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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,
68fb0eb7
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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.
a10d74f3
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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
a61fc69c
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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.
932f293e
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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
e41182b5
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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
b7df3edc
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
GS
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
e41182b5
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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
e41182b5
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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
HS
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
c87488a3
HS
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
ec481373
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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".
322422de
GS
660
661=head2 Internationalisation
662
b7df3edc
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
11264fdb
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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<$^O> variable that indicates the operating
780system it was built on. This was implemented
b7df3edc
GS
781to help speed up code that would otherwise have to C<use Config>
782and use the value of C<$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 $filespec3 = 'c:\\foo\\bar\\file.txt';
e41182b5 848
b7df3edc
GS
849System calls accept either C</> or C<\> as the path separator.
850However, many command-line utilities of DOS vintage treat C</> as
851the option prefix, so may get confused by filenames containing C</>.
852Aside from calling any external programs, C</> will work just fine,
853and probably better, as it is more consistent with popular usage,
854and avoids the problem of remembering what to backwhack and what
855not to.
e41182b5 856
b7df3edc
GS
857The DOS FAT filesystem can accommodate only "8.3" style filenames. Under
858the "case-insensitive, but case-preserving" HPFS (OS/2) and NTFS (NT)
0a47030a 859filesystems you may have to be careful about case returned with functions
e41182b5
GS
860like C<readdir> or used with functions like C<open> or C<opendir>.
861
b7df3edc
GS
862DOS also treats several filenames as special, such as AUX, PRN,
863NUL, CON, COM1, LPT1, LPT2, etc. Unfortunately, sometimes these
864filenames won't even work if you include an explicit directory
865prefix. It is best to avoid such filenames, if you want your code
866to be portable to DOS and its derivatives. It's hard to know what
867these all are, unfortunately.
e41182b5
GS
868
869Users of these operating systems may also wish to make use of
b7df3edc 870scripts such as I<pl2bat.bat> or I<pl2cmd> to
e41182b5
GS
871put wrappers around your scripts.
872
873Newline (C<\n>) is translated as C<\015\012> by STDIO when reading from
6ab3f9cb
GS
874and writing to files (see L<"Newlines">). C<binmode(FILEHANDLE)>
875will keep C<\n> translated as C<\012> for that filehandle. Since it is a
876no-op on other systems, C<binmode> should be used for cross-platform code
b7df3edc
GS
877that deals with binary data. That's assuming you realize in advance
878that your data is in binary. General-purpose programs should
879often assume nothing about their data.
e41182b5 880
b7df3edc 881The C<$^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
JH
919
920 c:\> perl -MPOSIX -we "print join '|', uname"
921 Windows NT|moonru|5.0|Build 2195 (Service Pack 2)|x86
d99f392e 922
e41182b5
GS
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
1198The value of C<$^O> on VOS is "VOS". To determine the
1199architecture that you are running on without resorting to loading
1200all of C<%Config> you can examine the content of the @INC array
1201like so:
495c5fdc 1202
24e8e380 1203 if ($^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
GP
1221
1222There is no specific mailing list for Perl on VOS. You can post
10fb90aa
PG
1223comments to the comp.sys.stratus newsgroup, or use the contact
1224information located in the distribution files on the Stratus
1225Anonymous FTP site.
495c5fdc 1226
c997b287
GS
1227=item *
1228
500f1b69 1229VOS Perl on the web at L<http://ftp.stratus.com/pub/vos/posix/posix.html>
495c5fdc
GP
1230
1231=back
1232
e41182b5
GS
1233=head2 EBCDIC Platforms
1234
1235Recent versions of Perl have been ported to platforms such as OS/400 on
d1e3b762
GS
1236AS/400 minicomputers as well as OS/390, VM/ESA, and BS2000 for S/390
1237Mainframes. Such computers use EBCDIC character sets internally (usually
0cc436d0
GS
1238Character Code Set ID 0037 for OS/400 and either 1047 or POSIX-BC for S/390
1239systems). On the mainframe perl currently works under the "Unix system
1240services for OS/390" (formerly known as OpenEdition), VM/ESA OpenEdition, or
1241the BS200 POSIX-BC system (BS2000 is supported in perl 5.6 and greater).
522b859a 1242See L<perlos390> for details. Note that for OS/400 there is also a port of
1bcbdd38 1243Perl 5.8.1/5.10.0 or later to the PASE which is ASCII-based (as opposed to
522b859a 1244ILE which is EBCDIC-based), see L<perlos400>.
e41182b5 1245
7c5ffed3
JH
1246As of R2.5 of USS for OS/390 and Version 2.3 of VM/ESA these Unix
1247sub-systems do not support the C<#!> shebang trick for script invocation.
1248Hence, on OS/390 and VM/ESA perl scripts can be executed with a header
1249similar to the following simple script:
e41182b5
GS
1250
1251 : # use perl
1252 eval 'exec /usr/local/bin/perl -S $0 ${1+"$@"}'
1253 if 0;
1254 #!/usr/local/bin/perl # just a comment really
1255
1256 print "Hello from perl!\n";
1257
d1e3b762
GS
1258OS/390 will support the C<#!> shebang trick in release 2.8 and beyond.
1259Calls to C<system> and backticks can use POSIX shell syntax on all
1260S/390 systems.
1261
b7df3edc 1262On the AS/400, if PERL5 is in your library list, you may need
6ab3f9cb
GS
1263to wrap your perl scripts in a CL procedure to invoke them like so:
1264
1265 BEGIN
1266 CALL PGM(PERL5/PERL) PARM('/QOpenSys/hello.pl')
1267 ENDPGM
1268
1269This will invoke the perl script F<hello.pl> in the root of the
1270QOpenSys file system. On the AS/400 calls to C<system> or backticks
1271must use CL syntax.
1272
e41182b5 1273On these platforms, bear in mind that the EBCDIC character set may have
0a47030a
GS
1274an effect on what happens with some perl functions (such as C<chr>,
1275C<pack>, C<print>, C<printf>, C<ord>, C<sort>, C<sprintf>, C<unpack>), as
1276well as bit-fiddling with ASCII constants using operators like C<^>, C<&>
1277and C<|>, not to mention dealing with socket interfaces to ASCII computers
6ab3f9cb 1278(see L<"Newlines">).
e41182b5 1279
b7df3edc
GS
1280Fortunately, most web servers for the mainframe will correctly
1281translate the C<\n> in the following statement to its ASCII equivalent
1282(C<\r> is the same under both Unix and OS/390 & VM/ESA):
e41182b5
GS
1283
1284 print "Content-type: text/html\r\n\r\n";
1285
d1e3b762 1286The values of C<$^O> on some of these platforms includes:
e41182b5 1287
d1e3b762
GS
1288 uname $^O $Config{'archname'}
1289 --------------------------------------------
1290 OS/390 os390 os390
1291 OS400 os400 os400
1292 POSIX-BC posix-bc BS2000-posix-bc
1293 VM/ESA vmesa vmesa
3c075c7d 1294
e41182b5
GS
1295Some simple tricks for determining if you are running on an EBCDIC
1296platform could include any of the following (perhaps all):
1297
ce7b6f06 1298 if ("\t" eq "\005") { print "EBCDIC may be spoken here!\n"; }
e41182b5
GS
1299
1300 if (ord('A') == 193) { print "EBCDIC may be spoken here!\n"; }
1301
1302 if (chr(169) eq 'z') { print "EBCDIC may be spoken here!\n"; }
1303
b7df3edc 1304One thing you may not want to rely on is the EBCDIC encoding
0a47030a
GS
1305of punctuation characters since these may differ from code page to code
1306page (and once your module or script is rumoured to work with EBCDIC,
1307folks will want it to work with all EBCDIC character sets).
e41182b5
GS
1308
1309Also see:
1310
1311=over 4
1312
c997b287
GS
1313=item *
1314
dc5c060f 1315L<perlos390>, F<README.os390>, F<perlbs2000>, F<README.vmesa>,
bb462878 1316L<perlebcdic>.
c997b287
GS
1317
1318=item *
e41182b5
GS
1319
1320The perl-mvs@perl.org list is for discussion of porting issues as well as
1321general usage issues for all EBCDIC Perls. Send a message body of
1322"subscribe perl-mvs" to majordomo@perl.org.
1323
7ee27b7c 1324=item *
c997b287
GS
1325
1326AS/400 Perl information at
500f1b69 1327L<http://as400.rochester.ibm.com/>
d1e3b762 1328as well as on CPAN in the F<ports/> directory.
e41182b5
GS
1329
1330=back
1331
b8099c3d
CN
1332=head2 Acorn RISC OS
1333
b7df3edc
GS
1334Because Acorns use ASCII with newlines (C<\n>) in text files as C<\012> like
1335Unix, and because Unix filename emulation is turned on by default,
1336most simple scripts will probably work "out of the box". The native
6ab3f9cb 1337filesystem is modular, and individual filesystems are free to be
0a47030a 1338case-sensitive or insensitive, and are usually case-preserving. Some
b7df3edc 1339native filesystems have name length limits, which file and directory
6ab3f9cb
GS
1340names are silently truncated to fit. Scripts should be aware that the
1341standard filesystem currently has a name length limit of B<10>
1342characters, with up to 77 items in a directory, but other filesystems
0a47030a 1343may not impose such limitations.
b8099c3d
CN
1344
1345Native filenames are of the form
1346
6ab3f9cb 1347 Filesystem#Special_Field::DiskName.$.Directory.Directory.File
dd9f0070 1348
b8099c3d
CN
1349where
1350
1351 Special_Field is not usually present, but may contain . and $ .
1352 Filesystem =~ m|[A-Za-z0-9_]|
1353 DsicName =~ m|[A-Za-z0-9_/]|
1354 $ represents the root directory
1355 . is the path separator
1356 @ is the current directory (per filesystem but machine global)
1357 ^ is the parent directory
1358 Directory and File =~ m|[^\0- "\.\$\%\&:\@\\^\|\177]+|
1359
1360The default filename translation is roughly C<tr|/.|./|;>
1361
6ab3f9cb 1362Note that C<"ADFS::HardDisk.$.File" ne 'ADFS::HardDisk.$.File'> and that
0a47030a
GS
1363the second stage of C<$> interpolation in regular expressions will fall
1364foul of the C<$.> if scripts are not careful.
1365
1366Logical paths specified by system variables containing comma-separated
b7df3edc 1367search lists are also allowed; hence C<System:Modules> is a valid
0a47030a 1368filename, and the filesystem will prefix C<Modules> with each section of
6ab3f9cb 1369C<System$Path> until a name is made that points to an object on disk.
b7df3edc 1370Writing to a new file C<System:Modules> would be allowed only if
0a47030a
GS
1371C<System$Path> contains a single item list. The filesystem will also
1372expand system variables in filenames if enclosed in angle brackets, so
c47ff5f1 1373C<< <System$Dir>.Modules >> would look for the file
0a47030a 1374S<C<$ENV{'System$Dir'} . 'Modules'>>. The obvious implication of this is
c47ff5f1 1375that B<fully qualified filenames can start with C<< <> >>> and should
0a47030a 1376be protected when C<open> is used for input.
b8099c3d
CN
1377
1378Because C<.> was in use as a directory separator and filenames could not
1379be assumed to be unique after 10 characters, Acorn implemented the C
1380compiler to strip the trailing C<.c> C<.h> C<.s> and C<.o> suffix from
1381filenames specified in source code and store the respective files in
b7df3edc 1382subdirectories named after the suffix. Hence files are translated:
b8099c3d
CN
1383
1384 foo.h h.foo
1385 C:foo.h C:h.foo (logical path variable)
1386 sys/os.h sys.h.os (C compiler groks Unix-speak)
1387 10charname.c c.10charname
1388 10charname.o o.10charname
1389 11charname_.c c.11charname (assuming filesystem truncates at 10)
1390
1391The Unix emulation library's translation of filenames to native assumes
b7df3edc
GS
1392that this sort of translation is required, and it allows a user-defined list
1393of known suffixes that it will transpose in this fashion. This may
92863ac5
KW
1394seem transparent, but consider that with these rules F<foo/bar/baz.h>
1395and F<foo/bar/h/baz> both map to F<foo.bar.h.baz>, and that C<readdir> and
0a47030a 1396C<glob> cannot and do not attempt to emulate the reverse mapping. Other
6ab3f9cb 1397C<.>'s in filenames are translated to C</>.
0a47030a 1398
b7df3edc 1399As implied above, the environment accessed through C<%ENV> is global, and
0a47030a 1400the convention is that program specific environment variables are of the
6ab3f9cb
GS
1401form C<Program$Name>. Each filesystem maintains a current directory,
1402and the current filesystem's current directory is the B<global> current
b7df3edc
GS
1403directory. Consequently, sociable programs don't change the current
1404directory but rely on full pathnames, and programs (and Makefiles) cannot
0a47030a
GS
1405assume that they can spawn a child process which can change the current
1406directory without affecting its parent (and everyone else for that
1407matter).
1408
b7df3edc
GS
1409Because native operating system filehandles are global and are currently
1410allocated down from 255, with 0 being a reserved value, the Unix emulation
0a47030a
GS
1411library emulates Unix filehandles. Consequently, you can't rely on
1412passing C<STDIN>, C<STDOUT>, or C<STDERR> to your children.
1413
1414The desire of users to express filenames of the form
c47ff5f1 1415C<< <Foo$Dir>.Bar >> on the command line unquoted causes problems,
0a47030a 1416too: C<``> command output capture has to perform a guessing game. It
c47ff5f1 1417assumes that a string C<< <[^<>]+\$[^<>]> >> is a
0a47030a 1418reference to an environment variable, whereas anything else involving
c47ff5f1 1419C<< < >> or C<< > >> is redirection, and generally manages to be 99%
0a47030a
GS
1420right. Of course, the problem remains that scripts cannot rely on any
1421Unix tools being available, or that any tools found have Unix-like command
1422line arguments.
1423
b7df3edc
GS
1424Extensions and XS are, in theory, buildable by anyone using free
1425tools. In practice, many don't, as users of the Acorn platform are
1426used to binary distributions. MakeMaker does run, but no available
1427make currently copes with MakeMaker's makefiles; even if and when
1428this should be fixed, the lack of a Unix-like shell will cause
1429problems with makefile rules, especially lines of the form C<cd
1430sdbm && make all>, and anything using quoting.
b8099c3d
CN
1431
1432"S<RISC OS>" is the proper name for the operating system, but the value
1433in C<$^O> is "riscos" (because we don't like shouting).
1434
e41182b5
GS
1435=head2 Other perls
1436
b7df3edc 1437Perl has been ported to many platforms that do not fit into any of
cd86ed9d
JV
1438the categories listed above. Some, such as AmigaOS, BeOS, HP MPE/iX,
1439QNX, Plan 9, and VOS, have been well-integrated into the standard
1440Perl source code kit. You may need to see the F<ports/> directory
1441on CPAN for information, and possibly binaries, for the likes of:
1442aos, Atari ST, lynxos, riscos, Novell Netware, Tandem Guardian,
1443I<etc.> (Yes, we know that some of these OSes may fall under the
1444Unix category, but we are not a standards body.)
e41182b5 1445
d1e3b762
GS
1446Some approximate operating system names and their C<$^O> values
1447in the "OTHER" category include:
1448
1449 OS $^O $Config{'archname'}
1450 ------------------------------------------
1451 Amiga DOS amigaos m68k-amigos
cec2c193 1452 BeOS beos
d1e3b762
GS
1453 MPE/iX mpeix PA-RISC1.1
1454
e41182b5
GS
1455See also:
1456
1457=over 4
1458
c997b287
GS
1459=item *
1460
1461Amiga, F<README.amiga> (installed as L<perlamiga>).
1462
1463=item *
d1e3b762 1464
c997b287 1465Be OS, F<README.beos>
e41182b5 1466
c997b287
GS
1467=item *
1468
1469HP 300 MPE/iX, F<README.mpeix> and Mark Bixby's web page
500f1b69 1470L<http://www.bixby.org/mark/porting.html>
c997b287
GS
1471
1472=item *
e41182b5 1473
6ab3f9cb 1474A free perl5-based PERL.NLM for Novell Netware is available in
500f1b69 1475precompiled binary and source code form from L<http://www.novell.com/>
6ab3f9cb 1476as well as from CPAN.
e41182b5 1477
13a2d996 1478=item *
c997b287 1479
e6f03d26 1480S<Plan 9>, F<README.plan9>
d1e3b762 1481
e41182b5
GS
1482=back
1483
e41182b5
GS
1484=head1 FUNCTION IMPLEMENTATIONS
1485
b7df3edc
GS
1486Listed below are functions that are either completely unimplemented
1487or else have been implemented differently on various platforms.
1488Following each description will be, in parentheses, a list of
1489platforms that the description applies to.
e41182b5 1490
b7df3edc
GS
1491The list may well be incomplete, or even wrong in some places. When
1492in doubt, consult the platform-specific README files in the Perl
1493source distribution, and any other documentation resources accompanying
1494a given port.
e41182b5 1495
0a47030a 1496Be aware, moreover, that even among Unix-ish systems there are variations.
e41182b5 1497
b7df3edc
GS
1498For many functions, you can also query C<%Config>, exported by
1499default from the Config module. For example, to check whether the
1500platform has the C<lstat> call, check C<$Config{d_lstat}>. See
1501L<Config> for a full description of available variables.
e41182b5
GS
1502
1503=head2 Alphabetical Listing of Perl Functions
1504
1505=over 8
1506
e41182b5
GS
1507=item -X
1508
038ae9a4
SH
1509C<-w> only inspects the read-only file attribute (FILE_ATTRIBUTE_READONLY),
1510which determines whether the directory can be deleted, not whether it can
1511be written to. Directories always have read and write access unless denied
1512by discretionary access control lists (DACLs). (S<Win32>)
1513
b7df3edc
GS
1514C<-r>, C<-w>, C<-x>, and C<-o> tell whether the file is accessible,
1515which may not reflect UIC-based file protections. (VMS)
e41182b5 1516
b8099c3d
CN
1517C<-s> by name on an open file will return the space reserved on disk,
1518rather than the current extent. C<-s> on an open filehandle returns the
b7df3edc 1519current size. (S<RISC OS>)
b8099c3d 1520
e41182b5 1521C<-R>, C<-W>, C<-X>, C<-O> are indistinguishable from C<-r>, C<-w>,
204ad8d5 1522C<-x>, C<-o>. (Win32, VMS, S<RISC OS>)
e41182b5 1523
287a962e 1524C<-g>, C<-k>, C<-l>, C<-u>, C<-A> are not particularly meaningful.
b8099c3d 1525(Win32, VMS, S<RISC OS>)
e41182b5 1526
287a962e
JD
1527C<-p> is not particularly meaningful. (VMS, S<RISC OS>)
1528
e41182b5
GS
1529C<-d> is true if passed a device spec without an explicit directory.
1530(VMS)
1531
e41182b5 1532C<-x> (or C<-X>) determine if a file ends in one of the executable
b7df3edc 1533suffixes. C<-S> is meaningless. (Win32)
e41182b5 1534
b8099c3d
CN
1535C<-x> (or C<-X>) determine if a file has an executable file type.
1536(S<RISC OS>)
1537
aca72608
JD
1538=item alarm
1539
1540Emulated using timers that must be explicitly polled whenever Perl
1541wants to dispatch "safe signals" and therefore cannot interrupt
1542blocking system calls. (Win32)
1543
47cd99a4 1544=item atan2
519bc777
RGS
1545
1546Due to issues with various CPUs, math libraries, compilers, and standards,
1547results for C<atan2()> may vary depending on any combination of the above.
1548Perl attempts to conform to the Open Group/IEEE standards for the results
1549returned from C<atan2()>, but cannot force the issue if the system Perl is
1550run on does not allow it. (Tru64, HP-UX 10.20)
1551
1552The current version of the standards for C<atan2()> is available at
1553L<http://www.opengroup.org/onlinepubs/009695399/functions/atan2.html>.
1554
47cd99a4 1555=item binmode
e41182b5 1556
204ad8d5 1557Meaningless. (S<RISC OS>)
e41182b5
GS
1558
1559Reopens file and restores pointer; if function fails, underlying
1560filehandle may be closed, or pointer may be in a different position.
1561(VMS)
1562
1563The value returned by C<tell> may be affected after the call, and
1564the filehandle may be flushed. (Win32)
1565
47cd99a4 1566=item chmod
e41182b5 1567
e41182b5
GS
1568Only good for changing "owner" read-write access, "group", and "other"
1569bits are meaningless. (Win32)
1570
b8099c3d
CN
1571Only good for changing "owner" and "other" read-write access. (S<RISC OS>)
1572
495c5fdc
GP
1573Access permissions are mapped onto VOS access-control list changes. (VOS)
1574
4e51f8e4 1575The actual permissions set depend on the value of the C<CYGWIN>
789f0d36 1576in the SYSTEM environment settings. (Cygwin)
4e51f8e4 1577
47cd99a4 1578=item chown
e41182b5 1579
204ad8d5 1580Not implemented. (Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1581
1582Does nothing, but won't fail. (Win32)
1583
3fd80bd6
PG
1584A little funky, because VOS's notion of ownership is a little funky (VOS).
1585
e41182b5
GS
1586=item chroot
1587
204ad8d5 1588Not implemented. (Win32, VMS, S<Plan 9>, S<RISC OS>, VOS, VM/ESA)
e41182b5 1589
47cd99a4 1590=item crypt
e41182b5
GS
1591
1592May not be available if library or source was not provided when building
b8099c3d 1593perl. (Win32)
e41182b5 1594
47cd99a4 1595=item dbmclose
e41182b5 1596
e6f03d26 1597Not implemented. (VMS, S<Plan 9>, VOS)
e41182b5 1598
47cd99a4 1599=item dbmopen
e41182b5 1600
e6f03d26 1601Not implemented. (VMS, S<Plan 9>, VOS)
e41182b5 1602
47cd99a4 1603=item dump
e41182b5 1604
204ad8d5 1605Not useful. (S<RISC OS>)
e41182b5 1606
84d78eb7 1607Not supported. (Cygwin, Win32)
e41182b5 1608
b8099c3d 1609Invokes VMS debugger. (VMS)
e41182b5 1610
47cd99a4 1611=item exec
e41182b5 1612
7c5ffed3 1613Implemented via Spawn. (VM/ESA)
3c075c7d 1614
0f897271
GS
1615Does not automatically flush output handles on some platforms.
1616(SunOS, Solaris, HP-UX)
1617
af8bb25a
FC
1618Not supported. (Symbian OS)
1619
fe12c0e8
MS
1620=item exit
1621
e1020413 1622Emulates Unix exit() (which considers C<exit 1> to indicate an error) by
fe12c0e8
MS
1623mapping the C<1> to SS$_ABORT (C<44>). This behavior may be overridden
1624with the pragma C<use vmsish 'exit'>. As with the CRTL's exit()
1625function, C<exit 0> is also mapped to an exit status of SS$_NORMAL
1626(C<1>); this mapping cannot be overridden. Any other argument to exit()
016930a6
JM
1627is used directly as Perl's exit status. On VMS, unless the future
1628POSIX_EXIT mode is enabled, the exit code should always be a valid
1629VMS exit code and not a generic number. When the POSIX_EXIT mode is
1630enabled, a generic number will be encoded in a method compatible with
1631the C library _POSIX_EXIT macro so that it can be decoded by other
1632programs, particularly ones written in C, like the GNV package. (VMS)
fe12c0e8 1633
bef2c191
RB
1634C<exit()> resets file pointers, which is a problem when called
1635from a child process (created by C<fork()>) in C<BEGIN>.
1636A workaround is to use C<POSIX::_exit>. (Solaris)
1637
1638 exit unless $Config{archname} =~ /\bsolaris\b/;
1639 require POSIX and POSIX::_exit(0);
1640
47cd99a4 1641=item fcntl
e41182b5 1642
016930a6 1643Not implemented. (Win32)
6a065175 1644
016930a6 1645Some functions available based on the version of VMS. (VMS)
e41182b5 1646
47cd99a4 1647=item flock
e41182b5 1648
204ad8d5 1649Not implemented (VMS, S<RISC OS>, VOS).
e41182b5 1650
e41182b5
GS
1651=item fork
1652
204ad8d5 1653Not implemented. (AmigaOS, S<RISC OS>, VM/ESA, VMS)
0f897271
GS
1654
1655Emulated using multiple interpreters. See L<perlfork>. (Win32)
1656
1657Does not automatically flush output handles on some platforms.
1658(SunOS, Solaris, HP-UX)
e41182b5
GS
1659
1660=item getlogin
1661
204ad8d5 1662Not implemented. (S<RISC OS>)
e41182b5 1663
47cd99a4 1664=item getpgrp
e41182b5 1665
204ad8d5 1666Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5
GS
1667
1668=item getppid
1669
204ad8d5 1670Not implemented. (Win32, S<RISC OS>)
e41182b5 1671
47cd99a4 1672=item getpriority
e41182b5 1673
204ad8d5 1674Not implemented. (Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5 1675
47cd99a4 1676=item getpwnam
e41182b5 1677
204ad8d5 1678Not implemented. (Win32)
e41182b5 1679
b8099c3d
CN
1680Not useful. (S<RISC OS>)
1681
47cd99a4 1682=item getgrnam
e41182b5 1683
204ad8d5 1684Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5 1685
47cd99a4 1686=item getnetbyname
e41182b5 1687
204ad8d5 1688Not implemented. (Win32, S<Plan 9>)
e41182b5 1689
47cd99a4 1690=item getpwuid
e41182b5 1691
204ad8d5 1692Not implemented. (Win32)
e41182b5 1693
b8099c3d
CN
1694Not useful. (S<RISC OS>)
1695
47cd99a4 1696=item getgrgid
e41182b5 1697
204ad8d5 1698Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5 1699
47cd99a4 1700=item getnetbyaddr
e41182b5 1701
204ad8d5 1702Not implemented. (Win32, S<Plan 9>)
e41182b5 1703
47cd99a4 1704=item getprotobynumber
e41182b5 1705
47cd99a4 1706=item getservbyport
e41182b5 1707
e41182b5
GS
1708=item getpwent
1709
204ad8d5 1710Not implemented. (Win32, VM/ESA)
e41182b5
GS
1711
1712=item getgrent
1713
204ad8d5 1714Not implemented. (Win32, VMS, VM/ESA)
e41182b5 1715
ef5a6dd7
JH
1716=item gethostbyname
1717
1718C<gethostbyname('localhost')> does not work everywhere: you may have
204ad8d5 1719to use C<gethostbyname('127.0.0.1')>. (S<Irix 5>)
ef5a6dd7 1720
e41182b5
GS
1721=item gethostent
1722
204ad8d5 1723Not implemented. (Win32)
e41182b5
GS
1724
1725=item getnetent
1726
204ad8d5 1727Not implemented. (Win32, S<Plan 9>)
e41182b5
GS
1728
1729=item getprotoent
1730
204ad8d5 1731Not implemented. (Win32, S<Plan 9>)
e41182b5
GS
1732
1733=item getservent
1734
e6f03d26 1735Not implemented. (Win32, S<Plan 9>)
e41182b5 1736
47cd99a4 1737=item sethostent
e41182b5 1738
204ad8d5 1739Not implemented. (Win32, S<Plan 9>, S<RISC OS>)
e41182b5 1740
47cd99a4 1741=item setnetent
e41182b5 1742
204ad8d5 1743Not implemented. (Win32, S<Plan 9>, S<RISC OS>)
e41182b5 1744
47cd99a4 1745=item setprotoent
e41182b5 1746
204ad8d5 1747Not implemented. (Win32, S<Plan 9>, S<RISC OS>)
e41182b5 1748
47cd99a4 1749=item setservent
e41182b5 1750
e6f03d26 1751Not implemented. (S<Plan 9>, Win32, S<RISC OS>)
e41182b5
GS
1752
1753=item endpwent
1754
204ad8d5 1755Not implemented. (MPE/iX, VM/ESA, Win32)
e41182b5
GS
1756
1757=item endgrent
1758
204ad8d5 1759Not implemented. (MPE/iX, S<RISC OS>, VM/ESA, VMS, Win32)
e41182b5
GS
1760
1761=item endhostent
1762
204ad8d5 1763Not implemented. (Win32)
e41182b5
GS
1764
1765=item endnetent
1766
204ad8d5 1767Not implemented. (Win32, S<Plan 9>)
e41182b5
GS
1768
1769=item endprotoent
1770
204ad8d5 1771Not implemented. (Win32, S<Plan 9>)
e41182b5
GS
1772
1773=item endservent
1774
e6f03d26 1775Not implemented. (S<Plan 9>, Win32)
e41182b5
GS
1776
1777=item getsockopt SOCKET,LEVEL,OPTNAME
1778
e6f03d26 1779Not implemented. (S<Plan 9>)
e41182b5 1780
e41182b5
GS
1781=item glob
1782
63f87e49
GS
1783This operator is implemented via the File::Glob extension on most
1784platforms. See L<File::Glob> for portability information.
b8099c3d 1785
62aa5637
MS
1786=item gmtime
1787
461d5a49
MS
1788In theory, gmtime() is reliable from -2**63 to 2**63-1. However,
1789because work arounds in the implementation use floating point numbers,
1790it will become inaccurate as the time gets larger. This is a bug and
1791will be fixed in the future.
62aa5637 1792
10fb90aa
PG
1793On VOS, time values are 32-bit quantities.
1794
e41182b5
GS
1795=item ioctl FILEHANDLE,FUNCTION,SCALAR
1796
1797Not implemented. (VMS)
1798
1799Available only for socket handles, and it does what the ioctlsocket() call
1800in the Winsock API does. (Win32)
1801
b8099c3d
CN
1802Available only for socket handles. (S<RISC OS>)
1803
47cd99a4 1804=item kill
e41182b5 1805
862b5365 1806Not implemented, hence not useful for taint checking. (S<RISC OS>)
e41182b5 1807
63f87e49
GS
1808C<kill()> doesn't have the semantics of C<raise()>, i.e. it doesn't send
1809a signal to the identified process like it does on Unix platforms.
1810Instead C<kill($sig, $pid)> terminates the process identified by $pid,
1811and makes it exit immediately with exit status $sig. As in Unix, if
1812$sig is 0 and the specified process exists, it returns true without
1813actually terminating it. (Win32)
e41182b5 1814
d0302514
JD
1815C<kill(-9, $pid)> will terminate the process specified by $pid and
1816recursively all child processes owned by it. This is different from
1817the Unix semantics, where the signal will be delivered to all
1818processes in the same process group as the process specified by
1819$pid. (Win32)
1820
016930a6
JM
1821Is not supported for process identification number of 0 or negative
1822numbers. (VMS)
1823
47cd99a4 1824=item link
e41182b5 1825
10fb90aa 1826Not implemented. (MPE/iX, S<RISC OS>, VOS)
e41182b5 1827
433acd8a
JH
1828Link count not updated because hard links are not quite that hard
1829(They are sort of half-way between hard and soft links). (AmigaOS)
1830
63d6c08b
JD
1831Hard links are implemented on Win32 under NTFS only. They are
1832natively supported on Windows 2000 and later. On Windows NT they
1833are implemented using the Windows POSIX subsystem support and the
1834Perl process will need Administrator or Backup Operator privileges
1835to create hard links.
a3dfe201 1836
016930a6
JM
1837Available on 64 bit OpenVMS 8.2 and later. (VMS)
1838
62aa5637
MS
1839=item localtime
1840
a61fc69c 1841localtime() has the same range as L</gmtime>, but because time zone
dc164757
MS
1842rules change its accuracy for historical and future times may degrade
1843but usually by no more than an hour.
62aa5637 1844
e41182b5
GS
1845=item lstat
1846
016930a6 1847Not implemented. (S<RISC OS>)
e41182b5 1848
63f87e49 1849Return values (especially for device and inode) may be bogus. (Win32)
e41182b5 1850
47cd99a4 1851=item msgctl
e41182b5 1852
47cd99a4 1853=item msgget
e41182b5 1854
47cd99a4 1855=item msgsnd
e41182b5 1856
47cd99a4 1857=item msgrcv
e41182b5 1858
204ad8d5 1859Not implemented. (Win32, VMS, S<Plan 9>, S<RISC OS>, VOS)
e41182b5 1860
47cd99a4 1861=item open
e41182b5 1862
204ad8d5 1863open to C<|-> and C<-|> are unsupported. (Win32, S<RISC OS>)
e41182b5 1864
0f897271
GS
1865Opening a process does not automatically flush output handles on some
1866platforms. (SunOS, Solaris, HP-UX)
1867
e41182b5
GS
1868=item readlink
1869
b8099c3d 1870Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5 1871
47cd99a4 1872=item rename
c9b2b9d4
SS
1873
1874Can't move directories between directories on different logical volumes. (Win32)
1875
3ba4b5c1
JD
1876=item rewinddir
1877
1878Will not cause readdir() to re-read the directory stream. The entries
1879already read before the rewinddir() call will just be returned again
1880from a cache buffer. (Win32)
1881
47cd99a4 1882=item select
e41182b5 1883
689c5c24 1884Only implemented on sockets. (Win32, VMS)
e41182b5 1885
b8099c3d
CN
1886Only reliable on sockets. (S<RISC OS>)
1887
76e05f0b 1888Note that the C<select FILEHANDLE> form is generally portable.
63f87e49 1889
47cd99a4 1890=item semctl
e41182b5 1891
47cd99a4 1892=item semget
e41182b5 1893
47cd99a4 1894=item semop
e41182b5 1895
10fb90aa 1896Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5 1897
a3dfe201
GS
1898=item setgrent
1899
10fb90aa 1900Not implemented. (MPE/iX, VMS, Win32, S<RISC OS>)
a3dfe201 1901
47cd99a4 1902=item setpgrp
e41182b5 1903
204ad8d5 1904Not implemented. (Win32, VMS, S<RISC OS>, VOS)
e41182b5 1905
47cd99a4 1906=item setpriority
e41182b5 1907
204ad8d5 1908Not implemented. (Win32, VMS, S<RISC OS>, VOS)
e41182b5 1909
a3dfe201
GS
1910=item setpwent
1911
10fb90aa 1912Not implemented. (MPE/iX, Win32, S<RISC OS>)
a3dfe201 1913
47cd99a4 1914=item setsockopt
e41182b5 1915
e6f03d26 1916Not implemented. (S<Plan 9>)
e41182b5 1917
47cd99a4 1918=item shmctl
e41182b5 1919
47cd99a4 1920=item shmget
e41182b5 1921
47cd99a4 1922=item shmread
e41182b5 1923
47cd99a4 1924=item shmwrite
e41182b5 1925
204ad8d5 1926Not implemented. (Win32, VMS, S<RISC OS>, VOS)
e41182b5 1927
47cd99a4 1928=item sockatmark
80cbd5ad
JH
1929
1930A relatively recent addition to socket functions, may not
e1020413 1931be implemented even in Unix platforms.
80cbd5ad 1932
47cd99a4 1933=item socketpair
e41182b5 1934
10fb90aa
PG
1935Not implemented. (S<RISC OS>, VM/ESA)
1936
1937Available on OpenVOS Release 17.0 or later. (VOS)
016930a6
JM
1938
1939Available on 64 bit OpenVMS 8.2 and later. (VMS)
e41182b5 1940
e41182b5
GS
1941=item stat
1942
d62e1b7f
JH
1943Platforms that do not have rdev, blksize, or blocks will return these
1944as '', so numeric comparison or manipulation of these fields may cause
1945'not numeric' warnings.
1946
3f1f789b 1947ctime not supported on UFS (S<Mac OS X>).
e41182b5 1948
95a3fe12
MS
1949ctime is creation time instead of inode change time (Win32).
1950
e41182b5
GS
1951device and inode are not meaningful. (Win32)
1952
1953device and inode are not necessarily reliable. (VMS)
1954
b8099c3d
CN
1955mtime, atime and ctime all return the last modification time. Device and
1956inode are not necessarily reliable. (S<RISC OS>)
1957
d62e1b7f
JH
1958dev, rdev, blksize, and blocks are not available. inode is not
1959meaningful and will differ between stat calls on the same file. (os2)
1960
73e9292c
JH
1961some versions of cygwin when doing a stat("foo") and if not finding it
1962may then attempt to stat("foo.exe") (Cygwin)
1963
1fafdf34
JD
1964On Win32 stat() needs to open the file to determine the link count
1965and update attributes that may have been changed through hard links.
1966Setting ${^WIN32_SLOPPY_STAT} to a true value speeds up stat() by
1967not performing this operation. (Win32)
1968
47cd99a4 1969=item symlink
e41182b5 1970
c73b03b7
JM
1971Not implemented. (Win32, S<RISC OS>)
1972
1973Implemented on 64 bit VMS 8.3. VMS requires the symbolic link to be in Unix
1974syntax if it is intended to resolve to a valid path.
e41182b5 1975
47cd99a4 1976=item syscall
e41182b5 1977
204ad8d5 1978Not implemented. (Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5 1979
47cd99a4 1980=item sysopen
f34d0673 1981
dd9f0070 1982The traditional "0", "1", and "2" MODEs are implemented with different
322422de
GS
1983numeric values on some systems. The flags exported by C<Fcntl>
1984(O_RDONLY, O_WRONLY, O_RDWR) should work everywhere though. (S<Mac
7c5ffed3 1985OS>, OS/390, VM/ESA)
f34d0673 1986
47cd99a4 1987=item system
e41182b5 1988
e41182b5 1989As an optimization, may not call the command shell specified in
b7df3edc 1990C<$ENV{PERL5SHELL}>. C<system(1, @args)> spawns an external
e41182b5
GS
1991process and immediately returns its process designator, without
1992waiting for it to terminate. Return value may be used subsequently
63f87e49
GS
1993in C<wait> or C<waitpid>. Failure to spawn() a subprocess is indicated
1994by setting $? to "255 << 8". C<$?> is set in a way compatible with
1995Unix (i.e. the exitstatus of the subprocess is obtained by "$? >> 8",
1996as described in the documentation). (Win32)
e41182b5 1997
b8099c3d
CN
1998There is no shell to process metacharacters, and the native standard is
1999to pass a command line terminated by "\n" "\r" or "\0" to the spawned
c47ff5f1 2000program. Redirection such as C<< > foo >> is performed (if at all) by
b8099c3d
CN
2001the run time library of the spawned program. C<system> I<list> will call
2002the Unix emulation library's C<exec> emulation, which attempts to provide
2003emulation of the stdin, stdout, stderr in force in the parent, providing
2004the child program uses a compatible version of the emulation library.
2005I<scalar> will call the native command line direct and no such emulation
2006of a child Unix program will exists. Mileage B<will> vary. (S<RISC OS>)
2007
0f897271
GS
2008Does not automatically flush output handles on some platforms.
2009(SunOS, Solaris, HP-UX)
2010
9bc98430
CB
2011The return value is POSIX-like (shifted up by 8 bits), which only allows
2012room for a made-up value derived from the severity bits of the native
201332-bit condition code (unless overridden by C<use vmsish 'status'>).
016930a6
JM
2014If the native condition code is one that has a POSIX value encoded, the
2015POSIX value will be decoded to extract the expected exit value.
9bc98430
CB
2016For more details see L<perlvms/$?>. (VMS)
2017
e41182b5
GS
2018=item times
2019
63f87e49
GS
2020"cumulative" times will be bogus. On anything other than Windows NT
2021or Windows 2000, "system" time will be bogus, and "user" time is
2022actually the time returned by the clock() function in the C runtime
2023library. (Win32)
e41182b5 2024
b8099c3d
CN
2025Not useful. (S<RISC OS>)
2026
47cd99a4 2027=item truncate
e41182b5 2028
6d738113 2029Not implemented. (Older versions of VMS)
e41182b5 2030
3fd80bd6 2031Truncation to same-or-shorter lengths only. (VOS)
495c5fdc 2032
4cfdb94f 2033If a FILEHANDLE is supplied, it must be writable and opened in append
e71a7dc8 2034mode (i.e., use C<<< open(FH, '>>filename') >>>
4cfdb94f
GS
2035or C<sysopen(FH,...,O_APPEND|O_RDWR)>. If a filename is supplied, it
2036should not be held open elsewhere. (Win32)
2037
e41182b5
GS
2038=item umask
2039
1bcbdd38 2040Returns undef where unavailable.
e41182b5 2041
b7df3edc
GS
2042C<umask> works but the correct permissions are set only when the file
2043is finally closed. (AmigaOS)
433acd8a 2044
47cd99a4 2045=item utime
e41182b5 2046
204ad8d5 2047Only the modification time is updated. (S<BeOS>, VMS, S<RISC OS>)
e41182b5 2048
322422de
GS
2049May not behave as expected. Behavior depends on the C runtime
2050library's implementation of utime(), and the filesystem being
2051used. The FAT filesystem typically does not support an "access
2052time" field, and it may limit timestamps to a granularity of
2053two seconds. (Win32)
e41182b5
GS
2054
2055=item wait
2056
47cd99a4 2057=item waitpid
e41182b5 2058
e41182b5 2059Can only be applied to process handles returned for processes spawned
a6f858fb 2060using C<system(1, ...)> or pseudo processes created with C<fork()>. (Win32)
e41182b5 2061
b8099c3d
CN
2062Not useful. (S<RISC OS>)
2063
e41182b5
GS
2064=back
2065
2066
7c35b6af 2067=head1 Supported Platforms
ba58ab26 2068
7c35b6af
RGS
2069The following platforms are known to build Perl 5.12 (as of April 2010,
2070its release date) from the standard source code distribution available
500f1b69 2071at L<http://www.cpan.org/src>
bb377ba2 2072
bb377ba2
JV
2073=over
2074
2075=item Linux (x86, ARM, IA64)
2076
e0d9a2c8 2077=item HP-UX
bb377ba2
JV
2078
2079=item AIX
2080
2081=item Win32
2082
2083=over
2084
2085=item Windows 2000
2086
2087=item Windows XP
2088
2089=item Windows Server 2003
2090
2091=item Windows Vista
2092
2093=item Windows Server 2008
2094
3b665c47
JD
2095=item Windows 7
2096
bb377ba2
JV
2097=back
2098
2d9ede6e
JH
2099=item Cygwin
2100
bb377ba2
JV
2101=item Solaris (x86, SPARC)
2102
1b0ab010
JV
2103=item OpenVMS
2104
2105=over
2106
2107=item Alpha (7.2 and later)
2108
2109=item I64 (8.2 and later)
2110
2111=back
bb377ba2
JV
2112
2113=item Symbian
2114
2115=item NetBSD
2116
2117=item FreeBSD
2118
2d8e9a35
CBW
2119=item Debian GNU/kFreeBSD
2120
bb377ba2
JV
2121=item Haiku
2122
2123=item Irix (6.5. What else?)
2124
2125=item OpenBSD
2126
2127=item Dragonfly BSD
2128
a62bfce3
CBW
2129=item QNX Neutrino RTOS (6.5.0)
2130
bb377ba2
JV
2131=item MirOS BSD
2132
2133Caveats:
2134
2135=over
2136
2137=item time_t issues that may or may not be fixed
2138
2139=back
2140
bb377ba2
JV
2141=item Symbian (Series 60 v3, 3.2 and 5 - what else?)
2142
10fb90aa 2143=item Stratus VOS / OpenVOS
bb377ba2
JV
2144
2145=item AIX
2146
2147=back
2148
8cbe99e5 2149=head1 EOL Platforms (Perl 5.14)
bb377ba2
JV
2150
2151The following platforms were supported by a previous version of
2152Perl but have been officially removed from Perl's source code
2153as of 5.12:
2154
2155=over
2156
2157=item Atari MiNT
2158
2159=item Apollo Domain/OS
2160
2161=item Apple Mac OS 8/9
2162
2163=item Tenon Machten
2164
2165=back
2166
8cbe99e5
JD
2167The following platforms were supported up to 5.10. They may still
2168have worked in 5.12, but supporting code has been removed for 5.14:
bb377ba2
JV
2169
2170=over
2171
2172=item Windows 95
2173
2174=item Windows 98
2175
2176=item Windows ME
2177
2178=item Windows NT4
2179
2180=back
2181
2182=head1 Supported Platforms (Perl 5.8)
2183
2184As of July 2002 (the Perl release 5.8.0), the following platforms were
cec2c193 2185able to build Perl from the standard source code distribution
500f1b69 2186available at L<http://www.cpan.org/src/>
cec2c193
JH
2187
2188 AIX
2189 BeOS
6f683aa2 2190 BSD/OS (BSDi)
cec2c193
JH
2191 Cygwin
2192 DG/UX
811b48f2 2193 DOS DJGPP 1)
cec2c193
JH
2194 DYNIX/ptx
2195 EPOC R5
2196 FreeBSD
6f683aa2 2197 HI-UXMPP (Hitachi) (5.8.0 worked but we didn't know it)
cec2c193
JH
2198 HP-UX
2199 IRIX
2200 Linux
8939ba94 2201 Mac OS Classic
6f683aa2 2202 Mac OS X (Darwin)
cec2c193
JH
2203 MPE/iX
2204 NetBSD
2205 NetWare
2206 NonStop-UX
6f683aa2 2207 ReliantUNIX (formerly SINIX)
cec2c193 2208 OpenBSD
6f683aa2 2209 OpenVMS (formerly VMS)
3ebac25b 2210 Open UNIX (Unixware) (since Perl 5.8.1/5.9.0)
cec2c193 2211 OS/2
522b859a 2212 OS/400 (using the PASE) (since Perl 5.8.1/5.9.0)
70de81db 2213 PowerUX
6f683aa2 2214 POSIX-BC (formerly BS2000)
cec2c193
JH
2215 QNX
2216 Solaris
70de81db 2217 SunOS 4
6f683aa2
JH
2218 SUPER-UX (NEC)
2219 Tru64 UNIX (formerly DEC OSF/1, Digital UNIX)
cec2c193
JH
2220 UNICOS
2221 UNICOS/mk
2222 UTS
2223 VOS
811b48f2 2224 Win95/98/ME/2K/XP 2)
c40b5d1d 2225 WinCE
6f683aa2 2226 z/OS (formerly OS/390)
cec2c193 2227 VM/ESA
ba58ab26 2228
811b48f2
JH
2229 1) in DOS mode either the DOS or OS/2 ports can be used
2230 2) compilers: Borland, MinGW (GCC), VC6
cec2c193 2231
c40b5d1d 2232The following platforms worked with the previous releases (5.6 and
cec2c193
JH
22335.7), but we did not manage either to fix or to test these in time
2234for the 5.8.0 release. There is a very good chance that many of these
70de81db 2235will work fine with the 5.8.0.
cec2c193 2236
8da2b1be 2237 BSD/OS
cec2c193
JH
2238 DomainOS
2239 Hurd
2240 LynxOS
2241 MachTen
2242 PowerMAX
2243 SCO SV
cec2c193
JH
2244 SVR4
2245 Unixware
2246 Windows 3.1
ba58ab26 2247
70de81db
JH
2248Known to be broken for 5.8.0 (but 5.6.1 and 5.7.2 can be used):
2249
2250 AmigaOS
2251
ba58ab26 2252The following platforms have been known to build Perl from source in
fd46a41b
JH
2253the past (5.005_03 and earlier), but we haven't been able to verify
2254their status for the current release, either because the
2255hardware/software platforms are rare or because we don't have an
2256active champion on these platforms--or both. They used to work,
2257though, so go ahead and try compiling them, and let perlbug@perl.org
2258of any trouble.
ba58ab26 2259
cec2c193
JH
2260 3b1
2261 A/UX
cec2c193
JH
2262 ConvexOS
2263 CX/UX
2264 DC/OSx
2265 DDE SMES
2266 DOS EMX
2267 Dynix
2268 EP/IX
2269 ESIX
2270 FPS
2271 GENIX
2272 Greenhills
2273 ISC
2274 MachTen 68k
cec2c193
JH
2275 MPC
2276 NEWS-OS
2277 NextSTEP
2278 OpenSTEP
2279 Opus
2280 Plan 9
cec2c193 2281 RISC/os
8da2b1be 2282 SCO ODT/OSR
cec2c193
JH
2283 Stellar
2284 SVR2
2285 TI1500
2286 TitanOS
2287 Ultrix
2288 Unisys Dynix
ba58ab26
JH
2289
2290The following platforms have their own source code distributions and
500f1b69 2291binaries available via L<http://www.cpan.org/ports/>
ba58ab26 2292
cec2c193 2293 Perl release
ba58ab26 2294
522b859a 2295 OS/400 (ILE) 5.005_02
cec2c193 2296 Tandem Guardian 5.004
ba58ab26
JH
2297
2298The following platforms have only binaries available via
500f1b69 2299L<http://www.cpan.org/ports/index.html> :
ba58ab26 2300
cec2c193 2301 Perl release
ba58ab26 2302
cec2c193
JH
2303 Acorn RISCOS 5.005_02
2304 AOS 5.002
2305 LynxOS 5.004_02
ba58ab26
JH
2306
2307Although we do suggest that you always build your own Perl from
2308the source code, both for maximal configurability and for security,
2309in case you are in a hurry you can check
500f1b69 2310L<http://www.cpan.org/ports/index.html> for binary distributions.
ba58ab26 2311
c997b287
GS
2312=head1 SEE ALSO
2313
aa6f04ce 2314L<perlaix>, L<perlamiga>, L<perlbeos>, L<perlbs2000>,
18a271bd 2315L<perlce>, L<perlcygwin>, L<perldgux>, L<perldos>, L<perlepoc>,
469e7be4 2316L<perlebcdic>, L<perlfreebsd>, L<perlhurd>, L<perlhpux>, L<perlirix>,
e94c1c05 2317L<perlmacos>, L<perlmacosx>, L<perlmpeix>,
522b859a
JH
2318L<perlnetware>, L<perlos2>, L<perlos390>, L<perlos400>,
2319L<perlplan9>, L<perlqnx>, L<perlsolaris>, L<perltru64>,
2320L<perlunicode>, L<perlvmesa>, L<perlvms>, L<perlvos>,
2321L<perlwin32>, and L<Win32>.
c997b287 2322
e41182b5
GS
2323=head1 AUTHORS / CONTRIBUTORS
2324
06e9666b 2325Abigail <abigail@foad.org>,
c47ff5f1
GS
2326Charles Bailey <bailey@newman.upenn.edu>,
2327Graham Barr <gbarr@pobox.com>,
2328Tom Christiansen <tchrist@perl.com>,
06e9666b 2329Nicholas Clark <nick@ccl4.org>,
c47ff5f1 2330Thomas Dorner <Thomas.Dorner@start.de>,
06e9666b
A
2331Andy Dougherty <doughera@lafayette.edu>,
2332Dominic Dunlop <domo@computer.org>,
2333Neale Ferguson <neale@vma.tabnsw.com.au>,
c47ff5f1 2334David J. Fiander <davidf@mks.com>,
3fd80bd6 2335Paul Green <Paul.Green@stratus.com>,
06e9666b 2336M.J.T. Guy <mjtg@cam.ac.uk>,
61f30a5e 2337Jarkko Hietaniemi <jhi@iki.fi>,
c47ff5f1 2338Luther Huffman <lutherh@stratcom.com>,
06e9666b
A
2339Nick Ing-Simmons <nick@ing-simmons.net>,
2340Andreas J. KE<ouml>nig <a.koenig@mind.de>,
c47ff5f1
GS
2341Markus Laker <mlaker@contax.co.uk>,
2342Andrew M. Langmead <aml@world.std.com>,
2343Larry Moore <ljmoore@freespace.net>,
2344Paul Moore <Paul.Moore@uk.origin-it.com>,
2345Chris Nandor <pudge@pobox.com>,
1afc07ec 2346Matthias Neeracher <neeracher@mac.com>,
e71a7dc8 2347Philip Newton <pne@cpan.org>,
c47ff5f1
GS
2348Gary Ng <71564.1743@CompuServe.COM>,
2349Tom Phoenix <rootbeer@teleport.com>,
2350AndrE<eacute> Pirard <A.Pirard@ulg.ac.be>,
2351Peter Prymmer <pvhp@forte.com>,
2352Hugo van der Sanden <hv@crypt0.demon.co.uk>,
2353Gurusamy Sarathy <gsar@activestate.com>,
2354Paul J. Schinder <schinder@pobox.com>,
2355Michael G Schwern <schwern@pobox.com>,
06e9666b 2356Dan Sugalski <dan@sidhe.org>,
bbe548ff 2357Nathan Torkington <gnat@frii.com>,
016930a6 2358John Malmberg <wb8tyw@qsl.net>