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1=head1 NAME
2
3perlport - Writing portable Perl
4
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5=head1 DESCRIPTION
6
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7Perl runs on numerous operating systems. While most of them share
8much in common, they also have their own unique features.
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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,
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12you know where the lines are drawn, and you can stay within them.
13
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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
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26problem.
27
28Looking at it another way, writing portable code is usually about
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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.
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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
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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
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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
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51writing portable code, and this document is entirely about those issues.
52
53=back
54
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55Here's the general rule: When you approach a task commonly done
56using a whole range of platforms, think about writing portable
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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,
204ad8d5 62VMS, etc.), consider writing platform-specific code.
e41182b5 63
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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
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67deliberate in your decision.
68
69The material below is separated into three main sections: main issues of
7ee27b7c 70portability (L<"ISSUES">), platform-specific issues (L<"PLATFORMS">), and
b7df3edc 71built-in perl functions that behave differently on various ports
7ee27b7c 72(L<"FUNCTION IMPLEMENTATIONS">).
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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
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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>,
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87and S<Mac OS> uses C<\015>.
88
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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
51d9476f 91means C<\015>. In DOSish perls, C<\n> usually means C<\012>, but when
92accessing a file in "text" mode, perl uses the C<:crlf> layer that
93translates it to (or from) C<\015\012>, depending on whether you're
94reading or writing. Unix does the same thing on ttys in canonical
95mode. C<\015\012> is commonly referred to as CRLF.
b7df3edc 96
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97To trim trailing newlines from text lines use chomp(). With default
98settings that function looks for a trailing C<\n> character and thus
99trims in a portable way.
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100
101When dealing with binary files (or text files in binary mode) be sure
102to explicitly set $/ to the appropriate value for your file format
103before using chomp().
104
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105Because of the "text" mode translation, DOSish perls have limitations
106in using C<seek> and C<tell> on a file accessed in "text" mode.
107Stick to C<seek>-ing to locations you got from C<tell> (and no
108others), and you are usually free to use C<seek> and C<tell> even
109in "text" mode. Using C<seek> or C<tell> or other file operations
110may be non-portable. If you use C<binmode> on a file, however, you
111can usually C<seek> and C<tell> with arbitrary values in safety.
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112
113A common misconception in socket programming is that C<\n> eq C<\012>
0a47030a 114everywhere. When using protocols such as common Internet protocols,
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115C<\012> and C<\015> are called for specifically, and the values of
116the logical C<\n> and C<\r> (carriage return) are not reliable.
117
118 print SOCKET "Hi there, client!\r\n"; # WRONG
119 print SOCKET "Hi there, client!\015\012"; # RIGHT
120
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121However, using C<\015\012> (or C<\cM\cJ>, or C<\x0D\x0A>) can be tedious
122and unsightly, as well as confusing to those maintaining the code. As
6ab3f9cb 123such, the Socket module supplies the Right Thing for those who want it.
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124
125 use Socket qw(:DEFAULT :crlf);
126 print SOCKET "Hi there, client!$CRLF" # RIGHT
127
6ab3f9cb 128When reading from a socket, remember that the default input record
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129separator C<$/> is C<\n>, but robust socket code will recognize as
130either C<\012> or C<\015\012> as end of line:
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131
132 while (<SOCKET>) {
133 # ...
134 }
135
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136Because both CRLF and LF end in LF, the input record separator can
137be set to LF and any CR stripped later. Better to write:
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138
139 use Socket qw(:DEFAULT :crlf);
140 local($/) = LF; # not needed if $/ is already \012
141
142 while (<SOCKET>) {
143 s/$CR?$LF/\n/; # not sure if socket uses LF or CRLF, OK
144 # s/\015?\012/\n/; # same thing
145 }
146
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147This example is preferred over the previous one--even for Unix
148platforms--because now any C<\015>'s (C<\cM>'s) are stripped out
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149(and there was much rejoicing).
150
6ab3f9cb 151Similarly, functions that return text data--such as a function that
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152fetches a web page--should sometimes translate newlines before
153returning the data, if they've not yet been translated to the local
154newline representation. A single line of code will often suffice:
2ee0eb3c 155
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156 $data =~ s/\015?\012/\n/g;
157 return $data;
2ee0eb3c 158
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159Some of this may be confusing. Here's a handy reference to the ASCII CR
160and LF characters. You can print it out and stick it in your wallet.
161
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162 LF eq \012 eq \x0A eq \cJ eq chr(10) eq ASCII 10
163 CR eq \015 eq \x0D eq \cM eq chr(13) eq ASCII 13
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164
165 | Unix | DOS | Mac |
166 ---------------------------
167 \n | LF | LF | CR |
168 \r | CR | CR | LF |
169 \n * | LF | CRLF | CR |
170 \r * | CR | CR | LF |
171 ---------------------------
172 * text-mode STDIO
173
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174The Unix column assumes that you are not accessing a serial line
175(like a tty) in canonical mode. If you are, then CR on input becomes
176"\n", and "\n" on output becomes CRLF.
177
6ab3f9cb 178These are just the most common definitions of C<\n> and C<\r> in Perl.
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179There may well be others. For example, on an EBCDIC implementation
180such as z/OS (OS/390) or OS/400 (using the ILE, the PASE is ASCII-based)
181the above material is similar to "Unix" but the code numbers change:
74555b7a 182
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183 LF eq \025 eq \x15 eq \cU eq chr(21) eq CP-1047 21
184 LF eq \045 eq \x25 eq chr(37) eq CP-0037 37
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185 CR eq \015 eq \x0D eq \cM eq chr(13) eq CP-1047 13
186 CR eq \015 eq \x0D eq \cM eq chr(13) eq CP-0037 13
187
188 | z/OS | OS/400 |
189 ----------------------
190 \n | LF | LF |
191 \r | CR | CR |
192 \n * | LF | LF |
193 \r * | CR | CR |
194 ----------------------
195 * text-mode STDIO
6ab3f9cb 196
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197=head2 Numbers endianness and Width
198
199Different CPUs store integers and floating point numbers in different
200orders (called I<endianness>) and widths (32-bit and 64-bit being the
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201most common today). This affects your programs when they attempt to transfer
202numbers in binary format from one CPU architecture to another,
203usually either "live" via network connection, or by storing the
204numbers to secondary storage such as a disk file or tape.
322422de 205
b7df3edc 206Conflicting storage orders make utter mess out of the numbers. If a
d1e3b762 207little-endian host (Intel, VAX) stores 0x12345678 (305419896 in
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208decimal), a big-endian host (Motorola, Sparc, PA) reads it as
2090x78563412 (2018915346 in decimal). Alpha and MIPS can be either:
210Digital/Compaq used/uses them in little-endian mode; SGI/Cray uses
211them in big-endian mode. To avoid this problem in network (socket)
212connections use the C<pack> and C<unpack> formats C<n> and C<N>, the
213"network" orders. These are guaranteed to be portable.
322422de 214
1bcbdd38 215As of perl 5.10.0, you can also use the C<E<gt>> and C<E<lt>> modifiers
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216to force big- or little-endian byte-order. This is useful if you want
217to store signed integers or 64-bit integers, for example.
218
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219You can explore the endianness of your platform by unpacking a
220data structure packed in native format such as:
221
222 print unpack("h*", pack("s2", 1, 2)), "\n";
223 # '10002000' on e.g. Intel x86 or Alpha 21064 in little-endian mode
224 # '00100020' on e.g. Motorola 68040
225
226If you need to distinguish between endian architectures you could use
227either of the variables set like so:
228
229 $is_big_endian = unpack("h*", pack("s", 1)) =~ /01/;
4375e838 230 $is_little_endian = unpack("h*", pack("s", 1)) =~ /^1/;
d1e3b762 231
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232Differing widths can cause truncation even between platforms of equal
233endianness. The platform of shorter width loses the upper parts of the
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234number. There is no good solution for this problem except to avoid
235transferring or storing raw binary numbers.
236
b7df3edc 237One can circumnavigate both these problems in two ways. Either
322422de 238transfer and store numbers always in text format, instead of raw
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239binary, or else consider using modules like Data::Dumper and Storable
240(included as of perl 5.8). Keeping all data as text significantly
241simplifies matters.
322422de 242
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243The v-strings are portable only up to v2147483647 (0x7FFFFFFF), that's
244how far EBCDIC, or more precisely UTF-EBCDIC will go.
245
433acd8a 246=head2 Files and Filesystems
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247
248Most platforms these days structure files in a hierarchical fashion.
b7df3edc 249So, it is reasonably safe to assume that all platforms support the
6ab3f9cb 250notion of a "path" to uniquely identify a file on the system. How
b7df3edc 251that path is really written, though, differs considerably.
e41182b5 252
4375e838 253Although similar, file path specifications differ between Unix,
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254Windows, S<Mac OS>, OS/2, VMS, VOS, S<RISC OS>, and probably others.
255Unix, for example, is one of the few OSes that has the elegant idea
256of a single root directory.
322422de 257
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258DOS, OS/2, VMS, VOS, and Windows can work similarly to Unix with C</>
259as path separator, or in their own idiosyncratic ways (such as having
260several root directories and various "unrooted" device files such NIL:
261and LPT:).
322422de 262
204ad8d5 263S<Mac OS> 9 and earlier used C<:> as a path separator instead of C</>.
322422de 264
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265The filesystem may support neither hard links (C<link>) nor
266symbolic links (C<symlink>, C<readlink>, C<lstat>).
433acd8a 267
6ab3f9cb 268The filesystem may support neither access timestamp nor change
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269timestamp (meaning that about the only portable timestamp is the
270modification timestamp), or one second granularity of any timestamps
271(e.g. the FAT filesystem limits the time granularity to two seconds).
272
74555b7a 273The "inode change timestamp" (the C<-C> filetest) may really be the
e1020413 274"creation timestamp" (which it is not in Unix).
95a3fe12 275
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276VOS perl can emulate Unix filenames with C</> as path separator. The
277native pathname characters greater-than, less-than, number-sign, and
278percent-sign are always accepted.
279
6ab3f9cb 280S<RISC OS> perl can emulate Unix filenames with C</> as path
322422de 281separator, or go native and use C<.> for path separator and C<:> to
6ab3f9cb 282signal filesystems and disk names.
e41182b5 283
e1020413 284Don't assume Unix filesystem access semantics: that read, write,
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285and execute are all the permissions there are, and even if they exist,
286that their semantics (for example what do r, w, and x mean on
e1020413 287a directory) are the Unix ones. The various Unix/POSIX compatibility
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288layers usually try to make interfaces like chmod() work, but sometimes
289there simply is no good mapping.
290
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291If all this is intimidating, have no (well, maybe only a little)
292fear. There are modules that can help. The File::Spec modules
293provide methods to do the Right Thing on whatever platform happens
294to be running the program.
e41182b5 295
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296 use File::Spec::Functions;
297 chdir(updir()); # go up one directory
ceaffd1d 298 my $file = catfile(curdir(), 'temp', 'file.txt');
e41182b5 299 # on Unix and Win32, './temp/file.txt'
204ad8d5 300 # on Mac OS Classic, ':temp:file.txt'
d1e3b762 301 # on VMS, '[.temp]file.txt'
e41182b5 302
b7df3edc 303File::Spec is available in the standard distribution as of version
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3045.004_05. File::Spec::Functions is only in File::Spec 0.7 and later,
305and some versions of perl come with version 0.6. If File::Spec
306is not updated to 0.7 or later, you must use the object-oriented
307interface from File::Spec (or upgrade File::Spec).
e41182b5 308
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309In general, production code should not have file paths hardcoded.
310Making them user-supplied or read from a configuration file is
311better, keeping in mind that file path syntax varies on different
312machines.
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313
314This is especially noticeable in scripts like Makefiles and test suites,
315which often assume C</> as a path separator for subdirectories.
316
b7df3edc 317Also of use is File::Basename from the standard distribution, which
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318splits a pathname into pieces (base filename, full path to directory,
319and file suffix).
320
19799a22 321Even when on a single platform (if you can call Unix a single platform),
b7df3edc 322remember not to count on the existence or the contents of particular
3c075c7d 323system-specific files or directories, like F</etc/passwd>,
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324F</etc/sendmail.conf>, F</etc/resolv.conf>, or even F</tmp/>. For
325example, F</etc/passwd> may exist but not contain the encrypted
326passwords, because the system is using some form of enhanced security.
327Or it may not contain all the accounts, because the system is using NIS.
3c075c7d 328If code does need to rely on such a file, include a description of the
b7df3edc 329file and its format in the code's documentation, then make it easy for
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330the user to override the default location of the file.
331
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332Don't assume a text file will end with a newline. They should,
333but people forget.
e41182b5 334
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335Do not have two files or directories of the same name with different
336case, like F<test.pl> and F<Test.pl>, as many platforms have
337case-insensitive (or at least case-forgiving) filenames. Also, try
338not to have non-word characters (except for C<.>) in the names, and
339keep them to the 8.3 convention, for maximum portability, onerous a
340burden though this may appear.
dd9f0070 341
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342Likewise, when using the AutoSplit module, try to keep your functions to
3438.3 naming and case-insensitive conventions; or, at the least,
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344make it so the resulting files have a unique (case-insensitively)
345first 8 characters.
346
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347Whitespace in filenames is tolerated on most systems, but not all,
348and even on systems where it might be tolerated, some utilities
fe829689 349might become confused by such whitespace.
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351Many systems (DOS, VMS ODS-2) cannot have more than one C<.> in their
352filenames.
433acd8a 353
c47ff5f1 354Don't assume C<< > >> won't be the first character of a filename.
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355Always use C<< < >> explicitly to open a file for reading, or even
356better, use the three-arg version of open, unless you want the user to
357be able to specify a pipe open.
0a47030a 358
ceaffd1d 359 open my $fh, '<', $existing_file) or die $!;
0a47030a 360
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361If filenames might use strange characters, it is safest to open it
362with C<sysopen> instead of C<open>. C<open> is magic and can
c47ff5f1 363translate characters like C<< > >>, C<< < >>, and C<|>, which may
b7df3edc 364be the wrong thing to do. (Sometimes, though, it's the right thing.)
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365Three-arg open can also help protect against this translation in cases
366where it is undesirable.
e41182b5 367
ec481373 368Don't use C<:> as a part of a filename since many systems use that for
8939ba94 369their own semantics (Mac OS Classic for separating pathname components,
ec481373 370many networking schemes and utilities for separating the nodename and
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371the pathname, and so on). For the same reasons, avoid C<@>, C<;> and
372C<|>.
ec481373 373
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374Don't assume that in pathnames you can collapse two leading slashes
375C<//> into one: some networking and clustering filesystems have special
376semantics for that. Let the operating system to sort it out.
377
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378The I<portable filename characters> as defined by ANSI C are
379
380 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
381 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
382 0 1 2 3 4 5 6 7 8 9
383 . _ -
384
08fef530 385and the "-" shouldn't be the first character. If you want to be
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386hypercorrect, stay case-insensitive and within the 8.3 naming
387convention (all the files and directories have to be unique within one
388directory if their names are lowercased and truncated to eight
389characters before the C<.>, if any, and to three characters after the
390C<.>, if any). (And do not use C<.>s in directory names.)
ec481373 391
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392=head2 System Interaction
393
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394Not all platforms provide a command line. These are usually platforms
395that rely primarily on a Graphical User Interface (GUI) for user
396interaction. A program requiring a command line interface might
397not work everywhere. This is probably for the user of the program
398to deal with, so don't stay up late worrying about it.
e41182b5 399
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400Some platforms can't delete or rename files held open by the system,
401this limitation may also apply to changing filesystem metainformation
402like file permissions or owners. Remember to C<close> files when you
403are done with them. Don't C<unlink> or C<rename> an open file. Don't
404C<tie> or C<open> a file already tied or opened; C<untie> or C<close>
405it first.
e41182b5 406
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407Don't open the same file more than once at a time for writing, as some
408operating systems put mandatory locks on such files.
409
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410Don't assume that write/modify permission on a directory gives the
411right to add or delete files/directories in that directory. That is
412filesystem specific: in some filesystems you need write/modify
413permission also (or even just) in the file/directory itself. In some
414filesystems (AFS, DFS) the permission to add/delete directory entries
415is a completely separate permission.
416
417Don't assume that a single C<unlink> completely gets rid of the file:
418some filesystems (most notably the ones in VMS) have versioned
419filesystems, and unlink() removes only the most recent one (it doesn't
420remove all the versions because by default the native tools on those
421platforms remove just the most recent version, too). The portable
422idiom to remove all the versions of a file is
423
94bb614c 424 1 while unlink "file";
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425
426This will terminate if the file is undeleteable for some reason
427(protected, not there, and so on).
428
e41182b5 429Don't count on a specific environment variable existing in C<%ENV>.
0a47030a 430Don't count on C<%ENV> entries being case-sensitive, or even
4a0d0822 431case-preserving. Don't try to clear %ENV by saying C<%ENV = ();>, or,
6be8f7a6 432if you really have to, make it conditional on C<$^O ne 'VMS'> since in
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433VMS the C<%ENV> table is much more than a per-process key-value string
434table.
e41182b5 435
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436On VMS, some entries in the %ENV hash are dynamically created when
437their key is used on a read if they did not previously exist. The
438values for C<$ENV{HOME}>, C<$ENV{TERM}>, C<$ENV{HOME}>, and C<$ENV{USER}>,
439are known to be dynamically generated. The specific names that are
440dynamically generated may vary with the version of the C library on VMS,
441and more may exist than is documented.
442
443On VMS by default, changes to the %ENV hash are persistent after the process
444exits. This can cause unintended issues.
445
d1e3b762 446Don't count on signals or C<%SIG> for anything.
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447
448Don't count on filename globbing. Use C<opendir>, C<readdir>, and
449C<closedir> instead.
450
b8099c3d 451Don't count on per-program environment variables, or per-program current
dd9f0070 452directories.
b8099c3d 453
c87488a3 454Don't count on specific values of C<$!>, neither numeric nor
ac036724 455especially the strings values. Users may switch their locales causing
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456error messages to be translated into their languages. If you can
457trust a POSIXish environment, you can portably use the symbols defined
458by the Errno module, like ENOENT. And don't trust on the values of C<$!>
459at all except immediately after a failed system call.
3c075c7d 460
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461=head2 Command names versus file pathnames
462
463Don't assume that the name used to invoke a command or program with
464C<system> or C<exec> can also be used to test for the existence of the
465file that holds the executable code for that command or program.
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466First, many systems have "internal" commands that are built-in to the
467shell or OS and while these commands can be invoked, there is no
468corresponding file. Second, some operating systems (e.g., Cygwin,
469DJGPP, OS/2, and VOS) have required suffixes for executable files;
470these suffixes are generally permitted on the command name but are not
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471required. Thus, a command like "perl" might exist in a file named
472"perl", "perl.exe", or "perl.pm", depending on the operating system.
473The variable "_exe" in the Config module holds the executable suffix,
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474if any. Third, the VMS port carefully sets up $^X and
475$Config{perlpath} so that no further processing is required. This is
476just as well, because the matching regular expression used below would
477then have to deal with a possible trailing version number in the VMS
478file name.
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479
480To convert $^X to a file pathname, taking account of the requirements
481of the various operating system possibilities, say:
7ee27b7c 482
a61fc69c
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483 use Config;
484 my $thisperl = $^X;
485 if ($^O ne 'VMS')
486 {$thisperl .= $Config{_exe} unless $thisperl =~ m/$Config{_exe}$/i;}
a10d74f3
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487
488To convert $Config{perlpath} to a file pathname, say:
7ee27b7c 489
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490 use Config;
491 my $thisperl = $Config{perlpath};
492 if ($^O ne 'VMS')
493 {$thisperl .= $Config{_exe} unless $thisperl =~ m/$Config{_exe}$/i;}
a10d74f3 494
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495=head2 Networking
496
497Don't assume that you can reach the public Internet.
498
499Don't assume that there is only one way to get through firewalls
500to the public Internet.
501
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502Don't assume that you can reach outside world through any other port
503than 80, or some web proxy. ftp is blocked by many firewalls.
504
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505Don't assume that you can send email by connecting to the local SMTP port.
506
7137b697 507Don't assume that you can reach yourself or any node by the name
dbc6a9ce 508'localhost'. The same goes for '127.0.0.1'. You will have to try both.
932f293e 509
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510Don't assume that the host has only one network card, or that it
511can't bind to many virtual IP addresses.
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512
513Don't assume a particular network device name.
7137b697 514
dbc6a9ce 515Don't assume a particular set of ioctl()s will work.
7137b697
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516
517Don't assume that you can ping hosts and get replies.
518
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519Don't assume that any particular port (service) will respond.
520
ac036724 521Don't assume that Sys::Hostname (or any other API or command) returns
522either a fully qualified hostname or a non-qualified hostname: it all
523depends on how the system had been configured. Also remember that for
524things such as DHCP and NAT, the hostname you get back might not be
525very useful.
dbc6a9ce 526
ac036724 527All the above "don't":s may look daunting, and they are, but the key
932f293e
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528is to degrade gracefully if one cannot reach the particular network
529service one wants. Croaking or hanging do not look very professional.
530
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531=head2 Interprocess Communication (IPC)
532
b7df3edc
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533In general, don't directly access the system in code meant to be
534portable. That means, no C<system>, C<exec>, C<fork>, C<pipe>,
535C<``>, C<qx//>, C<open> with a C<|>, nor any of the other things
536that makes being a perl hacker worth being.
e41182b5
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537
538Commands that launch external processes are generally supported on
b7df3edc
GS
539most platforms (though many of them do not support any type of
540forking). The problem with using them arises from what you invoke
541them on. External tools are often named differently on different
4375e838 542platforms, may not be available in the same location, might accept
b7df3edc
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543different arguments, can behave differently, and often present their
544results in a platform-dependent way. Thus, you should seldom depend
545on them to produce consistent results. (Then again, if you're calling
546I<netstat -a>, you probably don't expect it to run on both Unix and CP/M.)
e41182b5 547
b7df3edc 548One especially common bit of Perl code is opening a pipe to B<sendmail>:
e41182b5 549
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GS
550 open(MAIL, '|/usr/lib/sendmail -t')
551 or die "cannot fork sendmail: $!";
e41182b5
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552
553This is fine for systems programming when sendmail is known to be
554available. But it is not fine for many non-Unix systems, and even
555some Unix systems that may not have sendmail installed. If a portable
b7df3edc
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556solution is needed, see the various distributions on CPAN that deal
557with it. Mail::Mailer and Mail::Send in the MailTools distribution are
558commonly used, and provide several mailing methods, including mail,
559sendmail, and direct SMTP (via Net::SMTP) if a mail transfer agent is
560not available. Mail::Sendmail is a standalone module that provides
561simple, platform-independent mailing.
562
563The Unix System V IPC (C<msg*(), sem*(), shm*()>) is not available
564even on all Unix platforms.
e41182b5 565
a81e5e2e
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566Do not use either the bare result of C<pack("N", 10, 20, 30, 40)> or
567bare v-strings (such as C<v10.20.30.40>) to represent IPv4 addresses:
568both forms just pack the four bytes into network order. That this
569would be equal to the C language C<in_addr> struct (which is what the
570socket code internally uses) is not guaranteed. To be portable use
571the routines of the Socket extension, such as C<inet_aton()>,
572C<inet_ntoa()>, and C<sockaddr_in()>.
6b2463a0 573
e41182b5 574The rule of thumb for portable code is: Do it all in portable Perl, or
0a47030a
GS
575use a module (that may internally implement it with platform-specific
576code, but expose a common interface).
e41182b5 577
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578=head2 External Subroutines (XS)
579
b7df3edc 580XS code can usually be made to work with any platform, but dependent
e41182b5
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581libraries, header files, etc., might not be readily available or
582portable, or the XS code itself might be platform-specific, just as Perl
583code might be. If the libraries and headers are portable, then it is
584normally reasonable to make sure the XS code is portable, too.
585
b7df3edc
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586A different type of portability issue arises when writing XS code:
587availability of a C compiler on the end-user's system. C brings
588with it its own portability issues, and writing XS code will expose
589you to some of those. Writing purely in Perl is an easier way to
e41182b5
GS
590achieve portability.
591
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592=head2 Standard Modules
593
594In general, the standard modules work across platforms. Notable
6ab3f9cb 595exceptions are the CPAN module (which currently makes connections to external
e41182b5 596programs that may not be available), platform-specific modules (like
6ab3f9cb 597ExtUtils::MM_VMS), and DBM modules.
e41182b5 598
b7df3edc 599There is no one DBM module available on all platforms.
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600SDBM_File and the others are generally available on all Unix and DOSish
601ports, but not in MacPerl, where only NBDM_File and DB_File are
0a47030a 602available.
e41182b5
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603
604The good news is that at least some DBM module should be available, and
6ab3f9cb 605AnyDBM_File will use whichever module it can find. Of course, then
b7df3edc
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606the code needs to be fairly strict, dropping to the greatest common
607factor (e.g., not exceeding 1K for each record), so that it will
6ab3f9cb 608work with any DBM module. See L<AnyDBM_File> for more details.
e41182b5 609
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610=head2 Time and Date
611
0a47030a 612The system's notion of time of day and calendar date is controlled in
b7df3edc 613widely different ways. Don't assume the timezone is stored in C<$ENV{TZ}>,
0a47030a 614and even if it is, don't assume that you can control the timezone through
c87488a3
HS
615that variable. Don't assume anything about the three-letter timezone
616abbreviations (for example that MST would be the Mountain Standard Time,
617it's been known to stand for Moscow Standard Time). If you need to
618use timezones, express them in some unambiguous format like the
619exact number of minutes offset from UTC, or the POSIX timezone
620format.
e41182b5 621
322422de 622Don't assume that the epoch starts at 00:00:00, January 1, 1970,
c87488a3
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623because that is OS- and implementation-specific. It is better to
624store a date in an unambiguous representation. The ISO 8601 standard
766af94f 625defines YYYY-MM-DD as the date format, or YYYY-MM-DDTHH:MM:SS
c87488a3 626(that's a literal "T" separating the date from the time).
91d20606 627Please do use the ISO 8601 instead of making us guess what
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628date 02/03/04 might be. ISO 8601 even sorts nicely as-is.
629A text representation (like "1987-12-18") can be easily converted
630into an OS-specific value using a module like Date::Parse.
631An array of values, such as those returned by C<localtime>, can be
632converted to an OS-specific representation using Time::Local.
322422de 633
19799a22
GS
634When calculating specific times, such as for tests in time or date modules,
635it may be appropriate to calculate an offset for the epoch.
b7df3edc 636
19799a22 637 require Time::Local;
ceaffd1d 638 my $offset = Time::Local::timegm(0, 0, 0, 1, 0, 70);
b7df3edc 639
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JV
640The value for C<$offset> in Unix will be C<0>, but in Mac OS Classic
641will be some large number. C<$offset> can then be added to a Unix time
642value to get what should be the proper value on any system.
322422de
GS
643
644=head2 Character sets and character encoding
645
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646Assume very little about character sets.
647
648Assume nothing about numerical values (C<ord>, C<chr>) of characters.
649Do not use explicit code point ranges (like \xHH-\xHH); use for
650example symbolic character classes like C<[:print:]>.
651
652Do not assume that the alphabetic characters are encoded contiguously
653(in the numeric sense). There may be gaps.
654
655Do not assume anything about the ordering of the characters.
656The lowercase letters may come before or after the uppercase letters;
b432a672
AL
657the lowercase and uppercase may be interlaced so that both "a" and "A"
658come before "b"; the accented and other international characters may
659be interlaced so that E<auml> comes before "b".
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GS
660
661=head2 Internationalisation
662
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GS
663If you may assume POSIX (a rather large assumption), you may read
664more about the POSIX locale system from L<perllocale>. The locale
665system at least attempts to make things a little bit more portable,
666or at least more convenient and native-friendly for non-English
667users. The system affects character sets and encoding, and date
668and time formatting--amongst other things.
e41182b5 669
c87488a3
HS
670If you really want to be international, you should consider Unicode.
671See L<perluniintro> and L<perlunicode> for more information.
672
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673If you want to use non-ASCII bytes (outside the bytes 0x00..0x7f) in
674the "source code" of your code, to be portable you have to be explicit
675about what bytes they are. Someone might for example be using your
676code under a UTF-8 locale, in which case random native bytes might be
677illegal ("Malformed UTF-8 ...") This means that for example embedding
678ISO 8859-1 bytes beyond 0x7f into your strings might cause trouble
679later. If the bytes are native 8-bit bytes, you can use the C<bytes>
680pragma. If the bytes are in a string (regular expression being a
681curious string), you can often also use the C<\xHH> notation instead
1bcbdd38
BF
682of embedding the bytes as-is. If you want to write your code in UTF-8,
683you can use the C<utf8>.
11264fdb 684
e41182b5
GS
685=head2 System Resources
686
0a47030a
GS
687If your code is destined for systems with severely constrained (or
688missing!) virtual memory systems then you want to be I<especially> mindful
689of avoiding wasteful constructs such as:
e41182b5 690
ceaffd1d 691 my @lines = <$very_large_file>; # bad
e41182b5 692
ceaffd1d 693 while (<$fh>) {$file .= $_} # sometimes bad
694 my $file = join('', <$fh>); # better
e41182b5 695
b7df3edc
GS
696The last two constructs may appear unintuitive to most people. The
697first repeatedly grows a string, whereas the second allocates a
698large chunk of memory in one go. On some systems, the second is
699more efficient that the first.
0a47030a 700
e41182b5
GS
701=head2 Security
702
b7df3edc 703Most multi-user platforms provide basic levels of security, usually
ac036724 704implemented at the filesystem level. Some, however, unfortunately do
705not. Thus the notion of user id, or "home" directory,
b7df3edc
GS
706or even the state of being logged-in, may be unrecognizable on many
707platforms. If you write programs that are security-conscious, it
708is usually best to know what type of system you will be running
709under so that you can write code explicitly for that platform (or
710class of platforms).
0a47030a 711
e1020413 712Don't assume the Unix filesystem access semantics: the operating
a1667ba3
JH
713system or the filesystem may be using some ACL systems, which are
714richer languages than the usual rwx. Even if the rwx exist,
715their semantics might be different.
716
717(From security viewpoint testing for permissions before attempting to
718do something is silly anyway: if one tries this, there is potential
ac036724 719for race conditions. Someone or something might change the
a1667ba3
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720permissions between the permissions check and the actual operation.
721Just try the operation.)
722
e1020413 723Don't assume the Unix user and group semantics: especially, don't
2edcc0d9 724expect the C<< $< >> and C<< $> >> (or the C<$(> and C<$)>) to work
a1667ba3
JH
725for switching identities (or memberships).
726
727Don't assume set-uid and set-gid semantics. (And even if you do,
728think twice: set-uid and set-gid are a known can of security worms.)
729
e41182b5
GS
730=head2 Style
731
732For those times when it is necessary to have platform-specific code,
733consider keeping the platform-specific code in one place, making porting
6ab3f9cb 734to other platforms easier. Use the Config module and the special
0a47030a
GS
735variable C<$^O> to differentiate platforms, as described in
736L<"PLATFORMS">.
e41182b5 737
b7df3edc
GS
738Be careful in the tests you supply with your module or programs.
739Module code may be fully portable, but its tests might not be. This
740often happens when tests spawn off other processes or call external
741programs to aid in the testing, or when (as noted above) the tests
c87488a3
HS
742assume certain things about the filesystem and paths. Be careful not
743to depend on a specific output style for errors, such as when checking
744C<$!> after a failed system call. Using C<$!> for anything else than
745displaying it as output is doubtful (though see the Errno module for
746testing reasonably portably for error value). Some platforms expect
747a certain output format, and Perl on those platforms may have been
748adjusted accordingly. Most specifically, don't anchor a regex when
749testing an error value.
e41182b5 750
0a47030a 751=head1 CPAN Testers
e41182b5 752
0a47030a
GS
753Modules uploaded to CPAN are tested by a variety of volunteers on
754different platforms. These CPAN testers are notified by mail of each
e41182b5 755new upload, and reply to the list with PASS, FAIL, NA (not applicable to
0a47030a 756this platform), or UNKNOWN (unknown), along with any relevant notations.
e41182b5
GS
757
758The purpose of the testing is twofold: one, to help developers fix any
0a47030a 759problems in their code that crop up because of lack of testing on other
b7df3edc 760platforms; two, to provide users with information about whether
0a47030a 761a given module works on a given platform.
e41182b5 762
7ee27b7c
AT
763Also see:
764
e41182b5
GS
765=over 4
766
7ee27b7c
AT
767=item *
768
636280bd 769Mailing list: cpan-testers-discuss@perl.org
7ee27b7c
AT
770
771=item *
e41182b5 772
500f1b69 773Testing results: L<http://www.cpantesters.org/>
e41182b5
GS
774
775=back
776
e41182b5
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777=head1 PLATFORMS
778
1bcbdd38
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779Perl is built with a C<$^O> variable that indicates the operating
780system it was built on. This was implemented
b7df3edc
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781to help speed up code that would otherwise have to C<use Config>
782and use the value of C<$Config{osname}>. Of course, to get more
e41182b5
GS
783detailed information about the system, looking into C<%Config> is
784certainly recommended.
785
b7df3edc
GS
786C<%Config> cannot always be trusted, however, because it was built
787at compile time. If perl was built in one place, then transferred
788elsewhere, some values may be wrong. The values may even have been
789edited after the fact.
6ab3f9cb 790
e41182b5
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791=head2 Unix
792
793Perl works on a bewildering variety of Unix and Unix-like platforms (see
794e.g. most of the files in the F<hints/> directory in the source code kit).
795On most of these systems, the value of C<$^O> (hence C<$Config{'osname'}>,
d1e3b762
GS
796too) is determined either by lowercasing and stripping punctuation from the
797first field of the string returned by typing C<uname -a> (or a similar command)
798at the shell prompt or by testing the file system for the presence of
799uniquely named files such as a kernel or header file. Here, for example,
800are a few of the more popular Unix flavors:
e41182b5 801
b7df3edc 802 uname $^O $Config{'archname'}
6ab3f9cb 803 --------------------------------------------
b7df3edc 804 AIX aix aix
6ab3f9cb 805 BSD/OS bsdos i386-bsdos
e1516da7 806 Darwin darwin darwin
6ab3f9cb
GS
807 dgux dgux AViiON-dgux
808 DYNIX/ptx dynixptx i386-dynixptx
b7df3edc 809 FreeBSD freebsd freebsd-i386
df00ff3b 810 Haiku haiku BePC-haiku
d1e3b762 811 Linux linux arm-linux
b7df3edc 812 Linux linux i386-linux
6ab3f9cb
GS
813 Linux linux i586-linux
814 Linux linux ppc-linux
b7df3edc
GS
815 HP-UX hpux PA-RISC1.1
816 IRIX irix irix
b787fad4 817 Mac OS X darwin darwin
d1e3b762
GS
818 NeXT 3 next next-fat
819 NeXT 4 next OPENSTEP-Mach
6ab3f9cb 820 openbsd openbsd i386-openbsd
b7df3edc 821 OSF1 dec_osf alpha-dec_osf
6ab3f9cb
GS
822 reliantunix-n svr4 RM400-svr4
823 SCO_SV sco_sv i386-sco_sv
824 SINIX-N svr4 RM400-svr4
825 sn4609 unicos CRAY_C90-unicos
826 sn6521 unicosmk t3e-unicosmk
827 sn9617 unicos CRAY_J90-unicos
b7df3edc
GS
828 SunOS solaris sun4-solaris
829 SunOS solaris i86pc-solaris
830 SunOS4 sunos sun4-sunos
e41182b5 831
b7df3edc
GS
832Because the value of C<$Config{archname}> may depend on the
833hardware architecture, it can vary more than the value of C<$^O>.
6ab3f9cb 834
e41182b5
GS
835=head2 DOS and Derivatives
836
b7df3edc 837Perl has long been ported to Intel-style microcomputers running under
e41182b5
GS
838systems like PC-DOS, MS-DOS, OS/2, and most Windows platforms you can
839bring yourself to mention (except for Windows CE, if you count that).
b7df3edc 840Users familiar with I<COMMAND.COM> or I<CMD.EXE> style shells should
e41182b5
GS
841be aware that each of these file specifications may have subtle
842differences:
843
ceaffd1d 844 my $filespec0 = "c:/foo/bar/file.txt";
845 my $filespec1 = "c:\\foo\\bar\\file.txt";
846 my $filespec2 = 'c:\foo\bar\file.txt';
847 my $filespec3 = 'c:\\foo\\bar\\file.txt';
e41182b5 848
b7df3edc
GS
849System calls accept either C</> or C<\> as the path separator.
850However, many command-line utilities of DOS vintage treat C</> as
851the option prefix, so may get confused by filenames containing C</>.
852Aside from calling any external programs, C</> will work just fine,
853and probably better, as it is more consistent with popular usage,
854and avoids the problem of remembering what to backwhack and what
855not to.
e41182b5 856
b7df3edc
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857The DOS FAT filesystem can accommodate only "8.3" style filenames. Under
858the "case-insensitive, but case-preserving" HPFS (OS/2) and NTFS (NT)
0a47030a 859filesystems you may have to be careful about case returned with functions
e41182b5
GS
860like C<readdir> or used with functions like C<open> or C<opendir>.
861
b7df3edc
GS
862DOS also treats several filenames as special, such as AUX, PRN,
863NUL, CON, COM1, LPT1, LPT2, etc. Unfortunately, sometimes these
864filenames won't even work if you include an explicit directory
865prefix. It is best to avoid such filenames, if you want your code
866to be portable to DOS and its derivatives. It's hard to know what
867these all are, unfortunately.
e41182b5
GS
868
869Users of these operating systems may also wish to make use of
b7df3edc 870scripts such as I<pl2bat.bat> or I<pl2cmd> to
e41182b5
GS
871put wrappers around your scripts.
872
873Newline (C<\n>) is translated as C<\015\012> by STDIO when reading from
6ab3f9cb
GS
874and writing to files (see L<"Newlines">). C<binmode(FILEHANDLE)>
875will keep C<\n> translated as C<\012> for that filehandle. Since it is a
876no-op on other systems, C<binmode> should be used for cross-platform code
b7df3edc
GS
877that deals with binary data. That's assuming you realize in advance
878that your data is in binary. General-purpose programs should
879often assume nothing about their data.
e41182b5 880
b7df3edc 881The C<$^O> variable and the C<$Config{archname}> values for various
e41182b5
GS
882DOSish perls are as follows:
883
67ac489e
MS
884 OS $^O $Config{archname} ID Version
885 --------------------------------------------------------
886 MS-DOS dos ?
887 PC-DOS dos ?
888 OS/2 os2 ?
889 Windows 3.1 ? ? 0 3 01
890 Windows 95 MSWin32 MSWin32-x86 1 4 00
891 Windows 98 MSWin32 MSWin32-x86 1 4 10
892 Windows ME MSWin32 MSWin32-x86 1 ?
893 Windows NT MSWin32 MSWin32-x86 2 4 xx
894 Windows NT MSWin32 MSWin32-ALPHA 2 4 xx
895 Windows NT MSWin32 MSWin32-ppc 2 4 xx
7ee27b7c
AT
896 Windows 2000 MSWin32 MSWin32-x86 2 5 00
897 Windows XP MSWin32 MSWin32-x86 2 5 01
898 Windows 2003 MSWin32 MSWin32-x86 2 5 02
bc643a33
CJ
899 Windows Vista MSWin32 MSWin32-x86 2 6 00
900 Windows 7 MSWin32 MSWin32-x86 2 6 01
901 Windows 7 MSWin32 MSWin32-x64 2 6 01
ae525322
CBW
902 Windows 2008 MSWin32 MSWin32-x86 2 6 01
903 Windows 2008 MSWin32 MSWin32-x64 2 6 01
67ac489e 904 Windows CE MSWin32 ? 3
7ee27b7c 905 Cygwin cygwin cygwin
e41182b5 906
34aaaa84
PP
907The various MSWin32 Perl's can distinguish the OS they are running on
908via the value of the fifth element of the list returned from
909Win32::GetOSVersion(). For example:
910
911 if ($^O eq 'MSWin32') {
912 my @os_version_info = Win32::GetOSVersion();
913 print +('3.1','95','NT')[$os_version_info[4]],"\n";
914 }
915
7939d86b
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916There are also Win32::IsWinNT() and Win32::IsWin95(), try C<perldoc Win32>,
917and as of libwin32 0.19 (not part of the core Perl distribution)
918Win32::GetOSName(). The very portable POSIX::uname() will work too:
1d65be3a
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919
920 c:\> perl -MPOSIX -we "print join '|', uname"
921 Windows NT|moonru|5.0|Build 2195 (Service Pack 2)|x86
d99f392e 922
e41182b5
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923Also see:
924
925=over 4
926
c997b287 927=item *
e41182b5 928
500f1b69 929The djgpp environment for DOS, L<http://www.delorie.com/djgpp/>
c997b287 930and L<perldos>.
e41182b5 931
c997b287 932=item *
e41182b5 933
c997b287 934The EMX environment for DOS, OS/2, etc. emx@iaehv.nl,
500f1b69 935L<ftp://hobbes.nmsu.edu/pub/os2/dev/emx/> Also L<perlos2>.
e41182b5 936
c997b287 937=item *
d1e3b762 938
c997b287
GS
939Build instructions for Win32 in L<perlwin32>, or under the Cygnus environment
940in L<perlcygwin>.
941
942=item *
943
944The C<Win32::*> modules in L<Win32>.
945
946=item *
947
500f1b69 948The ActiveState Pages, L<http://www.activestate.com/>
c997b287
GS
949
950=item *
951
952The Cygwin environment for Win32; F<README.cygwin> (installed
500f1b69 953as L<perlcygwin>), L<http://www.cygwin.com/>
c997b287
GS
954
955=item *
956
957The U/WIN environment for Win32,
500f1b69 958L<http://www.research.att.com/sw/tools/uwin/>
c997b287 959
cea6626f 960=item *
d1e3b762 961
cea6626f 962Build instructions for OS/2, L<perlos2>
d1e3b762 963
e41182b5
GS
964=back
965
e41182b5
GS
966=head2 VMS
967
c997b287 968Perl on VMS is discussed in L<perlvms> in the perl distribution.
016930a6
JM
969
970The official name of VMS as of this writing is OpenVMS.
971
b7df3edc 972Perl on VMS can accept either VMS- or Unix-style file
e41182b5
GS
973specifications as in either of the following:
974
975 $ perl -ne "print if /perl_setup/i" SYS$LOGIN:LOGIN.COM
976 $ perl -ne "print if /perl_setup/i" /sys$login/login.com
977
978but not a mixture of both as in:
979
980 $ perl -ne "print if /perl_setup/i" sys$login:/login.com
981 Can't open sys$login:/login.com: file specification syntax error
982
983Interacting with Perl from the Digital Command Language (DCL) shell
984often requires a different set of quotation marks than Unix shells do.
985For example:
986
987 $ perl -e "print ""Hello, world.\n"""
988 Hello, world.
989
b7df3edc 990There are several ways to wrap your perl scripts in DCL F<.COM> files, if
e41182b5
GS
991you are so inclined. For example:
992
993 $ write sys$output "Hello from DCL!"
994 $ if p1 .eqs. ""
995 $ then perl -x 'f$environment("PROCEDURE")
996 $ else perl -x - 'p1 'p2 'p3 'p4 'p5 'p6 'p7 'p8
997 $ deck/dollars="__END__"
998 #!/usr/bin/perl
999
1000 print "Hello from Perl!\n";
1001
1002 __END__
1003 $ endif
1004
1005Do take care with C<$ ASSIGN/nolog/user SYS$COMMAND: SYS$INPUT> if your
c47ff5f1 1006perl-in-DCL script expects to do things like C<< $read = <STDIN>; >>.
e41182b5 1007
016930a6
JM
1008The VMS operating system has two filesystems, known as ODS-2 and ODS-5.
1009
1010For ODS-2, filenames are in the format "name.extension;version". The
1011maximum length for filenames is 39 characters, and the maximum length for
e41182b5
GS
1012extensions is also 39 characters. Version is a number from 1 to
101332767. Valid characters are C</[A-Z0-9$_-]/>.
1014
016930a6
JM
1015The ODS-2 filesystem is case-insensitive and does not preserve case.
1016Perl simulates this by converting all filenames to lowercase internally.
1017
1018For ODS-5, filenames may have almost any character in them and can include
1019Unicode characters. Characters that could be misinterpreted by the DCL
1020shell or file parsing utilities need to be prefixed with the C<^>
1021character, or replaced with hexadecimal characters prefixed with the
1022C<^> character. Such prefixing is only needed with the pathnames are
e1020413 1023in VMS format in applications. Programs that can accept the Unix format
016930a6
JM
1024of pathnames do not need the escape characters. The maximum length for
1025filenames is 255 characters. The ODS-5 file system can handle both
1026a case preserved and a case sensitive mode.
1027
1028ODS-5 is only available on the OpenVMS for 64 bit platforms.
1029
1030Support for the extended file specifications is being done as optional
1031settings to preserve backward compatibility with Perl scripts that
1032assume the previous VMS limitations.
1033
e1020413
TC
1034In general routines on VMS that get a Unix format file specification
1035should return it in a Unix format, and when they get a VMS format
016930a6
JM
1036specification they should return a VMS format unless they are documented
1037to do a conversion.
1038
1039For routines that generate return a file specification, VMS allows setting
1040if the C library which Perl is built on if it will be returned in VMS
e1020413 1041format or in Unix format.
016930a6
JM
1042
1043With the ODS-2 file system, there is not much difference in syntax of
e1020413 1044filenames without paths for VMS or Unix. With the extended character
016930a6
JM
1045set available with ODS-5 there can be a significant difference.
1046
1047Because of this, existing Perl scripts written for VMS were sometimes
e1020413 1048treating VMS and Unix filenames interchangeably. Without the extended
016930a6
JM
1049character set enabled, this behavior will mostly be maintained for
1050backwards compatibility.
1051
1052When extended characters are enabled with ODS-5, the handling of
e1020413 1053Unix formatted file specifications is to that of a Unix system.
016930a6
JM
1054
1055VMS file specifications without extensions have a trailing dot. An
e1020413 1056equivalent Unix file specification should not show the trailing dot.
016930a6
JM
1057
1058The result of all of this, is that for VMS, for portable scripts, you
1059can not depend on Perl to present the filenames in lowercase, to be
1060case sensitive, and that the filenames could be returned in either
e1020413 1061Unix or VMS format.
016930a6
JM
1062
1063And if a routine returns a file specification, unless it is intended to
1064convert it, it should return it in the same format as it found it.
1065
1066C<readdir> by default has traditionally returned lowercased filenames.
1067When the ODS-5 support is enabled, it will return the exact case of the
1068filename on the disk.
1069
1070Files without extensions have a trailing period on them, so doing a
1071C<readdir> in the default mode with a file named F<A.;5> will
1072return F<a.> when VMS is (though that file could be opened with
0a47030a 1073C<open(FH, 'A')>).
e41182b5 1074
016930a6 1075With support for extended file specifications and if C<opendir> was
e1020413 1076given a Unix format directory, a file named F<A.;5> will return F<a>
016930a6
JM
1077and optionally in the exact case on the disk. When C<opendir> is given
1078a VMS format directory, then C<readdir> should return F<a.>, and
1079again with the optionally the exact case.
1080
f34d0673 1081RMS had an eight level limit on directory depths from any rooted logical
1089a9e3
CB
1082(allowing 16 levels overall) prior to VMS 7.2, and even with versions of
1083VMS on VAX up through 7.3. Hence C<PERL_ROOT:[LIB.2.3.4.5.6.7.8]> is a
1084valid directory specification but C<PERL_ROOT:[LIB.2.3.4.5.6.7.8.9]> is
1085not. F<Makefile.PL> authors might have to take this into account, but at
1086least they can refer to the former as C</PERL_ROOT/lib/2/3/4/5/6/7/8/>.
1087
1088Pumpkings and module integrators can easily see whether files with too many
1089directory levels have snuck into the core by running the following in the
1090top-level source directory:
1091
a61fc69c 1092 $ perl -ne "$_=~s/\s+.*//; print if scalar(split /\//) > 8;" < MANIFEST
1089a9e3 1093
e41182b5 1094
6ab3f9cb 1095The VMS::Filespec module, which gets installed as part of the build
0a47030a
GS
1096process on VMS, is a pure Perl module that can easily be installed on
1097non-VMS platforms and can be helpful for conversions to and from RMS
016930a6
JM
1098native formats. It is also now the only way that you should check to
1099see if VMS is in a case sensitive mode.
e41182b5 1100
5e12dbfa
PP
1101What C<\n> represents depends on the type of file opened. It usually
1102represents C<\012> but it could also be C<\015>, C<\012>, C<\015\012>,
fa11829f 1103C<\000>, C<\040>, or nothing depending on the file organization and
5e12dbfa
PP
1104record format. The VMS::Stdio module provides access to the
1105special fopen() requirements of files with unusual attributes on VMS.
e41182b5
GS
1106
1107TCP/IP stacks are optional on VMS, so socket routines might not be
1108implemented. UDP sockets may not be supported.
1109
016930a6
JM
1110The TCP/IP library support for all current versions of VMS is dynamically
1111loaded if present, so even if the routines are configured, they may
1112return a status indicating that they are not implemented.
1113
e41182b5
GS
1114The value of C<$^O> on OpenVMS is "VMS". To determine the architecture
1115that you are running on without resorting to loading all of C<%Config>
1116you can examine the content of the C<@INC> array like so:
1117
1118 if (grep(/VMS_AXP/, @INC)) {
1119 print "I'm on Alpha!\n";
6ab3f9cb 1120
e41182b5
GS
1121 } elsif (grep(/VMS_VAX/, @INC)) {
1122 print "I'm on VAX!\n";
6ab3f9cb 1123
016930a6
JM
1124 } elsif (grep(/VMS_IA64/, @INC)) {
1125 print "I'm on IA64!\n";
1126
e41182b5
GS
1127 } else {
1128 print "I'm not so sure about where $^O is...\n";
1129 }
1130
016930a6
JM
1131In general, the significant differences should only be if Perl is running
1132on VMS_VAX or one of the 64 bit OpenVMS platforms.
1133
b7df3edc
GS
1134On VMS, perl determines the UTC offset from the C<SYS$TIMEZONE_DIFFERENTIAL>
1135logical name. Although the VMS epoch began at 17-NOV-1858 00:00:00.00,
6ab3f9cb 1136calls to C<localtime> are adjusted to count offsets from
b7df3edc 113701-JAN-1970 00:00:00.00, just like Unix.
6ab3f9cb 1138
e41182b5
GS
1139Also see:
1140
1141=over 4
1142
c997b287
GS
1143=item *
1144
96090e4f 1145F<README.vms> (installed as F<README_vms>), L<perlvms>
c997b287
GS
1146
1147=item *
1148
1089a9e3 1149vmsperl list, vmsperl-subscribe@perl.org
e41182b5 1150
c997b287 1151=item *
e41182b5 1152
500f1b69 1153vmsperl on the web, L<http://www.sidhe.org/vmsperl/index.html>
e41182b5
GS
1154
1155=back
1156
495c5fdc
GP
1157=head2 VOS
1158
10fb90aa
PG
1159Perl on VOS (also known as OpenVOS) is discussed in F<README.vos>
1160in the perl distribution (installed as L<perlvos>). Perl on VOS
1161can accept either VOS- or Unix-style file specifications as in
1162either of the following:
495c5fdc 1163
ea8b8ad2
VP
1164 $ perl -ne "print if /perl_setup/i" >system>notices
1165 $ perl -ne "print if /perl_setup/i" /system/notices
495c5fdc
GP
1166
1167or even a mixture of both as in:
1168
ea8b8ad2 1169 $ perl -ne "print if /perl_setup/i" >system/notices
495c5fdc 1170
b7df3edc 1171Even though VOS allows the slash character to appear in object
495c5fdc 1172names, because the VOS port of Perl interprets it as a pathname
10fb90aa
PG
1173delimiting character, VOS files, directories, or links whose
1174names contain a slash character cannot be processed. Such files
1175must be renamed before they can be processed by Perl.
1176
1177Older releases of VOS (prior to OpenVOS Release 17.0) limit file
1178names to 32 or fewer characters, prohibit file names from
1179starting with a C<-> character, and prohibit file names from
1180containing any character matching C<< tr/ !#%&'()*;<=>?// >>.
1181
1182Newer releases of VOS (OpenVOS Release 17.0 or later) support a
1183feature known as extended names. On these releases, file names
1184can contain up to 255 characters, are prohibited from starting
1185with a C<-> character, and the set of prohibited characters is
1186reduced to any character matching C<< tr/#%*<>?// >>. There are
c69ca1d4 1187restrictions involving spaces and apostrophes: these characters
10fb90aa
PG
1188must not begin or end a name, nor can they immediately precede or
1189follow a period. Additionally, a space must not immediately
1190precede another space or hyphen. Specifically, the following
1191character combinations are prohibited: space-space,
1192space-hyphen, period-space, space-period, period-apostrophe,
1193apostrophe-period, leading or trailing space, and leading or
1194trailing apostrophe. Although an extended file name is limited
1195to 255 characters, a path name is still limited to 256
1196characters.
1197
7d4dfb6d 1198The value of C<$^O> on VOS is "vos". To determine the
10fb90aa
PG
1199architecture that you are running on without resorting to loading
1200all of C<%Config> you can examine the content of the @INC array
1201like so:
495c5fdc 1202
7d4dfb6d 1203 if ($^O =~ /vos/) {
495c5fdc
GP
1204 print "I'm on a Stratus box!\n";
1205 } else {
1206 print "I'm not on a Stratus box!\n";
1207 die;
1208 }
1209
495c5fdc
GP
1210Also see:
1211
1212=over 4
1213
c997b287 1214=item *
495c5fdc 1215
cc07ed0b 1216F<README.vos> (installed as L<perlvos>)
c997b287
GS
1217
1218=item *
1219
1220The VOS mailing list.
495c5fdc 1221
7d4dfb6d
PG
1222There is no specific mailing list for Perl on VOS. You can contact
1223the Stratus Technologies Customer Assistance Center (CAC) for your
1224region, or you can use the contact information located in the
1225distribution files on the Stratus Anonymous FTP site.
495c5fdc 1226
c997b287
GS
1227=item *
1228
7d4dfb6d
PG
1229Stratus Technologies on the web at L<http://www.stratus.com>
1230
1231=item *
1232
1233VOS Open-Source Software on the web at L<http://ftp.stratus.com/pub/vos/vos.html>
495c5fdc
GP
1234
1235=back
1236
e41182b5
GS
1237=head2 EBCDIC Platforms
1238
1239Recent versions of Perl have been ported to platforms such as OS/400 on
d1e3b762
GS
1240AS/400 minicomputers as well as OS/390, VM/ESA, and BS2000 for S/390
1241Mainframes. Such computers use EBCDIC character sets internally (usually
0cc436d0
GS
1242Character Code Set ID 0037 for OS/400 and either 1047 or POSIX-BC for S/390
1243systems). On the mainframe perl currently works under the "Unix system
1244services for OS/390" (formerly known as OpenEdition), VM/ESA OpenEdition, or
1245the BS200 POSIX-BC system (BS2000 is supported in perl 5.6 and greater).
522b859a 1246See L<perlos390> for details. Note that for OS/400 there is also a port of
1bcbdd38 1247Perl 5.8.1/5.10.0 or later to the PASE which is ASCII-based (as opposed to
522b859a 1248ILE which is EBCDIC-based), see L<perlos400>.
e41182b5 1249
7c5ffed3
JH
1250As of R2.5 of USS for OS/390 and Version 2.3 of VM/ESA these Unix
1251sub-systems do not support the C<#!> shebang trick for script invocation.
1252Hence, on OS/390 and VM/ESA perl scripts can be executed with a header
1253similar to the following simple script:
e41182b5
GS
1254
1255 : # use perl
1256 eval 'exec /usr/local/bin/perl -S $0 ${1+"$@"}'
1257 if 0;
1258 #!/usr/local/bin/perl # just a comment really
1259
1260 print "Hello from perl!\n";
1261
d1e3b762
GS
1262OS/390 will support the C<#!> shebang trick in release 2.8 and beyond.
1263Calls to C<system> and backticks can use POSIX shell syntax on all
1264S/390 systems.
1265
b7df3edc 1266On the AS/400, if PERL5 is in your library list, you may need
6ab3f9cb
GS
1267to wrap your perl scripts in a CL procedure to invoke them like so:
1268
1269 BEGIN
1270 CALL PGM(PERL5/PERL) PARM('/QOpenSys/hello.pl')
1271 ENDPGM
1272
1273This will invoke the perl script F<hello.pl> in the root of the
1274QOpenSys file system. On the AS/400 calls to C<system> or backticks
1275must use CL syntax.
1276
e41182b5 1277On these platforms, bear in mind that the EBCDIC character set may have
0a47030a
GS
1278an effect on what happens with some perl functions (such as C<chr>,
1279C<pack>, C<print>, C<printf>, C<ord>, C<sort>, C<sprintf>, C<unpack>), as
1280well as bit-fiddling with ASCII constants using operators like C<^>, C<&>
1281and C<|>, not to mention dealing with socket interfaces to ASCII computers
6ab3f9cb 1282(see L<"Newlines">).
e41182b5 1283
b7df3edc
GS
1284Fortunately, most web servers for the mainframe will correctly
1285translate the C<\n> in the following statement to its ASCII equivalent
043fec90 1286(C<\r> is the same under both Unix and OS/390):
e41182b5
GS
1287
1288 print "Content-type: text/html\r\n\r\n";
1289
d1e3b762 1290The values of C<$^O> on some of these platforms includes:
e41182b5 1291
d1e3b762
GS
1292 uname $^O $Config{'archname'}
1293 --------------------------------------------
1294 OS/390 os390 os390
1295 OS400 os400 os400
1296 POSIX-BC posix-bc BS2000-posix-bc
3c075c7d 1297
e41182b5
GS
1298Some simple tricks for determining if you are running on an EBCDIC
1299platform could include any of the following (perhaps all):
1300
ce7b6f06 1301 if ("\t" eq "\005") { print "EBCDIC may be spoken here!\n"; }
e41182b5
GS
1302
1303 if (ord('A') == 193) { print "EBCDIC may be spoken here!\n"; }
1304
1305 if (chr(169) eq 'z') { print "EBCDIC may be spoken here!\n"; }
1306
b7df3edc 1307One thing you may not want to rely on is the EBCDIC encoding
0a47030a
GS
1308of punctuation characters since these may differ from code page to code
1309page (and once your module or script is rumoured to work with EBCDIC,
1310folks will want it to work with all EBCDIC character sets).
e41182b5
GS
1311
1312Also see:
1313
1314=over 4
1315
c997b287
GS
1316=item *
1317
043fec90 1318L<perlos390>, F<README.os390>, F<perlbs2000>, L<perlebcdic>.
c997b287
GS
1319
1320=item *
e41182b5
GS
1321
1322The perl-mvs@perl.org list is for discussion of porting issues as well as
1323general usage issues for all EBCDIC Perls. Send a message body of
1324"subscribe perl-mvs" to majordomo@perl.org.
1325
7ee27b7c 1326=item *
c997b287
GS
1327
1328AS/400 Perl information at
500f1b69 1329L<http://as400.rochester.ibm.com/>
d1e3b762 1330as well as on CPAN in the F<ports/> directory.
e41182b5
GS
1331
1332=back
1333
b8099c3d
CN
1334=head2 Acorn RISC OS
1335
b7df3edc
GS
1336Because Acorns use ASCII with newlines (C<\n>) in text files as C<\012> like
1337Unix, and because Unix filename emulation is turned on by default,
1338most simple scripts will probably work "out of the box". The native
6ab3f9cb 1339filesystem is modular, and individual filesystems are free to be
0a47030a 1340case-sensitive or insensitive, and are usually case-preserving. Some
b7df3edc 1341native filesystems have name length limits, which file and directory
6ab3f9cb
GS
1342names are silently truncated to fit. Scripts should be aware that the
1343standard filesystem currently has a name length limit of B<10>
1344characters, with up to 77 items in a directory, but other filesystems
0a47030a 1345may not impose such limitations.
b8099c3d
CN
1346
1347Native filenames are of the form
1348
6ab3f9cb 1349 Filesystem#Special_Field::DiskName.$.Directory.Directory.File
dd9f0070 1350
b8099c3d
CN
1351where
1352
1353 Special_Field is not usually present, but may contain . and $ .
1354 Filesystem =~ m|[A-Za-z0-9_]|
1355 DsicName =~ m|[A-Za-z0-9_/]|
1356 $ represents the root directory
1357 . is the path separator
1358 @ is the current directory (per filesystem but machine global)
1359 ^ is the parent directory
1360 Directory and File =~ m|[^\0- "\.\$\%\&:\@\\^\|\177]+|
1361
1362The default filename translation is roughly C<tr|/.|./|;>
1363
6ab3f9cb 1364Note that C<"ADFS::HardDisk.$.File" ne 'ADFS::HardDisk.$.File'> and that
0a47030a
GS
1365the second stage of C<$> interpolation in regular expressions will fall
1366foul of the C<$.> if scripts are not careful.
1367
1368Logical paths specified by system variables containing comma-separated
b7df3edc 1369search lists are also allowed; hence C<System:Modules> is a valid
0a47030a 1370filename, and the filesystem will prefix C<Modules> with each section of
6ab3f9cb 1371C<System$Path> until a name is made that points to an object on disk.
b7df3edc 1372Writing to a new file C<System:Modules> would be allowed only if
0a47030a
GS
1373C<System$Path> contains a single item list. The filesystem will also
1374expand system variables in filenames if enclosed in angle brackets, so
c47ff5f1 1375C<< <System$Dir>.Modules >> would look for the file
0a47030a 1376S<C<$ENV{'System$Dir'} . 'Modules'>>. The obvious implication of this is
c47ff5f1 1377that B<fully qualified filenames can start with C<< <> >>> and should
0a47030a 1378be protected when C<open> is used for input.
b8099c3d
CN
1379
1380Because C<.> was in use as a directory separator and filenames could not
1381be assumed to be unique after 10 characters, Acorn implemented the C
1382compiler to strip the trailing C<.c> C<.h> C<.s> and C<.o> suffix from
1383filenames specified in source code and store the respective files in
b7df3edc 1384subdirectories named after the suffix. Hence files are translated:
b8099c3d
CN
1385
1386 foo.h h.foo
1387 C:foo.h C:h.foo (logical path variable)
1388 sys/os.h sys.h.os (C compiler groks Unix-speak)
1389 10charname.c c.10charname
1390 10charname.o o.10charname
1391 11charname_.c c.11charname (assuming filesystem truncates at 10)
1392
1393The Unix emulation library's translation of filenames to native assumes
b7df3edc
GS
1394that this sort of translation is required, and it allows a user-defined list
1395of known suffixes that it will transpose in this fashion. This may
92863ac5
KW
1396seem transparent, but consider that with these rules F<foo/bar/baz.h>
1397and F<foo/bar/h/baz> both map to F<foo.bar.h.baz>, and that C<readdir> and
0a47030a 1398C<glob> cannot and do not attempt to emulate the reverse mapping. Other
6ab3f9cb 1399C<.>'s in filenames are translated to C</>.
0a47030a 1400
b7df3edc 1401As implied above, the environment accessed through C<%ENV> is global, and
0a47030a 1402the convention is that program specific environment variables are of the
6ab3f9cb
GS
1403form C<Program$Name>. Each filesystem maintains a current directory,
1404and the current filesystem's current directory is the B<global> current
b7df3edc
GS
1405directory. Consequently, sociable programs don't change the current
1406directory but rely on full pathnames, and programs (and Makefiles) cannot
0a47030a
GS
1407assume that they can spawn a child process which can change the current
1408directory without affecting its parent (and everyone else for that
1409matter).
1410
b7df3edc
GS
1411Because native operating system filehandles are global and are currently
1412allocated down from 255, with 0 being a reserved value, the Unix emulation
0a47030a
GS
1413library emulates Unix filehandles. Consequently, you can't rely on
1414passing C<STDIN>, C<STDOUT>, or C<STDERR> to your children.
1415
1416The desire of users to express filenames of the form
c47ff5f1 1417C<< <Foo$Dir>.Bar >> on the command line unquoted causes problems,
0a47030a 1418too: C<``> command output capture has to perform a guessing game. It
c47ff5f1 1419assumes that a string C<< <[^<>]+\$[^<>]> >> is a
0a47030a 1420reference to an environment variable, whereas anything else involving
c47ff5f1 1421C<< < >> or C<< > >> is redirection, and generally manages to be 99%
0a47030a
GS
1422right. Of course, the problem remains that scripts cannot rely on any
1423Unix tools being available, or that any tools found have Unix-like command
1424line arguments.
1425
b7df3edc
GS
1426Extensions and XS are, in theory, buildable by anyone using free
1427tools. In practice, many don't, as users of the Acorn platform are
1428used to binary distributions. MakeMaker does run, but no available
1429make currently copes with MakeMaker's makefiles; even if and when
1430this should be fixed, the lack of a Unix-like shell will cause
1431problems with makefile rules, especially lines of the form C<cd
1432sdbm && make all>, and anything using quoting.
b8099c3d
CN
1433
1434"S<RISC OS>" is the proper name for the operating system, but the value
1435in C<$^O> is "riscos" (because we don't like shouting).
1436
e41182b5
GS
1437=head2 Other perls
1438
b7df3edc 1439Perl has been ported to many platforms that do not fit into any of
b6c36746 1440the categories listed above. Some, such as AmigaOS,
cd86ed9d
JV
1441QNX, Plan 9, and VOS, have been well-integrated into the standard
1442Perl source code kit. You may need to see the F<ports/> directory
1443on CPAN for information, and possibly binaries, for the likes of:
1444aos, Atari ST, lynxos, riscos, Novell Netware, Tandem Guardian,
1445I<etc.> (Yes, we know that some of these OSes may fall under the
1446Unix category, but we are not a standards body.)
e41182b5 1447
d1e3b762
GS
1448Some approximate operating system names and their C<$^O> values
1449in the "OTHER" category include:
1450
1451 OS $^O $Config{'archname'}
1452 ------------------------------------------
1453 Amiga DOS amigaos m68k-amigos
d1e3b762 1454
e41182b5
GS
1455See also:
1456
1457=over 4
1458
c997b287
GS
1459=item *
1460
1461Amiga, F<README.amiga> (installed as L<perlamiga>).
1462
1463=item *
d1e3b762 1464
6ab3f9cb 1465A free perl5-based PERL.NLM for Novell Netware is available in
500f1b69 1466precompiled binary and source code form from L<http://www.novell.com/>
6ab3f9cb 1467as well as from CPAN.
e41182b5 1468
13a2d996 1469=item *
c997b287 1470
e6f03d26 1471S<Plan 9>, F<README.plan9>
d1e3b762 1472
e41182b5
GS
1473=back
1474
e41182b5
GS
1475=head1 FUNCTION IMPLEMENTATIONS
1476
b7df3edc
GS
1477Listed below are functions that are either completely unimplemented
1478or else have been implemented differently on various platforms.
1479Following each description will be, in parentheses, a list of
1480platforms that the description applies to.
e41182b5 1481
b7df3edc
GS
1482The list may well be incomplete, or even wrong in some places. When
1483in doubt, consult the platform-specific README files in the Perl
1484source distribution, and any other documentation resources accompanying
1485a given port.
e41182b5 1486
0a47030a 1487Be aware, moreover, that even among Unix-ish systems there are variations.
e41182b5 1488
b7df3edc
GS
1489For many functions, you can also query C<%Config>, exported by
1490default from the Config module. For example, to check whether the
1491platform has the C<lstat> call, check C<$Config{d_lstat}>. See
1492L<Config> for a full description of available variables.
e41182b5
GS
1493
1494=head2 Alphabetical Listing of Perl Functions
1495
1496=over 8
1497
e41182b5
GS
1498=item -X
1499
038ae9a4
SH
1500C<-w> only inspects the read-only file attribute (FILE_ATTRIBUTE_READONLY),
1501which determines whether the directory can be deleted, not whether it can
1502be written to. Directories always have read and write access unless denied
1503by discretionary access control lists (DACLs). (S<Win32>)
1504
b7df3edc
GS
1505C<-r>, C<-w>, C<-x>, and C<-o> tell whether the file is accessible,
1506which may not reflect UIC-based file protections. (VMS)
e41182b5 1507
b8099c3d
CN
1508C<-s> by name on an open file will return the space reserved on disk,
1509rather than the current extent. C<-s> on an open filehandle returns the
b7df3edc 1510current size. (S<RISC OS>)
b8099c3d 1511
e41182b5 1512C<-R>, C<-W>, C<-X>, C<-O> are indistinguishable from C<-r>, C<-w>,
204ad8d5 1513C<-x>, C<-o>. (Win32, VMS, S<RISC OS>)
e41182b5 1514
287a962e 1515C<-g>, C<-k>, C<-l>, C<-u>, C<-A> are not particularly meaningful.
b8099c3d 1516(Win32, VMS, S<RISC OS>)
e41182b5 1517
287a962e
JD
1518C<-p> is not particularly meaningful. (VMS, S<RISC OS>)
1519
e41182b5
GS
1520C<-d> is true if passed a device spec without an explicit directory.
1521(VMS)
1522
e41182b5 1523C<-x> (or C<-X>) determine if a file ends in one of the executable
b7df3edc 1524suffixes. C<-S> is meaningless. (Win32)
e41182b5 1525
b8099c3d
CN
1526C<-x> (or C<-X>) determine if a file has an executable file type.
1527(S<RISC OS>)
1528
aca72608
JD
1529=item alarm
1530
1531Emulated using timers that must be explicitly polled whenever Perl
1532wants to dispatch "safe signals" and therefore cannot interrupt
1533blocking system calls. (Win32)
1534
47cd99a4 1535=item atan2
519bc777
RGS
1536
1537Due to issues with various CPUs, math libraries, compilers, and standards,
1538results for C<atan2()> may vary depending on any combination of the above.
1539Perl attempts to conform to the Open Group/IEEE standards for the results
1540returned from C<atan2()>, but cannot force the issue if the system Perl is
1541run on does not allow it. (Tru64, HP-UX 10.20)
1542
1543The current version of the standards for C<atan2()> is available at
1544L<http://www.opengroup.org/onlinepubs/009695399/functions/atan2.html>.
1545
47cd99a4 1546=item binmode
e41182b5 1547
204ad8d5 1548Meaningless. (S<RISC OS>)
e41182b5
GS
1549
1550Reopens file and restores pointer; if function fails, underlying
1551filehandle may be closed, or pointer may be in a different position.
1552(VMS)
1553
1554The value returned by C<tell> may be affected after the call, and
1555the filehandle may be flushed. (Win32)
1556
47cd99a4 1557=item chmod
e41182b5 1558
e41182b5
GS
1559Only good for changing "owner" read-write access, "group", and "other"
1560bits are meaningless. (Win32)
1561
b8099c3d
CN
1562Only good for changing "owner" and "other" read-write access. (S<RISC OS>)
1563
495c5fdc
GP
1564Access permissions are mapped onto VOS access-control list changes. (VOS)
1565
4e51f8e4 1566The actual permissions set depend on the value of the C<CYGWIN>
789f0d36 1567in the SYSTEM environment settings. (Cygwin)
4e51f8e4 1568
47cd99a4 1569=item chown
e41182b5 1570
204ad8d5 1571Not implemented. (Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1572
1573Does nothing, but won't fail. (Win32)
1574
3fd80bd6
PG
1575A little funky, because VOS's notion of ownership is a little funky (VOS).
1576
e41182b5
GS
1577=item chroot
1578
043fec90 1579Not implemented. (Win32, VMS, S<Plan 9>, S<RISC OS>, VOS)
e41182b5 1580
47cd99a4 1581=item crypt
e41182b5
GS
1582
1583May not be available if library or source was not provided when building
b8099c3d 1584perl. (Win32)
e41182b5 1585
47cd99a4 1586=item dbmclose
e41182b5 1587
e6f03d26 1588Not implemented. (VMS, S<Plan 9>, VOS)
e41182b5 1589
47cd99a4 1590=item dbmopen
e41182b5 1591
e6f03d26 1592Not implemented. (VMS, S<Plan 9>, VOS)
e41182b5 1593
47cd99a4 1594=item dump
e41182b5 1595
204ad8d5 1596Not useful. (S<RISC OS>)
e41182b5 1597
84d78eb7 1598Not supported. (Cygwin, Win32)
e41182b5 1599
b8099c3d 1600Invokes VMS debugger. (VMS)
e41182b5 1601
47cd99a4 1602=item exec
e41182b5 1603
0f897271
GS
1604Does not automatically flush output handles on some platforms.
1605(SunOS, Solaris, HP-UX)
1606
af8bb25a
FC
1607Not supported. (Symbian OS)
1608
fe12c0e8
MS
1609=item exit
1610
e1020413 1611Emulates Unix exit() (which considers C<exit 1> to indicate an error) by
fe12c0e8
MS
1612mapping the C<1> to SS$_ABORT (C<44>). This behavior may be overridden
1613with the pragma C<use vmsish 'exit'>. As with the CRTL's exit()
1614function, C<exit 0> is also mapped to an exit status of SS$_NORMAL
1615(C<1>); this mapping cannot be overridden. Any other argument to exit()
016930a6
JM
1616is used directly as Perl's exit status. On VMS, unless the future
1617POSIX_EXIT mode is enabled, the exit code should always be a valid
1618VMS exit code and not a generic number. When the POSIX_EXIT mode is
1619enabled, a generic number will be encoded in a method compatible with
1620the C library _POSIX_EXIT macro so that it can be decoded by other
1621programs, particularly ones written in C, like the GNV package. (VMS)
fe12c0e8 1622
bef2c191
RB
1623C<exit()> resets file pointers, which is a problem when called
1624from a child process (created by C<fork()>) in C<BEGIN>.
1625A workaround is to use C<POSIX::_exit>. (Solaris)
1626
1627 exit unless $Config{archname} =~ /\bsolaris\b/;
1628 require POSIX and POSIX::_exit(0);
1629
47cd99a4 1630=item fcntl
e41182b5 1631
016930a6 1632Not implemented. (Win32)
6a065175 1633
016930a6 1634Some functions available based on the version of VMS. (VMS)
e41182b5 1635
47cd99a4 1636=item flock
e41182b5 1637
204ad8d5 1638Not implemented (VMS, S<RISC OS>, VOS).
e41182b5 1639
e41182b5
GS
1640=item fork
1641
043fec90 1642Not implemented. (AmigaOS, S<RISC OS>, VMS)
0f897271
GS
1643
1644Emulated using multiple interpreters. See L<perlfork>. (Win32)
1645
1646Does not automatically flush output handles on some platforms.
1647(SunOS, Solaris, HP-UX)
e41182b5
GS
1648
1649=item getlogin
1650
204ad8d5 1651Not implemented. (S<RISC OS>)
e41182b5 1652
47cd99a4 1653=item getpgrp
e41182b5 1654
204ad8d5 1655Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5
GS
1656
1657=item getppid
1658
204ad8d5 1659Not implemented. (Win32, S<RISC OS>)
e41182b5 1660
47cd99a4 1661=item getpriority
e41182b5 1662
043fec90 1663Not implemented. (Win32, VMS, S<RISC OS>, VOS)
e41182b5 1664
47cd99a4 1665=item getpwnam
e41182b5 1666
204ad8d5 1667Not implemented. (Win32)
e41182b5 1668
b8099c3d
CN
1669Not useful. (S<RISC OS>)
1670
47cd99a4 1671=item getgrnam
e41182b5 1672
204ad8d5 1673Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5 1674
47cd99a4 1675=item getnetbyname
e41182b5 1676
204ad8d5 1677Not implemented. (Win32, S<Plan 9>)
e41182b5 1678
47cd99a4 1679=item getpwuid
e41182b5 1680
204ad8d5 1681Not implemented. (Win32)
e41182b5 1682
b8099c3d
CN
1683Not useful. (S<RISC OS>)
1684
47cd99a4 1685=item getgrgid
e41182b5 1686
204ad8d5 1687Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5 1688
47cd99a4 1689=item getnetbyaddr
e41182b5 1690
204ad8d5 1691Not implemented. (Win32, S<Plan 9>)
e41182b5 1692
47cd99a4 1693=item getprotobynumber
e41182b5 1694
47cd99a4 1695=item getservbyport
e41182b5 1696
e41182b5
GS
1697=item getpwent
1698
043fec90 1699Not implemented. (Win32)
e41182b5
GS
1700
1701=item getgrent
1702
043fec90 1703Not implemented. (Win32, VMS)
e41182b5 1704
ef5a6dd7
JH
1705=item gethostbyname
1706
1707C<gethostbyname('localhost')> does not work everywhere: you may have
204ad8d5 1708to use C<gethostbyname('127.0.0.1')>. (S<Irix 5>)
ef5a6dd7 1709
e41182b5
GS
1710=item gethostent
1711
204ad8d5 1712Not implemented. (Win32)
e41182b5
GS
1713
1714=item getnetent
1715
204ad8d5 1716Not implemented. (Win32, S<Plan 9>)
e41182b5
GS
1717
1718=item getprotoent
1719
204ad8d5 1720Not implemented. (Win32, S<Plan 9>)
e41182b5
GS
1721
1722=item getservent
1723
e6f03d26 1724Not implemented. (Win32, S<Plan 9>)
e41182b5 1725
47cd99a4 1726=item sethostent
e41182b5 1727
204ad8d5 1728Not implemented. (Win32, S<Plan 9>, S<RISC OS>)
e41182b5 1729
47cd99a4 1730=item setnetent
e41182b5 1731
204ad8d5 1732Not implemented. (Win32, S<Plan 9>, S<RISC OS>)
e41182b5 1733
47cd99a4 1734=item setprotoent
e41182b5 1735
204ad8d5 1736Not implemented. (Win32, S<Plan 9>, S<RISC OS>)
e41182b5 1737
47cd99a4 1738=item setservent
e41182b5 1739
e6f03d26 1740Not implemented. (S<Plan 9>, Win32, S<RISC OS>)
e41182b5
GS
1741
1742=item endpwent
1743
b5afd346 1744Not implemented. (Win32)
e41182b5
GS
1745
1746=item endgrent
1747
b5afd346 1748Not implemented. (S<RISC OS>, VMS, Win32)
e41182b5
GS
1749
1750=item endhostent
1751
204ad8d5 1752Not implemented. (Win32)
e41182b5
GS
1753
1754=item endnetent
1755
204ad8d5 1756Not implemented. (Win32, S<Plan 9>)
e41182b5
GS
1757
1758=item endprotoent
1759
204ad8d5 1760Not implemented. (Win32, S<Plan 9>)
e41182b5
GS
1761
1762=item endservent
1763
e6f03d26 1764Not implemented. (S<Plan 9>, Win32)
e41182b5
GS
1765
1766=item getsockopt SOCKET,LEVEL,OPTNAME
1767
e6f03d26 1768Not implemented. (S<Plan 9>)
e41182b5 1769
e41182b5
GS
1770=item glob
1771
63f87e49
GS
1772This operator is implemented via the File::Glob extension on most
1773platforms. See L<File::Glob> for portability information.
b8099c3d 1774
62aa5637
MS
1775=item gmtime
1776
461d5a49
MS
1777In theory, gmtime() is reliable from -2**63 to 2**63-1. However,
1778because work arounds in the implementation use floating point numbers,
1779it will become inaccurate as the time gets larger. This is a bug and
1780will be fixed in the future.
62aa5637 1781
10fb90aa
PG
1782On VOS, time values are 32-bit quantities.
1783
e41182b5
GS
1784=item ioctl FILEHANDLE,FUNCTION,SCALAR
1785
1786Not implemented. (VMS)
1787
1788Available only for socket handles, and it does what the ioctlsocket() call
1789in the Winsock API does. (Win32)
1790
b8099c3d
CN
1791Available only for socket handles. (S<RISC OS>)
1792
47cd99a4 1793=item kill
e41182b5 1794
862b5365 1795Not implemented, hence not useful for taint checking. (S<RISC OS>)
e41182b5 1796
63f87e49
GS
1797C<kill()> doesn't have the semantics of C<raise()>, i.e. it doesn't send
1798a signal to the identified process like it does on Unix platforms.
1799Instead C<kill($sig, $pid)> terminates the process identified by $pid,
1800and makes it exit immediately with exit status $sig. As in Unix, if
1801$sig is 0 and the specified process exists, it returns true without
1802actually terminating it. (Win32)
e41182b5 1803
d0302514
JD
1804C<kill(-9, $pid)> will terminate the process specified by $pid and
1805recursively all child processes owned by it. This is different from
1806the Unix semantics, where the signal will be delivered to all
1807processes in the same process group as the process specified by
1808$pid. (Win32)
1809
016930a6
JM
1810Is not supported for process identification number of 0 or negative
1811numbers. (VMS)
1812
47cd99a4 1813=item link
e41182b5 1814
b5afd346 1815Not implemented. (S<RISC OS>, VOS)
e41182b5 1816
433acd8a
JH
1817Link count not updated because hard links are not quite that hard
1818(They are sort of half-way between hard and soft links). (AmigaOS)
1819
63d6c08b
JD
1820Hard links are implemented on Win32 under NTFS only. They are
1821natively supported on Windows 2000 and later. On Windows NT they
1822are implemented using the Windows POSIX subsystem support and the
1823Perl process will need Administrator or Backup Operator privileges
1824to create hard links.
a3dfe201 1825
016930a6
JM
1826Available on 64 bit OpenVMS 8.2 and later. (VMS)
1827
62aa5637
MS
1828=item localtime
1829
a61fc69c 1830localtime() has the same range as L</gmtime>, but because time zone
dc164757
MS
1831rules change its accuracy for historical and future times may degrade
1832but usually by no more than an hour.
62aa5637 1833
e41182b5
GS
1834=item lstat
1835
016930a6 1836Not implemented. (S<RISC OS>)
e41182b5 1837
63f87e49 1838Return values (especially for device and inode) may be bogus. (Win32)
e41182b5 1839
47cd99a4 1840=item msgctl
e41182b5 1841
47cd99a4 1842=item msgget
e41182b5 1843
47cd99a4 1844=item msgsnd
e41182b5 1845
47cd99a4 1846=item msgrcv
e41182b5 1847
204ad8d5 1848Not implemented. (Win32, VMS, S<Plan 9>, S<RISC OS>, VOS)
e41182b5 1849
47cd99a4 1850=item open
e41182b5 1851
204ad8d5 1852open to C<|-> and C<-|> are unsupported. (Win32, S<RISC OS>)
e41182b5 1853
0f897271
GS
1854Opening a process does not automatically flush output handles on some
1855platforms. (SunOS, Solaris, HP-UX)
1856
e41182b5
GS
1857=item readlink
1858
b8099c3d 1859Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5 1860
47cd99a4 1861=item rename
c9b2b9d4
SS
1862
1863Can't move directories between directories on different logical volumes. (Win32)
1864
3ba4b5c1
JD
1865=item rewinddir
1866
1867Will not cause readdir() to re-read the directory stream. The entries
1868already read before the rewinddir() call will just be returned again
1869from a cache buffer. (Win32)
1870
47cd99a4 1871=item select
e41182b5 1872
689c5c24 1873Only implemented on sockets. (Win32, VMS)
e41182b5 1874
b8099c3d
CN
1875Only reliable on sockets. (S<RISC OS>)
1876
76e05f0b 1877Note that the C<select FILEHANDLE> form is generally portable.
63f87e49 1878
47cd99a4 1879=item semctl
e41182b5 1880
47cd99a4 1881=item semget
e41182b5 1882
47cd99a4 1883=item semop
e41182b5 1884
10fb90aa 1885Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5 1886
a3dfe201
GS
1887=item setgrent
1888
b5afd346 1889Not implemented. (VMS, Win32, S<RISC OS>)
a3dfe201 1890
47cd99a4 1891=item setpgrp
e41182b5 1892
204ad8d5 1893Not implemented. (Win32, VMS, S<RISC OS>, VOS)
e41182b5 1894
47cd99a4 1895=item setpriority
e41182b5 1896
204ad8d5 1897Not implemented. (Win32, VMS, S<RISC OS>, VOS)
e41182b5 1898
a3dfe201
GS
1899=item setpwent
1900
b5afd346 1901Not implemented. (Win32, S<RISC OS>)
a3dfe201 1902
47cd99a4 1903=item setsockopt
e41182b5 1904
e6f03d26 1905Not implemented. (S<Plan 9>)
e41182b5 1906
47cd99a4 1907=item shmctl
e41182b5 1908
47cd99a4 1909=item shmget
e41182b5 1910
47cd99a4 1911=item shmread
e41182b5 1912
47cd99a4 1913=item shmwrite
e41182b5 1914
7d4dfb6d 1915Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5 1916
001e9f89
DD
1917=item sleep
1918
3cd50447
SH
1919Emulated using synchronization functions such that it can be
1920interrupted by alarm(), and limited to a maximum of 4294967 seconds,
1921approximately 49 days. (Win32)
001e9f89 1922
47cd99a4 1923=item sockatmark
80cbd5ad
JH
1924
1925A relatively recent addition to socket functions, may not
e1020413 1926be implemented even in Unix platforms.
80cbd5ad 1927
47cd99a4 1928=item socketpair
e41182b5 1929
043fec90 1930Not implemented. (S<RISC OS>)
10fb90aa 1931
016930a6 1932Available on 64 bit OpenVMS 8.2 and later. (VMS)
e41182b5 1933
e41182b5
GS
1934=item stat
1935
d62e1b7f
JH
1936Platforms that do not have rdev, blksize, or blocks will return these
1937as '', so numeric comparison or manipulation of these fields may cause
1938'not numeric' warnings.
1939
3f1f789b 1940ctime not supported on UFS (S<Mac OS X>).
e41182b5 1941
95a3fe12
MS
1942ctime is creation time instead of inode change time (Win32).
1943
e41182b5
GS
1944device and inode are not meaningful. (Win32)
1945
1946device and inode are not necessarily reliable. (VMS)
1947
b8099c3d
CN
1948mtime, atime and ctime all return the last modification time. Device and
1949inode are not necessarily reliable. (S<RISC OS>)
1950
d62e1b7f
JH
1951dev, rdev, blksize, and blocks are not available. inode is not
1952meaningful and will differ between stat calls on the same file. (os2)
1953
73e9292c
JH
1954some versions of cygwin when doing a stat("foo") and if not finding it
1955may then attempt to stat("foo.exe") (Cygwin)
1956
1fafdf34
JD
1957On Win32 stat() needs to open the file to determine the link count
1958and update attributes that may have been changed through hard links.
1959Setting ${^WIN32_SLOPPY_STAT} to a true value speeds up stat() by
1960not performing this operation. (Win32)
1961
47cd99a4 1962=item symlink
e41182b5 1963
c73b03b7
JM
1964Not implemented. (Win32, S<RISC OS>)
1965
1966Implemented on 64 bit VMS 8.3. VMS requires the symbolic link to be in Unix
1967syntax if it is intended to resolve to a valid path.
e41182b5 1968
47cd99a4 1969=item syscall
e41182b5 1970
043fec90 1971Not implemented. (Win32, VMS, S<RISC OS>, VOS)
e41182b5 1972
47cd99a4 1973=item sysopen
f34d0673 1974
dd9f0070 1975The traditional "0", "1", and "2" MODEs are implemented with different
322422de
GS
1976numeric values on some systems. The flags exported by C<Fcntl>
1977(O_RDONLY, O_WRONLY, O_RDWR) should work everywhere though. (S<Mac
043fec90 1978OS>, OS/390)
f34d0673 1979
47cd99a4 1980=item system
e41182b5 1981
e41182b5 1982As an optimization, may not call the command shell specified in
b7df3edc 1983C<$ENV{PERL5SHELL}>. C<system(1, @args)> spawns an external
e41182b5
GS
1984process and immediately returns its process designator, without
1985waiting for it to terminate. Return value may be used subsequently
63f87e49
GS
1986in C<wait> or C<waitpid>. Failure to spawn() a subprocess is indicated
1987by setting $? to "255 << 8". C<$?> is set in a way compatible with
1988Unix (i.e. the exitstatus of the subprocess is obtained by "$? >> 8",
1989as described in the documentation). (Win32)
e41182b5 1990
b8099c3d
CN
1991There is no shell to process metacharacters, and the native standard is
1992to pass a command line terminated by "\n" "\r" or "\0" to the spawned
c47ff5f1 1993program. Redirection such as C<< > foo >> is performed (if at all) by
b8099c3d
CN
1994the run time library of the spawned program. C<system> I<list> will call
1995the Unix emulation library's C<exec> emulation, which attempts to provide
1996emulation of the stdin, stdout, stderr in force in the parent, providing
1997the child program uses a compatible version of the emulation library.
1998I<scalar> will call the native command line direct and no such emulation
1999of a child Unix program will exists. Mileage B<will> vary. (S<RISC OS>)
2000
0f897271
GS
2001Does not automatically flush output handles on some platforms.
2002(SunOS, Solaris, HP-UX)
2003
9bc98430
CB
2004The return value is POSIX-like (shifted up by 8 bits), which only allows
2005room for a made-up value derived from the severity bits of the native
200632-bit condition code (unless overridden by C<use vmsish 'status'>).
016930a6
JM
2007If the native condition code is one that has a POSIX value encoded, the
2008POSIX value will be decoded to extract the expected exit value.
9bc98430
CB
2009For more details see L<perlvms/$?>. (VMS)
2010
e41182b5
GS
2011=item times
2012
63f87e49
GS
2013"cumulative" times will be bogus. On anything other than Windows NT
2014or Windows 2000, "system" time will be bogus, and "user" time is
2015actually the time returned by the clock() function in the C runtime
2016library. (Win32)
e41182b5 2017
b8099c3d
CN
2018Not useful. (S<RISC OS>)
2019
47cd99a4 2020=item truncate
e41182b5 2021
6d738113 2022Not implemented. (Older versions of VMS)
e41182b5 2023
3fd80bd6 2024Truncation to same-or-shorter lengths only. (VOS)
495c5fdc 2025
4cfdb94f 2026If a FILEHANDLE is supplied, it must be writable and opened in append
e71a7dc8 2027mode (i.e., use C<<< open(FH, '>>filename') >>>
4cfdb94f
GS
2028or C<sysopen(FH,...,O_APPEND|O_RDWR)>. If a filename is supplied, it
2029should not be held open elsewhere. (Win32)
2030
e41182b5
GS
2031=item umask
2032
1bcbdd38 2033Returns undef where unavailable.
e41182b5 2034
b7df3edc
GS
2035C<umask> works but the correct permissions are set only when the file
2036is finally closed. (AmigaOS)
433acd8a 2037
47cd99a4 2038=item utime
e41182b5 2039
b6c36746 2040Only the modification time is updated. (VMS, S<RISC OS>)
e41182b5 2041
322422de
GS
2042May not behave as expected. Behavior depends on the C runtime
2043library's implementation of utime(), and the filesystem being
2044used. The FAT filesystem typically does not support an "access
2045time" field, and it may limit timestamps to a granularity of
2046two seconds. (Win32)
e41182b5
GS
2047
2048=item wait
2049
47cd99a4 2050=item waitpid
e41182b5 2051
e41182b5 2052Can only be applied to process handles returned for processes spawned
a6f858fb 2053using C<system(1, ...)> or pseudo processes created with C<fork()>. (Win32)
e41182b5 2054
b8099c3d
CN
2055Not useful. (S<RISC OS>)
2056
e41182b5
GS
2057=back
2058
2059
7c35b6af 2060=head1 Supported Platforms
ba58ab26 2061
7c35b6af
RGS
2062The following platforms are known to build Perl 5.12 (as of April 2010,
2063its release date) from the standard source code distribution available
500f1b69 2064at L<http://www.cpan.org/src>
bb377ba2 2065
bb377ba2
JV
2066=over
2067
2068=item Linux (x86, ARM, IA64)
2069
e0d9a2c8 2070=item HP-UX
bb377ba2
JV
2071
2072=item AIX
2073
2074=item Win32
2075
2076=over
2077
2078=item Windows 2000
2079
2080=item Windows XP
2081
2082=item Windows Server 2003
2083
2084=item Windows Vista
2085
2086=item Windows Server 2008
2087
3b665c47
JD
2088=item Windows 7
2089
bb377ba2
JV
2090=back
2091
2d9ede6e
JH
2092=item Cygwin
2093
bb377ba2
JV
2094=item Solaris (x86, SPARC)
2095
1b0ab010
JV
2096=item OpenVMS
2097
2098=over
2099
2100=item Alpha (7.2 and later)
2101
2102=item I64 (8.2 and later)
2103
2104=back
bb377ba2
JV
2105
2106=item Symbian
2107
2108=item NetBSD
2109
2110=item FreeBSD
2111
2d8e9a35
CBW
2112=item Debian GNU/kFreeBSD
2113
bb377ba2
JV
2114=item Haiku
2115
2116=item Irix (6.5. What else?)
2117
2118=item OpenBSD
2119
2120=item Dragonfly BSD
2121
b60fc215
CBW
2122=item Midnight BSD
2123
a62bfce3
CBW
2124=item QNX Neutrino RTOS (6.5.0)
2125
bb377ba2
JV
2126=item MirOS BSD
2127
7d4dfb6d
PG
2128=item Stratus OpenVOS (17.0 or later)
2129
bb377ba2
JV
2130Caveats:
2131
2132=over
2133
2134=item time_t issues that may or may not be fixed
2135
2136=back
2137
bb377ba2
JV
2138=item Symbian (Series 60 v3, 3.2 and 5 - what else?)
2139
10fb90aa 2140=item Stratus VOS / OpenVOS
bb377ba2
JV
2141
2142=item AIX
2143
2144=back
2145
8cbe99e5 2146=head1 EOL Platforms (Perl 5.14)
bb377ba2
JV
2147
2148The following platforms were supported by a previous version of
2149Perl but have been officially removed from Perl's source code
2150as of 5.12:
2151
2152=over
2153
2154=item Atari MiNT
2155
2156=item Apollo Domain/OS
2157
2158=item Apple Mac OS 8/9
2159
2160=item Tenon Machten
2161
2162=back
2163
8cbe99e5
JD
2164The following platforms were supported up to 5.10. They may still
2165have worked in 5.12, but supporting code has been removed for 5.14:
bb377ba2
JV
2166
2167=over
2168
2169=item Windows 95
2170
2171=item Windows 98
2172
2173=item Windows ME
2174
2175=item Windows NT4
2176
2177=back
2178
2179=head1 Supported Platforms (Perl 5.8)
2180
2181As of July 2002 (the Perl release 5.8.0), the following platforms were
cec2c193 2182able to build Perl from the standard source code distribution
500f1b69 2183available at L<http://www.cpan.org/src/>
cec2c193
JH
2184
2185 AIX
2186 BeOS
6f683aa2 2187 BSD/OS (BSDi)
cec2c193
JH
2188 Cygwin
2189 DG/UX
811b48f2 2190 DOS DJGPP 1)
cec2c193
JH
2191 DYNIX/ptx
2192 EPOC R5
2193 FreeBSD
6f683aa2 2194 HI-UXMPP (Hitachi) (5.8.0 worked but we didn't know it)
cec2c193
JH
2195 HP-UX
2196 IRIX
2197 Linux
8939ba94 2198 Mac OS Classic
6f683aa2 2199 Mac OS X (Darwin)
cec2c193
JH
2200 MPE/iX
2201 NetBSD
2202 NetWare
2203 NonStop-UX
6f683aa2 2204 ReliantUNIX (formerly SINIX)
cec2c193 2205 OpenBSD
6f683aa2 2206 OpenVMS (formerly VMS)
3ebac25b 2207 Open UNIX (Unixware) (since Perl 5.8.1/5.9.0)
cec2c193 2208 OS/2
522b859a 2209 OS/400 (using the PASE) (since Perl 5.8.1/5.9.0)
70de81db 2210 PowerUX
6f683aa2 2211 POSIX-BC (formerly BS2000)
cec2c193
JH
2212 QNX
2213 Solaris
70de81db 2214 SunOS 4
6f683aa2
JH
2215 SUPER-UX (NEC)
2216 Tru64 UNIX (formerly DEC OSF/1, Digital UNIX)
cec2c193
JH
2217 UNICOS
2218 UNICOS/mk
2219 UTS
7d4dfb6d 2220 VOS / OpenVOS
811b48f2 2221 Win95/98/ME/2K/XP 2)
c40b5d1d 2222 WinCE
6f683aa2 2223 z/OS (formerly OS/390)
cec2c193 2224 VM/ESA
ba58ab26 2225
811b48f2
JH
2226 1) in DOS mode either the DOS or OS/2 ports can be used
2227 2) compilers: Borland, MinGW (GCC), VC6
cec2c193 2228
c40b5d1d 2229The following platforms worked with the previous releases (5.6 and
cec2c193
JH
22305.7), but we did not manage either to fix or to test these in time
2231for the 5.8.0 release. There is a very good chance that many of these
70de81db 2232will work fine with the 5.8.0.
cec2c193 2233
8da2b1be 2234 BSD/OS
cec2c193
JH
2235 DomainOS
2236 Hurd
2237 LynxOS
2238 MachTen
2239 PowerMAX
2240 SCO SV
cec2c193
JH
2241 SVR4
2242 Unixware
2243 Windows 3.1
ba58ab26 2244
70de81db
JH
2245Known to be broken for 5.8.0 (but 5.6.1 and 5.7.2 can be used):
2246
2247 AmigaOS
2248
ba58ab26 2249The following platforms have been known to build Perl from source in
fd46a41b
JH
2250the past (5.005_03 and earlier), but we haven't been able to verify
2251their status for the current release, either because the
2252hardware/software platforms are rare or because we don't have an
2253active champion on these platforms--or both. They used to work,
2254though, so go ahead and try compiling them, and let perlbug@perl.org
2255of any trouble.
ba58ab26 2256
cec2c193
JH
2257 3b1
2258 A/UX
cec2c193
JH
2259 ConvexOS
2260 CX/UX
2261 DC/OSx
2262 DDE SMES
2263 DOS EMX
2264 Dynix
2265 EP/IX
2266 ESIX
2267 FPS
2268 GENIX
2269 Greenhills
2270 ISC
2271 MachTen 68k
cec2c193
JH
2272 MPC
2273 NEWS-OS
2274 NextSTEP
2275 OpenSTEP
2276 Opus
2277 Plan 9
cec2c193 2278 RISC/os
8da2b1be 2279 SCO ODT/OSR
cec2c193
JH
2280 Stellar
2281 SVR2
2282 TI1500
2283 TitanOS
2284 Ultrix
2285 Unisys Dynix
ba58ab26
JH
2286
2287The following platforms have their own source code distributions and
500f1b69 2288binaries available via L<http://www.cpan.org/ports/>
ba58ab26 2289
cec2c193 2290 Perl release
ba58ab26 2291
522b859a 2292 OS/400 (ILE) 5.005_02
cec2c193 2293 Tandem Guardian 5.004
ba58ab26
JH
2294
2295The following platforms have only binaries available via
500f1b69 2296L<http://www.cpan.org/ports/index.html> :
ba58ab26 2297
cec2c193 2298 Perl release
ba58ab26 2299
cec2c193
JH
2300 Acorn RISCOS 5.005_02
2301 AOS 5.002
2302 LynxOS 5.004_02
ba58ab26
JH
2303
2304Although we do suggest that you always build your own Perl from
2305the source code, both for maximal configurability and for security,
2306in case you are in a hurry you can check
500f1b69 2307L<http://www.cpan.org/ports/index.html> for binary distributions.
ba58ab26 2308
c997b287
GS
2309=head1 SEE ALSO
2310
b6c36746 2311L<perlaix>, L<perlamiga>, L<perlbs2000>,
739a0b84 2312L<perlce>, L<perlcygwin>, L<perldgux>, L<perldos>,
469e7be4 2313L<perlebcdic>, L<perlfreebsd>, L<perlhurd>, L<perlhpux>, L<perlirix>,
b5afd346 2314L<perlmacos>, L<perlmacosx>,
522b859a
JH
2315L<perlnetware>, L<perlos2>, L<perlos390>, L<perlos400>,
2316L<perlplan9>, L<perlqnx>, L<perlsolaris>, L<perltru64>,
043fec90 2317L<perlunicode>, L<perlvms>, L<perlvos>, L<perlwin32>, and L<Win32>.
c997b287 2318
e41182b5
GS
2319=head1 AUTHORS / CONTRIBUTORS
2320
06e9666b 2321Abigail <abigail@foad.org>,
c47ff5f1
GS
2322Charles Bailey <bailey@newman.upenn.edu>,
2323Graham Barr <gbarr@pobox.com>,
2324Tom Christiansen <tchrist@perl.com>,
06e9666b 2325Nicholas Clark <nick@ccl4.org>,
c47ff5f1 2326Thomas Dorner <Thomas.Dorner@start.de>,
06e9666b
A
2327Andy Dougherty <doughera@lafayette.edu>,
2328Dominic Dunlop <domo@computer.org>,
2329Neale Ferguson <neale@vma.tabnsw.com.au>,
c47ff5f1 2330David J. Fiander <davidf@mks.com>,
3fd80bd6 2331Paul Green <Paul.Green@stratus.com>,
06e9666b 2332M.J.T. Guy <mjtg@cam.ac.uk>,
61f30a5e 2333Jarkko Hietaniemi <jhi@iki.fi>,
c47ff5f1 2334Luther Huffman <lutherh@stratcom.com>,
06e9666b
A
2335Nick Ing-Simmons <nick@ing-simmons.net>,
2336Andreas J. KE<ouml>nig <a.koenig@mind.de>,
c47ff5f1
GS
2337Markus Laker <mlaker@contax.co.uk>,
2338Andrew M. Langmead <aml@world.std.com>,
2339Larry Moore <ljmoore@freespace.net>,
2340Paul Moore <Paul.Moore@uk.origin-it.com>,
2341Chris Nandor <pudge@pobox.com>,
1afc07ec 2342Matthias Neeracher <neeracher@mac.com>,
e71a7dc8 2343Philip Newton <pne@cpan.org>,
c47ff5f1
GS
2344Gary Ng <71564.1743@CompuServe.COM>,
2345Tom Phoenix <rootbeer@teleport.com>,
2346AndrE<eacute> Pirard <A.Pirard@ulg.ac.be>,
2347Peter Prymmer <pvhp@forte.com>,
2348Hugo van der Sanden <hv@crypt0.demon.co.uk>,
2349Gurusamy Sarathy <gsar@activestate.com>,
2350Paul J. Schinder <schinder@pobox.com>,
2351Michael G Schwern <schwern@pobox.com>,
06e9666b 2352Dan Sugalski <dan@sidhe.org>,
bbe548ff 2353Nathan Torkington <gnat@frii.com>,
016930a6 2354John Malmberg <wb8tyw@qsl.net>