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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,
62S<Mac OS>, VMS, etc.), consider writing platform-specific code.
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
70portability (L<"ISSUES">, platform-specific issues (L<"PLATFORMS">, and
b7df3edc 71built-in perl functions that behave differently on various ports
0a47030a 72(L<"FUNCTION IMPLEMENTATIONS">.
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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
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77should be considered a perpetual work in progress
78(E<lt>IMG SRC="yellow_sign.gif" ALT="Under Construction"E<gt>).
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
91means C<\015>. In DOSish perls, C<\n> usually means C<\012>, but
92when accessing a file in "text" mode, STDIO translates it to (or
93from) C<\015\012>, depending on whether your reading or writing.
94Unix does the same thing on ttys in canonical mode. C<\015\012>
95is commonly referred to as CRLF.
96
97Because of the "text" mode translation, DOSish perls have limitations
98in using C<seek> and C<tell> on a file accessed in "text" mode.
99Stick to C<seek>-ing to locations you got from C<tell> (and no
100others), and you are usually free to use C<seek> and C<tell> even
101in "text" mode. Using C<seek> or C<tell> or other file operations
102may be non-portable. If you use C<binmode> on a file, however, you
103can usually C<seek> and C<tell> with arbitrary values in safety.
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104
105A common misconception in socket programming is that C<\n> eq C<\012>
0a47030a 106everywhere. When using protocols such as common Internet protocols,
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107C<\012> and C<\015> are called for specifically, and the values of
108the logical C<\n> and C<\r> (carriage return) are not reliable.
109
110 print SOCKET "Hi there, client!\r\n"; # WRONG
111 print SOCKET "Hi there, client!\015\012"; # RIGHT
112
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113However, using C<\015\012> (or C<\cM\cJ>, or C<\x0D\x0A>) can be tedious
114and unsightly, as well as confusing to those maintaining the code. As
6ab3f9cb 115such, the Socket module supplies the Right Thing for those who want it.
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116
117 use Socket qw(:DEFAULT :crlf);
118 print SOCKET "Hi there, client!$CRLF" # RIGHT
119
6ab3f9cb 120When reading from a socket, remember that the default input record
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121separator C<$/> is C<\n>, but robust socket code will recognize as
122either C<\012> or C<\015\012> as end of line:
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123
124 while (<SOCKET>) {
125 # ...
126 }
127
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128Because both CRLF and LF end in LF, the input record separator can
129be set to LF and any CR stripped later. Better to write:
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130
131 use Socket qw(:DEFAULT :crlf);
132 local($/) = LF; # not needed if $/ is already \012
133
134 while (<SOCKET>) {
135 s/$CR?$LF/\n/; # not sure if socket uses LF or CRLF, OK
136 # s/\015?\012/\n/; # same thing
137 }
138
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139This example is preferred over the previous one--even for Unix
140platforms--because now any C<\015>'s (C<\cM>'s) are stripped out
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141(and there was much rejoicing).
142
6ab3f9cb 143Similarly, functions that return text data--such as a function that
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144fetches a web page--should sometimes translate newlines before
145returning the data, if they've not yet been translated to the local
146newline representation. A single line of code will often suffice:
2ee0eb3c 147
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148 $data =~ s/\015?\012/\n/g;
149 return $data;
2ee0eb3c 150
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151Some of this may be confusing. Here's a handy reference to the ASCII CR
152and LF characters. You can print it out and stick it in your wallet.
153
154 LF == \012 == \x0A == \cJ == ASCII 10
155 CR == \015 == \x0D == \cM == ASCII 13
156
157 | Unix | DOS | Mac |
158 ---------------------------
159 \n | LF | LF | CR |
160 \r | CR | CR | LF |
161 \n * | LF | CRLF | CR |
162 \r * | CR | CR | LF |
163 ---------------------------
164 * text-mode STDIO
165
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166The Unix column assumes that you are not accessing a serial line
167(like a tty) in canonical mode. If you are, then CR on input becomes
168"\n", and "\n" on output becomes CRLF.
169
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170These are just the most common definitions of C<\n> and C<\r> in Perl.
171There may well be others.
172
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173=head2 Numbers endianness and Width
174
175Different CPUs store integers and floating point numbers in different
176orders (called I<endianness>) and widths (32-bit and 64-bit being the
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177most common today). This affects your programs when they attempt to transfer
178numbers in binary format from one CPU architecture to another,
179usually either "live" via network connection, or by storing the
180numbers to secondary storage such as a disk file or tape.
322422de 181
b7df3edc 182Conflicting storage orders make utter mess out of the numbers. If a
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183little-endian host (Intel, Alpha) stores 0x12345678 (305419896 in
184decimal), a big-endian host (Motorola, MIPS, Sparc, PA) reads it as
1850x78563412 (2018915346 in decimal). To avoid this problem in network
6ab3f9cb 186(socket) connections use the C<pack> and C<unpack> formats C<n>
b7df3edc 187and C<N>, the "network" orders. These are guaranteed to be portable.
322422de 188
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189Differing widths can cause truncation even between platforms of equal
190endianness. The platform of shorter width loses the upper parts of the
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191number. There is no good solution for this problem except to avoid
192transferring or storing raw binary numbers.
193
b7df3edc 194One can circumnavigate both these problems in two ways. Either
322422de 195transfer and store numbers always in text format, instead of raw
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196binary, or else consider using modules like Data::Dumper (included in
197the standard distribution as of Perl 5.005) and Storable. Keeping
198all data as text significantly simplifies matters.
322422de 199
433acd8a 200=head2 Files and Filesystems
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201
202Most platforms these days structure files in a hierarchical fashion.
b7df3edc 203So, it is reasonably safe to assume that all platforms support the
6ab3f9cb 204notion of a "path" to uniquely identify a file on the system. How
b7df3edc 205that path is really written, though, differs considerably.
e41182b5 206
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207Atlhough similar, file path specifications differ between Unix,
208Windows, S<Mac OS>, OS/2, VMS, VOS, S<RISC OS>, and probably others.
209Unix, for example, is one of the few OSes that has the elegant idea
210of a single root directory.
322422de 211
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212DOS, OS/2, VMS, VOS, and Windows can work similarly to Unix with C</>
213as path separator, or in their own idiosyncratic ways (such as having
214several root directories and various "unrooted" device files such NIL:
215and LPT:).
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216
217S<Mac OS> uses C<:> as a path separator instead of C</>.
218
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219The filesystem may support neither hard links (C<link>) nor
220symbolic links (C<symlink>, C<readlink>, C<lstat>).
433acd8a 221
6ab3f9cb 222The filesystem may support neither access timestamp nor change
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223timestamp (meaning that about the only portable timestamp is the
224modification timestamp), or one second granularity of any timestamps
225(e.g. the FAT filesystem limits the time granularity to two seconds).
226
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227VOS perl can emulate Unix filenames with C</> as path separator. The
228native pathname characters greater-than, less-than, number-sign, and
229percent-sign are always accepted.
230
6ab3f9cb 231S<RISC OS> perl can emulate Unix filenames with C</> as path
322422de 232separator, or go native and use C<.> for path separator and C<:> to
6ab3f9cb 233signal filesystems and disk names.
e41182b5 234
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235If all this is intimidating, have no (well, maybe only a little)
236fear. There are modules that can help. The File::Spec modules
237provide methods to do the Right Thing on whatever platform happens
238to be running the program.
e41182b5 239
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240 use File::Spec::Functions;
241 chdir(updir()); # go up one directory
242 $file = catfile(curdir(), 'temp', 'file.txt');
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243 # on Unix and Win32, './temp/file.txt'
244 # on Mac OS, ':temp:file.txt'
245
b7df3edc 246File::Spec is available in the standard distribution as of version
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2475.004_05.
248
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249In general, production code should not have file paths hardcoded.
250Making them user-supplied or read from a configuration file is
251better, keeping in mind that file path syntax varies on different
252machines.
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253
254This is especially noticeable in scripts like Makefiles and test suites,
255which often assume C</> as a path separator for subdirectories.
256
b7df3edc 257Also of use is File::Basename from the standard distribution, which
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258splits a pathname into pieces (base filename, full path to directory,
259and file suffix).
260
19799a22 261Even when on a single platform (if you can call Unix a single platform),
b7df3edc 262remember not to count on the existence or the contents of particular
3c075c7d 263system-specific files or directories, like F</etc/passwd>,
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264F</etc/sendmail.conf>, F</etc/resolv.conf>, or even F</tmp/>. For
265example, F</etc/passwd> may exist but not contain the encrypted
266passwords, because the system is using some form of enhanced security.
267Or it may not contain all the accounts, because the system is using NIS.
3c075c7d 268If code does need to rely on such a file, include a description of the
b7df3edc 269file and its format in the code's documentation, then make it easy for
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270the user to override the default location of the file.
271
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272Don't assume a text file will end with a newline. They should,
273but people forget.
e41182b5 274
dd9f0070 275Do not have two files of the same name with different case, like
3c075c7d 276F<test.pl> and F<Test.pl>, as many platforms have case-insensitive
dd9f0070 277filenames. Also, try not to have non-word characters (except for C<.>)
0a47030a 278in the names, and keep them to the 8.3 convention, for maximum
b7df3edc 279portability, onerous a burden though this may appear.
dd9f0070 280
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281Likewise, when using the AutoSplit module, try to keep your functions to
2828.3 naming and case-insensitive conventions; or, at the least,
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283make it so the resulting files have a unique (case-insensitively)
284first 8 characters.
285
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286Whitespace in filenames is tolerated on most systems, but not all.
287Many systems (DOS, VMS) cannot have more than one C<.> in their filenames.
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288
289Don't assume C<E<gt>> won't be the first character of a filename.
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290Always use C<E<lt>> explicitly to open a file for reading,
291unless you want the user to be able to specify a pipe open.
0a47030a 292
6ab3f9cb 293 open(FILE, "< $existing_file") or die $!;
0a47030a 294
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295If filenames might use strange characters, it is safest to open it
296with C<sysopen> instead of C<open>. C<open> is magic and can
297translate characters like C<E<gt>>, C<E<lt>>, and C<|>, which may
b7df3edc 298be the wrong thing to do. (Sometimes, though, it's the right thing.)
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299
300=head2 System Interaction
301
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302Not all platforms provide a command line. These are usually platforms
303that rely primarily on a Graphical User Interface (GUI) for user
304interaction. A program requiring a command line interface might
305not work everywhere. This is probably for the user of the program
306to deal with, so don't stay up late worrying about it.
e41182b5 307
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308Some platforms can't delete or rename files held open by the system.
309Remember to C<close> files when you are done with them. Don't
310C<unlink> or C<rename> an open file. Don't C<tie> or C<open> a
311file already tied or opened; C<untie> or C<close> it first.
e41182b5 312
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313Don't open the same file more than once at a time for writing, as some
314operating systems put mandatory locks on such files.
315
e41182b5 316Don't count on a specific environment variable existing in C<%ENV>.
0a47030a 317Don't count on C<%ENV> entries being case-sensitive, or even
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318case-preserving.
319
6ab3f9cb 320Don't count on signals for anything.
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321
322Don't count on filename globbing. Use C<opendir>, C<readdir>, and
323C<closedir> instead.
324
b8099c3d 325Don't count on per-program environment variables, or per-program current
dd9f0070 326directories.
b8099c3d 327
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328Don't count on specific values of C<$!>.
329
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330=head2 Interprocess Communication (IPC)
331
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332In general, don't directly access the system in code meant to be
333portable. That means, no C<system>, C<exec>, C<fork>, C<pipe>,
334C<``>, C<qx//>, C<open> with a C<|>, nor any of the other things
335that makes being a perl hacker worth being.
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336
337Commands that launch external processes are generally supported on
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338most platforms (though many of them do not support any type of
339forking). The problem with using them arises from what you invoke
340them on. External tools are often named differently on different
341platforms, may not be available in the same location, migth accept
342different arguments, can behave differently, and often present their
343results in a platform-dependent way. Thus, you should seldom depend
344on them to produce consistent results. (Then again, if you're calling
345I<netstat -a>, you probably don't expect it to run on both Unix and CP/M.)
e41182b5 346
b7df3edc 347One especially common bit of Perl code is opening a pipe to B<sendmail>:
e41182b5 348
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349 open(MAIL, '|/usr/lib/sendmail -t')
350 or die "cannot fork sendmail: $!";
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351
352This is fine for systems programming when sendmail is known to be
353available. But it is not fine for many non-Unix systems, and even
354some Unix systems that may not have sendmail installed. If a portable
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355solution is needed, see the various distributions on CPAN that deal
356with it. Mail::Mailer and Mail::Send in the MailTools distribution are
357commonly used, and provide several mailing methods, including mail,
358sendmail, and direct SMTP (via Net::SMTP) if a mail transfer agent is
359not available. Mail::Sendmail is a standalone module that provides
360simple, platform-independent mailing.
361
362The Unix System V IPC (C<msg*(), sem*(), shm*()>) is not available
363even on all Unix platforms.
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364
365The rule of thumb for portable code is: Do it all in portable Perl, or
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366use a module (that may internally implement it with platform-specific
367code, but expose a common interface).
e41182b5 368
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369=head2 External Subroutines (XS)
370
b7df3edc 371XS code can usually be made to work with any platform, but dependent
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372libraries, header files, etc., might not be readily available or
373portable, or the XS code itself might be platform-specific, just as Perl
374code might be. If the libraries and headers are portable, then it is
375normally reasonable to make sure the XS code is portable, too.
376
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377A different type of portability issue arises when writing XS code:
378availability of a C compiler on the end-user's system. C brings
379with it its own portability issues, and writing XS code will expose
380you to some of those. Writing purely in Perl is an easier way to
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381achieve portability.
382
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383=head2 Standard Modules
384
385In general, the standard modules work across platforms. Notable
6ab3f9cb 386exceptions are the CPAN module (which currently makes connections to external
e41182b5 387programs that may not be available), platform-specific modules (like
6ab3f9cb 388ExtUtils::MM_VMS), and DBM modules.
e41182b5 389
b7df3edc 390There is no one DBM module available on all platforms.
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391SDBM_File and the others are generally available on all Unix and DOSish
392ports, but not in MacPerl, where only NBDM_File and DB_File are
0a47030a 393available.
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394
395The good news is that at least some DBM module should be available, and
6ab3f9cb 396AnyDBM_File will use whichever module it can find. Of course, then
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397the code needs to be fairly strict, dropping to the greatest common
398factor (e.g., not exceeding 1K for each record), so that it will
6ab3f9cb 399work with any DBM module. See L<AnyDBM_File> for more details.
e41182b5 400
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401=head2 Time and Date
402
0a47030a 403The system's notion of time of day and calendar date is controlled in
b7df3edc 404widely different ways. Don't assume the timezone is stored in C<$ENV{TZ}>,
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405and even if it is, don't assume that you can control the timezone through
406that variable.
e41182b5 407
322422de 408Don't assume that the epoch starts at 00:00:00, January 1, 1970,
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409because that is OS- and implementation-specific. It is better to store a date
410in an unambiguous representation. The ISO-8601 standard defines
411"YYYY-MM-DD" as the date format. A text representation (like "1987-12-18")
412can be easily converted into an OS-specific value using a module like
413Date::Parse. An array of values, such as those returned by
322422de 414C<localtime>, can be converted to an OS-specific representation using
6ab3f9cb 415Time::Local.
322422de 416
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417When calculating specific times, such as for tests in time or date modules,
418it may be appropriate to calculate an offset for the epoch.
b7df3edc 419
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420 require Time::Local;
421 $offset = Time::Local::timegm(0, 0, 0, 1, 0, 70);
b7df3edc 422
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423The value for C<$offset> in Unix will be C<0>, but in Mac OS will be
424some large number. C<$offset> can then be added to a Unix time value
425to get what should be the proper value on any system.
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426
427=head2 Character sets and character encoding
428
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429Assume little about character sets. Assume nothing about
430numerical values (C<ord>, C<chr>) of characters. Do not
322422de 431assume that the alphabetic characters are encoded contiguously (in
b7df3edc 432the numeric sense). Do not assume anything about the ordering of the
322422de 433characters. The lowercase letters may come before or after the
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434uppercase letters; the lowercase and uppercase may be interlaced so
435that both `a' and `A' come before `b'; the accented and other
322422de 436international characters may be interlaced so that E<auml> comes
b7df3edc 437before `b'.
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438
439=head2 Internationalisation
440
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441If you may assume POSIX (a rather large assumption), you may read
442more about the POSIX locale system from L<perllocale>. The locale
443system at least attempts to make things a little bit more portable,
444or at least more convenient and native-friendly for non-English
445users. The system affects character sets and encoding, and date
446and time formatting--amongst other things.
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447
448=head2 System Resources
449
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450If your code is destined for systems with severely constrained (or
451missing!) virtual memory systems then you want to be I<especially> mindful
452of avoiding wasteful constructs such as:
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453
454 # NOTE: this is no longer "bad" in perl5.005
455 for (0..10000000) {} # bad
456 for (my $x = 0; $x <= 10000000; ++$x) {} # good
457
458 @lines = <VERY_LARGE_FILE>; # bad
459
460 while (<FILE>) {$file .= $_} # sometimes bad
0a47030a 461 $file = join('', <FILE>); # better
e41182b5 462
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463The last two constructs may appear unintuitive to most people. The
464first repeatedly grows a string, whereas the second allocates a
465large chunk of memory in one go. On some systems, the second is
466more efficient that the first.
0a47030a 467
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468=head2 Security
469
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470Most multi-user platforms provide basic levels of security, usually
471implemented at the filesystem level. Some, however, do
472not--unfortunately. Thus the notion of user id, or "home" directory,
473or even the state of being logged-in, may be unrecognizable on many
474platforms. If you write programs that are security-conscious, it
475is usually best to know what type of system you will be running
476under so that you can write code explicitly for that platform (or
477class of platforms).
0a47030a 478
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479=head2 Style
480
481For those times when it is necessary to have platform-specific code,
482consider keeping the platform-specific code in one place, making porting
6ab3f9cb 483to other platforms easier. Use the Config module and the special
0a47030a
GS
484variable C<$^O> to differentiate platforms, as described in
485L<"PLATFORMS">.
e41182b5 486
b7df3edc
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487Be careful in the tests you supply with your module or programs.
488Module code may be fully portable, but its tests might not be. This
489often happens when tests spawn off other processes or call external
490programs to aid in the testing, or when (as noted above) the tests
491assume certain things about the filesystem and paths. Be careful
492not to depend on a specific output style for errors, such as when
493checking C<$!> after an system call. Some platforms expect a certain
494output format, and perl on those platforms may have been adjusted
495accordingly. Most specifically, don't anchor a regex when testing
496an error value.
e41182b5 497
0a47030a 498=head1 CPAN Testers
e41182b5 499
0a47030a
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500Modules uploaded to CPAN are tested by a variety of volunteers on
501different platforms. These CPAN testers are notified by mail of each
e41182b5 502new upload, and reply to the list with PASS, FAIL, NA (not applicable to
0a47030a 503this platform), or UNKNOWN (unknown), along with any relevant notations.
e41182b5
GS
504
505The purpose of the testing is twofold: one, to help developers fix any
0a47030a 506problems in their code that crop up because of lack of testing on other
b7df3edc 507platforms; two, to provide users with information about whether
0a47030a 508a given module works on a given platform.
e41182b5
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509
510=over 4
511
512=item Mailing list: cpan-testers@perl.org
513
6ab3f9cb 514=item Testing results: C<http://www.perl.org/cpan-testers/>
e41182b5
GS
515
516=back
517
e41182b5
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518=head1 PLATFORMS
519
520As of version 5.002, Perl is built with a C<$^O> variable that
521indicates the operating system it was built on. This was implemented
b7df3edc
GS
522to help speed up code that would otherwise have to C<use Config>
523and use the value of C<$Config{osname}>. Of course, to get more
e41182b5
GS
524detailed information about the system, looking into C<%Config> is
525certainly recommended.
526
b7df3edc
GS
527C<%Config> cannot always be trusted, however, because it was built
528at compile time. If perl was built in one place, then transferred
529elsewhere, some values may be wrong. The values may even have been
530edited after the fact.
6ab3f9cb 531
e41182b5
GS
532=head2 Unix
533
534Perl works on a bewildering variety of Unix and Unix-like platforms (see
535e.g. most of the files in the F<hints/> directory in the source code kit).
536On most of these systems, the value of C<$^O> (hence C<$Config{'osname'}>,
537too) is determined by lowercasing and stripping punctuation from the first
0a47030a
GS
538field of the string returned by typing C<uname -a> (or a similar command)
539at the shell prompt. Here, for example, are a few of the more popular
540Unix flavors:
e41182b5 541
b7df3edc 542 uname $^O $Config{'archname'}
6ab3f9cb 543 --------------------------------------------
b7df3edc 544 AIX aix aix
6ab3f9cb
GS
545 BSD/OS bsdos i386-bsdos
546 dgux dgux AViiON-dgux
547 DYNIX/ptx dynixptx i386-dynixptx
b7df3edc
GS
548 FreeBSD freebsd freebsd-i386
549 Linux linux i386-linux
6ab3f9cb
GS
550 Linux linux i586-linux
551 Linux linux ppc-linux
b7df3edc
GS
552 HP-UX hpux PA-RISC1.1
553 IRIX irix irix
6ab3f9cb 554 openbsd openbsd i386-openbsd
b7df3edc 555 OSF1 dec_osf alpha-dec_osf
6ab3f9cb
GS
556 reliantunix-n svr4 RM400-svr4
557 SCO_SV sco_sv i386-sco_sv
558 SINIX-N svr4 RM400-svr4
559 sn4609 unicos CRAY_C90-unicos
560 sn6521 unicosmk t3e-unicosmk
561 sn9617 unicos CRAY_J90-unicos
b7df3edc
GS
562 SunOS solaris sun4-solaris
563 SunOS solaris i86pc-solaris
564 SunOS4 sunos sun4-sunos
e41182b5 565
b7df3edc
GS
566Because the value of C<$Config{archname}> may depend on the
567hardware architecture, it can vary more than the value of C<$^O>.
6ab3f9cb 568
e41182b5
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569=head2 DOS and Derivatives
570
b7df3edc 571Perl has long been ported to Intel-style microcomputers running under
e41182b5
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572systems like PC-DOS, MS-DOS, OS/2, and most Windows platforms you can
573bring yourself to mention (except for Windows CE, if you count that).
b7df3edc 574Users familiar with I<COMMAND.COM> or I<CMD.EXE> style shells should
e41182b5
GS
575be aware that each of these file specifications may have subtle
576differences:
577
578 $filespec0 = "c:/foo/bar/file.txt";
579 $filespec1 = "c:\\foo\\bar\\file.txt";
580 $filespec2 = 'c:\foo\bar\file.txt';
581 $filespec3 = 'c:\\foo\\bar\\file.txt';
582
b7df3edc
GS
583System calls accept either C</> or C<\> as the path separator.
584However, many command-line utilities of DOS vintage treat C</> as
585the option prefix, so may get confused by filenames containing C</>.
586Aside from calling any external programs, C</> will work just fine,
587and probably better, as it is more consistent with popular usage,
588and avoids the problem of remembering what to backwhack and what
589not to.
e41182b5 590
b7df3edc
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591The DOS FAT filesystem can accommodate only "8.3" style filenames. Under
592the "case-insensitive, but case-preserving" HPFS (OS/2) and NTFS (NT)
0a47030a 593filesystems you may have to be careful about case returned with functions
e41182b5
GS
594like C<readdir> or used with functions like C<open> or C<opendir>.
595
b7df3edc
GS
596DOS also treats several filenames as special, such as AUX, PRN,
597NUL, CON, COM1, LPT1, LPT2, etc. Unfortunately, sometimes these
598filenames won't even work if you include an explicit directory
599prefix. It is best to avoid such filenames, if you want your code
600to be portable to DOS and its derivatives. It's hard to know what
601these all are, unfortunately.
e41182b5
GS
602
603Users of these operating systems may also wish to make use of
b7df3edc 604scripts such as I<pl2bat.bat> or I<pl2cmd> to
e41182b5
GS
605put wrappers around your scripts.
606
607Newline (C<\n>) is translated as C<\015\012> by STDIO when reading from
6ab3f9cb
GS
608and writing to files (see L<"Newlines">). C<binmode(FILEHANDLE)>
609will keep C<\n> translated as C<\012> for that filehandle. Since it is a
610no-op on other systems, C<binmode> should be used for cross-platform code
b7df3edc
GS
611that deals with binary data. That's assuming you realize in advance
612that your data is in binary. General-purpose programs should
613often assume nothing about their data.
e41182b5 614
b7df3edc 615The C<$^O> variable and the C<$Config{archname}> values for various
e41182b5
GS
616DOSish perls are as follows:
617
618 OS $^O $Config{'archname'}
619 --------------------------------------------
620 MS-DOS dos
621 PC-DOS dos
622 OS/2 os2
623 Windows 95 MSWin32 MSWin32-x86
6ab3f9cb 624 Windows 98 MSWin32 MSWin32-x86
e41182b5 625 Windows NT MSWin32 MSWin32-x86
6ab3f9cb 626 Windows NT MSWin32 MSWin32-ALPHA
e41182b5
GS
627 Windows NT MSWin32 MSWin32-ppc
628
629Also see:
630
631=over 4
632
633=item The djgpp environment for DOS, C<http://www.delorie.com/djgpp/>
634
635=item The EMX environment for DOS, OS/2, etc. C<emx@iaehv.nl>,
2ee0eb3c
CN
636C<http://www.leo.org/pub/comp/os/os2/leo/gnu/emx+gcc/index.html> or
637C<ftp://hobbes.nmsu.edu/pub/os2/dev/emx>
e41182b5
GS
638
639=item Build instructions for Win32, L<perlwin32>.
640
641=item The ActiveState Pages, C<http://www.activestate.com/>
642
643=back
644
dd9f0070 645=head2 S<Mac OS>
e41182b5
GS
646
647Any module requiring XS compilation is right out for most people, because
648MacPerl is built using non-free (and non-cheap!) compilers. Some XS
649modules that can work with MacPerl are built and distributed in binary
6ab3f9cb 650form on CPAN.
e41182b5
GS
651
652Directories are specified as:
653
654 volume:folder:file for absolute pathnames
655 volume:folder: for absolute pathnames
656 :folder:file for relative pathnames
657 :folder: for relative pathnames
658 :file for relative pathnames
659 file for relative pathnames
660
b7df3edc 661Files are stored in the directory in alphabetical order. Filenames are
6ab3f9cb 662limited to 31 characters, and may include any character except for
b7df3edc 663null and C<:>, which is reserved as the path separator.
e41182b5 664
0a47030a 665Instead of C<flock>, see C<FSpSetFLock> and C<FSpRstFLock> in the
6ab3f9cb 666Mac::Files module, or C<chmod(0444, ...)> and C<chmod(0666, ...)>.
e41182b5
GS
667
668In the MacPerl application, you can't run a program from the command line;
669programs that expect C<@ARGV> to be populated can be edited with something
670like the following, which brings up a dialog box asking for the command
671line arguments.
672
673 if (!@ARGV) {
674 @ARGV = split /\s+/, MacPerl::Ask('Arguments?');
675 }
676
b7df3edc 677A MacPerl script saved as a "droplet" will populate C<@ARGV> with the full
e41182b5
GS
678pathnames of the files dropped onto the script.
679
b7df3edc
GS
680Mac users can run programs under a type of command line interface
681under MPW (Macintosh Programmer's Workshop, a free development
682environment from Apple). MacPerl was first introduced as an MPW
683tool, and MPW can be used like a shell:
e41182b5
GS
684
685 perl myscript.plx some arguments
686
687ToolServer is another app from Apple that provides access to MPW tools
0a47030a 688from MPW and the MacPerl app, which allows MacPerl programs to use
e41182b5
GS
689C<system>, backticks, and piped C<open>.
690
691"S<Mac OS>" is the proper name for the operating system, but the value
692in C<$^O> is "MacOS". To determine architecture, version, or whether
693the application or MPW tool version is running, check:
694
695 $is_app = $MacPerl::Version =~ /App/;
696 $is_tool = $MacPerl::Version =~ /MPW/;
697 ($version) = $MacPerl::Version =~ /^(\S+)/;
698 $is_ppc = $MacPerl::Architecture eq 'MacPPC';
699 $is_68k = $MacPerl::Architecture eq 'Mac68K';
700
6ab3f9cb
GS
701S<Mac OS X> and S<Mac OS X Server>, based on NeXT's OpenStep OS, will
702(in theory) be able to run MacPerl natively, under the "Classic"
703environment. The new "Cocoa" environment (formerly called the "Yellow Box")
704may run a slightly modified version of MacPerl, using the Carbon interfaces.
705
706S<Mac OS X Server> and its Open Source version, Darwin, both run Unix
b7df3edc 707perl natively (with a few patches). Full support for these
87275199 708is slated for perl 5.6.
6ab3f9cb 709
e41182b5
GS
710Also see:
711
712=over 4
713
6ab3f9cb 714=item The MacPerl Pages, C<http://www.macperl.com/>.
e41182b5 715
6ab3f9cb
GS
716=item The MacPerl mailing lists, C<http://www.macperl.org/>.
717
718=item MacPerl Module Porters, C<http://pudge.net/mmp/>.
e41182b5
GS
719
720=back
721
e41182b5
GS
722=head2 VMS
723
724Perl on VMS is discussed in F<vms/perlvms.pod> in the perl distribution.
b7df3edc 725Perl on VMS can accept either VMS- or Unix-style file
e41182b5
GS
726specifications as in either of the following:
727
728 $ perl -ne "print if /perl_setup/i" SYS$LOGIN:LOGIN.COM
729 $ perl -ne "print if /perl_setup/i" /sys$login/login.com
730
731but not a mixture of both as in:
732
733 $ perl -ne "print if /perl_setup/i" sys$login:/login.com
734 Can't open sys$login:/login.com: file specification syntax error
735
736Interacting with Perl from the Digital Command Language (DCL) shell
737often requires a different set of quotation marks than Unix shells do.
738For example:
739
740 $ perl -e "print ""Hello, world.\n"""
741 Hello, world.
742
b7df3edc 743There are several ways to wrap your perl scripts in DCL F<.COM> files, if
e41182b5
GS
744you are so inclined. For example:
745
746 $ write sys$output "Hello from DCL!"
747 $ if p1 .eqs. ""
748 $ then perl -x 'f$environment("PROCEDURE")
749 $ else perl -x - 'p1 'p2 'p3 'p4 'p5 'p6 'p7 'p8
750 $ deck/dollars="__END__"
751 #!/usr/bin/perl
752
753 print "Hello from Perl!\n";
754
755 __END__
756 $ endif
757
758Do take care with C<$ ASSIGN/nolog/user SYS$COMMAND: SYS$INPUT> if your
759perl-in-DCL script expects to do things like C<$read = E<lt>STDINE<gt>;>.
760
761Filenames are in the format "name.extension;version". The maximum
762length for filenames is 39 characters, and the maximum length for
763extensions is also 39 characters. Version is a number from 1 to
76432767. Valid characters are C</[A-Z0-9$_-]/>.
765
b7df3edc 766VMS's RMS filesystem is case-insensitive and does not preserve case.
e41182b5 767C<readdir> returns lowercased filenames, but specifying a file for
b7df3edc 768opening remains case-insensitive. Files without extensions have a
e41182b5 769trailing period on them, so doing a C<readdir> with a file named F<A.;5>
0a47030a
GS
770will return F<a.> (though that file could be opened with
771C<open(FH, 'A')>).
e41182b5 772
f34d0673 773RMS had an eight level limit on directory depths from any rooted logical
dd9f0070
CN
774(allowing 16 levels overall) prior to VMS 7.2. Hence
775C<PERL_ROOT:[LIB.2.3.4.5.6.7.8]> is a valid directory specification but
776C<PERL_ROOT:[LIB.2.3.4.5.6.7.8.9]> is not. F<Makefile.PL> authors might
777have to take this into account, but at least they can refer to the former
f34d0673 778as C</PERL_ROOT/lib/2/3/4/5/6/7/8/>.
e41182b5 779
6ab3f9cb 780The VMS::Filespec module, which gets installed as part of the build
0a47030a
GS
781process on VMS, is a pure Perl module that can easily be installed on
782non-VMS platforms and can be helpful for conversions to and from RMS
783native formats.
e41182b5 784
b7df3edc 785What C<\n> represents depends on the type of file opened. It could
e41182b5
GS
786be C<\015>, C<\012>, C<\015\012>, or nothing. Reading from a file
787translates newlines to C<\012>, unless C<binmode> was executed on that
788handle, just like DOSish perls.
789
790TCP/IP stacks are optional on VMS, so socket routines might not be
791implemented. UDP sockets may not be supported.
792
793The value of C<$^O> on OpenVMS is "VMS". To determine the architecture
794that you are running on without resorting to loading all of C<%Config>
795you can examine the content of the C<@INC> array like so:
796
797 if (grep(/VMS_AXP/, @INC)) {
798 print "I'm on Alpha!\n";
6ab3f9cb 799
e41182b5
GS
800 } elsif (grep(/VMS_VAX/, @INC)) {
801 print "I'm on VAX!\n";
6ab3f9cb 802
e41182b5
GS
803 } else {
804 print "I'm not so sure about where $^O is...\n";
805 }
806
b7df3edc
GS
807On VMS, perl determines the UTC offset from the C<SYS$TIMEZONE_DIFFERENTIAL>
808logical name. Although the VMS epoch began at 17-NOV-1858 00:00:00.00,
6ab3f9cb 809calls to C<localtime> are adjusted to count offsets from
b7df3edc 81001-JAN-1970 00:00:00.00, just like Unix.
6ab3f9cb 811
e41182b5
GS
812Also see:
813
814=over 4
815
816=item L<perlvms.pod>
817
6ab3f9cb 818=item vmsperl list, C<majordomo@perl.org>
e41182b5 819
6ab3f9cb 820Put the words C<subscribe vmsperl> in message body.
e41182b5
GS
821
822=item vmsperl on the web, C<http://www.sidhe.org/vmsperl/index.html>
823
824=back
825
495c5fdc
GP
826=head2 VOS
827
828Perl on VOS is discussed in F<README.vos> in the perl distribution.
b7df3edc 829Perl on VOS can accept either VOS- or Unix-style file
495c5fdc
GP
830specifications as in either of the following:
831
832 $ perl -ne "print if /perl_setup/i" >system>notices
833 $ perl -ne "print if /perl_setup/i" /system/notices
834
835or even a mixture of both as in:
836
837 $ perl -ne "print if /perl_setup/i" >system/notices
838
b7df3edc 839Even though VOS allows the slash character to appear in object
495c5fdc
GP
840names, because the VOS port of Perl interprets it as a pathname
841delimiting character, VOS files, directories, or links whose names
842contain a slash character cannot be processed. Such files must be
843renamed before they can be processed by Perl.
844
2ee0eb3c 845The following C functions are unimplemented on VOS, and any attempt by
495c5fdc 846Perl to use them will result in a fatal error message and an immediate
2ee0eb3c
CN
847exit from Perl: dup, do_aspawn, do_spawn, fork, waitpid. Once these
848functions become available in the VOS POSIX.1 implementation, you can
849either recompile and rebind Perl, or you can download a newer port from
850ftp.stratus.com.
495c5fdc
GP
851
852The value of C<$^O> on VOS is "VOS". To determine the architecture that
853you are running on without resorting to loading all of C<%Config> you
854can examine the content of the C<@INC> array like so:
855
856 if (grep(/VOS/, @INC)) {
857 print "I'm on a Stratus box!\n";
858 } else {
859 print "I'm not on a Stratus box!\n";
860 die;
861 }
862
863 if (grep(/860/, @INC)) {
864 print "This box is a Stratus XA/R!\n";
6ab3f9cb 865
495c5fdc
GP
866 } elsif (grep(/7100/, @INC)) {
867 print "This box is a Stratus HP 7100 or 8000!\n";
6ab3f9cb 868
495c5fdc
GP
869 } elsif (grep(/8000/, @INC)) {
870 print "This box is a Stratus HP 8000!\n";
6ab3f9cb 871
495c5fdc
GP
872 } else {
873 print "This box is a Stratus 68K...\n";
874 }
875
876Also see:
877
878=over 4
879
880=item L<README.vos>
881
882=item VOS mailing list
883
884There is no specific mailing list for Perl on VOS. You can post
885comments to the comp.sys.stratus newsgroup, or subscribe to the general
886Stratus mailing list. Send a letter with "Subscribe Info-Stratus" in
887the message body to majordomo@list.stratagy.com.
888
889=item VOS Perl on the web at C<http://ftp.stratus.com/pub/vos/vos.html>
890
891=back
892
e41182b5
GS
893=head2 EBCDIC Platforms
894
895Recent versions of Perl have been ported to platforms such as OS/400 on
7c5ffed3
JH
896AS/400 minicomputers as well as OS/390 & VM/ESA for IBM Mainframes. Such
897computers use EBCDIC character sets internally (usually Character Code
b7df3edc 898Set ID 00819 for OS/400 and IBM-1047 for OS/390 & VM/ESA). On
7c5ffed3
JH
899the mainframe perl currently works under the "Unix system services
900for OS/390" (formerly known as OpenEdition) and VM/ESA OpenEdition.
e41182b5 901
7c5ffed3
JH
902As of R2.5 of USS for OS/390 and Version 2.3 of VM/ESA these Unix
903sub-systems do not support the C<#!> shebang trick for script invocation.
904Hence, on OS/390 and VM/ESA perl scripts can be executed with a header
905similar to the following simple script:
e41182b5
GS
906
907 : # use perl
908 eval 'exec /usr/local/bin/perl -S $0 ${1+"$@"}'
909 if 0;
910 #!/usr/local/bin/perl # just a comment really
911
912 print "Hello from perl!\n";
913
b7df3edc 914On the AS/400, if PERL5 is in your library list, you may need
6ab3f9cb
GS
915to wrap your perl scripts in a CL procedure to invoke them like so:
916
917 BEGIN
918 CALL PGM(PERL5/PERL) PARM('/QOpenSys/hello.pl')
919 ENDPGM
920
921This will invoke the perl script F<hello.pl> in the root of the
922QOpenSys file system. On the AS/400 calls to C<system> or backticks
923must use CL syntax.
924
e41182b5 925On these platforms, bear in mind that the EBCDIC character set may have
0a47030a
GS
926an effect on what happens with some perl functions (such as C<chr>,
927C<pack>, C<print>, C<printf>, C<ord>, C<sort>, C<sprintf>, C<unpack>), as
928well as bit-fiddling with ASCII constants using operators like C<^>, C<&>
929and C<|>, not to mention dealing with socket interfaces to ASCII computers
6ab3f9cb 930(see L<"Newlines">).
e41182b5 931
b7df3edc
GS
932Fortunately, most web servers for the mainframe will correctly
933translate the C<\n> in the following statement to its ASCII equivalent
934(C<\r> is the same under both Unix and OS/390 & VM/ESA):
e41182b5
GS
935
936 print "Content-type: text/html\r\n\r\n";
937
938The value of C<$^O> on OS/390 is "os390".
939
7c5ffed3 940The value of C<$^O> on VM/ESA is "vmesa".
3c075c7d 941
e41182b5
GS
942Some simple tricks for determining if you are running on an EBCDIC
943platform could include any of the following (perhaps all):
944
945 if ("\t" eq "\05") { print "EBCDIC may be spoken here!\n"; }
946
947 if (ord('A') == 193) { print "EBCDIC may be spoken here!\n"; }
948
949 if (chr(169) eq 'z') { print "EBCDIC may be spoken here!\n"; }
950
b7df3edc 951One thing you may not want to rely on is the EBCDIC encoding
0a47030a
GS
952of punctuation characters since these may differ from code page to code
953page (and once your module or script is rumoured to work with EBCDIC,
954folks will want it to work with all EBCDIC character sets).
e41182b5
GS
955
956Also see:
957
958=over 4
959
960=item perl-mvs list
961
962The perl-mvs@perl.org list is for discussion of porting issues as well as
963general usage issues for all EBCDIC Perls. Send a message body of
964"subscribe perl-mvs" to majordomo@perl.org.
965
0a47030a 966=item AS/400 Perl information at C<http://as400.rochester.ibm.com/>
e41182b5
GS
967
968=back
969
b8099c3d
CN
970=head2 Acorn RISC OS
971
b7df3edc
GS
972Because Acorns use ASCII with newlines (C<\n>) in text files as C<\012> like
973Unix, and because Unix filename emulation is turned on by default,
974most simple scripts will probably work "out of the box". The native
6ab3f9cb 975filesystem is modular, and individual filesystems are free to be
0a47030a 976case-sensitive or insensitive, and are usually case-preserving. Some
b7df3edc 977native filesystems have name length limits, which file and directory
6ab3f9cb
GS
978names are silently truncated to fit. Scripts should be aware that the
979standard filesystem currently has a name length limit of B<10>
980characters, with up to 77 items in a directory, but other filesystems
0a47030a 981may not impose such limitations.
b8099c3d
CN
982
983Native filenames are of the form
984
6ab3f9cb 985 Filesystem#Special_Field::DiskName.$.Directory.Directory.File
dd9f0070 986
b8099c3d
CN
987where
988
989 Special_Field is not usually present, but may contain . and $ .
990 Filesystem =~ m|[A-Za-z0-9_]|
991 DsicName =~ m|[A-Za-z0-9_/]|
992 $ represents the root directory
993 . is the path separator
994 @ is the current directory (per filesystem but machine global)
995 ^ is the parent directory
996 Directory and File =~ m|[^\0- "\.\$\%\&:\@\\^\|\177]+|
997
998The default filename translation is roughly C<tr|/.|./|;>
999
6ab3f9cb 1000Note that C<"ADFS::HardDisk.$.File" ne 'ADFS::HardDisk.$.File'> and that
0a47030a
GS
1001the second stage of C<$> interpolation in regular expressions will fall
1002foul of the C<$.> if scripts are not careful.
1003
1004Logical paths specified by system variables containing comma-separated
b7df3edc 1005search lists are also allowed; hence C<System:Modules> is a valid
0a47030a 1006filename, and the filesystem will prefix C<Modules> with each section of
6ab3f9cb 1007C<System$Path> until a name is made that points to an object on disk.
b7df3edc 1008Writing to a new file C<System:Modules> would be allowed only if
0a47030a
GS
1009C<System$Path> contains a single item list. The filesystem will also
1010expand system variables in filenames if enclosed in angle brackets, so
1011C<E<lt>System$DirE<gt>.Modules> would look for the file
1012S<C<$ENV{'System$Dir'} . 'Modules'>>. The obvious implication of this is
3c075c7d 1013that B<fully qualified filenames can start with C<E<lt>E<gt>>> and should
0a47030a 1014be protected when C<open> is used for input.
b8099c3d
CN
1015
1016Because C<.> was in use as a directory separator and filenames could not
1017be assumed to be unique after 10 characters, Acorn implemented the C
1018compiler to strip the trailing C<.c> C<.h> C<.s> and C<.o> suffix from
1019filenames specified in source code and store the respective files in
b7df3edc 1020subdirectories named after the suffix. Hence files are translated:
b8099c3d
CN
1021
1022 foo.h h.foo
1023 C:foo.h C:h.foo (logical path variable)
1024 sys/os.h sys.h.os (C compiler groks Unix-speak)
1025 10charname.c c.10charname
1026 10charname.o o.10charname
1027 11charname_.c c.11charname (assuming filesystem truncates at 10)
1028
1029The Unix emulation library's translation of filenames to native assumes
b7df3edc
GS
1030that this sort of translation is required, and it allows a user-defined list
1031of known suffixes that it will transpose in this fashion. This may
1032seem transparent, but consider that with these rules C<foo/bar/baz.h>
0a47030a
GS
1033and C<foo/bar/h/baz> both map to C<foo.bar.h.baz>, and that C<readdir> and
1034C<glob> cannot and do not attempt to emulate the reverse mapping. Other
6ab3f9cb 1035C<.>'s in filenames are translated to C</>.
0a47030a 1036
b7df3edc 1037As implied above, the environment accessed through C<%ENV> is global, and
0a47030a 1038the convention is that program specific environment variables are of the
6ab3f9cb
GS
1039form C<Program$Name>. Each filesystem maintains a current directory,
1040and the current filesystem's current directory is the B<global> current
b7df3edc
GS
1041directory. Consequently, sociable programs don't change the current
1042directory but rely on full pathnames, and programs (and Makefiles) cannot
0a47030a
GS
1043assume that they can spawn a child process which can change the current
1044directory without affecting its parent (and everyone else for that
1045matter).
1046
b7df3edc
GS
1047Because native operating system filehandles are global and are currently
1048allocated down from 255, with 0 being a reserved value, the Unix emulation
0a47030a
GS
1049library emulates Unix filehandles. Consequently, you can't rely on
1050passing C<STDIN>, C<STDOUT>, or C<STDERR> to your children.
1051
1052The desire of users to express filenames of the form
1053C<E<lt>Foo$DirE<gt>.Bar> on the command line unquoted causes problems,
1054too: C<``> command output capture has to perform a guessing game. It
1055assumes that a string C<E<lt>[^E<lt>E<gt>]+\$[^E<lt>E<gt>]E<gt>> is a
1056reference to an environment variable, whereas anything else involving
1057C<E<lt>> or C<E<gt>> is redirection, and generally manages to be 99%
1058right. Of course, the problem remains that scripts cannot rely on any
1059Unix tools being available, or that any tools found have Unix-like command
1060line arguments.
1061
b7df3edc
GS
1062Extensions and XS are, in theory, buildable by anyone using free
1063tools. In practice, many don't, as users of the Acorn platform are
1064used to binary distributions. MakeMaker does run, but no available
1065make currently copes with MakeMaker's makefiles; even if and when
1066this should be fixed, the lack of a Unix-like shell will cause
1067problems with makefile rules, especially lines of the form C<cd
1068sdbm && make all>, and anything using quoting.
b8099c3d
CN
1069
1070"S<RISC OS>" is the proper name for the operating system, but the value
1071in C<$^O> is "riscos" (because we don't like shouting).
1072
e41182b5
GS
1073=head2 Other perls
1074
b7df3edc
GS
1075Perl has been ported to many platforms that do not fit into any of
1076the categories listed above. Some, such as AmigaOS, Atari MiNT,
1077BeOS, HP MPE/iX, QNX, Plan 9, and VOS, have been well-integrated
1078into the standard Perl source code kit. You may need to see the
1079F<ports/> directory on CPAN for information, and possibly binaries,
1080for the likes of: aos, Atari ST, lynxos, riscos, Novell Netware,
1081Tandem Guardian, I<etc.> (Yes, we know that some of these OSes may
1082fall under the Unix category, but we are not a standards body.)
e41182b5
GS
1083
1084See also:
1085
1086=over 4
1087
1088=item Atari, Guido Flohr's page C<http://stud.uni-sb.de/~gufl0000/>
1089
1090=item HP 300 MPE/iX C<http://www.cccd.edu/~markb/perlix.html>
1091
1092=item Novell Netware
1093
6ab3f9cb
GS
1094A free perl5-based PERL.NLM for Novell Netware is available in
1095precompiled binary and source code form from C<http://www.novell.com/>
1096as well as from CPAN.
e41182b5
GS
1097
1098=back
1099
e41182b5
GS
1100=head1 FUNCTION IMPLEMENTATIONS
1101
b7df3edc
GS
1102Listed below are functions that are either completely unimplemented
1103or else have been implemented differently on various platforms.
1104Following each description will be, in parentheses, a list of
1105platforms that the description applies to.
e41182b5 1106
b7df3edc
GS
1107The list may well be incomplete, or even wrong in some places. When
1108in doubt, consult the platform-specific README files in the Perl
1109source distribution, and any other documentation resources accompanying
1110a given port.
e41182b5 1111
0a47030a 1112Be aware, moreover, that even among Unix-ish systems there are variations.
e41182b5 1113
b7df3edc
GS
1114For many functions, you can also query C<%Config>, exported by
1115default from the Config module. For example, to check whether the
1116platform has the C<lstat> call, check C<$Config{d_lstat}>. See
1117L<Config> for a full description of available variables.
e41182b5
GS
1118
1119=head2 Alphabetical Listing of Perl Functions
1120
1121=over 8
1122
1123=item -X FILEHANDLE
1124
1125=item -X EXPR
1126
1127=item -X
1128
b7df3edc 1129C<-r>, C<-w>, and C<-x> have a limited meaning only; directories
e41182b5 1130and applications are executable, and there are no uid/gid
b7df3edc 1131considerations. C<-o> is not supported. (S<Mac OS>)
e41182b5 1132
b7df3edc
GS
1133C<-r>, C<-w>, C<-x>, and C<-o> tell whether the file is accessible,
1134which may not reflect UIC-based file protections. (VMS)
e41182b5 1135
b8099c3d
CN
1136C<-s> returns the size of the data fork, not the total size of data fork
1137plus resource fork. (S<Mac OS>).
1138
1139C<-s> by name on an open file will return the space reserved on disk,
1140rather than the current extent. C<-s> on an open filehandle returns the
b7df3edc 1141current size. (S<RISC OS>)
b8099c3d 1142
e41182b5 1143C<-R>, C<-W>, C<-X>, C<-O> are indistinguishable from C<-r>, C<-w>,
b8099c3d 1144C<-x>, C<-o>. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1145
1146C<-b>, C<-c>, C<-k>, C<-g>, C<-p>, C<-u>, C<-A> are not implemented.
1147(S<Mac OS>)
1148
1149C<-g>, C<-k>, C<-l>, C<-p>, C<-u>, C<-A> are not particularly meaningful.
b8099c3d 1150(Win32, VMS, S<RISC OS>)
e41182b5
GS
1151
1152C<-d> is true if passed a device spec without an explicit directory.
1153(VMS)
1154
1155C<-T> and C<-B> are implemented, but might misclassify Mac text files
0a47030a 1156with foreign characters; this is the case will all platforms, but may
b7df3edc 1157affect S<Mac OS> often. (S<Mac OS>)
e41182b5
GS
1158
1159C<-x> (or C<-X>) determine if a file ends in one of the executable
b7df3edc 1160suffixes. C<-S> is meaningless. (Win32)
e41182b5 1161
b8099c3d
CN
1162C<-x> (or C<-X>) determine if a file has an executable file type.
1163(S<RISC OS>)
1164
e41182b5
GS
1165=item binmode FILEHANDLE
1166
b7df3edc 1167Meaningless. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1168
1169Reopens file and restores pointer; if function fails, underlying
1170filehandle may be closed, or pointer may be in a different position.
1171(VMS)
1172
1173The value returned by C<tell> may be affected after the call, and
1174the filehandle may be flushed. (Win32)
1175
1176=item chmod LIST
1177
b7df3edc 1178Only limited meaning. Disabling/enabling write permission is mapped to
e41182b5
GS
1179locking/unlocking the file. (S<Mac OS>)
1180
1181Only good for changing "owner" read-write access, "group", and "other"
1182bits are meaningless. (Win32)
1183
b8099c3d
CN
1184Only good for changing "owner" and "other" read-write access. (S<RISC OS>)
1185
495c5fdc
GP
1186Access permissions are mapped onto VOS access-control list changes. (VOS)
1187
e41182b5
GS
1188=item chown LIST
1189
495c5fdc 1190Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>, VOS)
e41182b5
GS
1191
1192Does nothing, but won't fail. (Win32)
1193
1194=item chroot FILENAME
1195
1196=item chroot
1197
7c5ffed3 1198Not implemented. (S<Mac OS>, Win32, VMS, Plan9, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1199
1200=item crypt PLAINTEXT,SALT
1201
1202May not be available if library or source was not provided when building
b8099c3d 1203perl. (Win32)
e41182b5 1204
495c5fdc
GP
1205Not implemented. (VOS)
1206
e41182b5
GS
1207=item dbmclose HASH
1208
495c5fdc 1209Not implemented. (VMS, Plan9, VOS)
e41182b5
GS
1210
1211=item dbmopen HASH,DBNAME,MODE
1212
495c5fdc 1213Not implemented. (VMS, Plan9, VOS)
e41182b5
GS
1214
1215=item dump LABEL
1216
b8099c3d 1217Not useful. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1218
1219Not implemented. (Win32)
1220
b8099c3d 1221Invokes VMS debugger. (VMS)
e41182b5
GS
1222
1223=item exec LIST
1224
1225Not implemented. (S<Mac OS>)
1226
7c5ffed3 1227Implemented via Spawn. (VM/ESA)
3c075c7d 1228
e41182b5
GS
1229=item fcntl FILEHANDLE,FUNCTION,SCALAR
1230
1231Not implemented. (Win32, VMS)
1232
1233=item flock FILEHANDLE,OPERATION
1234
495c5fdc 1235Not implemented (S<Mac OS>, VMS, S<RISC OS>, VOS).
e41182b5
GS
1236
1237Available only on Windows NT (not on Windows 95). (Win32)
1238
1239=item fork
1240
7c5ffed3 1241Not implemented. (S<Mac OS>, Win32, AmigaOS, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1242
1243=item getlogin
1244
b8099c3d 1245Not implemented. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1246
1247=item getpgrp PID
1248
495c5fdc 1249Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5
GS
1250
1251=item getppid
1252
b8099c3d 1253Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1254
1255=item getpriority WHICH,WHO
1256
7c5ffed3 1257Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1258
1259=item getpwnam NAME
1260
1261Not implemented. (S<Mac OS>, Win32)
1262
b8099c3d
CN
1263Not useful. (S<RISC OS>)
1264
e41182b5
GS
1265=item getgrnam NAME
1266
b8099c3d 1267Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1268
1269=item getnetbyname NAME
1270
1271Not implemented. (S<Mac OS>, Win32, Plan9)
1272
1273=item getpwuid UID
1274
1275Not implemented. (S<Mac OS>, Win32)
1276
b8099c3d
CN
1277Not useful. (S<RISC OS>)
1278
e41182b5
GS
1279=item getgrgid GID
1280
b8099c3d 1281Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1282
1283=item getnetbyaddr ADDR,ADDRTYPE
1284
1285Not implemented. (S<Mac OS>, Win32, Plan9)
1286
1287=item getprotobynumber NUMBER
1288
1289Not implemented. (S<Mac OS>)
1290
1291=item getservbyport PORT,PROTO
1292
1293Not implemented. (S<Mac OS>)
1294
1295=item getpwent
1296
7c5ffed3 1297Not implemented. (S<Mac OS>, Win32, VM/ESA)
e41182b5
GS
1298
1299=item getgrent
1300
7c5ffed3 1301Not implemented. (S<Mac OS>, Win32, VMS, VM/ESA)
e41182b5
GS
1302
1303=item gethostent
1304
1305Not implemented. (S<Mac OS>, Win32)
1306
1307=item getnetent
1308
1309Not implemented. (S<Mac OS>, Win32, Plan9)
1310
1311=item getprotoent
1312
1313Not implemented. (S<Mac OS>, Win32, Plan9)
1314
1315=item getservent
1316
1317Not implemented. (Win32, Plan9)
1318
1319=item setpwent
1320
b8099c3d 1321Not implemented. (S<Mac OS>, Win32, S<RISC OS>)
e41182b5
GS
1322
1323=item setgrent
1324
b8099c3d 1325Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1326
1327=item sethostent STAYOPEN
1328
b8099c3d 1329Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>)
e41182b5
GS
1330
1331=item setnetent STAYOPEN
1332
b8099c3d 1333Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>)
e41182b5
GS
1334
1335=item setprotoent STAYOPEN
1336
b8099c3d 1337Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>)
e41182b5
GS
1338
1339=item setservent STAYOPEN
1340
b8099c3d 1341Not implemented. (Plan9, Win32, S<RISC OS>)
e41182b5
GS
1342
1343=item endpwent
1344
7c5ffed3 1345Not implemented. (S<Mac OS>, Win32, VM/ESA)
e41182b5
GS
1346
1347=item endgrent
1348
7c5ffed3 1349Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VM/ESA)
e41182b5
GS
1350
1351=item endhostent
1352
1353Not implemented. (S<Mac OS>, Win32)
1354
1355=item endnetent
1356
1357Not implemented. (S<Mac OS>, Win32, Plan9)
1358
1359=item endprotoent
1360
1361Not implemented. (S<Mac OS>, Win32, Plan9)
1362
1363=item endservent
1364
1365Not implemented. (Plan9, Win32)
1366
1367=item getsockopt SOCKET,LEVEL,OPTNAME
1368
1369Not implemented. (S<Mac OS>, Plan9)
1370
1371=item glob EXPR
1372
1373=item glob
1374
1375Globbing built-in, but only C<*> and C<?> metacharacters are supported.
1376(S<Mac OS>)
1377
b7df3edc 1378Features depend on external perlglob.exe or perlglob.bat. May be
0a47030a
GS
1379overridden with something like File::DosGlob, which is recommended.
1380(Win32)
e41182b5 1381
b8099c3d 1382Globbing built-in, but only C<*> and C<?> metacharacters are supported.
0a47030a
GS
1383Globbing relies on operating system calls, which may return filenames
1384in any order. As most filesystems are case-insensitive, even "sorted"
1385filenames will not be in case-sensitive order. (S<RISC OS>)
b8099c3d 1386
e41182b5
GS
1387=item ioctl FILEHANDLE,FUNCTION,SCALAR
1388
1389Not implemented. (VMS)
1390
1391Available only for socket handles, and it does what the ioctlsocket() call
1392in the Winsock API does. (Win32)
1393
b8099c3d
CN
1394Available only for socket handles. (S<RISC OS>)
1395
e41182b5
GS
1396=item kill LIST
1397
0a47030a
GS
1398Not implemented, hence not useful for taint checking. (S<Mac OS>,
1399S<RISC OS>)
e41182b5 1400
0a47030a
GS
1401Available only for process handles returned by the C<system(1, ...)>
1402method of spawning a process. (Win32)
e41182b5
GS
1403
1404=item link OLDFILE,NEWFILE
1405
b8099c3d 1406Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5 1407
433acd8a
JH
1408Link count not updated because hard links are not quite that hard
1409(They are sort of half-way between hard and soft links). (AmigaOS)
1410
e41182b5
GS
1411=item lstat FILEHANDLE
1412
1413=item lstat EXPR
1414
1415=item lstat
1416
b8099c3d 1417Not implemented. (VMS, S<RISC OS>)
e41182b5 1418
b8099c3d 1419Return values may be bogus. (Win32)
e41182b5
GS
1420
1421=item msgctl ID,CMD,ARG
1422
1423=item msgget KEY,FLAGS
1424
1425=item msgsnd ID,MSG,FLAGS
1426
1427=item msgrcv ID,VAR,SIZE,TYPE,FLAGS
1428
495c5fdc 1429Not implemented. (S<Mac OS>, Win32, VMS, Plan9, S<RISC OS>, VOS)
e41182b5
GS
1430
1431=item open FILEHANDLE,EXPR
1432
1433=item open FILEHANDLE
1434
b7df3edc 1435The C<|> variants are supported only if ToolServer is installed.
e41182b5
GS
1436(S<Mac OS>)
1437
b8099c3d 1438open to C<|-> and C<-|> are unsupported. (S<Mac OS>, Win32, S<RISC OS>)
e41182b5
GS
1439
1440=item pipe READHANDLE,WRITEHANDLE
1441
1442Not implemented. (S<Mac OS>)
1443
433acd8a
JH
1444Very limited functionality. (MiNT)
1445
e41182b5
GS
1446=item readlink EXPR
1447
1448=item readlink
1449
b8099c3d 1450Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5
GS
1451
1452=item select RBITS,WBITS,EBITS,TIMEOUT
1453
1454Only implemented on sockets. (Win32)
1455
b8099c3d
CN
1456Only reliable on sockets. (S<RISC OS>)
1457
e41182b5
GS
1458=item semctl ID,SEMNUM,CMD,ARG
1459
1460=item semget KEY,NSEMS,FLAGS
1461
1462=item semop KEY,OPSTRING
1463
495c5fdc 1464Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5
GS
1465
1466=item setpgrp PID,PGRP
1467
495c5fdc 1468Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5
GS
1469
1470=item setpriority WHICH,WHO,PRIORITY
1471
495c5fdc 1472Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5
GS
1473
1474=item setsockopt SOCKET,LEVEL,OPTNAME,OPTVAL
1475
1476Not implemented. (S<Mac OS>, Plan9)
1477
1478=item shmctl ID,CMD,ARG
1479
1480=item shmget KEY,SIZE,FLAGS
1481
1482=item shmread ID,VAR,POS,SIZE
1483
1484=item shmwrite ID,STRING,POS,SIZE
1485
495c5fdc 1486Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5
GS
1487
1488=item socketpair SOCKET1,SOCKET2,DOMAIN,TYPE,PROTOCOL
1489
7c5ffed3 1490Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1491
1492=item stat FILEHANDLE
1493
1494=item stat EXPR
1495
1496=item stat
1497
1498mtime and atime are the same thing, and ctime is creation time instead of
1499inode change time. (S<Mac OS>)
1500
1501device and inode are not meaningful. (Win32)
1502
1503device and inode are not necessarily reliable. (VMS)
1504
b8099c3d
CN
1505mtime, atime and ctime all return the last modification time. Device and
1506inode are not necessarily reliable. (S<RISC OS>)
1507
e41182b5
GS
1508=item symlink OLDFILE,NEWFILE
1509
b8099c3d 1510Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5
GS
1511
1512=item syscall LIST
1513
7c5ffed3 1514Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5 1515
f34d0673
GS
1516=item sysopen FILEHANDLE,FILENAME,MODE,PERMS
1517
dd9f0070 1518The traditional "0", "1", and "2" MODEs are implemented with different
322422de
GS
1519numeric values on some systems. The flags exported by C<Fcntl>
1520(O_RDONLY, O_WRONLY, O_RDWR) should work everywhere though. (S<Mac
7c5ffed3 1521OS>, OS/390, VM/ESA)
f34d0673 1522
e41182b5
GS
1523=item system LIST
1524
1525Only implemented if ToolServer is installed. (S<Mac OS>)
1526
1527As an optimization, may not call the command shell specified in
b7df3edc 1528C<$ENV{PERL5SHELL}>. C<system(1, @args)> spawns an external
e41182b5
GS
1529process and immediately returns its process designator, without
1530waiting for it to terminate. Return value may be used subsequently
1531in C<wait> or C<waitpid>. (Win32)
1532
b8099c3d
CN
1533There is no shell to process metacharacters, and the native standard is
1534to pass a command line terminated by "\n" "\r" or "\0" to the spawned
1535program. Redirection such as C<E<gt> foo> is performed (if at all) by
1536the run time library of the spawned program. C<system> I<list> will call
1537the Unix emulation library's C<exec> emulation, which attempts to provide
1538emulation of the stdin, stdout, stderr in force in the parent, providing
1539the child program uses a compatible version of the emulation library.
1540I<scalar> will call the native command line direct and no such emulation
1541of a child Unix program will exists. Mileage B<will> vary. (S<RISC OS>)
1542
433acd8a
JH
1543Far from being POSIX compliant. Because there may be no underlying
1544/bin/sh tries to work around the problem by forking and execing the
9b63e9ec
CN
1545first token in its argument string. Handles basic redirection
1546("E<lt>" or "E<gt>") on its own behalf. (MiNT)
433acd8a 1547
e41182b5
GS
1548=item times
1549
1550Only the first entry returned is nonzero. (S<Mac OS>)
1551
1552"cumulative" times will be bogus. On anything other than Windows NT,
1553"system" time will be bogus, and "user" time is actually the time
1554returned by the clock() function in the C runtime library. (Win32)
1555
b8099c3d
CN
1556Not useful. (S<RISC OS>)
1557
e41182b5
GS
1558=item truncate FILEHANDLE,LENGTH
1559
1560=item truncate EXPR,LENGTH
1561
1562Not implemented. (VMS)
1563
495c5fdc
GP
1564Truncation to zero-length only. (VOS)
1565
4cfdb94f
GS
1566If a FILEHANDLE is supplied, it must be writable and opened in append
1567mode (i.e., use C<open(FH, '>>filename')>
1568or C<sysopen(FH,...,O_APPEND|O_RDWR)>. If a filename is supplied, it
1569should not be held open elsewhere. (Win32)
1570
e41182b5
GS
1571=item umask EXPR
1572
1573=item umask
1574
1575Returns undef where unavailable, as of version 5.005.
1576
b7df3edc
GS
1577C<umask> works but the correct permissions are set only when the file
1578is finally closed. (AmigaOS)
433acd8a 1579
e41182b5
GS
1580=item utime LIST
1581
b8099c3d 1582Only the modification time is updated. (S<Mac OS>, VMS, S<RISC OS>)
e41182b5 1583
322422de
GS
1584May not behave as expected. Behavior depends on the C runtime
1585library's implementation of utime(), and the filesystem being
1586used. The FAT filesystem typically does not support an "access
1587time" field, and it may limit timestamps to a granularity of
1588two seconds. (Win32)
e41182b5
GS
1589
1590=item wait
1591
1592=item waitpid PID,FLAGS
1593
495c5fdc 1594Not implemented. (S<Mac OS>, VOS)
e41182b5
GS
1595
1596Can only be applied to process handles returned for processes spawned
1597using C<system(1, ...)>. (Win32)
1598
b8099c3d
CN
1599Not useful. (S<RISC OS>)
1600
e41182b5
GS
1601=back
1602
b8099c3d
CN
1603=head1 CHANGES
1604
1605=over 4
1606
b7df3edc
GS
1607=item v1.43, 24 May 1999
1608
1609Added a lot of cleaning up from Tom Christiansen.
1610
19799a22 1611=item v1.42, 22 May 1999
b7df3edc 1612
19799a22 1613Added notes about tests, sprintf/printf, and epoch offsets.
b7df3edc 1614
6ab3f9cb
GS
1615=item v1.41, 19 May 1999
1616
1617Lots more little changes to formatting and content.
1618
1619Added a bunch of <$^O> and related values
1620for various platforms; fixed mail and web addresses, and added
1621and changed miscellaneous notes. (Peter Prymmer)
1622
1623=item v1.40, 11 April 1999
1624
1625Miscellaneous changes.
1626
1627=item v1.39, 11 February 1999
2ee0eb3c
CN
1628
1629Changes from Jarkko and EMX URL fixes Michael Schwern. Additional
1630note about newlines added.
1631
9b63e9ec
CN
1632=item v1.38, 31 December 1998
1633
1634More changes from Jarkko.
1635
3c075c7d
CN
1636=item v1.37, 19 December 1998
1637
1638More minor changes. Merge two separate version 1.35 documents.
1639
1640=item v1.36, 9 September 1998
1641
1642Updated for Stratus VOS. Also known as version 1.35.
1643
1644=item v1.35, 13 August 1998
495c5fdc 1645
3c075c7d
CN
1646Integrate more minor changes, plus addition of new sections under
1647L<"ISSUES">: L<"Numbers endianness and Width">,
1648L<"Character sets and character encoding">,
1649L<"Internationalisation">.
495c5fdc 1650
3c075c7d 1651=item v1.33, 06 August 1998
0a47030a
GS
1652
1653Integrate more minor changes.
1654
3c075c7d 1655=item v1.32, 05 August 1998
dd9f0070
CN
1656
1657Integrate more minor changes.
1658
3c075c7d 1659=item v1.30, 03 August 1998
b8099c3d
CN
1660
1661Major update for RISC OS, other minor changes.
1662
3c075c7d 1663=item v1.23, 10 July 1998
b8099c3d
CN
1664
1665First public release with perl5.005.
1666
1667=back
e41182b5
GS
1668
1669=head1 AUTHORS / CONTRIBUTORS
1670
dd9f0070 1671Abigail E<lt>abigail@fnx.comE<gt>,
bd3fa61c 1672Charles Bailey E<lt>bailey@newman.upenn.eduE<gt>,
dd9f0070 1673Graham Barr E<lt>gbarr@pobox.comE<gt>,
e41182b5 1674Tom Christiansen E<lt>tchrist@perl.comE<gt>,
dd9f0070
CN
1675Nicholas Clark E<lt>Nicholas.Clark@liverpool.ac.ukE<gt>,
1676Andy Dougherty E<lt>doughera@lafcol.lafayette.eduE<gt>,
1677Dominic Dunlop E<lt>domo@vo.luE<gt>,
7c5ffed3 1678Neale Ferguson E<lt>neale@mailbox.tabnsw.com.auE<gt>
495c5fdc 1679Paul Green E<lt>Paul_Green@stratus.comE<gt>,
dd9f0070 1680M.J.T. Guy E<lt>mjtg@cus.cam.ac.ukE<gt>,
7c5ffed3 1681Jarkko Hietaniemi E<lt>jhi@iki.fi<gt>,
dd9f0070
CN
1682Luther Huffman E<lt>lutherh@stratcom.comE<gt>,
1683Nick Ing-Simmons E<lt>nick@ni-s.u-net.comE<gt>,
322422de 1684Andreas J. KE<ouml>nig E<lt>koenig@kulturbox.deE<gt>,
3c075c7d 1685Markus Laker E<lt>mlaker@contax.co.ukE<gt>,
dd9f0070 1686Andrew M. Langmead E<lt>aml@world.std.comE<gt>,
19799a22 1687Larry Moore E<lt>ljmoore@freespace.netE<gt>,
e41182b5 1688Paul Moore E<lt>Paul.Moore@uk.origin-it.comE<gt>,
dd9f0070 1689Chris Nandor E<lt>pudge@pobox.comE<gt>,
322422de 1690Matthias Neeracher E<lt>neeri@iis.ee.ethz.chE<gt>,
e41182b5 1691Gary Ng E<lt>71564.1743@CompuServe.COME<gt>,
e41182b5 1692Tom Phoenix E<lt>rootbeer@teleport.comE<gt>,
dd9f0070 1693Peter Prymmer E<lt>pvhp@forte.comE<gt>,
322422de 1694Hugo van der Sanden E<lt>hv@crypt0.demon.co.ukE<gt>,
dd9f0070
CN
1695Gurusamy Sarathy E<lt>gsar@umich.eduE<gt>,
1696Paul J. Schinder E<lt>schinder@pobox.comE<gt>,
2ee0eb3c 1697Michael G Schwern E<lt>schwern@pobox.comE<gt>,
e41182b5 1698Dan Sugalski E<lt>sugalskd@ous.eduE<gt>,
dd9f0070 1699Nathan Torkington E<lt>gnat@frii.comE<gt>.
e41182b5 1700
3c075c7d
CN
1701This document is maintained by Chris Nandor
1702E<lt>pudge@pobox.comE<gt>.
e41182b5
GS
1703
1704=head1 VERSION
1705
b7df3edc 1706Version 1.43, last modified 24 May 1999