k l m n o p q r t u v w x y z
388 A B C D E F G H I J K L M N O P Q R T U V W X Y Z
389 0 1 2 3 4 5 6 7 8 9
390 . _ -
391
08fef530 392and the "-" shouldn't be the first character. If you want to be
e1516da7
JH
393hypercorrect, stay case-insensitive and within the 8.3 naming
394convention (all the files and directories have to be unique within one
395directory if their names are lowercased and truncated to eight
396characters before the C<.>, if any, and to three characters after the
397C<.>, if any). (And do not use C<.>s in directory names.)
ec481373 398
e41182b5
GS
399=head2 System Interaction
400
b7df3edc
GS
401Not all platforms provide a command line. These are usually platforms
402that rely primarily on a Graphical User Interface (GUI) for user
403interaction. A program requiring a command line interface might
404not work everywhere. This is probably for the user of the program
405to deal with, so don't stay up late worrying about it.
e41182b5 406
b7df3edc
GS
407Some platforms can't delete or rename files held open by the system.
408Remember to C<close> files when you are done with them. Don't
409C<unlink> or C<rename> an open file. Don't C<tie> or C<open> a
410file already tied or opened; C<untie> or C<close> it first.
e41182b5 411
0a47030a
GS
412Don't open the same file more than once at a time for writing, as some
413operating systems put mandatory locks on such files.
414
73e9292c
JH
415Don't assume that write/modify permission on a directory gives the
416right to add or delete files/directories in that directory. That is
417filesystem specific: in some filesystems you need write/modify
418permission also (or even just) in the file/directory itself. In some
419filesystems (AFS, DFS) the permission to add/delete directory entries
420is a completely separate permission.
421
422Don't assume that a single C<unlink> completely gets rid of the file:
423some filesystems (most notably the ones in VMS) have versioned
424filesystems, and unlink() removes only the most recent one (it doesn't
425remove all the versions because by default the native tools on those
426platforms remove just the most recent version, too). The portable
427idiom to remove all the versions of a file is
428
94bb614c 429 1 while unlink "file";
73e9292c
JH
430
431This will terminate if the file is undeleteable for some reason
432(protected, not there, and so on).
433
e41182b5 434Don't count on a specific environment variable existing in C<%ENV>.
0a47030a 435Don't count on C<%ENV> entries being case-sensitive, or even
4a0d0822 436case-preserving. Don't try to clear %ENV by saying C<%ENV = ();>, or,
6be8f7a6 437if you really have to, make it conditional on C<$^O ne 'VMS'> since in
4a0d0822
JH
438VMS the C<%ENV> table is much more than a per-process key-value string
439table.
e41182b5 440
d1e3b762 441Don't count on signals or C<%SIG> for anything.
e41182b5
GS
442
443Don't count on filename globbing. Use C<opendir>, C<readdir>, and
444C<closedir> instead.
445
b8099c3d 446Don't count on per-program environment variables, or per-program current
dd9f0070 447directories.
b8099c3d 448
3c075c7d
CN
449Don't count on specific values of C<$!>.
450
a10d74f3
PG
451=head2 Command names versus file pathnames
452
453Don't assume that the name used to invoke a command or program with
454C<system> or C<exec> can also be used to test for the existence of the
455file that holds the executable code for that command or program.
456First, many operating systems have "internal" commands that are
457built-in to the OS and while these commands can be invoked, there is
458no corresponding file. Second, some operating systems (Cygwin, DJGPP,
459OS/2, and VOS) have required suffixes for executable files; these
460suffixes are generally permitted on the command name but are not
461required. Thus, a command like "perl" might exist in a file named
462"perl", "perl.exe", or "perl.pm", depending on the operating system.
463The variable "_exe" in the Config module holds the executable suffix,
464if any. Third, VMS files always end in a version number, which comes
465after the executable suffix.
466
467To convert $^X to a file pathname, taking account of the requirements
468of the various operating system possibilities, say:
469 use Config;
470 use File::Spec;
471 $thisperl = $^X;
472 $thisperl .= $Config{_exe} unless $thisperl ~= m/$Config{_exe}([;\d]*)$/i;
473
474To convert $Config{perlpath} to a file pathname, say:
475
476 use Config;
477 use File::Spec;
478 $thisperl = File::Spec->canonpath($Config{perlpath});
479 $thisperl .= $Config{_exe} unless $thisperl ~= m/$Config{_exe}([;\d]*)$/i;
480
e41182b5
GS
481=head2 Interprocess Communication (IPC)
482
b7df3edc
GS
483In general, don't directly access the system in code meant to be
484portable. That means, no C<system>, C<exec>, C<fork>, C<pipe>,
485C<``>, C<qx//>, C<open> with a C<|>, nor any of the other things
486that makes being a perl hacker worth being.
e41182b5
GS
487
488Commands that launch external processes are generally supported on
b7df3edc
GS
489most platforms (though many of them do not support any type of
490forking). The problem with using them arises from what you invoke
491them on. External tools are often named differently on different
4375e838 492platforms, may not be available in the same location, might accept
b7df3edc
GS
493different arguments, can behave differently, and often present their
494results in a platform-dependent way. Thus, you should seldom depend
495on them to produce consistent results. (Then again, if you're calling
496I<netstat -a>, you probably don't expect it to run on both Unix and CP/M.)
e41182b5 497
b7df3edc 498One especially common bit of Perl code is opening a pipe to B<sendmail>:
e41182b5 499
b7df3edc
GS
500 open(MAIL, '|/usr/lib/sendmail -t')
501 or die "cannot fork sendmail: $!";
e41182b5
GS
502
503This is fine for systems programming when sendmail is known to be
504available. But it is not fine for many non-Unix systems, and even
505some Unix systems that may not have sendmail installed. If a portable
b7df3edc
GS
506solution is needed, see the various distributions on CPAN that deal
507with it. Mail::Mailer and Mail::Send in the MailTools distribution are
508commonly used, and provide several mailing methods, including mail,
509sendmail, and direct SMTP (via Net::SMTP) if a mail transfer agent is
510not available. Mail::Sendmail is a standalone module that provides
511simple, platform-independent mailing.
512
513The Unix System V IPC (C<msg*(), sem*(), shm*()>) is not available
514even on all Unix platforms.
e41182b5 515
a81e5e2e
A
516Do not use either the bare result of C<pack("N", 10, 20, 30, 40)> or
517bare v-strings (such as C<v10.20.30.40>) to represent IPv4 addresses:
518both forms just pack the four bytes into network order. That this
519would be equal to the C language C<in_addr> struct (which is what the
520socket code internally uses) is not guaranteed. To be portable use
521the routines of the Socket extension, such as C<inet_aton()>,
522C<inet_ntoa()>, and C<sockaddr_in()>.
6b2463a0 523
e41182b5 524The rule of thumb for portable code is: Do it all in portable Perl, or
0a47030a
GS
525use a module (that may internally implement it with platform-specific
526code, but expose a common interface).
e41182b5 527
e41182b5
GS
528=head2 External Subroutines (XS)
529
b7df3edc 530XS code can usually be made to work with any platform, but dependent
e41182b5
GS
531libraries, header files, etc., might not be readily available or
532portable, or the XS code itself might be platform-specific, just as Perl
533code might be. If the libraries and headers are portable, then it is
534normally reasonable to make sure the XS code is portable, too.
535
b7df3edc
GS
536A different type of portability issue arises when writing XS code:
537availability of a C compiler on the end-user's system. C brings
538with it its own portability issues, and writing XS code will expose
539you to some of those. Writing purely in Perl is an easier way to
e41182b5
GS
540achieve portability.
541
e41182b5
GS
542=head2 Standard Modules
543
544In general, the standard modules work across platforms. Notable
6ab3f9cb 545exceptions are the CPAN module (which currently makes connections to external
e41182b5 546programs that may not be available), platform-specific modules (like
6ab3f9cb 547ExtUtils::MM_VMS), and DBM modules.
e41182b5 548
b7df3edc 549There is no one DBM module available on all platforms.
6ab3f9cb
GS
550SDBM_File and the others are generally available on all Unix and DOSish
551ports, but not in MacPerl, where only NBDM_File and DB_File are
0a47030a 552available.
e41182b5
GS
553
554The good news is that at least some DBM module should be available, and
6ab3f9cb 555AnyDBM_File will use whichever module it can find. Of course, then
b7df3edc
GS
556the code needs to be fairly strict, dropping to the greatest common
557factor (e.g., not exceeding 1K for each record), so that it will
6ab3f9cb 558work with any DBM module. See L<AnyDBM_File> for more details.
e41182b5 559
e41182b5
GS
560=head2 Time and Date
561
0a47030a 562The system's notion of time of day and calendar date is controlled in
b7df3edc 563widely different ways. Don't assume the timezone is stored in C<$ENV{TZ}>,
0a47030a
GS
564and even if it is, don't assume that you can control the timezone through
565that variable.
e41182b5 566
322422de 567Don't assume that the epoch starts at 00:00:00, January 1, 1970,
6ab3f9cb
GS
568because that is OS- and implementation-specific. It is better to store a date
569in an unambiguous representation. The ISO-8601 standard defines
570"YYYY-MM-DD" as the date format. A text representation (like "1987-12-18")
571can be easily converted into an OS-specific value using a module like
572Date::Parse. An array of values, such as those returned by
322422de 573C<localtime>, can be converted to an OS-specific representation using
6ab3f9cb 574Time::Local.
322422de 575
19799a22
GS
576When calculating specific times, such as for tests in time or date modules,
577it may be appropriate to calculate an offset for the epoch.
b7df3edc 578
19799a22
GS
579 require Time::Local;
580 $offset = Time::Local::timegm(0, 0, 0, 1, 0, 70);
b7df3edc 581
19799a22
GS
582The value for C<$offset> in Unix will be C<0>, but in Mac OS will be
583some large number. C<$offset> can then be added to a Unix time value
584to get what should be the proper value on any system.
322422de
GS
585
586=head2 Character sets and character encoding
587
ec481373
JH
588Assume very little about character sets.
589
590Assume nothing about numerical values (C<ord>, C<chr>) of characters.
591Do not use explicit code point ranges (like \xHH-\xHH); use for
592example symbolic character classes like C<[:print:]>.
593
594Do not assume that the alphabetic characters are encoded contiguously
595(in the numeric sense). There may be gaps.
596
597Do not assume anything about the ordering of the characters.
598The lowercase letters may come before or after the uppercase letters;
599the lowercase and uppercase may be interlaced so that both `a' and `A'
600come before `b'; the accented and other international characters may
601be interlaced so that E<auml> comes before `b'.
322422de
GS
602
603=head2 Internationalisation
604
b7df3edc
GS
605If you may assume POSIX (a rather large assumption), you may read
606more about the POSIX locale system from L<perllocale>. The locale
607system at least attempts to make things a little bit more portable,
608or at least more convenient and native-friendly for non-English
609users. The system affects character sets and encoding, and date
610and time formatting--amongst other things.
e41182b5
GS
611
612=head2 System Resources
613
0a47030a
GS
614If your code is destined for systems with severely constrained (or
615missing!) virtual memory systems then you want to be I<especially> mindful
616of avoiding wasteful constructs such as:
e41182b5
GS
617
618 # NOTE: this is no longer "bad" in perl5.005
619 for (0..10000000) {} # bad
620 for (my $x = 0; $x <= 10000000; ++$x) {} # good
621
622 @lines = <VERY_LARGE_FILE>; # bad
623
624 while (<FILE>) {$file .= $_} # sometimes bad
0a47030a 625 $file = join('', <FILE>); # better
e41182b5 626
b7df3edc
GS
627The last two constructs may appear unintuitive to most people. The
628first repeatedly grows a string, whereas the second allocates a
629large chunk of memory in one go. On some systems, the second is
630more efficient that the first.
0a47030a 631
e41182b5
GS
632=head2 Security
633
b7df3edc
GS
634Most multi-user platforms provide basic levels of security, usually
635implemented at the filesystem level. Some, however, do
a1667ba3 636not-- unfortunately. Thus the notion of user id, or "home" directory,
b7df3edc
GS
637or even the state of being logged-in, may be unrecognizable on many
638platforms. If you write programs that are security-conscious, it
639is usually best to know what type of system you will be running
640under so that you can write code explicitly for that platform (or
641class of platforms).
0a47030a 642
a1667ba3
JH
643Don't assume the UNIX filesystem access semantics: the operating
644system or the filesystem may be using some ACL systems, which are
645richer languages than the usual rwx. Even if the rwx exist,
646their semantics might be different.
647
648(From security viewpoint testing for permissions before attempting to
649do something is silly anyway: if one tries this, there is potential
650for race conditions-- someone or something might change the
651permissions between the permissions check and the actual operation.
652Just try the operation.)
653
654Don't assume the UNIX user and group semantics: especially, don't
2edcc0d9 655expect the C<< $< >> and C<< $> >> (or the C<$(> and C<$)>) to work
a1667ba3
JH
656for switching identities (or memberships).
657
658Don't assume set-uid and set-gid semantics. (And even if you do,
659think twice: set-uid and set-gid are a known can of security worms.)
660
e41182b5
GS
661=head2 Style
662
663For those times when it is necessary to have platform-specific code,
664consider keeping the platform-specific code in one place, making porting
6ab3f9cb 665to other platforms easier. Use the Config module and the special
0a47030a
GS
666variable C<$^O> to differentiate platforms, as described in
667L<"PLATFORMS">.
e41182b5 668
b7df3edc
GS
669Be careful in the tests you supply with your module or programs.
670Module code may be fully portable, but its tests might not be. This
671often happens when tests spawn off other processes or call external
672programs to aid in the testing, or when (as noted above) the tests
673assume certain things about the filesystem and paths. Be careful
674not to depend on a specific output style for errors, such as when
d1be9408 675checking C<$!> after a system call. Some platforms expect a certain
b7df3edc
GS
676output format, and perl on those platforms may have been adjusted
677accordingly. Most specifically, don't anchor a regex when testing
678an error value.
e41182b5 679
0a47030a 680=head1 CPAN Testers
e41182b5 681
0a47030a
GS
682Modules uploaded to CPAN are tested by a variety of volunteers on
683different platforms. These CPAN testers are notified by mail of each
e41182b5 684new upload, and reply to the list with PASS, FAIL, NA (not applicable to
0a47030a 685this platform), or UNKNOWN (unknown), along with any relevant notations.
e41182b5
GS
686
687The purpose of the testing is twofold: one, to help developers fix any
0a47030a 688problems in their code that crop up because of lack of testing on other
b7df3edc 689platforms; two, to provide users with information about whether
0a47030a 690a given module works on a given platform.
e41182b5
GS
691
692=over 4
693
694=item Mailing list: cpan-testers@perl.org
695
c997b287 696=item Testing results: http://testers.cpan.org/
e41182b5
GS
697
698=back
699
e41182b5
GS
700=head1 PLATFORMS
701
702As of version 5.002, Perl is built with a C<$^O> variable that
703indicates the operating system it was built on. This was implemented
b7df3edc
GS
704to help speed up code that would otherwise have to C<use Config>
705and use the value of C<$Config{osname}>. Of course, to get more
e41182b5
GS
706detailed information about the system, looking into C<%Config> is
707certainly recommended.
708
b7df3edc
GS
709C<%Config> cannot always be trusted, however, because it was built
710at compile time. If perl was built in one place, then transferred
711elsewhere, some values may be wrong. The values may even have been
712edited after the fact.
6ab3f9cb 713
e41182b5
GS
714=head2 Unix
715
716Perl works on a bewildering variety of Unix and Unix-like platforms (see
717e.g. most of the files in the F<hints/> directory in the source code kit).
718On most of these systems, the value of C<$^O> (hence C<$Config{'osname'}>,
d1e3b762
GS
719too) is determined either by lowercasing and stripping punctuation from the
720first field of the string returned by typing C<uname -a> (or a similar command)
721at the shell prompt or by testing the file system for the presence of
722uniquely named files such as a kernel or header file. Here, for example,
723are a few of the more popular Unix flavors:
e41182b5 724
b7df3edc 725 uname $^O $Config{'archname'}
6ab3f9cb 726 --------------------------------------------
b7df3edc 727 AIX aix aix
6ab3f9cb 728 BSD/OS bsdos i386-bsdos
e1516da7 729 Darwin darwin darwin
6ab3f9cb
GS
730 dgux dgux AViiON-dgux
731 DYNIX/ptx dynixptx i386-dynixptx
b7df3edc 732 FreeBSD freebsd freebsd-i386
d1e3b762 733 Linux linux arm-linux
b7df3edc 734 Linux linux i386-linux
6ab3f9cb
GS
735 Linux linux i586-linux
736 Linux linux ppc-linux
b7df3edc
GS
737 HP-UX hpux PA-RISC1.1
738 IRIX irix irix
b787fad4 739 Mac OS X darwin darwin
d1e3b762
GS
740 MachTen PPC machten powerpc-machten
741 NeXT 3 next next-fat
742 NeXT 4 next OPENSTEP-Mach
6ab3f9cb 743 openbsd openbsd i386-openbsd
b7df3edc 744 OSF1 dec_osf alpha-dec_osf
6ab3f9cb
GS
745 reliantunix-n svr4 RM400-svr4
746 SCO_SV sco_sv i386-sco_sv
747 SINIX-N svr4 RM400-svr4
748 sn4609 unicos CRAY_C90-unicos
749 sn6521 unicosmk t3e-unicosmk
750 sn9617 unicos CRAY_J90-unicos
b7df3edc
GS
751 SunOS solaris sun4-solaris
752 SunOS solaris i86pc-solaris
753 SunOS4 sunos sun4-sunos
e41182b5 754
b7df3edc
GS
755Because the value of C<$Config{archname}> may depend on the
756hardware architecture, it can vary more than the value of C<$^O>.
6ab3f9cb 757
e41182b5
GS
758=head2 DOS and Derivatives
759
b7df3edc 760Perl has long been ported to Intel-style microcomputers running under
e41182b5
GS
761systems like PC-DOS, MS-DOS, OS/2, and most Windows platforms you can
762bring yourself to mention (except for Windows CE, if you count that).
b7df3edc 763Users familiar with I<COMMAND.COM> or I<CMD.EXE> style shells should
e41182b5
GS
764be aware that each of these file specifications may have subtle
765differences:
766
767 $filespec0 = "c:/foo/bar/file.txt";
768 $filespec1 = "c:\\foo\\bar\\file.txt";
769 $filespec2 = 'c:\foo\bar\file.txt';
770 $filespec3 = 'c:\\foo\\bar\\file.txt';
771
b7df3edc
GS
772System calls accept either C</> or C<\> as the path separator.
773However, many command-line utilities of DOS vintage treat C</> as
774the option prefix, so may get confused by filenames containing C</>.
775Aside from calling any external programs, C</> will work just fine,
776and probably better, as it is more consistent with popular usage,
777and avoids the problem of remembering what to backwhack and what
778not to.
e41182b5 779
b7df3edc
GS
780The DOS FAT filesystem can accommodate only "8.3" style filenames. Under
781the "case-insensitive, but case-preserving" HPFS (OS/2) and NTFS (NT)
0a47030a 782filesystems you may have to be careful about case returned with functions
e41182b5
GS
783like C<readdir> or used with functions like C<open> or C<opendir>.
784
b7df3edc
GS
785DOS also treats several filenames as special, such as AUX, PRN,
786NUL, CON, COM1, LPT1, LPT2, etc. Unfortunately, sometimes these
787filenames won't even work if you include an explicit directory
788prefix. It is best to avoid such filenames, if you want your code
789to be portable to DOS and its derivatives. It's hard to know what
790these all are, unfortunately.
e41182b5
GS
791
792Users of these operating systems may also wish to make use of
b7df3edc 793scripts such as I<pl2bat.bat> or I<pl2cmd> to
e41182b5
GS
794put wrappers around your scripts.
795
796Newline (C<\n>) is translated as C<\015\012> by STDIO when reading from
6ab3f9cb
GS
797and writing to files (see L<"Newlines">). C<binmode(FILEHANDLE)>
798will keep C<\n> translated as C<\012> for that filehandle. Since it is a
799no-op on other systems, C<binmode> should be used for cross-platform code
b7df3edc
GS
800that deals with binary data. That's assuming you realize in advance
801that your data is in binary. General-purpose programs should
802often assume nothing about their data.
e41182b5 803
b7df3edc 804The C<$^O> variable and the C<$Config{archname}> values for various
e41182b5
GS
805DOSish perls are as follows:
806
67ac489e
MS
807 OS $^O $Config{archname} ID Version
808 --------------------------------------------------------
809 MS-DOS dos ?
810 PC-DOS dos ?
811 OS/2 os2 ?
812 Windows 3.1 ? ? 0 3 01
813 Windows 95 MSWin32 MSWin32-x86 1 4 00
814 Windows 98 MSWin32 MSWin32-x86 1 4 10
815 Windows ME MSWin32 MSWin32-x86 1 ?
816 Windows NT MSWin32 MSWin32-x86 2 4 xx
817 Windows NT MSWin32 MSWin32-ALPHA 2 4 xx
818 Windows NT MSWin32 MSWin32-ppc 2 4 xx
819 Windows 2000 MSWin32 MSWin32-x86 2 5 xx
820 Windows XP MSWin32 MSWin32-x86 2 ?
821 Windows CE MSWin32 ? 3
822 Cygwin cygwin ?
e41182b5 823
34aaaa84
PP
824The various MSWin32 Perl's can distinguish the OS they are running on
825via the value of the fifth element of the list returned from
826Win32::GetOSVersion(). For example:
827
828 if ($^O eq 'MSWin32') {
829 my @os_version_info = Win32::GetOSVersion();
830 print +('3.1','95','NT')[$os_version_info[4]],"\n";
831 }
832
e41182b5
GS
833Also see:
834
835=over 4
836
c997b287 837=item *
e41182b5 838
c997b287
GS
839The djgpp environment for DOS, http://www.delorie.com/djgpp/
840and L<perldos>.
e41182b5 841
c997b287 842=item *
e41182b5 843
c997b287
GS
844The EMX environment for DOS, OS/2, etc. emx@iaehv.nl,
845http://www.leo.org/pub/comp/os/os2/leo/gnu/emx+gcc/index.html or
f224927c 846ftp://hobbes.nmsu.edu/pub/os2/dev/emx/ Also L<perlos2>.
e41182b5 847
c997b287 848=item *
d1e3b762 849
c997b287
GS
850Build instructions for Win32 in L<perlwin32>, or under the Cygnus environment
851in L<perlcygwin>.
852
853=item *
854
855The C<Win32::*> modules in L<Win32>.
856
857=item *
858
859The ActiveState Pages, http://www.activestate.com/
860
861=item *
862
863The Cygwin environment for Win32; F<README.cygwin> (installed
47dafe4d 864as L<perlcygwin>), http://www.cygwin.com/
c997b287
GS
865
866=item *
867
868The U/WIN environment for Win32,
cea6626f 869http://www.research.att.com/sw/tools/uwin/
c997b287 870
cea6626f 871=item *
d1e3b762 872
cea6626f 873Build instructions for OS/2, L<perlos2>
d1e3b762 874
e41182b5
GS
875=back
876
dd9f0070 877=head2 S<Mac OS>
e41182b5
GS
878
879Any module requiring XS compilation is right out for most people, because
880MacPerl is built using non-free (and non-cheap!) compilers. Some XS
881modules that can work with MacPerl are built and distributed in binary
6ab3f9cb 882form on CPAN.
e41182b5
GS
883
884Directories are specified as:
885
886 volume:folder:file for absolute pathnames
887 volume:folder: for absolute pathnames
888 :folder:file for relative pathnames
889 :folder: for relative pathnames
890 :file for relative pathnames
891 file for relative pathnames
892
b7df3edc 893Files are stored in the directory in alphabetical order. Filenames are
6ab3f9cb 894limited to 31 characters, and may include any character except for
b7df3edc 895null and C<:>, which is reserved as the path separator.
e41182b5 896
0a47030a 897Instead of C<flock>, see C<FSpSetFLock> and C<FSpRstFLock> in the
6ab3f9cb 898Mac::Files module, or C<chmod(0444, ...)> and C<chmod(0666, ...)>.
e41182b5
GS
899
900In the MacPerl application, you can't run a program from the command line;
901programs that expect C<@ARGV> to be populated can be edited with something
902like the following, which brings up a dialog box asking for the command
903line arguments.
904
905 if (!@ARGV) {
906 @ARGV = split /\s+/, MacPerl::Ask('Arguments?');
907 }
908
b7df3edc 909A MacPerl script saved as a "droplet" will populate C<@ARGV> with the full
e41182b5
GS
910pathnames of the files dropped onto the script.
911
b7df3edc
GS
912Mac users can run programs under a type of command line interface
913under MPW (Macintosh Programmer's Workshop, a free development
914environment from Apple). MacPerl was first introduced as an MPW
915tool, and MPW can be used like a shell:
e41182b5
GS
916
917 perl myscript.plx some arguments
918
919ToolServer is another app from Apple that provides access to MPW tools
0a47030a 920from MPW and the MacPerl app, which allows MacPerl programs to use
e41182b5
GS
921C<system>, backticks, and piped C<open>.
922
923"S<Mac OS>" is the proper name for the operating system, but the value
924in C<$^O> is "MacOS". To determine architecture, version, or whether
925the application or MPW tool version is running, check:
926
927 $is_app = $MacPerl::Version =~ /App/;
928 $is_tool = $MacPerl::Version =~ /MPW/;
929 ($version) = $MacPerl::Version =~ /^(\S+)/;
930 $is_ppc = $MacPerl::Architecture eq 'MacPPC';
931 $is_68k = $MacPerl::Architecture eq 'Mac68K';
932
b787fad4
JH
933S<Mac OS X>, based on NeXT's OpenStep OS, runs MacPerl natively, under the
934"Classic" environment. There is no "Carbon" version of MacPerl to run
935under the primary Mac OS X environment. S<Mac OS X> and its Open Source
936version, Darwin, both run Unix perl natively.
6ab3f9cb 937
e41182b5
GS
938Also see:
939
940=over 4
941
c997b287
GS
942=item *
943
862b5365 944MacPerl Development, http://dev.macperl.org/ .
c997b287
GS
945
946=item *
947
862b5365 948The MacPerl Pages, http://www.macperl.com/ .
e41182b5 949
c997b287 950=item *
6ab3f9cb 951
862b5365 952The MacPerl mailing lists, http://lists.perl.org/ .
e41182b5
GS
953
954=back
955
e41182b5
GS
956=head2 VMS
957
c997b287 958Perl on VMS is discussed in L<perlvms> in the perl distribution.
b7df3edc 959Perl on VMS can accept either VMS- or Unix-style file
e41182b5
GS
960specifications as in either of the following:
961
962 $ perl -ne "print if /perl_setup/i" SYS$LOGIN:LOGIN.COM
963 $ perl -ne "print if /perl_setup/i" /sys$login/login.com
964
965but not a mixture of both as in:
966
967 $ perl -ne "print if /perl_setup/i" sys$login:/login.com
968 Can't open sys$login:/login.com: file specification syntax error
969
970Interacting with Perl from the Digital Command Language (DCL) shell
971often requires a different set of quotation marks than Unix shells do.
972For example:
973
974 $ perl -e "print ""Hello, world.\n"""
975 Hello, world.
976
b7df3edc 977There are several ways to wrap your perl scripts in DCL F<.COM> files, if
e41182b5
GS
978you are so inclined. For example:
979
980 $ write sys$output "Hello from DCL!"
981 $ if p1 .eqs. ""
982 $ then perl -x 'f$environment("PROCEDURE")
983 $ else perl -x - 'p1 'p2 'p3 'p4 'p5 'p6 'p7 'p8
984 $ deck/dollars="__END__"
985 #!/usr/bin/perl
986
987 print "Hello from Perl!\n";
988
989 __END__
990 $ endif
991
992Do take care with C<$ ASSIGN/nolog/user SYS$COMMAND: SYS$INPUT> if your
c47ff5f1 993perl-in-DCL script expects to do things like C<< $read = <STDIN>; >>.
e41182b5
GS
994
995Filenames are in the format "name.extension;version". The maximum
996length for filenames is 39 characters, and the maximum length for
997extensions is also 39 characters. Version is a number from 1 to
99832767. Valid characters are C</[A-Z0-9$_-]/>.
999
b7df3edc 1000VMS's RMS filesystem is case-insensitive and does not preserve case.
e41182b5 1001C<readdir> returns lowercased filenames, but specifying a file for
b7df3edc 1002opening remains case-insensitive. Files without extensions have a
e41182b5 1003trailing period on them, so doing a C<readdir> with a file named F<A.;5>
0a47030a
GS
1004will return F<a.> (though that file could be opened with
1005C<open(FH, 'A')>).
e41182b5 1006
f34d0673 1007RMS had an eight level limit on directory depths from any rooted logical
dd9f0070
CN
1008(allowing 16 levels overall) prior to VMS 7.2. Hence
1009C<PERL_ROOT:[LIB.2.3.4.5.6.7.8]> is a valid directory specification but
1010C<PERL_ROOT:[LIB.2.3.4.5.6.7.8.9]> is not. F<Makefile.PL> authors might
1011have to take this into account, but at least they can refer to the former
f34d0673 1012as C</PERL_ROOT/lib/2/3/4/5/6/7/8/>.
e41182b5 1013
6ab3f9cb 1014The VMS::Filespec module, which gets installed as part of the build
0a47030a
GS
1015process on VMS, is a pure Perl module that can easily be installed on
1016non-VMS platforms and can be helpful for conversions to and from RMS
1017native formats.
e41182b5 1018
5e12dbfa
PP
1019What C<\n> represents depends on the type of file opened. It usually
1020represents C<\012> but it could also be C<\015>, C<\012>, C<\015\012>,
1021C<\000>, C<\040>, or nothing depending on the file organiztion and
1022record format. The VMS::Stdio module provides access to the
1023special fopen() requirements of files with unusual attributes on VMS.
e41182b5
GS
1024
1025TCP/IP stacks are optional on VMS, so socket routines might not be
1026implemented. UDP sockets may not be supported.
1027
1028The value of C<$^O> on OpenVMS is "VMS". To determine the architecture
1029that you are running on without resorting to loading all of C<%Config>
1030you can examine the content of the C<@INC> array like so:
1031
1032 if (grep(/VMS_AXP/, @INC)) {
1033 print "I'm on Alpha!\n";
6ab3f9cb 1034
e41182b5
GS
1035 } elsif (grep(/VMS_VAX/, @INC)) {
1036 print "I'm on VAX!\n";
6ab3f9cb 1037
e41182b5
GS
1038 } else {
1039 print "I'm not so sure about where $^O is...\n";
1040 }
1041
b7df3edc
GS
1042On VMS, perl determines the UTC offset from the C<SYS$TIMEZONE_DIFFERENTIAL>
1043logical name. Although the VMS epoch began at 17-NOV-1858 00:00:00.00,
6ab3f9cb 1044calls to C<localtime> are adjusted to count offsets from
b7df3edc 104501-JAN-1970 00:00:00.00, just like Unix.
6ab3f9cb 1046
e41182b5
GS
1047Also see:
1048
1049=over 4
1050
c997b287
GS
1051=item *
1052
1053F<README.vms> (installed as L<README_vms>), L<perlvms>
1054
1055=item *
1056
1057vmsperl list, majordomo@perl.org
e41182b5 1058
c997b287 1059(Put the words C<subscribe vmsperl> in message body.)
e41182b5 1060
c997b287 1061=item *
e41182b5 1062
c997b287 1063vmsperl on the web, http://www.sidhe.org/vmsperl/index.html
e41182b5
GS
1064
1065=back
1066
495c5fdc
GP
1067=head2 VOS
1068
9a997319
JH
1069Perl on VOS is discussed in F<README.vos> in the perl distribution
1070(installed as L<perlvos>). Perl on VOS can accept either VOS- or
1071Unix-style file specifications as in either of the following:
495c5fdc 1072
cc07ed0b
PG
1073 C<< $ perl -ne "print if /perl_setup/i" >system>notices >>
1074 C<< $ perl -ne "print if /perl_setup/i" /system/notices >>
495c5fdc
GP
1075
1076or even a mixture of both as in:
1077
cc07ed0b 1078 C<< $ perl -ne "print if /perl_setup/i" >system/notices >>
495c5fdc 1079
b7df3edc 1080Even though VOS allows the slash character to appear in object
495c5fdc
GP
1081names, because the VOS port of Perl interprets it as a pathname
1082delimiting character, VOS files, directories, or links whose names
1083contain a slash character cannot be processed. Such files must be
a3dfe201
GS
1084renamed before they can be processed by Perl. Note that VOS limits
1085file names to 32 or fewer characters.
495c5fdc 1086
cc07ed0b
PG
1087Perl on VOS can be built using two different compilers and two different
1088versions of the POSIX runtime. The recommended method for building full
1089Perl is with the GNU C compiler and the generally-available version of
1090VOS POSIX support. See F<README.vos> (installed as L<perlvos>) for
1091restrictions that apply when Perl is built using the VOS Standard C
1092compiler or the alpha version of VOS POSIX support.
495c5fdc
GP
1093
1094The value of C<$^O> on VOS is "VOS". To determine the architecture that
1095you are running on without resorting to loading all of C<%Config> you
c997b287 1096can examine the content of the @INC array like so:
495c5fdc 1097
24e8e380 1098 if ($^O =~ /VOS/) {
495c5fdc
GP
1099 print "I'm on a Stratus box!\n";
1100 } else {
1101 print "I'm not on a Stratus box!\n";
1102 die;
1103 }
1104
1105 if (grep(/860/, @INC)) {
1106 print "This box is a Stratus XA/R!\n";
6ab3f9cb 1107
495c5fdc 1108 } elsif (grep(/7100/, @INC)) {
24e8e380 1109 print "This box is a Stratus HP 7100 or 8xxx!\n";
6ab3f9cb 1110
495c5fdc 1111 } elsif (grep(/8000/, @INC)) {
24e8e380 1112 print "This box is a Stratus HP 8xxx!\n";
6ab3f9cb 1113
495c5fdc 1114 } else {
24e8e380 1115 print "This box is a Stratus 68K!\n";
495c5fdc
GP
1116 }
1117
1118Also see:
1119
1120=over 4
1121
c997b287 1122=item *
495c5fdc 1123
cc07ed0b 1124F<README.vos> (installed as L<perlvos>)
c997b287
GS
1125
1126=item *
1127
1128The VOS mailing list.
495c5fdc
GP
1129
1130There is no specific mailing list for Perl on VOS. You can post
1131comments to the comp.sys.stratus newsgroup, or subscribe to the general
cc07ed0b 1132Stratus mailing list. Send a letter with "subscribe Info-Stratus" in
495c5fdc
GP
1133the message body to majordomo@list.stratagy.com.
1134
c997b287
GS
1135=item *
1136
cc07ed0b 1137VOS Perl on the web at http://ftp.stratus.com/pub/vos/posix/posix.html
495c5fdc
GP
1138
1139=back
1140
e41182b5
GS
1141=head2 EBCDIC Platforms
1142
1143Recent versions of Perl have been ported to platforms such as OS/400 on
d1e3b762
GS
1144AS/400 minicomputers as well as OS/390, VM/ESA, and BS2000 for S/390
1145Mainframes. Such computers use EBCDIC character sets internally (usually
0cc436d0
GS
1146Character Code Set ID 0037 for OS/400 and either 1047 or POSIX-BC for S/390
1147systems). On the mainframe perl currently works under the "Unix system
1148services for OS/390" (formerly known as OpenEdition), VM/ESA OpenEdition, or
1149the BS200 POSIX-BC system (BS2000 is supported in perl 5.6 and greater).
c997b287 1150See L<perlos390> for details.
e41182b5 1151
7c5ffed3
JH
1152As of R2.5 of USS for OS/390 and Version 2.3 of VM/ESA these Unix
1153sub-systems do not support the C<#!> shebang trick for script invocation.
1154Hence, on OS/390 and VM/ESA perl scripts can be executed with a header
1155similar to the following simple script:
e41182b5
GS
1156
1157 : # use perl
1158 eval 'exec /usr/local/bin/perl -S $0 ${1+"$@"}'
1159 if 0;
1160 #!/usr/local/bin/perl # just a comment really
1161
1162 print "Hello from perl!\n";
1163
d1e3b762
GS
1164OS/390 will support the C<#!> shebang trick in release 2.8 and beyond.
1165Calls to C<system> and backticks can use POSIX shell syntax on all
1166S/390 systems.
1167
b7df3edc 1168On the AS/400, if PERL5 is in your library list, you may need
6ab3f9cb
GS
1169to wrap your perl scripts in a CL procedure to invoke them like so:
1170
1171 BEGIN
1172 CALL PGM(PERL5/PERL) PARM('/QOpenSys/hello.pl')
1173 ENDPGM
1174
1175This will invoke the perl script F<hello.pl> in the root of the
1176QOpenSys file system. On the AS/400 calls to C<system> or backticks
1177must use CL syntax.
1178
e41182b5 1179On these platforms, bear in mind that the EBCDIC character set may have
0a47030a
GS
1180an effect on what happens with some perl functions (such as C<chr>,
1181C<pack>, C<print>, C<printf>, C<ord>, C<sort>, C<sprintf>, C<unpack>), as
1182well as bit-fiddling with ASCII constants using operators like C<^>, C<&>
1183and C<|>, not to mention dealing with socket interfaces to ASCII computers
6ab3f9cb 1184(see L<"Newlines">).
e41182b5 1185
b7df3edc
GS
1186Fortunately, most web servers for the mainframe will correctly
1187translate the C<\n> in the following statement to its ASCII equivalent
1188(C<\r> is the same under both Unix and OS/390 & VM/ESA):
e41182b5
GS
1189
1190 print "Content-type: text/html\r\n\r\n";
1191
d1e3b762 1192The values of C<$^O> on some of these platforms includes:
e41182b5 1193
d1e3b762
GS
1194 uname $^O $Config{'archname'}
1195 --------------------------------------------
1196 OS/390 os390 os390
1197 OS400 os400 os400
1198 POSIX-BC posix-bc BS2000-posix-bc
1199 VM/ESA vmesa vmesa
3c075c7d 1200
e41182b5
GS
1201Some simple tricks for determining if you are running on an EBCDIC
1202platform could include any of the following (perhaps all):
1203
1204 if ("\t" eq "\05") { print "EBCDIC may be spoken here!\n"; }
1205
1206 if (ord('A') == 193) { print "EBCDIC may be spoken here!\n"; }
1207
1208 if (chr(169) eq 'z') { print "EBCDIC may be spoken here!\n"; }
1209
b7df3edc 1210One thing you may not want to rely on is the EBCDIC encoding
0a47030a
GS
1211of punctuation characters since these may differ from code page to code
1212page (and once your module or script is rumoured to work with EBCDIC,
1213folks will want it to work with all EBCDIC character sets).
e41182b5
GS
1214
1215Also see:
1216
1217=over 4
1218
c997b287
GS
1219=item *
1220
1221*
d1e3b762 1222
dc5c060f 1223L<perlos390>, F<README.os390>, F<perlbs2000>, F<README.vmesa>,
bb462878 1224L<perlebcdic>.
c997b287
GS
1225
1226=item *
e41182b5
GS
1227
1228The perl-mvs@perl.org list is for discussion of porting issues as well as
1229general usage issues for all EBCDIC Perls. Send a message body of
1230"subscribe perl-mvs" to majordomo@perl.org.
1231
c997b287
GS
1232=item *
1233
1234AS/400 Perl information at
b1866b2d 1235http://as400.rochester.ibm.com/
d1e3b762 1236as well as on CPAN in the F<ports/> directory.
e41182b5
GS
1237
1238=back
1239
b8099c3d
CN
1240=head2 Acorn RISC OS
1241
b7df3edc
GS
1242Because Acorns use ASCII with newlines (C<\n>) in text files as C<\012> like
1243Unix, and because Unix filename emulation is turned on by default,
1244most simple scripts will probably work "out of the box". The native
6ab3f9cb 1245filesystem is modular, and individual filesystems are free to be
0a47030a 1246case-sensitive or insensitive, and are usually case-preserving. Some
b7df3edc 1247native filesystems have name length limits, which file and directory
6ab3f9cb
GS
1248names are silently truncated to fit. Scripts should be aware that the
1249standard filesystem currently has a name length limit of B<10>
1250characters, with up to 77 items in a directory, but other filesystems
0a47030a 1251may not impose such limitations.
b8099c3d
CN
1252
1253Native filenames are of the form
1254
6ab3f9cb 1255 Filesystem#Special_Field::DiskName.$.Directory.Directory.File
dd9f0070 1256
b8099c3d
CN
1257where
1258
1259 Special_Field is not usually present, but may contain . and $ .
1260 Filesystem =~ m|[A-Za-z0-9_]|
1261 DsicName =~ m|[A-Za-z0-9_/]|
1262 $ represents the root directory
1263 . is the path separator
1264 @ is the current directory (per filesystem but machine global)
1265 ^ is the parent directory
1266 Directory and File =~ m|[^\0- "\.\$\%\&:\@\\^\|\177]+|
1267
1268The default filename translation is roughly C<tr|/.|./|;>
1269
6ab3f9cb 1270Note that C<"ADFS::HardDisk.$.File" ne 'ADFS::HardDisk.$.File'> and that
0a47030a
GS
1271the second stage of C<$> interpolation in regular expressions will fall
1272foul of the C<$.> if scripts are not careful.
1273
1274Logical paths specified by system variables containing comma-separated
b7df3edc 1275search lists are also allowed; hence C<System:Modules> is a valid
0a47030a 1276filename, and the filesystem will prefix C<Modules> with each section of
6ab3f9cb 1277C<System$Path> until a name is made that points to an object on disk.
b7df3edc 1278Writing to a new file C<System:Modules> would be allowed only if
0a47030a
GS
1279C<System$Path> contains a single item list. The filesystem will also
1280expand system variables in filenames if enclosed in angle brackets, so
c47ff5f1 1281C<< <System$Dir>.Modules >> would look for the file
0a47030a 1282S<C<$ENV{'System$Dir'} . 'Modules'>>. The obvious implication of this is
c47ff5f1 1283that B<fully qualified filenames can start with C<< <> >>> and should
0a47030a 1284be protected when C<open> is used for input.
b8099c3d
CN
1285
1286Because C<.> was in use as a directory separator and filenames could not
1287be assumed to be unique after 10 characters, Acorn implemented the C
1288compiler to strip the trailing C<.c> C<.h> C<.s> and C<.o> suffix from
1289filenames specified in source code and store the respective files in
b7df3edc 1290subdirectories named after the suffix. Hence files are translated:
b8099c3d
CN
1291
1292 foo.h h.foo
1293 C:foo.h C:h.foo (logical path variable)
1294 sys/os.h sys.h.os (C compiler groks Unix-speak)
1295 10charname.c c.10charname
1296 10charname.o o.10charname
1297 11charname_.c c.11charname (assuming filesystem truncates at 10)
1298
1299The Unix emulation library's translation of filenames to native assumes
b7df3edc
GS
1300that this sort of translation is required, and it allows a user-defined list
1301of known suffixes that it will transpose in this fashion. This may
1302seem transparent, but consider that with these rules C<foo/bar/baz.h>
0a47030a
GS
1303and C<foo/bar/h/baz> both map to C<foo.bar.h.baz>, and that C<readdir> and
1304C<glob> cannot and do not attempt to emulate the reverse mapping. Other
6ab3f9cb 1305C<.>'s in filenames are translated to C</>.
0a47030a 1306
b7df3edc 1307As implied above, the environment accessed through C<%ENV> is global, and
0a47030a 1308the convention is that program specific environment variables are of the
6ab3f9cb
GS
1309form C<Program$Name>. Each filesystem maintains a current directory,
1310and the current filesystem's current directory is the B<global> current
b7df3edc
GS
1311directory. Consequently, sociable programs don't change the current
1312directory but rely on full pathnames, and programs (and Makefiles) cannot
0a47030a
GS
1313assume that they can spawn a child process which can change the current
1314directory without affecting its parent (and everyone else for that
1315matter).
1316
b7df3edc
GS
1317Because native operating system filehandles are global and are currently
1318allocated down from 255, with 0 being a reserved value, the Unix emulation
0a47030a
GS
1319library emulates Unix filehandles. Consequently, you can't rely on
1320passing C<STDIN>, C<STDOUT>, or C<STDERR> to your children.
1321
1322The desire of users to express filenames of the form
c47ff5f1 1323C<< <Foo$Dir>.Bar >> on the command line unquoted causes problems,
0a47030a 1324too: C<``> command output capture has to perform a guessing game. It
c47ff5f1 1325assumes that a string C<< <[^<>]+\$[^<>]> >> is a
0a47030a 1326reference to an environment variable, whereas anything else involving
c47ff5f1 1327C<< < >> or C<< > >> is redirection, and generally manages to be 99%
0a47030a
GS
1328right. Of course, the problem remains that scripts cannot rely on any
1329Unix tools being available, or that any tools found have Unix-like command
1330line arguments.
1331
b7df3edc
GS
1332Extensions and XS are, in theory, buildable by anyone using free
1333tools. In practice, many don't, as users of the Acorn platform are
1334used to binary distributions. MakeMaker does run, but no available
1335make currently copes with MakeMaker's makefiles; even if and when
1336this should be fixed, the lack of a Unix-like shell will cause
1337problems with makefile rules, especially lines of the form C<cd
1338sdbm && make all>, and anything using quoting.
b8099c3d
CN
1339
1340"S<RISC OS>" is the proper name for the operating system, but the value
1341in C<$^O> is "riscos" (because we don't like shouting).
1342
e41182b5
GS
1343=head2 Other perls
1344
b7df3edc
GS
1345Perl has been ported to many platforms that do not fit into any of
1346the categories listed above. Some, such as AmigaOS, Atari MiNT,
1347BeOS, HP MPE/iX, QNX, Plan 9, and VOS, have been well-integrated
1348into the standard Perl source code kit. You may need to see the
1349F<ports/> directory on CPAN for information, and possibly binaries,
1350for the likes of: aos, Atari ST, lynxos, riscos, Novell Netware,
1351Tandem Guardian, I<etc.> (Yes, we know that some of these OSes may
1352fall under the Unix category, but we are not a standards body.)
e41182b5 1353
d1e3b762
GS
1354Some approximate operating system names and their C<$^O> values
1355in the "OTHER" category include:
1356
1357 OS $^O $Config{'archname'}
1358 ------------------------------------------
1359 Amiga DOS amigaos m68k-amigos
1360 MPE/iX mpeix PA-RISC1.1
1361
e41182b5
GS
1362See also:
1363
1364=over 4
1365
c997b287
GS
1366=item *
1367
1368Amiga, F<README.amiga> (installed as L<perlamiga>).
1369
1370=item *
d1e3b762 1371
c997b287
GS
1372Atari, F<README.mint> and Guido Flohr's web page
1373http://stud.uni-sb.de/~gufl0000/
e41182b5 1374
c997b287 1375=item *
d1e3b762 1376
c997b287 1377Be OS, F<README.beos>
e41182b5 1378
c997b287
GS
1379=item *
1380
1381HP 300 MPE/iX, F<README.mpeix> and Mark Bixby's web page
34aaaa84 1382http://www.bixby.org/mark/perlix.html
c997b287
GS
1383
1384=item *
e41182b5 1385
6ab3f9cb 1386A free perl5-based PERL.NLM for Novell Netware is available in
c997b287 1387precompiled binary and source code form from http://www.novell.com/
6ab3f9cb 1388as well as from CPAN.
e41182b5 1389
13a2d996 1390=item *
c997b287
GS
1391
1392Plan 9, F<README.plan9>
d1e3b762 1393
e41182b5
GS
1394=back
1395
e41182b5
GS
1396=head1 FUNCTION IMPLEMENTATIONS
1397
b7df3edc
GS
1398Listed below are functions that are either completely unimplemented
1399or else have been implemented differently on various platforms.
1400Following each description will be, in parentheses, a list of
1401platforms that the description applies to.
e41182b5 1402
b7df3edc
GS
1403The list may well be incomplete, or even wrong in some places. When
1404in doubt, consult the platform-specific README files in the Perl
1405source distribution, and any other documentation resources accompanying
1406a given port.
e41182b5 1407
0a47030a 1408Be aware, moreover, that even among Unix-ish systems there are variations.
e41182b5 1409
b7df3edc
GS
1410For many functions, you can also query C<%Config>, exported by
1411default from the Config module. For example, to check whether the
1412platform has the C<lstat> call, check C<$Config{d_lstat}>. See
1413L<Config> for a full description of available variables.
e41182b5
GS
1414
1415=head2 Alphabetical Listing of Perl Functions
1416
1417=over 8
1418
1419=item -X FILEHANDLE
1420
1421=item -X EXPR
1422
1423=item -X
1424
b7df3edc 1425C<-r>, C<-w>, and C<-x> have a limited meaning only; directories
e41182b5 1426and applications are executable, and there are no uid/gid
b7df3edc 1427considerations. C<-o> is not supported. (S<Mac OS>)
e41182b5 1428
b7df3edc
GS
1429C<-r>, C<-w>, C<-x>, and C<-o> tell whether the file is accessible,
1430which may not reflect UIC-based file protections. (VMS)
e41182b5 1431
b8099c3d
CN
1432C<-s> returns the size of the data fork, not the total size of data fork
1433plus resource fork. (S<Mac OS>).
1434
1435C<-s> by name on an open file will return the space reserved on disk,
1436rather than the current extent. C<-s> on an open filehandle returns the
b7df3edc 1437current size. (S<RISC OS>)
b8099c3d 1438
e41182b5 1439C<-R>, C<-W>, C<-X>, C<-O> are indistinguishable from C<-r>, C<-w>,
b8099c3d 1440C<-x>, C<-o>. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1441
1442C<-b>, C<-c>, C<-k>, C<-g>, C<-p>, C<-u>, C<-A> are not implemented.
1443(S<Mac OS>)
1444
1445C<-g>, C<-k>, C<-l>, C<-p>, C<-u>, C<-A> are not particularly meaningful.
b8099c3d 1446(Win32, VMS, S<RISC OS>)
e41182b5
GS
1447
1448C<-d> is true if passed a device spec without an explicit directory.
1449(VMS)
1450
1451C<-T> and C<-B> are implemented, but might misclassify Mac text files
0a47030a 1452with foreign characters; this is the case will all platforms, but may
b7df3edc 1453affect S<Mac OS> often. (S<Mac OS>)
e41182b5
GS
1454
1455C<-x> (or C<-X>) determine if a file ends in one of the executable
b7df3edc 1456suffixes. C<-S> is meaningless. (Win32)
e41182b5 1457
b8099c3d
CN
1458C<-x> (or C<-X>) determine if a file has an executable file type.
1459(S<RISC OS>)
1460
63f87e49
GS
1461=item alarm SECONDS
1462
1463=item alarm
1464
1465Not implemented. (Win32)
1466
e41182b5
GS
1467=item binmode FILEHANDLE
1468
b7df3edc 1469Meaningless. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1470
1471Reopens file and restores pointer; if function fails, underlying
1472filehandle may be closed, or pointer may be in a different position.
1473(VMS)
1474
1475The value returned by C<tell> may be affected after the call, and
1476the filehandle may be flushed. (Win32)
1477
1478=item chmod LIST
1479
b7df3edc 1480Only limited meaning. Disabling/enabling write permission is mapped to
e41182b5
GS
1481locking/unlocking the file. (S<Mac OS>)
1482
1483Only good for changing "owner" read-write access, "group", and "other"
1484bits are meaningless. (Win32)
1485
b8099c3d
CN
1486Only good for changing "owner" and "other" read-write access. (S<RISC OS>)
1487
495c5fdc
GP
1488Access permissions are mapped onto VOS access-control list changes. (VOS)
1489
4e51f8e4 1490The actual permissions set depend on the value of the C<CYGWIN>
789f0d36 1491in the SYSTEM environment settings. (Cygwin)
4e51f8e4 1492
e41182b5
GS
1493=item chown LIST
1494
495c5fdc 1495Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>, VOS)
e41182b5
GS
1496
1497Does nothing, but won't fail. (Win32)
1498
1499=item chroot FILENAME
1500
1501=item chroot
1502
7c5ffed3 1503Not implemented. (S<Mac OS>, Win32, VMS, Plan9, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1504
1505=item crypt PLAINTEXT,SALT
1506
1507May not be available if library or source was not provided when building
b8099c3d 1508perl. (Win32)
e41182b5 1509
495c5fdc
GP
1510Not implemented. (VOS)
1511
e41182b5
GS
1512=item dbmclose HASH
1513
495c5fdc 1514Not implemented. (VMS, Plan9, VOS)
e41182b5
GS
1515
1516=item dbmopen HASH,DBNAME,MODE
1517
495c5fdc 1518Not implemented. (VMS, Plan9, VOS)
e41182b5
GS
1519
1520=item dump LABEL
1521
b8099c3d 1522Not useful. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1523
1524Not implemented. (Win32)
1525
b8099c3d 1526Invokes VMS debugger. (VMS)
e41182b5
GS
1527
1528=item exec LIST
1529
1530Not implemented. (S<Mac OS>)
1531
7c5ffed3 1532Implemented via Spawn. (VM/ESA)
3c075c7d 1533
0f897271
GS
1534Does not automatically flush output handles on some platforms.
1535(SunOS, Solaris, HP-UX)
1536
fe12c0e8
MS
1537=item exit EXPR
1538
1539=item exit
1540
1541Emulates UNIX exit() (which considers C<exit 1> to indicate an error) by
1542mapping the C<1> to SS$_ABORT (C<44>). This behavior may be overridden
1543with the pragma C<use vmsish 'exit'>. As with the CRTL's exit()
1544function, C<exit 0> is also mapped to an exit status of SS$_NORMAL
1545(C<1>); this mapping cannot be overridden. Any other argument to exit()
1546is used directly as Perl's exit status. (VMS)
1547
e41182b5
GS
1548=item fcntl FILEHANDLE,FUNCTION,SCALAR
1549
1550Not implemented. (Win32, VMS)
1551
1552=item flock FILEHANDLE,OPERATION
1553
495c5fdc 1554Not implemented (S<Mac OS>, VMS, S<RISC OS>, VOS).
e41182b5
GS
1555
1556Available only on Windows NT (not on Windows 95). (Win32)
1557
1558=item fork
1559
0f897271
GS
1560Not implemented. (S<Mac OS>, AmigaOS, S<RISC OS>, VOS, VM/ESA)
1561
1562Emulated using multiple interpreters. See L<perlfork>. (Win32)
1563
1564Does not automatically flush output handles on some platforms.
1565(SunOS, Solaris, HP-UX)
e41182b5
GS
1566
1567=item getlogin
1568
b8099c3d 1569Not implemented. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1570
1571=item getpgrp PID
1572
495c5fdc 1573Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5
GS
1574
1575=item getppid
1576
b8099c3d 1577Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1578
1579=item getpriority WHICH,WHO
1580
7c5ffed3 1581Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1582
1583=item getpwnam NAME
1584
1585Not implemented. (S<Mac OS>, Win32)
1586
b8099c3d
CN
1587Not useful. (S<RISC OS>)
1588
e41182b5
GS
1589=item getgrnam NAME
1590
b8099c3d 1591Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1592
1593=item getnetbyname NAME
1594
1595Not implemented. (S<Mac OS>, Win32, Plan9)
1596
1597=item getpwuid UID
1598
1599Not implemented. (S<Mac OS>, Win32)
1600
b8099c3d
CN
1601Not useful. (S<RISC OS>)
1602
e41182b5
GS
1603=item getgrgid GID
1604
b8099c3d 1605Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1606
1607=item getnetbyaddr ADDR,ADDRTYPE
1608
1609Not implemented. (S<Mac OS>, Win32, Plan9)
1610
1611=item getprotobynumber NUMBER
1612
1613Not implemented. (S<Mac OS>)
1614
1615=item getservbyport PORT,PROTO
1616
1617Not implemented. (S<Mac OS>)
1618
1619=item getpwent
1620
7c5ffed3 1621Not implemented. (S<Mac OS>, Win32, VM/ESA)
e41182b5
GS
1622
1623=item getgrent
1624
7c5ffed3 1625Not implemented. (S<Mac OS>, Win32, VMS, VM/ESA)
e41182b5
GS
1626
1627=item gethostent
1628
1629Not implemented. (S<Mac OS>, Win32)
1630
1631=item getnetent
1632
1633Not implemented. (S<Mac OS>, Win32, Plan9)
1634
1635=item getprotoent
1636
1637Not implemented. (S<Mac OS>, Win32, Plan9)
1638
1639=item getservent
1640
1641Not implemented. (Win32, Plan9)
1642
e41182b5
GS
1643=item sethostent STAYOPEN
1644
b8099c3d 1645Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>)
e41182b5
GS
1646
1647=item setnetent STAYOPEN
1648
b8099c3d 1649Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>)
e41182b5
GS
1650
1651=item setprotoent STAYOPEN
1652
b8099c3d 1653Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>)
e41182b5
GS
1654
1655=item setservent STAYOPEN
1656
b8099c3d 1657Not implemented. (Plan9, Win32, S<RISC OS>)
e41182b5
GS
1658
1659=item endpwent
1660
a3dfe201 1661Not implemented. (S<Mac OS>, MPE/iX, VM/ESA, Win32)
e41182b5
GS
1662
1663=item endgrent
1664
a3dfe201 1665Not implemented. (S<Mac OS>, MPE/iX, S<RISC OS>, VM/ESA, VMS, Win32)
e41182b5
GS
1666
1667=item endhostent
1668
1669Not implemented. (S<Mac OS>, Win32)
1670
1671=item endnetent
1672
1673Not implemented. (S<Mac OS>, Win32, Plan9)
1674
1675=item endprotoent
1676
1677Not implemented. (S<Mac OS>, Win32, Plan9)
1678
1679=item endservent
1680
1681Not implemented. (Plan9, Win32)
1682
1683=item getsockopt SOCKET,LEVEL,OPTNAME
1684
97c10e77 1685Not implemented. (Plan9)
e41182b5
GS
1686
1687=item glob EXPR
1688
1689=item glob
1690
63f87e49
GS
1691This operator is implemented via the File::Glob extension on most
1692platforms. See L<File::Glob> for portability information.
b8099c3d 1693
e41182b5
GS
1694=item ioctl FILEHANDLE,FUNCTION,SCALAR
1695
1696Not implemented. (VMS)
1697
1698Available only for socket handles, and it does what the ioctlsocket() call
1699in the Winsock API does. (Win32)
1700
b8099c3d
CN
1701Available only for socket handles. (S<RISC OS>)
1702
b350dd2f 1703=item kill SIGNAL, LIST
e41182b5 1704
862b5365
JH
1705C<kill(0, LIST)> is implemented for the sake of taint checking;
1706use with other signals is unimplemented. (S<Mac OS>)
1707
1708Not implemented, hence not useful for taint checking. (S<RISC OS>)
e41182b5 1709
63f87e49
GS
1710C<kill()> doesn't have the semantics of C<raise()>, i.e. it doesn't send
1711a signal to the identified process like it does on Unix platforms.
1712Instead C<kill($sig, $pid)> terminates the process identified by $pid,
1713and makes it exit immediately with exit status $sig. As in Unix, if
1714$sig is 0 and the specified process exists, it returns true without
1715actually terminating it. (Win32)
e41182b5
GS
1716
1717=item link OLDFILE,NEWFILE
1718
a3dfe201 1719Not implemented. (S<Mac OS>, MPE/iX, VMS, S<RISC OS>)
e41182b5 1720
433acd8a
JH
1721Link count not updated because hard links are not quite that hard
1722(They are sort of half-way between hard and soft links). (AmigaOS)
1723
a3dfe201
GS
1724Hard links are implemented on Win32 (Windows NT and Windows 2000)
1725under NTFS only.
1726
e41182b5
GS
1727=item lstat FILEHANDLE
1728
1729=item lstat EXPR
1730
1731=item lstat
1732
b8099c3d 1733Not implemented. (VMS, S<RISC OS>)
e41182b5 1734
63f87e49 1735Return values (especially for device and inode) may be bogus. (Win32)
e41182b5
GS
1736
1737=item msgctl ID,CMD,ARG
1738
1739=item msgget KEY,FLAGS
1740
1741=item msgsnd ID,MSG,FLAGS
1742
1743=item msgrcv ID,VAR,SIZE,TYPE,FLAGS
1744
495c5fdc 1745Not implemented. (S<Mac OS>, Win32, VMS, Plan9, S<RISC OS>, VOS)
e41182b5
GS
1746
1747=item open FILEHANDLE,EXPR
1748
1749=item open FILEHANDLE
1750
b7df3edc 1751The C<|> variants are supported only if ToolServer is installed.
e41182b5
GS
1752(S<Mac OS>)
1753
c47ff5f1 1754open to C<|-> and C<-|> are unsupported. (S<Mac OS>, Win32, S<RISC OS>)
e41182b5 1755
0f897271
GS
1756Opening a process does not automatically flush output handles on some
1757platforms. (SunOS, Solaris, HP-UX)
1758
e41182b5
GS
1759=item pipe READHANDLE,WRITEHANDLE
1760
433acd8a
JH
1761Very limited functionality. (MiNT)
1762
e41182b5
GS
1763=item readlink EXPR
1764
1765=item readlink
1766
b8099c3d 1767Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5
GS
1768
1769=item select RBITS,WBITS,EBITS,TIMEOUT
1770
689c5c24 1771Only implemented on sockets. (Win32, VMS)
e41182b5 1772
b8099c3d
CN
1773Only reliable on sockets. (S<RISC OS>)
1774
76e05f0b 1775Note that the C<select FILEHANDLE> form is generally portable.
63f87e49 1776
e41182b5
GS
1777=item semctl ID,SEMNUM,CMD,ARG
1778
1779=item semget KEY,NSEMS,FLAGS
1780
1781=item semop KEY,OPSTRING
1782
495c5fdc 1783Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1784
a3dfe201
GS
1785=item setgrent
1786
74555b7a 1787Not implemented. (S<Mac OS>, MPE/iX, VMS, Win32, VMS, S<RISC OS>)
a3dfe201 1788
e41182b5
GS
1789=item setpgrp PID,PGRP
1790
495c5fdc 1791Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5
GS
1792
1793=item setpriority WHICH,WHO,PRIORITY
1794
495c5fdc 1795Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1796
a3dfe201
GS
1797=item setpwent
1798
74555b7a 1799Not implemented. (S<Mac OS>, MPE/iX, Win32, S<RISC OS>)
a3dfe201 1800
e41182b5
GS
1801=item setsockopt SOCKET,LEVEL,OPTNAME,OPTVAL
1802
97c10e77 1803Not implemented. (Plan9)
e41182b5
GS
1804
1805=item shmctl ID,CMD,ARG
1806
1807=item shmget KEY,SIZE,FLAGS
1808
1809=item shmread ID,VAR,POS,SIZE
1810
1811=item shmwrite ID,STRING,POS,SIZE
1812
495c5fdc 1813Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1814
80cbd5ad
JH
1815=item sockatmark SOCKET
1816
1817A relatively recent addition to socket functions, may not
1818be implemented even in UNIX platforms.
1819
e41182b5
GS
1820=item socketpair SOCKET1,SOCKET2,DOMAIN,TYPE,PROTOCOL
1821
862b5365 1822Not implemented. (Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1823
1824=item stat FILEHANDLE
1825
1826=item stat EXPR
1827
1828=item stat
1829
d62e1b7f
JH
1830Platforms that do not have rdev, blksize, or blocks will return these
1831as '', so numeric comparison or manipulation of these fields may cause
1832'not numeric' warnings.
1833
e41182b5 1834mtime and atime are the same thing, and ctime is creation time instead of
3f1f789b
JH
1835inode change time. (S<Mac OS>).
1836
1837ctime not supported on UFS (S<Mac OS X>).
e41182b5 1838
95a3fe12
MS
1839ctime is creation time instead of inode change time (Win32).
1840
e41182b5
GS
1841device and inode are not meaningful. (Win32)
1842
1843device and inode are not necessarily reliable. (VMS)
1844
b8099c3d
CN
1845mtime, atime and ctime all return the last modification time. Device and
1846inode are not necessarily reliable. (S<RISC OS>)
1847
d62e1b7f
JH
1848dev, rdev, blksize, and blocks are not available. inode is not
1849meaningful and will differ between stat calls on the same file. (os2)
1850
73e9292c
JH
1851some versions of cygwin when doing a stat("foo") and if not finding it
1852may then attempt to stat("foo.exe") (Cygwin)
1853
e41182b5
GS
1854=item symlink OLDFILE,NEWFILE
1855
b8099c3d 1856Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5
GS
1857
1858=item syscall LIST
1859
7c5ffed3 1860Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5 1861
f34d0673
GS
1862=item sysopen FILEHANDLE,FILENAME,MODE,PERMS
1863
dd9f0070 1864The traditional "0", "1", and "2" MODEs are implemented with different
322422de
GS
1865numeric values on some systems. The flags exported by C<Fcntl>
1866(O_RDONLY, O_WRONLY, O_RDWR) should work everywhere though. (S<Mac
7c5ffed3 1867OS>, OS/390, VM/ESA)
f34d0673 1868
e41182b5
GS
1869=item system LIST
1870
9d6eb86e 1871In general, do not assume the UNIX/POSIX semantics that you can shift
7717d0e7 1872C<$?> right by eight to get the exit value, or that C<$? & 127>
9d6eb86e
JH
1873would give you the number of the signal that terminated the program,
1874or that C<$? & 128> would test true if the program was terminated by a
1875coredump. Instead, use the POSIX W*() interfaces: for example, use
74555b7a
PP
1876WIFEXITED($?) and WEXITVALUE($?) to test for a normal exit and the exit
1877value, WIFSIGNALED($?) and WTERMSIG($?) for a signal exit and the
7717d0e7 1878signal. Core dumping is not a portable concept, so there's no portable
9d6eb86e
JH
1879way to test for that.
1880
e41182b5
GS
1881Only implemented if ToolServer is installed. (S<Mac OS>)
1882
1883As an optimization, may not call the command shell specified in
b7df3edc 1884C<$ENV{PERL5SHELL}>. C<system(1, @args)> spawns an external
e41182b5
GS
1885process and immediately returns its process designator, without
1886waiting for it to terminate. Return value may be used subsequently
63f87e49
GS
1887in C<wait> or C<waitpid>. Failure to spawn() a subprocess is indicated
1888by setting $? to "255 << 8". C<$?> is set in a way compatible with
1889Unix (i.e. the exitstatus of the subprocess is obtained by "$? >> 8",
1890as described in the documentation). (Win32)
e41182b5 1891
b8099c3d
CN
1892There is no shell to process metacharacters, and the native standard is
1893to pass a command line terminated by "\n" "\r" or "\0" to the spawned
c47ff5f1 1894program. Redirection such as C<< > foo >> is performed (if at all) by
b8099c3d
CN
1895the run time library of the spawned program. C<system> I<list> will call
1896the Unix emulation library's C<exec> emulation, which attempts to provide
1897emulation of the stdin, stdout, stderr in force in the parent, providing
1898the child program uses a compatible version of the emulation library.
1899I<scalar> will call the native command line direct and no such emulation
1900of a child Unix program will exists. Mileage B<will> vary. (S<RISC OS>)
1901
433acd8a
JH
1902Far from being POSIX compliant. Because there may be no underlying
1903/bin/sh tries to work around the problem by forking and execing the
9b63e9ec 1904first token in its argument string. Handles basic redirection
c47ff5f1 1905("<" or ">") on its own behalf. (MiNT)
433acd8a 1906
0f897271
GS
1907Does not automatically flush output handles on some platforms.
1908(SunOS, Solaris, HP-UX)
1909
9bc98430
CB
1910The return value is POSIX-like (shifted up by 8 bits), which only allows
1911room for a made-up value derived from the severity bits of the native
191232-bit condition code (unless overridden by C<use vmsish 'status'>).
1913For more details see L<perlvms/$?>. (VMS)
1914
e41182b5
GS
1915=item times
1916
1917Only the first entry returned is nonzero. (S<Mac OS>)
1918
63f87e49
GS
1919"cumulative" times will be bogus. On anything other than Windows NT
1920or Windows 2000, "system" time will be bogus, and "user" time is
1921actually the time returned by the clock() function in the C runtime
1922library. (Win32)
e41182b5 1923
b8099c3d
CN
1924Not useful. (S<RISC OS>)
1925
e41182b5
GS
1926=item truncate FILEHANDLE,LENGTH
1927
1928=item truncate EXPR,LENGTH
1929
6d738113 1930Not implemented. (Older versions of VMS)
e41182b5 1931
495c5fdc
GP
1932Truncation to zero-length only. (VOS)
1933
4cfdb94f 1934If a FILEHANDLE is supplied, it must be writable and opened in append
e71a7dc8 1935mode (i.e., use C<<< open(FH, '>>filename') >>>
4cfdb94f
GS
1936or C<sysopen(FH,...,O_APPEND|O_RDWR)>. If a filename is supplied, it
1937should not be held open elsewhere. (Win32)
1938
e41182b5
GS
1939=item umask EXPR
1940
1941=item umask
1942
1943Returns undef where unavailable, as of version 5.005.
1944
b7df3edc
GS
1945C<umask> works but the correct permissions are set only when the file
1946is finally closed. (AmigaOS)
433acd8a 1947
e41182b5
GS
1948=item utime LIST
1949
15c65113 1950Only the modification time is updated. (S<BeOS>, S<Mac OS>, VMS, S<RISC OS>)
e41182b5 1951
322422de
GS
1952May not behave as expected. Behavior depends on the C runtime
1953library's implementation of utime(), and the filesystem being
1954used. The FAT filesystem typically does not support an "access
1955time" field, and it may limit timestamps to a granularity of
1956two seconds. (Win32)
e41182b5
GS
1957
1958=item wait
1959
1960=item waitpid PID,FLAGS
1961
495c5fdc 1962Not implemented. (S<Mac OS>, VOS)
e41182b5
GS
1963
1964Can only be applied to process handles returned for processes spawned
a6f858fb 1965using C<system(1, ...)> or pseudo processes created with C<fork()>. (Win32)
e41182b5 1966
b8099c3d
CN
1967Not useful. (S<RISC OS>)
1968
e41182b5
GS
1969=back
1970
b8099c3d
CN
1971=head1 CHANGES
1972
1973=over 4
1974
fd46a41b
JH
1975=item v1.48, 02 February 2001
1976
1977Various updates from perl5-porters over the past year, supported
1978platforms update from Jarkko Hietaniemi.
1979
c997b287
GS
1980=item v1.47, 22 March 2000
1981
1982Various cleanups from Tom Christiansen, including migration of
1983long platform listings from L<perl>.
1984
56d7751a
GS
1985=item v1.46, 12 February 2000
1986
1987Updates for VOS and MPE/iX. (Peter Prymmer) Other small changes.
1988
0cc436d0
GS
1989=item v1.45, 20 December 1999
1990
1991Small changes from 5.005_63 distribution, more changes to EBCDIC info.
1992
d1e3b762
GS
1993=item v1.44, 19 July 1999
1994
1995A bunch of updates from Peter Prymmer for C<$^O> values,
1996endianness, File::Spec, VMS, BS2000, OS/400.
1997
b7df3edc
GS
1998=item v1.43, 24 May 1999
1999
2000Added a lot of cleaning up from Tom Christiansen.
2001
19799a22 2002=item v1.42, 22 May 1999
b7df3edc 2003
19799a22 2004Added notes about tests, sprintf/printf, and epoch offsets.
b7df3edc 2005
6ab3f9cb
GS
2006=item v1.41, 19 May 1999
2007
2008Lots more little changes to formatting and content.
2009
d1e3b762 2010Added a bunch of C<$^O> and related values
6ab3f9cb
GS
2011for various platforms; fixed mail and web addresses, and added
2012and changed miscellaneous notes. (Peter Prymmer)
2013
2014=item v1.40, 11 April 1999
2015
2016Miscellaneous changes.
2017
2018=item v1.39, 11 February 1999
2ee0eb3c
CN
2019
2020Changes from Jarkko and EMX URL fixes Michael Schwern. Additional
2021note about newlines added.
2022
9b63e9ec
CN
2023=item v1.38, 31 December 1998
2024
2025More changes from Jarkko.
2026
3c075c7d
CN
2027=item v1.37, 19 December 1998
2028
2029More minor changes. Merge two separate version 1.35 documents.
2030
2031=item v1.36, 9 September 1998
2032
2033Updated for Stratus VOS. Also known as version 1.35.
2034
2035=item v1.35, 13 August 1998
495c5fdc 2036
3c075c7d
CN
2037Integrate more minor changes, plus addition of new sections under
2038L<"ISSUES">: L<"Numbers endianness and Width">,
2039L<"Character sets and character encoding">,
2040L<"Internationalisation">.
495c5fdc 2041
3c075c7d 2042=item v1.33, 06 August 1998
0a47030a
GS
2043
2044Integrate more minor changes.
2045
3c075c7d 2046=item v1.32, 05 August 1998
dd9f0070
CN
2047
2048Integrate more minor changes.
2049
3c075c7d 2050=item v1.30, 03 August 1998
b8099c3d
CN
2051
2052Major update for RISC OS, other minor changes.
2053
3c075c7d 2054=item v1.23, 10 July 1998
b8099c3d
CN
2055
2056First public release with perl5.005.
2057
2058=back
e41182b5 2059
ba58ab26
JH
2060=head1 Supported Platforms
2061
9ca74005
JH
2062As of early 2001 (the Perl releases 5.6.1 and 5.7.1), the following
2063platforms are able to build Perl from the standard source code
a93751fa 2064distribution available at http://www.cpan.org/src/index.html
ba58ab26
JH
2065
2066 AIX
fd46a41b 2067 AmigaOS
b787fad4 2068 Darwin (Mac OS X)
fd46a41b 2069 DG/UX
ba58ab26 2070 DOS DJGPP 1)
fd46a41b 2071 DYNIX/ptx
2585f9a3 2072 EPOC R5
ba58ab26
JH
2073 FreeBSD
2074 HP-UX
2075 IRIX
2076 Linux
ba58ab26 2077 MachTen
fd46a41b
JH
2078 MacOS Classic 2)
2079 NonStop-UX
2080 ReliantUNIX (SINIX)
ba58ab26 2081 OpenBSD
fd46a41b 2082 OpenVMS (VMS)
ba58ab26 2083 OS/2
fd46a41b 2084 OS X
ba58ab26 2085 QNX
ba58ab26 2086 Solaris
fd46a41b 2087 Tru64 UNIX (DEC OSF/1, Digital UNIX)
ba58ab26
JH
2088 UNICOS
2089 UNICOS/mk
ba58ab26 2090 VOS
fd46a41b 2091 Win32/NT/2K 3)
ba58ab26
JH
2092
2093 1) in DOS mode either the DOS or OS/2 ports can be used
fd46a41b
JH
2094 2) Mac OS Classic (pre-X) is almost 5.6.1-ready; building from
2095 the source does work with 5.6.1, but additional MacOS specific
862b5365
JH
2096 source code is needed for a complete build. See the web
2097 site http://dev.macperl.org/ for more information.
fd46a41b 2098 3) compilers: Borland, Cygwin, Mingw32 EGCS/GCC, VC++
ba58ab26 2099
9ca74005
JH
2100The following platforms worked for the previous releases (5.6.0 and 5.7.0),
2101but we did not manage to test these in time for the 5.7.1 release.
2102There is a very good chance that these will work fine with the 5.7.1.
ba58ab26 2103
ba58ab26
JH
2104 DomainOS
2105 Hurd
fd46a41b
JH
2106 LynxOS
2107 MinGW
2108 MPE/iX
2109 NetBSD
ba58ab26 2110 PowerMAX
fd46a41b 2111 SCO SV
ba58ab26 2112 SunOS
fd46a41b
JH
2113 SVR4
2114 Unixware
2115 Windows 3.1
2116 Windows 95
2117 Windows 98
2118 Windows Me
ba58ab26 2119
fd46a41b 2120The following platform worked for the 5.005_03 major release but not
9ca74005
JH
2121for 5.6.0. Standardization on UTF-8 as the internal string
2122representation in 5.6.0 and 5.6.1 introduced incompatibilities in this
2123EBCDIC platform. While Perl 5.7.1 will build on this platform some
fd46a41b 2124regression tests may fail and the C<use utf8;> pragma typically
9ca74005 2125introduces text handling errors.
ba58ab26 2126
fd46a41b 2127 OS/390 1)
ba58ab26 2128
fd46a41b 2129 1) previously known as MVS, about to become z/OS.
ba58ab26 2130
fd46a41b 2131Strongly related to the OS/390 platform by also being EBCDIC-based
ba58ab26
JH
2132mainframe platforms are the following platforms:
2133
fd46a41b 2134 POSIX-BC (BS2000)
ba58ab26
JH
2135 VM/ESA
2136
fd46a41b
JH
2137These are also expected to work, albeit with no UTF-8 support, under 5.6.1
2138for the same reasons as OS/390. Contact the mailing list perl-mvs@perl.org
2139for more details.
ba58ab26
JH
2140
2141The following platforms have been known to build Perl from source in
fd46a41b
JH
2142the past (5.005_03 and earlier), but we haven't been able to verify
2143their status for the current release, either because the
2144hardware/software platforms are rare or because we don't have an
2145active champion on these platforms--or both. They used to work,
2146though, so go ahead and try compiling them, and let perlbug@perl.org
2147of any trouble.
ba58ab26
JH
2148
2149 3b1
fd46a41b
JH
2150 A/UX
2151 BeOS
2152 BSD/OS
ba58ab26
JH
2153 ConvexOS
2154 CX/UX
2155 DC/OSx
2156 DDE SMES
2157 DOS EMX
2158 Dynix
2159 EP/IX
2160 ESIX
2161 FPS
2162 GENIX
2163 Greenhills
2164 ISC
2165 MachTen 68k
2166 MiNT
2167 MPC
2168 NEWS-OS
fd46a41b
JH
2169 NextSTEP
2170 OpenSTEP
ba58ab26
JH
2171 Opus
2172 Plan 9
2173 PowerUX
2174 RISC/os
fd46a41b 2175 SCO ODT/OSR
ba58ab26
JH
2176 Stellar
2177 SVR2
2178 TI1500
2179 TitanOS
fd46a41b 2180 Ultrix
ba58ab26
JH
2181 Unisys Dynix
2182 Unixware
fd46a41b 2183 UTS
ba58ab26
JH
2184
2185Support for the following platform is planned for a future Perl release:
2186
2187 Netware
2188
2189The following platforms have their own source code distributions and
1577cd80 2190binaries available via http://www.cpan.org/ports/
ba58ab26
JH
2191
2192 Perl release
2193
ba58ab26 2194 Netware 5.003_07
fd46a41b 2195 OS/400 5.005_02
ba58ab26
JH
2196 Tandem Guardian 5.004
2197
2198The following platforms have only binaries available via
a93751fa 2199http://www.cpan.org/ports/index.html :
ba58ab26
JH
2200
2201 Perl release
2202
2203 Acorn RISCOS 5.005_02
2204 AOS 5.002
2205 LynxOS 5.004_02
2206
2207Although we do suggest that you always build your own Perl from
2208the source code, both for maximal configurability and for security,
2209in case you are in a hurry you can check
a93751fa 2210http://www.cpan.org/ports/index.html for binary distributions.
ba58ab26 2211
c997b287
GS
2212=head1 SEE ALSO
2213
a83b6f46 2214L<perlaix>, L<perlapollo>, L<perlamiga>, L<perlbeos>, L<perlbs200>,
a1f19229 2215L<perlce>, L<perlcygwin>, L<perldgux>, L<perldos>, L<perlepoc>, L<perlebcdic>,
a83b6f46 2216L<perlhurd>, L<perlhpux>, L<perlmachten>, L<perlmacos>, L<perlmint>,
9038e305
JH
2217L<perlmpeix>, L<perlnetware>, L<perlos2>, L<perlos390>, L<perlplan9>,
2218L<perlqnx>, L<perlsolaris>, L<perltru64>, L<perlunicode>,
2219L<perlvmesa>, L<perlvms>, L<perlvos>, L<perlwin32>, and L<Win32>.
c997b287 2220
e41182b5
GS
2221=head1 AUTHORS / CONTRIBUTORS
2222
06e9666b 2223Abigail <abigail@foad.org>,
c47ff5f1
GS
2224Charles Bailey <bailey@newman.upenn.edu>,
2225Graham Barr <gbarr@pobox.com>,
2226Tom Christiansen <tchrist@perl.com>,
06e9666b 2227Nicholas Clark <nick@ccl4.org>,
c47ff5f1 2228Thomas Dorner <Thomas.Dorner@start.de>,
06e9666b
A
2229Andy Dougherty <doughera@lafayette.edu>,
2230Dominic Dunlop <domo@computer.org>,
2231Neale Ferguson <neale@vma.tabnsw.com.au>,
c47ff5f1
GS
2232David J. Fiander <davidf@mks.com>,
2233Paul Green <Paul_Green@stratus.com>,
06e9666b 2234M.J.T. Guy <mjtg@cam.ac.uk>,
61f30a5e 2235Jarkko Hietaniemi <jhi@iki.fi>,
c47ff5f1 2236Luther Huffman <lutherh@stratcom.com>,
06e9666b
A
2237Nick Ing-Simmons <nick@ing-simmons.net>,
2238Andreas J. KE<ouml>nig <a.koenig@mind.de>,
c47ff5f1
GS
2239Markus Laker <mlaker@contax.co.uk>,
2240Andrew M. Langmead <aml@world.std.com>,
2241Larry Moore <ljmoore@freespace.net>,
2242Paul Moore <Paul.Moore@uk.origin-it.com>,
2243Chris Nandor <pudge@pobox.com>,
1afc07ec 2244Matthias Neeracher <neeracher@mac.com>,
e71a7dc8 2245Philip Newton <pne@cpan.org>,
c47ff5f1
GS
2246Gary Ng <71564.1743@CompuServe.COM>,
2247Tom Phoenix <rootbeer@teleport.com>,
2248AndrE<eacute> Pirard <A.Pirard@ulg.ac.be>,
2249Peter Prymmer <pvhp@forte.com>,
2250Hugo van der Sanden <hv@crypt0.demon.co.uk>,
2251Gurusamy Sarathy <gsar@activestate.com>,
2252Paul J. Schinder <schinder@pobox.com>,
2253Michael G Schwern <schwern@pobox.com>,
06e9666b 2254Dan Sugalski <dan@sidhe.org>,
c47ff5f1 2255Nathan Torkington <gnat@frii.com>.
e41182b5 2256