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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
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
91means C<\015>. In DOSish perls, C<\n> usually means C<\012>, but
92when accessing a file in "text" mode, STDIO translates it to (or
56d7751a 93from) C<\015\012>, depending on whether you're reading or writing.
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94Unix does the same thing on ttys in canonical mode. C<\015\012>
95is commonly referred to as CRLF.
96
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97A common cause of unportable programs is the misuse of chop() to trim
98newlines:
99
100 # XXX UNPORTABLE!
101 while(<FILE>) {
102 chop;
103 @array = split(/:/);
104 #...
105 }
106
8939ba94 107You can get away with this on Unix and Mac OS (they have a single
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108character end-of-line), but the same program will break under DOSish
109perls because you're only chop()ing half the end-of-line. Instead,
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110chomp() should be used to trim newlines. The L<Dunce::Files> module
111can help audit your code for misuses of chop().
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112
113When dealing with binary files (or text files in binary mode) be sure
114to explicitly set $/ to the appropriate value for your file format
115before using chomp().
116
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117Because of the "text" mode translation, DOSish perls have limitations
118in using C<seek> and C<tell> on a file accessed in "text" mode.
119Stick to C<seek>-ing to locations you got from C<tell> (and no
120others), and you are usually free to use C<seek> and C<tell> even
121in "text" mode. Using C<seek> or C<tell> or other file operations
122may be non-portable. If you use C<binmode> on a file, however, you
123can usually C<seek> and C<tell> with arbitrary values in safety.
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124
125A common misconception in socket programming is that C<\n> eq C<\012>
0a47030a 126everywhere. When using protocols such as common Internet protocols,
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127C<\012> and C<\015> are called for specifically, and the values of
128the logical C<\n> and C<\r> (carriage return) are not reliable.
129
130 print SOCKET "Hi there, client!\r\n"; # WRONG
131 print SOCKET "Hi there, client!\015\012"; # RIGHT
132
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133However, using C<\015\012> (or C<\cM\cJ>, or C<\x0D\x0A>) can be tedious
134and unsightly, as well as confusing to those maintaining the code. As
6ab3f9cb 135such, the Socket module supplies the Right Thing for those who want it.
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136
137 use Socket qw(:DEFAULT :crlf);
138 print SOCKET "Hi there, client!$CRLF" # RIGHT
139
6ab3f9cb 140When reading from a socket, remember that the default input record
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141separator C<$/> is C<\n>, but robust socket code will recognize as
142either C<\012> or C<\015\012> as end of line:
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143
144 while (<SOCKET>) {
145 # ...
146 }
147
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148Because both CRLF and LF end in LF, the input record separator can
149be set to LF and any CR stripped later. Better to write:
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150
151 use Socket qw(:DEFAULT :crlf);
152 local($/) = LF; # not needed if $/ is already \012
153
154 while (<SOCKET>) {
155 s/$CR?$LF/\n/; # not sure if socket uses LF or CRLF, OK
156 # s/\015?\012/\n/; # same thing
157 }
158
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159This example is preferred over the previous one--even for Unix
160platforms--because now any C<\015>'s (C<\cM>'s) are stripped out
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161(and there was much rejoicing).
162
6ab3f9cb 163Similarly, functions that return text data--such as a function that
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164fetches a web page--should sometimes translate newlines before
165returning the data, if they've not yet been translated to the local
166newline representation. A single line of code will often suffice:
2ee0eb3c 167
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168 $data =~ s/\015?\012/\n/g;
169 return $data;
2ee0eb3c 170
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171Some of this may be confusing. Here's a handy reference to the ASCII CR
172and LF characters. You can print it out and stick it in your wallet.
173
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174 LF eq \012 eq \x0A eq \cJ eq chr(10) eq ASCII 10
175 CR eq \015 eq \x0D eq \cM eq chr(13) eq ASCII 13
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176
177 | Unix | DOS | Mac |
178 ---------------------------
179 \n | LF | LF | CR |
180 \r | CR | CR | LF |
181 \n * | LF | CRLF | CR |
182 \r * | CR | CR | LF |
183 ---------------------------
184 * text-mode STDIO
185
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186The Unix column assumes that you are not accessing a serial line
187(like a tty) in canonical mode. If you are, then CR on input becomes
188"\n", and "\n" on output becomes CRLF.
189
6ab3f9cb 190These are just the most common definitions of C<\n> and C<\r> in Perl.
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191There may well be others. For example, on an EBCDIC implementation
192such as z/OS (OS/390) or OS/400 (using the ILE, the PASE is ASCII-based)
193the above material is similar to "Unix" but the code numbers change:
74555b7a 194
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195 LF eq \025 eq \x15 eq \cU eq chr(21) eq CP-1047 21
196 LF eq \045 eq \x25 eq chr(37) eq CP-0037 37
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197 CR eq \015 eq \x0D eq \cM eq chr(13) eq CP-1047 13
198 CR eq \015 eq \x0D eq \cM eq chr(13) eq CP-0037 13
199
200 | z/OS | OS/400 |
201 ----------------------
202 \n | LF | LF |
203 \r | CR | CR |
204 \n * | LF | LF |
205 \r * | CR | CR |
206 ----------------------
207 * text-mode STDIO
6ab3f9cb 208
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209=head2 Numbers endianness and Width
210
211Different CPUs store integers and floating point numbers in different
212orders (called I<endianness>) and widths (32-bit and 64-bit being the
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213most common today). This affects your programs when they attempt to transfer
214numbers in binary format from one CPU architecture to another,
215usually either "live" via network connection, or by storing the
216numbers to secondary storage such as a disk file or tape.
322422de 217
b7df3edc 218Conflicting storage orders make utter mess out of the numbers. If a
d1e3b762 219little-endian host (Intel, VAX) stores 0x12345678 (305419896 in
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220decimal), a big-endian host (Motorola, Sparc, PA) reads it as
2210x78563412 (2018915346 in decimal). Alpha and MIPS can be either:
222Digital/Compaq used/uses them in little-endian mode; SGI/Cray uses
223them in big-endian mode. To avoid this problem in network (socket)
224connections use the C<pack> and C<unpack> formats C<n> and C<N>, the
225"network" orders. These are guaranteed to be portable.
322422de 226
7a4d2905 227As of perl 5.9.2, you can also use the C<E<gt>> and C<E<lt>> modifiers
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228to force big- or little-endian byte-order. This is useful if you want
229to store signed integers or 64-bit integers, for example.
230
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231You can explore the endianness of your platform by unpacking a
232data structure packed in native format such as:
233
234 print unpack("h*", pack("s2", 1, 2)), "\n";
235 # '10002000' on e.g. Intel x86 or Alpha 21064 in little-endian mode
236 # '00100020' on e.g. Motorola 68040
237
238If you need to distinguish between endian architectures you could use
239either of the variables set like so:
240
241 $is_big_endian = unpack("h*", pack("s", 1)) =~ /01/;
4375e838 242 $is_little_endian = unpack("h*", pack("s", 1)) =~ /^1/;
d1e3b762 243
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244Differing widths can cause truncation even between platforms of equal
245endianness. The platform of shorter width loses the upper parts of the
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246number. There is no good solution for this problem except to avoid
247transferring or storing raw binary numbers.
248
b7df3edc 249One can circumnavigate both these problems in two ways. Either
322422de 250transfer and store numbers always in text format, instead of raw
b7df3edc 251binary, or else consider using modules like Data::Dumper (included in
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252the standard distribution as of Perl 5.005) and Storable (included as
253of perl 5.8). Keeping all data as text significantly simplifies matters.
322422de 254
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255The v-strings are portable only up to v2147483647 (0x7FFFFFFF), that's
256how far EBCDIC, or more precisely UTF-EBCDIC will go.
257
433acd8a 258=head2 Files and Filesystems
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259
260Most platforms these days structure files in a hierarchical fashion.
b7df3edc 261So, it is reasonably safe to assume that all platforms support the
6ab3f9cb 262notion of a "path" to uniquely identify a file on the system. How
b7df3edc 263that path is really written, though, differs considerably.
e41182b5 264
4375e838 265Although similar, file path specifications differ between Unix,
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266Windows, S<Mac OS>, OS/2, VMS, VOS, S<RISC OS>, and probably others.
267Unix, for example, is one of the few OSes that has the elegant idea
268of a single root directory.
322422de 269
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270DOS, OS/2, VMS, VOS, and Windows can work similarly to Unix with C</>
271as path separator, or in their own idiosyncratic ways (such as having
272several root directories and various "unrooted" device files such NIL:
273and LPT:).
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274
275S<Mac OS> uses C<:> as a path separator instead of C</>.
276
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277The filesystem may support neither hard links (C<link>) nor
278symbolic links (C<symlink>, C<readlink>, C<lstat>).
433acd8a 279
6ab3f9cb 280The filesystem may support neither access timestamp nor change
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281timestamp (meaning that about the only portable timestamp is the
282modification timestamp), or one second granularity of any timestamps
283(e.g. the FAT filesystem limits the time granularity to two seconds).
284
74555b7a 285The "inode change timestamp" (the C<-C> filetest) may really be the
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286"creation timestamp" (which it is not in UNIX).
287
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288VOS perl can emulate Unix filenames with C</> as path separator. The
289native pathname characters greater-than, less-than, number-sign, and
290percent-sign are always accepted.
291
6ab3f9cb 292S<RISC OS> perl can emulate Unix filenames with C</> as path
322422de 293separator, or go native and use C<.> for path separator and C<:> to
6ab3f9cb 294signal filesystems and disk names.
e41182b5 295
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296Don't assume UNIX filesystem access semantics: that read, write,
297and execute are all the permissions there are, and even if they exist,
298that their semantics (for example what do r, w, and x mean on
299a directory) are the UNIX ones. The various UNIX/POSIX compatibility
300layers usually try to make interfaces like chmod() work, but sometimes
301there simply is no good mapping.
302
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303If all this is intimidating, have no (well, maybe only a little)
304fear. There are modules that can help. The File::Spec modules
305provide methods to do the Right Thing on whatever platform happens
306to be running the program.
e41182b5 307
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308 use File::Spec::Functions;
309 chdir(updir()); # go up one directory
310 $file = catfile(curdir(), 'temp', 'file.txt');
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311 # on Unix and Win32, './temp/file.txt'
312 # on Mac OS, ':temp:file.txt'
d1e3b762 313 # on VMS, '[.temp]file.txt'
e41182b5 314
b7df3edc 315File::Spec is available in the standard distribution as of version
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3165.004_05. File::Spec::Functions is only in File::Spec 0.7 and later,
317and some versions of perl come with version 0.6. If File::Spec
318is not updated to 0.7 or later, you must use the object-oriented
319interface from File::Spec (or upgrade File::Spec).
e41182b5 320
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321In general, production code should not have file paths hardcoded.
322Making them user-supplied or read from a configuration file is
323better, keeping in mind that file path syntax varies on different
324machines.
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325
326This is especially noticeable in scripts like Makefiles and test suites,
327which often assume C</> as a path separator for subdirectories.
328
b7df3edc 329Also of use is File::Basename from the standard distribution, which
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330splits a pathname into pieces (base filename, full path to directory,
331and file suffix).
332
19799a22 333Even when on a single platform (if you can call Unix a single platform),
b7df3edc 334remember not to count on the existence or the contents of particular
3c075c7d 335system-specific files or directories, like F</etc/passwd>,
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336F</etc/sendmail.conf>, F</etc/resolv.conf>, or even F</tmp/>. For
337example, F</etc/passwd> may exist but not contain the encrypted
338passwords, because the system is using some form of enhanced security.
339Or it may not contain all the accounts, because the system is using NIS.
3c075c7d 340If code does need to rely on such a file, include a description of the
b7df3edc 341file and its format in the code's documentation, then make it easy for
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342the user to override the default location of the file.
343
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344Don't assume a text file will end with a newline. They should,
345but people forget.
e41182b5 346
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347Do not have two files or directories of the same name with different
348case, like F<test.pl> and F<Test.pl>, as many platforms have
349case-insensitive (or at least case-forgiving) filenames. Also, try
350not to have non-word characters (except for C<.>) in the names, and
351keep them to the 8.3 convention, for maximum portability, onerous a
352burden though this may appear.
dd9f0070 353
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354Likewise, when using the AutoSplit module, try to keep your functions to
3558.3 naming and case-insensitive conventions; or, at the least,
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356make it so the resulting files have a unique (case-insensitively)
357first 8 characters.
358
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359Whitespace in filenames is tolerated on most systems, but not all,
360and even on systems where it might be tolerated, some utilities
fe829689 361might become confused by such whitespace.
ec481373 362
b7df3edc 363Many systems (DOS, VMS) cannot have more than one C<.> in their filenames.
433acd8a 364
c47ff5f1 365Don't assume C<< > >> won't be the first character of a filename.
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366Always use C<< < >> explicitly to open a file for reading, or even
367better, use the three-arg version of open, unless you want the user to
368be able to specify a pipe open.
0a47030a 369
fe829689 370 open(FILE, '<', $existing_file) or die $!;
0a47030a 371
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372If filenames might use strange characters, it is safest to open it
373with C<sysopen> instead of C<open>. C<open> is magic and can
c47ff5f1 374translate characters like C<< > >>, C<< < >>, and C<|>, which may
b7df3edc 375be the wrong thing to do. (Sometimes, though, it's the right thing.)
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376Three-arg open can also help protect against this translation in cases
377where it is undesirable.
e41182b5 378
ec481373 379Don't use C<:> as a part of a filename since many systems use that for
8939ba94 380their own semantics (Mac OS Classic for separating pathname components,
ec481373 381many networking schemes and utilities for separating the nodename and
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382the pathname, and so on). For the same reasons, avoid C<@>, C<;> and
383C<|>.
ec481373 384
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385Don't assume that in pathnames you can collapse two leading slashes
386C<//> into one: some networking and clustering filesystems have special
387semantics for that. Let the operating system to sort it out.
388
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389The I<portable filename characters> as defined by ANSI C are
390
391 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
392 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
393 0 1 2 3 4 5 6 7 8 9
394 . _ -
395
08fef530 396and the "-" shouldn't be the first character. If you want to be
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397hypercorrect, stay case-insensitive and within the 8.3 naming
398convention (all the files and directories have to be unique within one
399directory if their names are lowercased and truncated to eight
400characters before the C<.>, if any, and to three characters after the
401C<.>, if any). (And do not use C<.>s in directory names.)
ec481373 402
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403=head2 System Interaction
404
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405Not all platforms provide a command line. These are usually platforms
406that rely primarily on a Graphical User Interface (GUI) for user
407interaction. A program requiring a command line interface might
408not work everywhere. This is probably for the user of the program
409to deal with, so don't stay up late worrying about it.
e41182b5 410
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411Some platforms can't delete or rename files held open by the system,
412this limitation may also apply to changing filesystem metainformation
413like file permissions or owners. Remember to C<close> files when you
414are done with them. Don't C<unlink> or C<rename> an open file. Don't
415C<tie> or C<open> a file already tied or opened; C<untie> or C<close>
416it first.
e41182b5 417
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418Don't open the same file more than once at a time for writing, as some
419operating systems put mandatory locks on such files.
420
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421Don't assume that write/modify permission on a directory gives the
422right to add or delete files/directories in that directory. That is
423filesystem specific: in some filesystems you need write/modify
424permission also (or even just) in the file/directory itself. In some
425filesystems (AFS, DFS) the permission to add/delete directory entries
426is a completely separate permission.
427
428Don't assume that a single C<unlink> completely gets rid of the file:
429some filesystems (most notably the ones in VMS) have versioned
430filesystems, and unlink() removes only the most recent one (it doesn't
431remove all the versions because by default the native tools on those
432platforms remove just the most recent version, too). The portable
433idiom to remove all the versions of a file is
434
94bb614c 435 1 while unlink "file";
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436
437This will terminate if the file is undeleteable for some reason
438(protected, not there, and so on).
439
e41182b5 440Don't count on a specific environment variable existing in C<%ENV>.
0a47030a 441Don't count on C<%ENV> entries being case-sensitive, or even
4a0d0822 442case-preserving. Don't try to clear %ENV by saying C<%ENV = ();>, or,
6be8f7a6 443if you really have to, make it conditional on C<$^O ne 'VMS'> since in
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444VMS the C<%ENV> table is much more than a per-process key-value string
445table.
e41182b5 446
d1e3b762 447Don't count on signals or C<%SIG> for anything.
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448
449Don't count on filename globbing. Use C<opendir>, C<readdir>, and
450C<closedir> instead.
451
b8099c3d 452Don't count on per-program environment variables, or per-program current
dd9f0070 453directories.
b8099c3d 454
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455Don't count on specific values of C<$!>, neither numeric nor
456especially the strings values-- users may switch their locales causing
457error messages to be translated into their languages. If you can
458trust a POSIXish environment, you can portably use the symbols defined
459by the Errno module, like ENOENT. And don't trust on the values of C<$!>
460at all except immediately after a failed system call.
3c075c7d 461
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462=head2 Command names versus file pathnames
463
464Don't assume that the name used to invoke a command or program with
465C<system> or C<exec> can also be used to test for the existence of the
466file that holds the executable code for that command or program.
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467First, many systems have "internal" commands that are built-in to the
468shell or OS and while these commands can be invoked, there is no
469corresponding file. Second, some operating systems (e.g., Cygwin,
470DJGPP, OS/2, and VOS) have required suffixes for executable files;
471these suffixes are generally permitted on the command name but are not
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472required. Thus, a command like "perl" might exist in a file named
473"perl", "perl.exe", or "perl.pm", depending on the operating system.
474The variable "_exe" in the Config module holds the executable suffix,
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475if any. Third, the VMS port carefully sets up $^X and
476$Config{perlpath} so that no further processing is required. This is
477just as well, because the matching regular expression used below would
478then have to deal with a possible trailing version number in the VMS
479file name.
a10d74f3
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480
481To convert $^X to a file pathname, taking account of the requirements
482of the various operating system possibilities, say:
7ee27b7c 483
a10d74f3 484 use Config;
a10d74f3 485 $thisperl = $^X;
68fb0eb7
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486 if ($^O ne 'VMS')
487 {$thisperl .= $Config{_exe} unless $thisperl =~ m/$Config{_exe}$/i;}
a10d74f3
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488
489To convert $Config{perlpath} to a file pathname, say:
7ee27b7c 490
a10d74f3 491 use Config;
68fb0eb7
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492 $thisperl = $Config{perlpath};
493 if ($^O ne 'VMS')
494 {$thisperl .= $Config{_exe} unless $thisperl =~ m/$Config{_exe}$/i;}
a10d74f3 495
7137b697
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496=head2 Networking
497
498Don't assume that you can reach the public Internet.
499
500Don't assume that there is only one way to get through firewalls
501to the public Internet.
502
932f293e
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503Don't assume that you can reach outside world through any other port
504than 80, or some web proxy. ftp is blocked by many firewalls.
505
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506Don't assume that you can send email by connecting to the local SMTP port.
507
7137b697 508Don't assume that you can reach yourself or any node by the name
dbc6a9ce 509'localhost'. The same goes for '127.0.0.1'. You will have to try both.
932f293e 510
86feb2c5
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511Don't assume that the host has only one network card, or that it
512can't bind to many virtual IP addresses.
932f293e
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513
514Don't assume a particular network device name.
7137b697 515
dbc6a9ce 516Don't assume a particular set of ioctl()s will work.
7137b697
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517
518Don't assume that you can ping hosts and get replies.
519
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520Don't assume that any particular port (service) will respond.
521
7ee27b7c 522Don't assume that Sys::Hostname (or any other API or command)
dbc6a9ce
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523returns either a fully qualified hostname or a non-qualified hostname:
524it all depends on how the system had been configured. Also remember
525things like DHCP and NAT-- the hostname you get back might not be very
526useful.
527
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528All the above "don't":s may look daunting, and they are -- but the key
529is to degrade gracefully if one cannot reach the particular network
530service one wants. Croaking or hanging do not look very professional.
531
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532=head2 Interprocess Communication (IPC)
533
b7df3edc
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534In general, don't directly access the system in code meant to be
535portable. That means, no C<system>, C<exec>, C<fork>, C<pipe>,
536C<``>, C<qx//>, C<open> with a C<|>, nor any of the other things
537that makes being a perl hacker worth being.
e41182b5
GS
538
539Commands that launch external processes are generally supported on
b7df3edc
GS
540most platforms (though many of them do not support any type of
541forking). The problem with using them arises from what you invoke
542them on. External tools are often named differently on different
4375e838 543platforms, may not be available in the same location, might accept
b7df3edc
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544different arguments, can behave differently, and often present their
545results in a platform-dependent way. Thus, you should seldom depend
546on them to produce consistent results. (Then again, if you're calling
547I<netstat -a>, you probably don't expect it to run on both Unix and CP/M.)
e41182b5 548
b7df3edc 549One especially common bit of Perl code is opening a pipe to B<sendmail>:
e41182b5 550
b7df3edc
GS
551 open(MAIL, '|/usr/lib/sendmail -t')
552 or die "cannot fork sendmail: $!";
e41182b5
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553
554This is fine for systems programming when sendmail is known to be
555available. But it is not fine for many non-Unix systems, and even
556some Unix systems that may not have sendmail installed. If a portable
b7df3edc
GS
557solution is needed, see the various distributions on CPAN that deal
558with it. Mail::Mailer and Mail::Send in the MailTools distribution are
559commonly used, and provide several mailing methods, including mail,
560sendmail, and direct SMTP (via Net::SMTP) if a mail transfer agent is
561not available. Mail::Sendmail is a standalone module that provides
562simple, platform-independent mailing.
563
564The Unix System V IPC (C<msg*(), sem*(), shm*()>) is not available
565even on all Unix platforms.
e41182b5 566
a81e5e2e
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567Do not use either the bare result of C<pack("N", 10, 20, 30, 40)> or
568bare v-strings (such as C<v10.20.30.40>) to represent IPv4 addresses:
569both forms just pack the four bytes into network order. That this
570would be equal to the C language C<in_addr> struct (which is what the
571socket code internally uses) is not guaranteed. To be portable use
572the routines of the Socket extension, such as C<inet_aton()>,
573C<inet_ntoa()>, and C<sockaddr_in()>.
6b2463a0 574
e41182b5 575The rule of thumb for portable code is: Do it all in portable Perl, or
0a47030a
GS
576use a module (that may internally implement it with platform-specific
577code, but expose a common interface).
e41182b5 578
e41182b5
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579=head2 External Subroutines (XS)
580
b7df3edc 581XS code can usually be made to work with any platform, but dependent
e41182b5
GS
582libraries, header files, etc., might not be readily available or
583portable, or the XS code itself might be platform-specific, just as Perl
584code might be. If the libraries and headers are portable, then it is
585normally reasonable to make sure the XS code is portable, too.
586
b7df3edc
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587A different type of portability issue arises when writing XS code:
588availability of a C compiler on the end-user's system. C brings
589with it its own portability issues, and writing XS code will expose
590you to some of those. Writing purely in Perl is an easier way to
e41182b5
GS
591achieve portability.
592
e41182b5
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593=head2 Standard Modules
594
595In general, the standard modules work across platforms. Notable
6ab3f9cb 596exceptions are the CPAN module (which currently makes connections to external
e41182b5 597programs that may not be available), platform-specific modules (like
6ab3f9cb 598ExtUtils::MM_VMS), and DBM modules.
e41182b5 599
b7df3edc 600There is no one DBM module available on all platforms.
6ab3f9cb
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601SDBM_File and the others are generally available on all Unix and DOSish
602ports, but not in MacPerl, where only NBDM_File and DB_File are
0a47030a 603available.
e41182b5
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604
605The good news is that at least some DBM module should be available, and
6ab3f9cb 606AnyDBM_File will use whichever module it can find. Of course, then
b7df3edc
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607the code needs to be fairly strict, dropping to the greatest common
608factor (e.g., not exceeding 1K for each record), so that it will
6ab3f9cb 609work with any DBM module. See L<AnyDBM_File> for more details.
e41182b5 610
e41182b5
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611=head2 Time and Date
612
0a47030a 613The system's notion of time of day and calendar date is controlled in
b7df3edc 614widely different ways. Don't assume the timezone is stored in C<$ENV{TZ}>,
0a47030a 615and even if it is, don't assume that you can control the timezone through
c87488a3
HS
616that variable. Don't assume anything about the three-letter timezone
617abbreviations (for example that MST would be the Mountain Standard Time,
618it's been known to stand for Moscow Standard Time). If you need to
619use timezones, express them in some unambiguous format like the
620exact number of minutes offset from UTC, or the POSIX timezone
621format.
e41182b5 622
322422de 623Don't assume that the epoch starts at 00:00:00, January 1, 1970,
c87488a3
HS
624because that is OS- and implementation-specific. It is better to
625store a date in an unambiguous representation. The ISO 8601 standard
626defines YYYY-MM-DD as the date format, or YYYY-MM-DDTHH-MM-SS
627(that's a literal "T" separating the date from the time).
628Please do use the ISO 8601 instead of making us to guess what
629date 02/03/04 might be. ISO 8601 even sorts nicely as-is.
630A text representation (like "1987-12-18") can be easily converted
631into an OS-specific value using a module like Date::Parse.
632An array of values, such as those returned by C<localtime>, can be
633converted to an OS-specific representation using Time::Local.
322422de 634
19799a22
GS
635When calculating specific times, such as for tests in time or date modules,
636it may be appropriate to calculate an offset for the epoch.
b7df3edc 637
19799a22
GS
638 require Time::Local;
639 $offset = Time::Local::timegm(0, 0, 0, 1, 0, 70);
b7df3edc 640
19799a22
GS
641The value for C<$offset> in Unix will be C<0>, but in Mac OS will be
642some large number. C<$offset> can then be added to a Unix time value
643to get what should be the proper value on any system.
322422de 644
bbac04ed
RGS
645On Windows (at least), you shouldn't pass a negative value to C<gmtime> or
646C<localtime>.
647
322422de
GS
648=head2 Character sets and character encoding
649
ec481373
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650Assume very little about character sets.
651
652Assume nothing about numerical values (C<ord>, C<chr>) of characters.
653Do not use explicit code point ranges (like \xHH-\xHH); use for
654example symbolic character classes like C<[:print:]>.
655
656Do not assume that the alphabetic characters are encoded contiguously
657(in the numeric sense). There may be gaps.
658
659Do not assume anything about the ordering of the characters.
660The lowercase letters may come before or after the uppercase letters;
661the lowercase and uppercase may be interlaced so that both `a' and `A'
662come before `b'; the accented and other international characters may
663be interlaced so that E<auml> comes before `b'.
322422de
GS
664
665=head2 Internationalisation
666
b7df3edc
GS
667If you may assume POSIX (a rather large assumption), you may read
668more about the POSIX locale system from L<perllocale>. The locale
669system at least attempts to make things a little bit more portable,
670or at least more convenient and native-friendly for non-English
671users. The system affects character sets and encoding, and date
672and time formatting--amongst other things.
e41182b5 673
c87488a3
HS
674If you really want to be international, you should consider Unicode.
675See L<perluniintro> and L<perlunicode> for more information.
676
11264fdb
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677If you want to use non-ASCII bytes (outside the bytes 0x00..0x7f) in
678the "source code" of your code, to be portable you have to be explicit
679about what bytes they are. Someone might for example be using your
680code under a UTF-8 locale, in which case random native bytes might be
681illegal ("Malformed UTF-8 ...") This means that for example embedding
682ISO 8859-1 bytes beyond 0x7f into your strings might cause trouble
683later. If the bytes are native 8-bit bytes, you can use the C<bytes>
684pragma. If the bytes are in a string (regular expression being a
685curious string), you can often also use the C<\xHH> notation instead
686of embedding the bytes as-is. If they are in some particular legacy
687encoding (ether single-byte or something more complicated), you can
688use the C<encoding> pragma. (If you want to write your code in UTF-8,
689you can use either the C<utf8> pragma, or the C<encoding> pragma.)
690The C<bytes> and C<utf8> pragmata are available since Perl 5.6.0, and
691the C<encoding> pragma since Perl 5.8.0.
692
e41182b5
GS
693=head2 System Resources
694
0a47030a
GS
695If your code is destined for systems with severely constrained (or
696missing!) virtual memory systems then you want to be I<especially> mindful
697of avoiding wasteful constructs such as:
e41182b5
GS
698
699 # NOTE: this is no longer "bad" in perl5.005
700 for (0..10000000) {} # bad
701 for (my $x = 0; $x <= 10000000; ++$x) {} # good
702
703 @lines = <VERY_LARGE_FILE>; # bad
704
705 while (<FILE>) {$file .= $_} # sometimes bad
0a47030a 706 $file = join('', <FILE>); # better
e41182b5 707
b7df3edc
GS
708The last two constructs may appear unintuitive to most people. The
709first repeatedly grows a string, whereas the second allocates a
710large chunk of memory in one go. On some systems, the second is
711more efficient that the first.
0a47030a 712
e41182b5
GS
713=head2 Security
714
b7df3edc
GS
715Most multi-user platforms provide basic levels of security, usually
716implemented at the filesystem level. Some, however, do
a1667ba3 717not-- unfortunately. Thus the notion of user id, or "home" directory,
b7df3edc
GS
718or even the state of being logged-in, may be unrecognizable on many
719platforms. If you write programs that are security-conscious, it
720is usually best to know what type of system you will be running
721under so that you can write code explicitly for that platform (or
722class of platforms).
0a47030a 723
a1667ba3
JH
724Don't assume the UNIX filesystem access semantics: the operating
725system or the filesystem may be using some ACL systems, which are
726richer languages than the usual rwx. Even if the rwx exist,
727their semantics might be different.
728
729(From security viewpoint testing for permissions before attempting to
730do something is silly anyway: if one tries this, there is potential
731for race conditions-- someone or something might change the
732permissions between the permissions check and the actual operation.
733Just try the operation.)
734
735Don't assume the UNIX user and group semantics: especially, don't
2edcc0d9 736expect the C<< $< >> and C<< $> >> (or the C<$(> and C<$)>) to work
a1667ba3
JH
737for switching identities (or memberships).
738
739Don't assume set-uid and set-gid semantics. (And even if you do,
740think twice: set-uid and set-gid are a known can of security worms.)
741
e41182b5
GS
742=head2 Style
743
744For those times when it is necessary to have platform-specific code,
745consider keeping the platform-specific code in one place, making porting
6ab3f9cb 746to other platforms easier. Use the Config module and the special
0a47030a
GS
747variable C<$^O> to differentiate platforms, as described in
748L<"PLATFORMS">.
e41182b5 749
b7df3edc
GS
750Be careful in the tests you supply with your module or programs.
751Module code may be fully portable, but its tests might not be. This
752often happens when tests spawn off other processes or call external
753programs to aid in the testing, or when (as noted above) the tests
c87488a3
HS
754assume certain things about the filesystem and paths. Be careful not
755to depend on a specific output style for errors, such as when checking
756C<$!> after a failed system call. Using C<$!> for anything else than
757displaying it as output is doubtful (though see the Errno module for
758testing reasonably portably for error value). Some platforms expect
759a certain output format, and Perl on those platforms may have been
760adjusted accordingly. Most specifically, don't anchor a regex when
761testing an error value.
e41182b5 762
0a47030a 763=head1 CPAN Testers
e41182b5 764
0a47030a
GS
765Modules uploaded to CPAN are tested by a variety of volunteers on
766different platforms. These CPAN testers are notified by mail of each
e41182b5 767new upload, and reply to the list with PASS, FAIL, NA (not applicable to
0a47030a 768this platform), or UNKNOWN (unknown), along with any relevant notations.
e41182b5
GS
769
770The purpose of the testing is twofold: one, to help developers fix any
0a47030a 771problems in their code that crop up because of lack of testing on other
b7df3edc 772platforms; two, to provide users with information about whether
0a47030a 773a given module works on a given platform.
e41182b5 774
7ee27b7c
AT
775Also see:
776
e41182b5
GS
777=over 4
778
7ee27b7c
AT
779=item *
780
781Mailing list: cpan-testers@perl.org
782
783=item *
e41182b5 784
7ee27b7c 785Testing results: http://testers.cpan.org/
e41182b5
GS
786
787=back
788
e41182b5
GS
789=head1 PLATFORMS
790
791As of version 5.002, Perl is built with a C<$^O> variable that
792indicates the operating system it was built on. This was implemented
b7df3edc
GS
793to help speed up code that would otherwise have to C<use Config>
794and use the value of C<$Config{osname}>. Of course, to get more
e41182b5
GS
795detailed information about the system, looking into C<%Config> is
796certainly recommended.
797
b7df3edc
GS
798C<%Config> cannot always be trusted, however, because it was built
799at compile time. If perl was built in one place, then transferred
800elsewhere, some values may be wrong. The values may even have been
801edited after the fact.
6ab3f9cb 802
e41182b5
GS
803=head2 Unix
804
805Perl works on a bewildering variety of Unix and Unix-like platforms (see
806e.g. most of the files in the F<hints/> directory in the source code kit).
807On most of these systems, the value of C<$^O> (hence C<$Config{'osname'}>,
d1e3b762
GS
808too) is determined either by lowercasing and stripping punctuation from the
809first field of the string returned by typing C<uname -a> (or a similar command)
810at the shell prompt or by testing the file system for the presence of
811uniquely named files such as a kernel or header file. Here, for example,
812are a few of the more popular Unix flavors:
e41182b5 813
b7df3edc 814 uname $^O $Config{'archname'}
6ab3f9cb 815 --------------------------------------------
b7df3edc 816 AIX aix aix
6ab3f9cb 817 BSD/OS bsdos i386-bsdos
e1516da7 818 Darwin darwin darwin
6ab3f9cb
GS
819 dgux dgux AViiON-dgux
820 DYNIX/ptx dynixptx i386-dynixptx
b7df3edc 821 FreeBSD freebsd freebsd-i386
d1e3b762 822 Linux linux arm-linux
b7df3edc 823 Linux linux i386-linux
6ab3f9cb
GS
824 Linux linux i586-linux
825 Linux linux ppc-linux
b7df3edc
GS
826 HP-UX hpux PA-RISC1.1
827 IRIX irix irix
b787fad4 828 Mac OS X darwin darwin
d1e3b762
GS
829 MachTen PPC machten powerpc-machten
830 NeXT 3 next next-fat
831 NeXT 4 next OPENSTEP-Mach
6ab3f9cb 832 openbsd openbsd i386-openbsd
b7df3edc 833 OSF1 dec_osf alpha-dec_osf
6ab3f9cb
GS
834 reliantunix-n svr4 RM400-svr4
835 SCO_SV sco_sv i386-sco_sv
836 SINIX-N svr4 RM400-svr4
837 sn4609 unicos CRAY_C90-unicos
838 sn6521 unicosmk t3e-unicosmk
839 sn9617 unicos CRAY_J90-unicos
b7df3edc
GS
840 SunOS solaris sun4-solaris
841 SunOS solaris i86pc-solaris
842 SunOS4 sunos sun4-sunos
e41182b5 843
b7df3edc
GS
844Because the value of C<$Config{archname}> may depend on the
845hardware architecture, it can vary more than the value of C<$^O>.
6ab3f9cb 846
e41182b5
GS
847=head2 DOS and Derivatives
848
b7df3edc 849Perl has long been ported to Intel-style microcomputers running under
e41182b5
GS
850systems like PC-DOS, MS-DOS, OS/2, and most Windows platforms you can
851bring yourself to mention (except for Windows CE, if you count that).
b7df3edc 852Users familiar with I<COMMAND.COM> or I<CMD.EXE> style shells should
e41182b5
GS
853be aware that each of these file specifications may have subtle
854differences:
855
856 $filespec0 = "c:/foo/bar/file.txt";
857 $filespec1 = "c:\\foo\\bar\\file.txt";
858 $filespec2 = 'c:\foo\bar\file.txt';
859 $filespec3 = 'c:\\foo\\bar\\file.txt';
860
b7df3edc
GS
861System calls accept either C</> or C<\> as the path separator.
862However, many command-line utilities of DOS vintage treat C</> as
863the option prefix, so may get confused by filenames containing C</>.
864Aside from calling any external programs, C</> will work just fine,
865and probably better, as it is more consistent with popular usage,
866and avoids the problem of remembering what to backwhack and what
867not to.
e41182b5 868
b7df3edc
GS
869The DOS FAT filesystem can accommodate only "8.3" style filenames. Under
870the "case-insensitive, but case-preserving" HPFS (OS/2) and NTFS (NT)
0a47030a 871filesystems you may have to be careful about case returned with functions
e41182b5
GS
872like C<readdir> or used with functions like C<open> or C<opendir>.
873
b7df3edc
GS
874DOS also treats several filenames as special, such as AUX, PRN,
875NUL, CON, COM1, LPT1, LPT2, etc. Unfortunately, sometimes these
876filenames won't even work if you include an explicit directory
877prefix. It is best to avoid such filenames, if you want your code
878to be portable to DOS and its derivatives. It's hard to know what
879these all are, unfortunately.
e41182b5
GS
880
881Users of these operating systems may also wish to make use of
b7df3edc 882scripts such as I<pl2bat.bat> or I<pl2cmd> to
e41182b5
GS
883put wrappers around your scripts.
884
885Newline (C<\n>) is translated as C<\015\012> by STDIO when reading from
6ab3f9cb
GS
886and writing to files (see L<"Newlines">). C<binmode(FILEHANDLE)>
887will keep C<\n> translated as C<\012> for that filehandle. Since it is a
888no-op on other systems, C<binmode> should be used for cross-platform code
b7df3edc
GS
889that deals with binary data. That's assuming you realize in advance
890that your data is in binary. General-purpose programs should
891often assume nothing about their data.
e41182b5 892
b7df3edc 893The C<$^O> variable and the C<$Config{archname}> values for various
e41182b5
GS
894DOSish perls are as follows:
895
67ac489e
MS
896 OS $^O $Config{archname} ID Version
897 --------------------------------------------------------
898 MS-DOS dos ?
899 PC-DOS dos ?
900 OS/2 os2 ?
901 Windows 3.1 ? ? 0 3 01
902 Windows 95 MSWin32 MSWin32-x86 1 4 00
903 Windows 98 MSWin32 MSWin32-x86 1 4 10
904 Windows ME MSWin32 MSWin32-x86 1 ?
905 Windows NT MSWin32 MSWin32-x86 2 4 xx
906 Windows NT MSWin32 MSWin32-ALPHA 2 4 xx
907 Windows NT MSWin32 MSWin32-ppc 2 4 xx
7ee27b7c
AT
908 Windows 2000 MSWin32 MSWin32-x86 2 5 00
909 Windows XP MSWin32 MSWin32-x86 2 5 01
910 Windows 2003 MSWin32 MSWin32-x86 2 5 02
67ac489e 911 Windows CE MSWin32 ? 3
7ee27b7c 912 Cygwin cygwin cygwin
e41182b5 913
34aaaa84
PP
914The various MSWin32 Perl's can distinguish the OS they are running on
915via the value of the fifth element of the list returned from
916Win32::GetOSVersion(). For example:
917
918 if ($^O eq 'MSWin32') {
919 my @os_version_info = Win32::GetOSVersion();
920 print +('3.1','95','NT')[$os_version_info[4]],"\n";
921 }
922
7939d86b
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923There are also Win32::IsWinNT() and Win32::IsWin95(), try C<perldoc Win32>,
924and as of libwin32 0.19 (not part of the core Perl distribution)
925Win32::GetOSName(). The very portable POSIX::uname() will work too:
1d65be3a
JH
926
927 c:\> perl -MPOSIX -we "print join '|', uname"
928 Windows NT|moonru|5.0|Build 2195 (Service Pack 2)|x86
d99f392e 929
e41182b5
GS
930Also see:
931
932=over 4
933
c997b287 934=item *
e41182b5 935
c997b287
GS
936The djgpp environment for DOS, http://www.delorie.com/djgpp/
937and L<perldos>.
e41182b5 938
c997b287 939=item *
e41182b5 940
c997b287
GS
941The EMX environment for DOS, OS/2, etc. emx@iaehv.nl,
942http://www.leo.org/pub/comp/os/os2/leo/gnu/emx+gcc/index.html or
f224927c 943ftp://hobbes.nmsu.edu/pub/os2/dev/emx/ Also L<perlos2>.
e41182b5 944
c997b287 945=item *
d1e3b762 946
c997b287
GS
947Build instructions for Win32 in L<perlwin32>, or under the Cygnus environment
948in L<perlcygwin>.
949
950=item *
951
952The C<Win32::*> modules in L<Win32>.
953
954=item *
955
956The ActiveState Pages, http://www.activestate.com/
957
958=item *
959
960The Cygwin environment for Win32; F<README.cygwin> (installed
47dafe4d 961as L<perlcygwin>), http://www.cygwin.com/
c997b287
GS
962
963=item *
964
965The U/WIN environment for Win32,
cea6626f 966http://www.research.att.com/sw/tools/uwin/
c997b287 967
cea6626f 968=item *
d1e3b762 969
cea6626f 970Build instructions for OS/2, L<perlos2>
d1e3b762 971
e41182b5
GS
972=back
973
dd9f0070 974=head2 S<Mac OS>
e41182b5
GS
975
976Any module requiring XS compilation is right out for most people, because
977MacPerl is built using non-free (and non-cheap!) compilers. Some XS
978modules that can work with MacPerl are built and distributed in binary
6ab3f9cb 979form on CPAN.
e41182b5
GS
980
981Directories are specified as:
982
983 volume:folder:file for absolute pathnames
984 volume:folder: for absolute pathnames
985 :folder:file for relative pathnames
986 :folder: for relative pathnames
987 :file for relative pathnames
988 file for relative pathnames
989
b7df3edc 990Files are stored in the directory in alphabetical order. Filenames are
6ab3f9cb 991limited to 31 characters, and may include any character except for
b7df3edc 992null and C<:>, which is reserved as the path separator.
e41182b5 993
0a47030a 994Instead of C<flock>, see C<FSpSetFLock> and C<FSpRstFLock> in the
6ab3f9cb 995Mac::Files module, or C<chmod(0444, ...)> and C<chmod(0666, ...)>.
e41182b5
GS
996
997In the MacPerl application, you can't run a program from the command line;
998programs that expect C<@ARGV> to be populated can be edited with something
999like the following, which brings up a dialog box asking for the command
1000line arguments.
1001
1002 if (!@ARGV) {
1003 @ARGV = split /\s+/, MacPerl::Ask('Arguments?');
1004 }
1005
b7df3edc 1006A MacPerl script saved as a "droplet" will populate C<@ARGV> with the full
e41182b5
GS
1007pathnames of the files dropped onto the script.
1008
b7df3edc
GS
1009Mac users can run programs under a type of command line interface
1010under MPW (Macintosh Programmer's Workshop, a free development
1011environment from Apple). MacPerl was first introduced as an MPW
1012tool, and MPW can be used like a shell:
e41182b5
GS
1013
1014 perl myscript.plx some arguments
1015
1016ToolServer is another app from Apple that provides access to MPW tools
0a47030a 1017from MPW and the MacPerl app, which allows MacPerl programs to use
e41182b5
GS
1018C<system>, backticks, and piped C<open>.
1019
1020"S<Mac OS>" is the proper name for the operating system, but the value
1021in C<$^O> is "MacOS". To determine architecture, version, or whether
1022the application or MPW tool version is running, check:
1023
1024 $is_app = $MacPerl::Version =~ /App/;
1025 $is_tool = $MacPerl::Version =~ /MPW/;
1026 ($version) = $MacPerl::Version =~ /^(\S+)/;
1027 $is_ppc = $MacPerl::Architecture eq 'MacPPC';
1028 $is_68k = $MacPerl::Architecture eq 'Mac68K';
1029
b787fad4
JH
1030S<Mac OS X>, based on NeXT's OpenStep OS, runs MacPerl natively, under the
1031"Classic" environment. There is no "Carbon" version of MacPerl to run
1032under the primary Mac OS X environment. S<Mac OS X> and its Open Source
1033version, Darwin, both run Unix perl natively.
6ab3f9cb 1034
e41182b5
GS
1035Also see:
1036
1037=over 4
1038
c997b287
GS
1039=item *
1040
862b5365 1041MacPerl Development, http://dev.macperl.org/ .
c997b287
GS
1042
1043=item *
1044
862b5365 1045The MacPerl Pages, http://www.macperl.com/ .
e41182b5 1046
c997b287 1047=item *
6ab3f9cb 1048
862b5365 1049The MacPerl mailing lists, http://lists.perl.org/ .
e41182b5 1050
7ee27b7c
AT
1051=item *
1052
1053MPW, ftp://ftp.apple.com/developer/Tool_Chest/Core_Mac_OS_Tools/
1054
e41182b5
GS
1055=back
1056
e41182b5
GS
1057=head2 VMS
1058
c997b287 1059Perl on VMS is discussed in L<perlvms> in the perl distribution.
b7df3edc 1060Perl on VMS can accept either VMS- or Unix-style file
e41182b5
GS
1061specifications as in either of the following:
1062
1063 $ perl -ne "print if /perl_setup/i" SYS$LOGIN:LOGIN.COM
1064 $ perl -ne "print if /perl_setup/i" /sys$login/login.com
1065
1066but not a mixture of both as in:
1067
1068 $ perl -ne "print if /perl_setup/i" sys$login:/login.com
1069 Can't open sys$login:/login.com: file specification syntax error
1070
1071Interacting with Perl from the Digital Command Language (DCL) shell
1072often requires a different set of quotation marks than Unix shells do.
1073For example:
1074
1075 $ perl -e "print ""Hello, world.\n"""
1076 Hello, world.
1077
b7df3edc 1078There are several ways to wrap your perl scripts in DCL F<.COM> files, if
e41182b5
GS
1079you are so inclined. For example:
1080
1081 $ write sys$output "Hello from DCL!"
1082 $ if p1 .eqs. ""
1083 $ then perl -x 'f$environment("PROCEDURE")
1084 $ else perl -x - 'p1 'p2 'p3 'p4 'p5 'p6 'p7 'p8
1085 $ deck/dollars="__END__"
1086 #!/usr/bin/perl
1087
1088 print "Hello from Perl!\n";
1089
1090 __END__
1091 $ endif
1092
1093Do take care with C<$ ASSIGN/nolog/user SYS$COMMAND: SYS$INPUT> if your
c47ff5f1 1094perl-in-DCL script expects to do things like C<< $read = <STDIN>; >>.
e41182b5
GS
1095
1096Filenames are in the format "name.extension;version". The maximum
1097length for filenames is 39 characters, and the maximum length for
1098extensions is also 39 characters. Version is a number from 1 to
109932767. Valid characters are C</[A-Z0-9$_-]/>.
1100
b7df3edc 1101VMS's RMS filesystem is case-insensitive and does not preserve case.
e41182b5 1102C<readdir> returns lowercased filenames, but specifying a file for
b7df3edc 1103opening remains case-insensitive. Files without extensions have a
e41182b5 1104trailing period on them, so doing a C<readdir> with a file named F<A.;5>
0a47030a
GS
1105will return F<a.> (though that file could be opened with
1106C<open(FH, 'A')>).
e41182b5 1107
f34d0673 1108RMS had an eight level limit on directory depths from any rooted logical
dd9f0070
CN
1109(allowing 16 levels overall) prior to VMS 7.2. Hence
1110C<PERL_ROOT:[LIB.2.3.4.5.6.7.8]> is a valid directory specification but
1111C<PERL_ROOT:[LIB.2.3.4.5.6.7.8.9]> is not. F<Makefile.PL> authors might
1112have to take this into account, but at least they can refer to the former
f34d0673 1113as C</PERL_ROOT/lib/2/3/4/5/6/7/8/>.
e41182b5 1114
6ab3f9cb 1115The VMS::Filespec module, which gets installed as part of the build
0a47030a
GS
1116process on VMS, is a pure Perl module that can easily be installed on
1117non-VMS platforms and can be helpful for conversions to and from RMS
1118native formats.
e41182b5 1119
5e12dbfa
PP
1120What C<\n> represents depends on the type of file opened. It usually
1121represents C<\012> but it could also be C<\015>, C<\012>, C<\015\012>,
fa11829f 1122C<\000>, C<\040>, or nothing depending on the file organization and
5e12dbfa
PP
1123record format. The VMS::Stdio module provides access to the
1124special fopen() requirements of files with unusual attributes on VMS.
e41182b5
GS
1125
1126TCP/IP stacks are optional on VMS, so socket routines might not be
1127implemented. UDP sockets may not be supported.
1128
1129The value of C<$^O> on OpenVMS is "VMS". To determine the architecture
1130that you are running on without resorting to loading all of C<%Config>
1131you can examine the content of the C<@INC> array like so:
1132
1133 if (grep(/VMS_AXP/, @INC)) {
1134 print "I'm on Alpha!\n";
6ab3f9cb 1135
e41182b5
GS
1136 } elsif (grep(/VMS_VAX/, @INC)) {
1137 print "I'm on VAX!\n";
6ab3f9cb 1138
e41182b5
GS
1139 } else {
1140 print "I'm not so sure about where $^O is...\n";
1141 }
1142
b7df3edc
GS
1143On VMS, perl determines the UTC offset from the C<SYS$TIMEZONE_DIFFERENTIAL>
1144logical name. Although the VMS epoch began at 17-NOV-1858 00:00:00.00,
6ab3f9cb 1145calls to C<localtime> are adjusted to count offsets from
b7df3edc 114601-JAN-1970 00:00:00.00, just like Unix.
6ab3f9cb 1147
e41182b5
GS
1148Also see:
1149
1150=over 4
1151
c997b287
GS
1152=item *
1153
1154F<README.vms> (installed as L<README_vms>), L<perlvms>
1155
1156=item *
1157
1158vmsperl list, majordomo@perl.org
e41182b5 1159
c997b287 1160(Put the words C<subscribe vmsperl> in message body.)
e41182b5 1161
c997b287 1162=item *
e41182b5 1163
c997b287 1164vmsperl on the web, http://www.sidhe.org/vmsperl/index.html
e41182b5
GS
1165
1166=back
1167
495c5fdc
GP
1168=head2 VOS
1169
9a997319
JH
1170Perl on VOS is discussed in F<README.vos> in the perl distribution
1171(installed as L<perlvos>). Perl on VOS can accept either VOS- or
1172Unix-style file specifications as in either of the following:
495c5fdc 1173
cc07ed0b
PG
1174 C<< $ perl -ne "print if /perl_setup/i" >system>notices >>
1175 C<< $ perl -ne "print if /perl_setup/i" /system/notices >>
495c5fdc
GP
1176
1177or even a mixture of both as in:
1178
cc07ed0b 1179 C<< $ perl -ne "print if /perl_setup/i" >system/notices >>
495c5fdc 1180
b7df3edc 1181Even though VOS allows the slash character to appear in object
495c5fdc
GP
1182names, because the VOS port of Perl interprets it as a pathname
1183delimiting character, VOS files, directories, or links whose names
1184contain a slash character cannot be processed. Such files must be
a3dfe201
GS
1185renamed before they can be processed by Perl. Note that VOS limits
1186file names to 32 or fewer characters.
495c5fdc 1187
495c5fdc
GP
1188The value of C<$^O> on VOS is "VOS". To determine the architecture that
1189you are running on without resorting to loading all of C<%Config> you
c997b287 1190can examine the content of the @INC array like so:
495c5fdc 1191
24e8e380 1192 if ($^O =~ /VOS/) {
495c5fdc
GP
1193 print "I'm on a Stratus box!\n";
1194 } else {
1195 print "I'm not on a Stratus box!\n";
1196 die;
1197 }
1198
495c5fdc
GP
1199Also see:
1200
1201=over 4
1202
c997b287 1203=item *
495c5fdc 1204
cc07ed0b 1205F<README.vos> (installed as L<perlvos>)
c997b287
GS
1206
1207=item *
1208
1209The VOS mailing list.
495c5fdc
GP
1210
1211There is no specific mailing list for Perl on VOS. You can post
1212comments to the comp.sys.stratus newsgroup, or subscribe to the general
cc07ed0b 1213Stratus mailing list. Send a letter with "subscribe Info-Stratus" in
495c5fdc
GP
1214the message body to majordomo@list.stratagy.com.
1215
c997b287
GS
1216=item *
1217
cc07ed0b 1218VOS Perl on the web at http://ftp.stratus.com/pub/vos/posix/posix.html
495c5fdc
GP
1219
1220=back
1221
e41182b5
GS
1222=head2 EBCDIC Platforms
1223
1224Recent versions of Perl have been ported to platforms such as OS/400 on
d1e3b762
GS
1225AS/400 minicomputers as well as OS/390, VM/ESA, and BS2000 for S/390
1226Mainframes. Such computers use EBCDIC character sets internally (usually
0cc436d0
GS
1227Character Code Set ID 0037 for OS/400 and either 1047 or POSIX-BC for S/390
1228systems). On the mainframe perl currently works under the "Unix system
1229services for OS/390" (formerly known as OpenEdition), VM/ESA OpenEdition, or
1230the BS200 POSIX-BC system (BS2000 is supported in perl 5.6 and greater).
522b859a
JH
1231See L<perlos390> for details. Note that for OS/400 there is also a port of
1232Perl 5.8.1/5.9.0 or later to the PASE which is ASCII-based (as opposed to
1233ILE which is EBCDIC-based), see L<perlos400>.
e41182b5 1234
7c5ffed3
JH
1235As of R2.5 of USS for OS/390 and Version 2.3 of VM/ESA these Unix
1236sub-systems do not support the C<#!> shebang trick for script invocation.
1237Hence, on OS/390 and VM/ESA perl scripts can be executed with a header
1238similar to the following simple script:
e41182b5
GS
1239
1240 : # use perl
1241 eval 'exec /usr/local/bin/perl -S $0 ${1+"$@"}'
1242 if 0;
1243 #!/usr/local/bin/perl # just a comment really
1244
1245 print "Hello from perl!\n";
1246
d1e3b762
GS
1247OS/390 will support the C<#!> shebang trick in release 2.8 and beyond.
1248Calls to C<system> and backticks can use POSIX shell syntax on all
1249S/390 systems.
1250
b7df3edc 1251On the AS/400, if PERL5 is in your library list, you may need
6ab3f9cb
GS
1252to wrap your perl scripts in a CL procedure to invoke them like so:
1253
1254 BEGIN
1255 CALL PGM(PERL5/PERL) PARM('/QOpenSys/hello.pl')
1256 ENDPGM
1257
1258This will invoke the perl script F<hello.pl> in the root of the
1259QOpenSys file system. On the AS/400 calls to C<system> or backticks
1260must use CL syntax.
1261
e41182b5 1262On these platforms, bear in mind that the EBCDIC character set may have
0a47030a
GS
1263an effect on what happens with some perl functions (such as C<chr>,
1264C<pack>, C<print>, C<printf>, C<ord>, C<sort>, C<sprintf>, C<unpack>), as
1265well as bit-fiddling with ASCII constants using operators like C<^>, C<&>
1266and C<|>, not to mention dealing with socket interfaces to ASCII computers
6ab3f9cb 1267(see L<"Newlines">).
e41182b5 1268
b7df3edc
GS
1269Fortunately, most web servers for the mainframe will correctly
1270translate the C<\n> in the following statement to its ASCII equivalent
1271(C<\r> is the same under both Unix and OS/390 & VM/ESA):
e41182b5
GS
1272
1273 print "Content-type: text/html\r\n\r\n";
1274
d1e3b762 1275The values of C<$^O> on some of these platforms includes:
e41182b5 1276
d1e3b762
GS
1277 uname $^O $Config{'archname'}
1278 --------------------------------------------
1279 OS/390 os390 os390
1280 OS400 os400 os400
1281 POSIX-BC posix-bc BS2000-posix-bc
1282 VM/ESA vmesa vmesa
3c075c7d 1283
e41182b5
GS
1284Some simple tricks for determining if you are running on an EBCDIC
1285platform could include any of the following (perhaps all):
1286
1287 if ("\t" eq "\05") { print "EBCDIC may be spoken here!\n"; }
1288
1289 if (ord('A') == 193) { print "EBCDIC may be spoken here!\n"; }
1290
1291 if (chr(169) eq 'z') { print "EBCDIC may be spoken here!\n"; }
1292
b7df3edc 1293One thing you may not want to rely on is the EBCDIC encoding
0a47030a
GS
1294of punctuation characters since these may differ from code page to code
1295page (and once your module or script is rumoured to work with EBCDIC,
1296folks will want it to work with all EBCDIC character sets).
e41182b5
GS
1297
1298Also see:
1299
1300=over 4
1301
c997b287
GS
1302=item *
1303
dc5c060f 1304L<perlos390>, F<README.os390>, F<perlbs2000>, F<README.vmesa>,
bb462878 1305L<perlebcdic>.
c997b287
GS
1306
1307=item *
e41182b5
GS
1308
1309The perl-mvs@perl.org list is for discussion of porting issues as well as
1310general usage issues for all EBCDIC Perls. Send a message body of
1311"subscribe perl-mvs" to majordomo@perl.org.
1312
7ee27b7c 1313=item *
c997b287
GS
1314
1315AS/400 Perl information at
b1866b2d 1316http://as400.rochester.ibm.com/
d1e3b762 1317as well as on CPAN in the F<ports/> directory.
e41182b5
GS
1318
1319=back
1320
b8099c3d
CN
1321=head2 Acorn RISC OS
1322
b7df3edc
GS
1323Because Acorns use ASCII with newlines (C<\n>) in text files as C<\012> like
1324Unix, and because Unix filename emulation is turned on by default,
1325most simple scripts will probably work "out of the box". The native
6ab3f9cb 1326filesystem is modular, and individual filesystems are free to be
0a47030a 1327case-sensitive or insensitive, and are usually case-preserving. Some
b7df3edc 1328native filesystems have name length limits, which file and directory
6ab3f9cb
GS
1329names are silently truncated to fit. Scripts should be aware that the
1330standard filesystem currently has a name length limit of B<10>
1331characters, with up to 77 items in a directory, but other filesystems
0a47030a 1332may not impose such limitations.
b8099c3d
CN
1333
1334Native filenames are of the form
1335
6ab3f9cb 1336 Filesystem#Special_Field::DiskName.$.Directory.Directory.File
dd9f0070 1337
b8099c3d
CN
1338where
1339
1340 Special_Field is not usually present, but may contain . and $ .
1341 Filesystem =~ m|[A-Za-z0-9_]|
1342 DsicName =~ m|[A-Za-z0-9_/]|
1343 $ represents the root directory
1344 . is the path separator
1345 @ is the current directory (per filesystem but machine global)
1346 ^ is the parent directory
1347 Directory and File =~ m|[^\0- "\.\$\%\&:\@\\^\|\177]+|
1348
1349The default filename translation is roughly C<tr|/.|./|;>
1350
6ab3f9cb 1351Note that C<"ADFS::HardDisk.$.File" ne 'ADFS::HardDisk.$.File'> and that
0a47030a
GS
1352the second stage of C<$> interpolation in regular expressions will fall
1353foul of the C<$.> if scripts are not careful.
1354
1355Logical paths specified by system variables containing comma-separated
b7df3edc 1356search lists are also allowed; hence C<System:Modules> is a valid
0a47030a 1357filename, and the filesystem will prefix C<Modules> with each section of
6ab3f9cb 1358C<System$Path> until a name is made that points to an object on disk.
b7df3edc 1359Writing to a new file C<System:Modules> would be allowed only if
0a47030a
GS
1360C<System$Path> contains a single item list. The filesystem will also
1361expand system variables in filenames if enclosed in angle brackets, so
c47ff5f1 1362C<< <System$Dir>.Modules >> would look for the file
0a47030a 1363S<C<$ENV{'System$Dir'} . 'Modules'>>. The obvious implication of this is
c47ff5f1 1364that B<fully qualified filenames can start with C<< <> >>> and should
0a47030a 1365be protected when C<open> is used for input.
b8099c3d
CN
1366
1367Because C<.> was in use as a directory separator and filenames could not
1368be assumed to be unique after 10 characters, Acorn implemented the C
1369compiler to strip the trailing C<.c> C<.h> C<.s> and C<.o> suffix from
1370filenames specified in source code and store the respective files in
b7df3edc 1371subdirectories named after the suffix. Hence files are translated:
b8099c3d
CN
1372
1373 foo.h h.foo
1374 C:foo.h C:h.foo (logical path variable)
1375 sys/os.h sys.h.os (C compiler groks Unix-speak)
1376 10charname.c c.10charname
1377 10charname.o o.10charname
1378 11charname_.c c.11charname (assuming filesystem truncates at 10)
1379
1380The Unix emulation library's translation of filenames to native assumes
b7df3edc
GS
1381that this sort of translation is required, and it allows a user-defined list
1382of known suffixes that it will transpose in this fashion. This may
1383seem transparent, but consider that with these rules C<foo/bar/baz.h>
0a47030a
GS
1384and C<foo/bar/h/baz> both map to C<foo.bar.h.baz>, and that C<readdir> and
1385C<glob> cannot and do not attempt to emulate the reverse mapping. Other
6ab3f9cb 1386C<.>'s in filenames are translated to C</>.
0a47030a 1387
b7df3edc 1388As implied above, the environment accessed through C<%ENV> is global, and
0a47030a 1389the convention is that program specific environment variables are of the
6ab3f9cb
GS
1390form C<Program$Name>. Each filesystem maintains a current directory,
1391and the current filesystem's current directory is the B<global> current
b7df3edc
GS
1392directory. Consequently, sociable programs don't change the current
1393directory but rely on full pathnames, and programs (and Makefiles) cannot
0a47030a
GS
1394assume that they can spawn a child process which can change the current
1395directory without affecting its parent (and everyone else for that
1396matter).
1397
b7df3edc
GS
1398Because native operating system filehandles are global and are currently
1399allocated down from 255, with 0 being a reserved value, the Unix emulation
0a47030a
GS
1400library emulates Unix filehandles. Consequently, you can't rely on
1401passing C<STDIN>, C<STDOUT>, or C<STDERR> to your children.
1402
1403The desire of users to express filenames of the form
c47ff5f1 1404C<< <Foo$Dir>.Bar >> on the command line unquoted causes problems,
0a47030a 1405too: C<``> command output capture has to perform a guessing game. It
c47ff5f1 1406assumes that a string C<< <[^<>]+\$[^<>]> >> is a
0a47030a 1407reference to an environment variable, whereas anything else involving
c47ff5f1 1408C<< < >> or C<< > >> is redirection, and generally manages to be 99%
0a47030a
GS
1409right. Of course, the problem remains that scripts cannot rely on any
1410Unix tools being available, or that any tools found have Unix-like command
1411line arguments.
1412
b7df3edc
GS
1413Extensions and XS are, in theory, buildable by anyone using free
1414tools. In practice, many don't, as users of the Acorn platform are
1415used to binary distributions. MakeMaker does run, but no available
1416make currently copes with MakeMaker's makefiles; even if and when
1417this should be fixed, the lack of a Unix-like shell will cause
1418problems with makefile rules, especially lines of the form C<cd
1419sdbm && make all>, and anything using quoting.
b8099c3d
CN
1420
1421"S<RISC OS>" is the proper name for the operating system, but the value
1422in C<$^O> is "riscos" (because we don't like shouting).
1423
e41182b5
GS
1424=head2 Other perls
1425
b7df3edc
GS
1426Perl has been ported to many platforms that do not fit into any of
1427the categories listed above. Some, such as AmigaOS, Atari MiNT,
1428BeOS, HP MPE/iX, QNX, Plan 9, and VOS, have been well-integrated
1429into the standard Perl source code kit. You may need to see the
1430F<ports/> directory on CPAN for information, and possibly binaries,
1431for the likes of: aos, Atari ST, lynxos, riscos, Novell Netware,
1432Tandem Guardian, I<etc.> (Yes, we know that some of these OSes may
1433fall under the Unix category, but we are not a standards body.)
e41182b5 1434
d1e3b762
GS
1435Some approximate operating system names and their C<$^O> values
1436in the "OTHER" category include:
1437
1438 OS $^O $Config{'archname'}
1439 ------------------------------------------
1440 Amiga DOS amigaos m68k-amigos
cec2c193 1441 BeOS beos
d1e3b762
GS
1442 MPE/iX mpeix PA-RISC1.1
1443
e41182b5
GS
1444See also:
1445
1446=over 4
1447
c997b287
GS
1448=item *
1449
1450Amiga, F<README.amiga> (installed as L<perlamiga>).
1451
1452=item *
d1e3b762 1453
c997b287
GS
1454Atari, F<README.mint> and Guido Flohr's web page
1455http://stud.uni-sb.de/~gufl0000/
e41182b5 1456
c997b287 1457=item *
d1e3b762 1458
c997b287 1459Be OS, F<README.beos>
e41182b5 1460
c997b287
GS
1461=item *
1462
1463HP 300 MPE/iX, F<README.mpeix> and Mark Bixby's web page
34aaaa84 1464http://www.bixby.org/mark/perlix.html
c997b287
GS
1465
1466=item *
e41182b5 1467
6ab3f9cb 1468A free perl5-based PERL.NLM for Novell Netware is available in
c997b287 1469precompiled binary and source code form from http://www.novell.com/
6ab3f9cb 1470as well as from CPAN.
e41182b5 1471
13a2d996 1472=item *
c997b287 1473
e6f03d26 1474S<Plan 9>, F<README.plan9>
d1e3b762 1475
e41182b5
GS
1476=back
1477
e41182b5
GS
1478=head1 FUNCTION IMPLEMENTATIONS
1479
b7df3edc
GS
1480Listed below are functions that are either completely unimplemented
1481or else have been implemented differently on various platforms.
1482Following each description will be, in parentheses, a list of
1483platforms that the description applies to.
e41182b5 1484
b7df3edc
GS
1485The list may well be incomplete, or even wrong in some places. When
1486in doubt, consult the platform-specific README files in the Perl
1487source distribution, and any other documentation resources accompanying
1488a given port.
e41182b5 1489
0a47030a 1490Be aware, moreover, that even among Unix-ish systems there are variations.
e41182b5 1491
b7df3edc
GS
1492For many functions, you can also query C<%Config>, exported by
1493default from the Config module. For example, to check whether the
1494platform has the C<lstat> call, check C<$Config{d_lstat}>. See
1495L<Config> for a full description of available variables.
e41182b5
GS
1496
1497=head2 Alphabetical Listing of Perl Functions
1498
1499=over 8
1500
1501=item -X FILEHANDLE
1502
1503=item -X EXPR
1504
1505=item -X
1506
b7df3edc 1507C<-r>, C<-w>, and C<-x> have a limited meaning only; directories
e41182b5 1508and applications are executable, and there are no uid/gid
b7df3edc 1509considerations. C<-o> is not supported. (S<Mac OS>)
e41182b5 1510
b7df3edc
GS
1511C<-r>, C<-w>, C<-x>, and C<-o> tell whether the file is accessible,
1512which may not reflect UIC-based file protections. (VMS)
e41182b5 1513
b8099c3d
CN
1514C<-s> returns the size of the data fork, not the total size of data fork
1515plus resource fork. (S<Mac OS>).
1516
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>,
b8099c3d 1522C<-x>, C<-o>. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1523
1524C<-b>, C<-c>, C<-k>, C<-g>, C<-p>, C<-u>, C<-A> are not implemented.
1525(S<Mac OS>)
1526
1527C<-g>, C<-k>, C<-l>, C<-p>, C<-u>, C<-A> are not particularly meaningful.
b8099c3d 1528(Win32, VMS, S<RISC OS>)
e41182b5
GS
1529
1530C<-d> is true if passed a device spec without an explicit directory.
1531(VMS)
1532
1533C<-T> and C<-B> are implemented, but might misclassify Mac text files
0a47030a 1534with foreign characters; this is the case will all platforms, but may
b7df3edc 1535affect S<Mac OS> often. (S<Mac OS>)
e41182b5
GS
1536
1537C<-x> (or C<-X>) determine if a file ends in one of the executable
b7df3edc 1538suffixes. C<-S> is meaningless. (Win32)
e41182b5 1539
b8099c3d
CN
1540C<-x> (or C<-X>) determine if a file has an executable file type.
1541(S<RISC OS>)
1542
519bc777
RGS
1543=item atan2 Y,X
1544
1545Due to issues with various CPUs, math libraries, compilers, and standards,
1546results for C<atan2()> may vary depending on any combination of the above.
1547Perl attempts to conform to the Open Group/IEEE standards for the results
1548returned from C<atan2()>, but cannot force the issue if the system Perl is
1549run on does not allow it. (Tru64, HP-UX 10.20)
1550
1551The current version of the standards for C<atan2()> is available at
1552L<http://www.opengroup.org/onlinepubs/009695399/functions/atan2.html>.
1553
e41182b5
GS
1554=item binmode FILEHANDLE
1555
b7df3edc 1556Meaningless. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1557
1558Reopens file and restores pointer; if function fails, underlying
1559filehandle may be closed, or pointer may be in a different position.
1560(VMS)
1561
1562The value returned by C<tell> may be affected after the call, and
1563the filehandle may be flushed. (Win32)
1564
1565=item chmod LIST
1566
b7df3edc 1567Only limited meaning. Disabling/enabling write permission is mapped to
e41182b5
GS
1568locking/unlocking the file. (S<Mac OS>)
1569
1570Only good for changing "owner" read-write access, "group", and "other"
1571bits are meaningless. (Win32)
1572
b8099c3d
CN
1573Only good for changing "owner" and "other" read-write access. (S<RISC OS>)
1574
495c5fdc
GP
1575Access permissions are mapped onto VOS access-control list changes. (VOS)
1576
4e51f8e4 1577The actual permissions set depend on the value of the C<CYGWIN>
789f0d36 1578in the SYSTEM environment settings. (Cygwin)
4e51f8e4 1579
e41182b5
GS
1580=item chown LIST
1581
3fd80bd6 1582Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1583
1584Does nothing, but won't fail. (Win32)
1585
3fd80bd6
PG
1586A little funky, because VOS's notion of ownership is a little funky (VOS).
1587
e41182b5
GS
1588=item chroot FILENAME
1589
1590=item chroot
1591
e6f03d26 1592Not implemented. (S<Mac OS>, Win32, VMS, S<Plan 9>, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1593
1594=item crypt PLAINTEXT,SALT
1595
1596May not be available if library or source was not provided when building
b8099c3d 1597perl. (Win32)
e41182b5
GS
1598
1599=item dbmclose HASH
1600
e6f03d26 1601Not implemented. (VMS, S<Plan 9>, VOS)
e41182b5
GS
1602
1603=item dbmopen HASH,DBNAME,MODE
1604
e6f03d26 1605Not implemented. (VMS, S<Plan 9>, VOS)
e41182b5
GS
1606
1607=item dump LABEL
1608
b8099c3d 1609Not useful. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1610
1611Not implemented. (Win32)
1612
b8099c3d 1613Invokes VMS debugger. (VMS)
e41182b5
GS
1614
1615=item exec LIST
1616
1617Not implemented. (S<Mac OS>)
1618
7c5ffed3 1619Implemented via Spawn. (VM/ESA)
3c075c7d 1620
0f897271
GS
1621Does not automatically flush output handles on some platforms.
1622(SunOS, Solaris, HP-UX)
1623
fe12c0e8
MS
1624=item exit EXPR
1625
1626=item exit
1627
1628Emulates UNIX exit() (which considers C<exit 1> to indicate an error) by
1629mapping the C<1> to SS$_ABORT (C<44>). This behavior may be overridden
1630with the pragma C<use vmsish 'exit'>. As with the CRTL's exit()
1631function, C<exit 0> is also mapped to an exit status of SS$_NORMAL
1632(C<1>); this mapping cannot be overridden. Any other argument to exit()
1633is used directly as Perl's exit status. (VMS)
1634
e41182b5
GS
1635=item fcntl FILEHANDLE,FUNCTION,SCALAR
1636
1637Not implemented. (Win32, VMS)
1638
1639=item flock FILEHANDLE,OPERATION
1640
495c5fdc 1641Not implemented (S<Mac OS>, VMS, S<RISC OS>, VOS).
e41182b5
GS
1642
1643Available only on Windows NT (not on Windows 95). (Win32)
1644
1645=item fork
1646
3fd80bd6 1647Not implemented. (S<Mac OS>, AmigaOS, S<RISC OS>, VM/ESA, VMS)
0f897271
GS
1648
1649Emulated using multiple interpreters. See L<perlfork>. (Win32)
1650
1651Does not automatically flush output handles on some platforms.
1652(SunOS, Solaris, HP-UX)
e41182b5
GS
1653
1654=item getlogin
1655
b8099c3d 1656Not implemented. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1657
1658=item getpgrp PID
1659
3fd80bd6 1660Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1661
1662=item getppid
1663
41cbbefa 1664Not implemented. (S<Mac OS>, Win32, S<RISC OS>)
e41182b5
GS
1665
1666=item getpriority WHICH,WHO
1667
7c5ffed3 1668Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1669
1670=item getpwnam NAME
1671
1672Not implemented. (S<Mac OS>, Win32)
1673
b8099c3d
CN
1674Not useful. (S<RISC OS>)
1675
e41182b5
GS
1676=item getgrnam NAME
1677
b8099c3d 1678Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1679
1680=item getnetbyname NAME
1681
e6f03d26 1682Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1683
1684=item getpwuid UID
1685
1686Not implemented. (S<Mac OS>, Win32)
1687
b8099c3d
CN
1688Not useful. (S<RISC OS>)
1689
e41182b5
GS
1690=item getgrgid GID
1691
b8099c3d 1692Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1693
1694=item getnetbyaddr ADDR,ADDRTYPE
1695
e6f03d26 1696Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1697
1698=item getprotobynumber NUMBER
1699
1700Not implemented. (S<Mac OS>)
1701
1702=item getservbyport PORT,PROTO
1703
1704Not implemented. (S<Mac OS>)
1705
1706=item getpwent
1707
7c5ffed3 1708Not implemented. (S<Mac OS>, Win32, VM/ESA)
e41182b5
GS
1709
1710=item getgrent
1711
7c5ffed3 1712Not implemented. (S<Mac OS>, Win32, VMS, VM/ESA)
e41182b5 1713
ef5a6dd7
JH
1714=item gethostbyname
1715
1716C<gethostbyname('localhost')> does not work everywhere: you may have
1717to use C<gethostbyname('127.0.0.1')>. (S<Mac OS>, S<Irix 5>)
1718
e41182b5
GS
1719=item gethostent
1720
1721Not implemented. (S<Mac OS>, Win32)
1722
1723=item getnetent
1724
e6f03d26 1725Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1726
1727=item getprotoent
1728
e6f03d26 1729Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1730
1731=item getservent
1732
e6f03d26 1733Not implemented. (Win32, S<Plan 9>)
e41182b5 1734
e41182b5
GS
1735=item sethostent STAYOPEN
1736
e6f03d26 1737Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1738
1739=item setnetent STAYOPEN
1740
e6f03d26 1741Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1742
1743=item setprotoent STAYOPEN
1744
e6f03d26 1745Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1746
1747=item setservent STAYOPEN
1748
e6f03d26 1749Not implemented. (S<Plan 9>, Win32, S<RISC OS>)
e41182b5
GS
1750
1751=item endpwent
1752
a3dfe201 1753Not implemented. (S<Mac OS>, MPE/iX, VM/ESA, Win32)
e41182b5
GS
1754
1755=item endgrent
1756
a3dfe201 1757Not implemented. (S<Mac OS>, MPE/iX, S<RISC OS>, VM/ESA, VMS, Win32)
e41182b5
GS
1758
1759=item endhostent
1760
1761Not implemented. (S<Mac OS>, Win32)
1762
1763=item endnetent
1764
e6f03d26 1765Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1766
1767=item endprotoent
1768
e6f03d26 1769Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1770
1771=item endservent
1772
e6f03d26 1773Not implemented. (S<Plan 9>, Win32)
e41182b5
GS
1774
1775=item getsockopt SOCKET,LEVEL,OPTNAME
1776
e6f03d26 1777Not implemented. (S<Plan 9>)
e41182b5
GS
1778
1779=item glob EXPR
1780
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
e41182b5
GS
1786=item ioctl FILEHANDLE,FUNCTION,SCALAR
1787
1788Not implemented. (VMS)
1789
1790Available only for socket handles, and it does what the ioctlsocket() call
1791in the Winsock API does. (Win32)
1792
b8099c3d
CN
1793Available only for socket handles. (S<RISC OS>)
1794
b350dd2f 1795=item kill SIGNAL, LIST
e41182b5 1796
862b5365
JH
1797C<kill(0, LIST)> is implemented for the sake of taint checking;
1798use with other signals is unimplemented. (S<Mac OS>)
1799
1800Not implemented, hence not useful for taint checking. (S<RISC OS>)
e41182b5 1801
63f87e49
GS
1802C<kill()> doesn't have the semantics of C<raise()>, i.e. it doesn't send
1803a signal to the identified process like it does on Unix platforms.
1804Instead C<kill($sig, $pid)> terminates the process identified by $pid,
1805and makes it exit immediately with exit status $sig. As in Unix, if
1806$sig is 0 and the specified process exists, it returns true without
1807actually terminating it. (Win32)
e41182b5
GS
1808
1809=item link OLDFILE,NEWFILE
1810
a3dfe201 1811Not implemented. (S<Mac OS>, MPE/iX, VMS, S<RISC OS>)
e41182b5 1812
433acd8a
JH
1813Link count not updated because hard links are not quite that hard
1814(They are sort of half-way between hard and soft links). (AmigaOS)
1815
a3dfe201
GS
1816Hard links are implemented on Win32 (Windows NT and Windows 2000)
1817under NTFS only.
1818
e41182b5
GS
1819=item lstat FILEHANDLE
1820
1821=item lstat EXPR
1822
1823=item lstat
1824
b8099c3d 1825Not implemented. (VMS, S<RISC OS>)
e41182b5 1826
63f87e49 1827Return values (especially for device and inode) may be bogus. (Win32)
e41182b5
GS
1828
1829=item msgctl ID,CMD,ARG
1830
1831=item msgget KEY,FLAGS
1832
1833=item msgsnd ID,MSG,FLAGS
1834
1835=item msgrcv ID,VAR,SIZE,TYPE,FLAGS
1836
e6f03d26 1837Not implemented. (S<Mac OS>, Win32, VMS, S<Plan 9>, S<RISC OS>, VOS)
e41182b5
GS
1838
1839=item open FILEHANDLE,EXPR
1840
1841=item open FILEHANDLE
1842
b7df3edc 1843The C<|> variants are supported only if ToolServer is installed.
e41182b5
GS
1844(S<Mac OS>)
1845
c47ff5f1 1846open to C<|-> and C<-|> are unsupported. (S<Mac OS>, Win32, S<RISC OS>)
e41182b5 1847
0f897271
GS
1848Opening a process does not automatically flush output handles on some
1849platforms. (SunOS, Solaris, HP-UX)
1850
e41182b5
GS
1851=item pipe READHANDLE,WRITEHANDLE
1852
433acd8a
JH
1853Very limited functionality. (MiNT)
1854
e41182b5
GS
1855=item readlink EXPR
1856
1857=item readlink
1858
b8099c3d 1859Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5 1860
c9b2b9d4
SS
1861=item rename OLDNAME,NEWNAME
1862
1863Can't move directories between directories on different logical volumes. (Win32)
1864
e41182b5
GS
1865=item select RBITS,WBITS,EBITS,TIMEOUT
1866
689c5c24 1867Only implemented on sockets. (Win32, VMS)
e41182b5 1868
b8099c3d
CN
1869Only reliable on sockets. (S<RISC OS>)
1870
76e05f0b 1871Note that the C<select FILEHANDLE> form is generally portable.
63f87e49 1872
e41182b5
GS
1873=item semctl ID,SEMNUM,CMD,ARG
1874
1875=item semget KEY,NSEMS,FLAGS
1876
1877=item semop KEY,OPSTRING
1878
495c5fdc 1879Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1880
a3dfe201
GS
1881=item setgrent
1882
3fd80bd6 1883Not implemented. (S<Mac OS>, MPE/iX, VMS, Win32, S<RISC OS>, VOS)
a3dfe201 1884
e41182b5
GS
1885=item setpgrp PID,PGRP
1886
495c5fdc 1887Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5
GS
1888
1889=item setpriority WHICH,WHO,PRIORITY
1890
495c5fdc 1891Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1892
a3dfe201
GS
1893=item setpwent
1894
3fd80bd6 1895Not implemented. (S<Mac OS>, MPE/iX, Win32, S<RISC OS>, VOS)
a3dfe201 1896
e41182b5
GS
1897=item setsockopt SOCKET,LEVEL,OPTNAME,OPTVAL
1898
e6f03d26 1899Not implemented. (S<Plan 9>)
e41182b5
GS
1900
1901=item shmctl ID,CMD,ARG
1902
1903=item shmget KEY,SIZE,FLAGS
1904
1905=item shmread ID,VAR,POS,SIZE
1906
1907=item shmwrite ID,STRING,POS,SIZE
1908
495c5fdc 1909Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1910
80cbd5ad
JH
1911=item sockatmark SOCKET
1912
1913A relatively recent addition to socket functions, may not
1914be implemented even in UNIX platforms.
1915
e41182b5
GS
1916=item socketpair SOCKET1,SOCKET2,DOMAIN,TYPE,PROTOCOL
1917
862b5365 1918Not implemented. (Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1919
1920=item stat FILEHANDLE
1921
1922=item stat EXPR
1923
1924=item stat
1925
d62e1b7f
JH
1926Platforms that do not have rdev, blksize, or blocks will return these
1927as '', so numeric comparison or manipulation of these fields may cause
1928'not numeric' warnings.
1929
e41182b5 1930mtime and atime are the same thing, and ctime is creation time instead of
3f1f789b
JH
1931inode change time. (S<Mac OS>).
1932
1933ctime not supported on UFS (S<Mac OS X>).
e41182b5 1934
95a3fe12
MS
1935ctime is creation time instead of inode change time (Win32).
1936
e41182b5
GS
1937device and inode are not meaningful. (Win32)
1938
1939device and inode are not necessarily reliable. (VMS)
1940
b8099c3d
CN
1941mtime, atime and ctime all return the last modification time. Device and
1942inode are not necessarily reliable. (S<RISC OS>)
1943
d62e1b7f
JH
1944dev, rdev, blksize, and blocks are not available. inode is not
1945meaningful and will differ between stat calls on the same file. (os2)
1946
73e9292c
JH
1947some versions of cygwin when doing a stat("foo") and if not finding it
1948may then attempt to stat("foo.exe") (Cygwin)
1949
e41182b5
GS
1950=item symlink OLDFILE,NEWFILE
1951
b8099c3d 1952Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5
GS
1953
1954=item syscall LIST
1955
7c5ffed3 1956Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5 1957
f34d0673
GS
1958=item sysopen FILEHANDLE,FILENAME,MODE,PERMS
1959
dd9f0070 1960The traditional "0", "1", and "2" MODEs are implemented with different
322422de
GS
1961numeric values on some systems. The flags exported by C<Fcntl>
1962(O_RDONLY, O_WRONLY, O_RDWR) should work everywhere though. (S<Mac
7c5ffed3 1963OS>, OS/390, VM/ESA)
f34d0673 1964
e41182b5
GS
1965=item system LIST
1966
9d6eb86e 1967In general, do not assume the UNIX/POSIX semantics that you can shift
7717d0e7 1968C<$?> right by eight to get the exit value, or that C<$? & 127>
9d6eb86e
JH
1969would give you the number of the signal that terminated the program,
1970or that C<$? & 128> would test true if the program was terminated by a
1971coredump. Instead, use the POSIX W*() interfaces: for example, use
74555b7a
PP
1972WIFEXITED($?) and WEXITVALUE($?) to test for a normal exit and the exit
1973value, WIFSIGNALED($?) and WTERMSIG($?) for a signal exit and the
7717d0e7 1974signal. Core dumping is not a portable concept, so there's no portable
9d6eb86e
JH
1975way to test for that.
1976
e41182b5
GS
1977Only implemented if ToolServer is installed. (S<Mac OS>)
1978
1979As an optimization, may not call the command shell specified in
b7df3edc 1980C<$ENV{PERL5SHELL}>. C<system(1, @args)> spawns an external
e41182b5
GS
1981process and immediately returns its process designator, without
1982waiting for it to terminate. Return value may be used subsequently
63f87e49
GS
1983in C<wait> or C<waitpid>. Failure to spawn() a subprocess is indicated
1984by setting $? to "255 << 8". C<$?> is set in a way compatible with
1985Unix (i.e. the exitstatus of the subprocess is obtained by "$? >> 8",
1986as described in the documentation). (Win32)
e41182b5 1987
b8099c3d
CN
1988There is no shell to process metacharacters, and the native standard is
1989to pass a command line terminated by "\n" "\r" or "\0" to the spawned
c47ff5f1 1990program. Redirection such as C<< > foo >> is performed (if at all) by
b8099c3d
CN
1991the run time library of the spawned program. C<system> I<list> will call
1992the Unix emulation library's C<exec> emulation, which attempts to provide
1993emulation of the stdin, stdout, stderr in force in the parent, providing
1994the child program uses a compatible version of the emulation library.
1995I<scalar> will call the native command line direct and no such emulation
1996of a child Unix program will exists. Mileage B<will> vary. (S<RISC OS>)
1997
433acd8a
JH
1998Far from being POSIX compliant. Because there may be no underlying
1999/bin/sh tries to work around the problem by forking and execing the
9b63e9ec 2000first token in its argument string. Handles basic redirection
c47ff5f1 2001("<" or ">") on its own behalf. (MiNT)
433acd8a 2002
0f897271
GS
2003Does not automatically flush output handles on some platforms.
2004(SunOS, Solaris, HP-UX)
2005
9bc98430
CB
2006The return value is POSIX-like (shifted up by 8 bits), which only allows
2007room for a made-up value derived from the severity bits of the native
200832-bit condition code (unless overridden by C<use vmsish 'status'>).
2009For more details see L<perlvms/$?>. (VMS)
2010
e41182b5
GS
2011=item times
2012
2013Only the first entry returned is nonzero. (S<Mac OS>)
2014
63f87e49
GS
2015"cumulative" times will be bogus. On anything other than Windows NT
2016or Windows 2000, "system" time will be bogus, and "user" time is
2017actually the time returned by the clock() function in the C runtime
2018library. (Win32)
e41182b5 2019
b8099c3d
CN
2020Not useful. (S<RISC OS>)
2021
e41182b5
GS
2022=item truncate FILEHANDLE,LENGTH
2023
2024=item truncate EXPR,LENGTH
2025
6d738113 2026Not implemented. (Older versions of VMS)
e41182b5 2027
3fd80bd6 2028Truncation to same-or-shorter lengths only. (VOS)
495c5fdc 2029
4cfdb94f 2030If a FILEHANDLE is supplied, it must be writable and opened in append
e71a7dc8 2031mode (i.e., use C<<< open(FH, '>>filename') >>>
4cfdb94f
GS
2032or C<sysopen(FH,...,O_APPEND|O_RDWR)>. If a filename is supplied, it
2033should not be held open elsewhere. (Win32)
2034
e41182b5
GS
2035=item umask EXPR
2036
2037=item umask
2038
2039Returns undef where unavailable, as of version 5.005.
2040
b7df3edc
GS
2041C<umask> works but the correct permissions are set only when the file
2042is finally closed. (AmigaOS)
433acd8a 2043
e41182b5
GS
2044=item utime LIST
2045
15c65113 2046Only the modification time is updated. (S<BeOS>, S<Mac OS>, VMS, S<RISC OS>)
e41182b5 2047
322422de
GS
2048May not behave as expected. Behavior depends on the C runtime
2049library's implementation of utime(), and the filesystem being
2050used. The FAT filesystem typically does not support an "access
2051time" field, and it may limit timestamps to a granularity of
2052two seconds. (Win32)
e41182b5
GS
2053
2054=item wait
2055
2056=item waitpid PID,FLAGS
2057
3fd80bd6 2058Not implemented. (S<Mac OS>)
e41182b5
GS
2059
2060Can only be applied to process handles returned for processes spawned
a6f858fb 2061using C<system(1, ...)> or pseudo processes created with C<fork()>. (Win32)
e41182b5 2062
b8099c3d
CN
2063Not useful. (S<RISC OS>)
2064
e41182b5
GS
2065=back
2066
b8099c3d
CN
2067=head1 CHANGES
2068
2069=over 4
2070
3fd80bd6
PG
2071=item v1.49, 12 August 2002
2072
2073Updates for VOS from Paul Green.
2074
fd46a41b
JH
2075=item v1.48, 02 February 2001
2076
2077Various updates from perl5-porters over the past year, supported
2078platforms update from Jarkko Hietaniemi.
2079
c997b287
GS
2080=item v1.47, 22 March 2000
2081
2082Various cleanups from Tom Christiansen, including migration of
2083long platform listings from L<perl>.
2084
56d7751a
GS
2085=item v1.46, 12 February 2000
2086
2087Updates for VOS and MPE/iX. (Peter Prymmer) Other small changes.
2088
0cc436d0
GS
2089=item v1.45, 20 December 1999
2090
2091Small changes from 5.005_63 distribution, more changes to EBCDIC info.
2092
d1e3b762
GS
2093=item v1.44, 19 July 1999
2094
2095A bunch of updates from Peter Prymmer for C<$^O> values,
2096endianness, File::Spec, VMS, BS2000, OS/400.
2097
b7df3edc
GS
2098=item v1.43, 24 May 1999
2099
2100Added a lot of cleaning up from Tom Christiansen.
2101
19799a22 2102=item v1.42, 22 May 1999
b7df3edc 2103
19799a22 2104Added notes about tests, sprintf/printf, and epoch offsets.
b7df3edc 2105
6ab3f9cb
GS
2106=item v1.41, 19 May 1999
2107
2108Lots more little changes to formatting and content.
2109
d1e3b762 2110Added a bunch of C<$^O> and related values
6ab3f9cb
GS
2111for various platforms; fixed mail and web addresses, and added
2112and changed miscellaneous notes. (Peter Prymmer)
2113
2114=item v1.40, 11 April 1999
2115
2116Miscellaneous changes.
2117
2118=item v1.39, 11 February 1999
2ee0eb3c
CN
2119
2120Changes from Jarkko and EMX URL fixes Michael Schwern. Additional
2121note about newlines added.
2122
9b63e9ec
CN
2123=item v1.38, 31 December 1998
2124
2125More changes from Jarkko.
2126
3c075c7d
CN
2127=item v1.37, 19 December 1998
2128
2129More minor changes. Merge two separate version 1.35 documents.
2130
2131=item v1.36, 9 September 1998
2132
2133Updated for Stratus VOS. Also known as version 1.35.
2134
2135=item v1.35, 13 August 1998
495c5fdc 2136
3c075c7d
CN
2137Integrate more minor changes, plus addition of new sections under
2138L<"ISSUES">: L<"Numbers endianness and Width">,
2139L<"Character sets and character encoding">,
2140L<"Internationalisation">.
495c5fdc 2141
3c075c7d 2142=item v1.33, 06 August 1998
0a47030a
GS
2143
2144Integrate more minor changes.
2145
3c075c7d 2146=item v1.32, 05 August 1998
dd9f0070
CN
2147
2148Integrate more minor changes.
2149
3c075c7d 2150=item v1.30, 03 August 1998
b8099c3d
CN
2151
2152Major update for RISC OS, other minor changes.
2153
3c075c7d 2154=item v1.23, 10 July 1998
b8099c3d
CN
2155
2156First public release with perl5.005.
2157
2158=back
e41182b5 2159
ba58ab26
JH
2160=head1 Supported Platforms
2161
522b859a 2162As of July 2002 (the Perl release 5.8.0), the following platforms are
cec2c193
JH
2163able to build Perl from the standard source code distribution
2164available at http://www.cpan.org/src/index.html
2165
2166 AIX
2167 BeOS
6f683aa2 2168 BSD/OS (BSDi)
cec2c193
JH
2169 Cygwin
2170 DG/UX
811b48f2 2171 DOS DJGPP 1)
cec2c193
JH
2172 DYNIX/ptx
2173 EPOC R5
2174 FreeBSD
6f683aa2 2175 HI-UXMPP (Hitachi) (5.8.0 worked but we didn't know it)
cec2c193
JH
2176 HP-UX
2177 IRIX
2178 Linux
8939ba94 2179 Mac OS Classic
6f683aa2 2180 Mac OS X (Darwin)
cec2c193
JH
2181 MPE/iX
2182 NetBSD
2183 NetWare
2184 NonStop-UX
6f683aa2 2185 ReliantUNIX (formerly SINIX)
cec2c193 2186 OpenBSD
6f683aa2 2187 OpenVMS (formerly VMS)
3ebac25b 2188 Open UNIX (Unixware) (since Perl 5.8.1/5.9.0)
cec2c193 2189 OS/2
522b859a 2190 OS/400 (using the PASE) (since Perl 5.8.1/5.9.0)
70de81db 2191 PowerUX
6f683aa2 2192 POSIX-BC (formerly BS2000)
cec2c193
JH
2193 QNX
2194 Solaris
70de81db 2195 SunOS 4
6f683aa2
JH
2196 SUPER-UX (NEC)
2197 Tru64 UNIX (formerly DEC OSF/1, Digital UNIX)
cec2c193
JH
2198 UNICOS
2199 UNICOS/mk
2200 UTS
2201 VOS
811b48f2 2202 Win95/98/ME/2K/XP 2)
c40b5d1d 2203 WinCE
6f683aa2 2204 z/OS (formerly OS/390)
cec2c193 2205 VM/ESA
ba58ab26 2206
811b48f2
JH
2207 1) in DOS mode either the DOS or OS/2 ports can be used
2208 2) compilers: Borland, MinGW (GCC), VC6
cec2c193 2209
c40b5d1d 2210The following platforms worked with the previous releases (5.6 and
cec2c193
JH
22115.7), but we did not manage either to fix or to test these in time
2212for the 5.8.0 release. There is a very good chance that many of these
70de81db 2213will work fine with the 5.8.0.
cec2c193 2214
8da2b1be 2215 BSD/OS
cec2c193
JH
2216 DomainOS
2217 Hurd
2218 LynxOS
2219 MachTen
2220 PowerMAX
2221 SCO SV
cec2c193
JH
2222 SVR4
2223 Unixware
2224 Windows 3.1
ba58ab26 2225
70de81db
JH
2226Known to be broken for 5.8.0 (but 5.6.1 and 5.7.2 can be used):
2227
2228 AmigaOS
2229
ba58ab26 2230The following platforms have been known to build Perl from source in
fd46a41b
JH
2231the past (5.005_03 and earlier), but we haven't been able to verify
2232their status for the current release, either because the
2233hardware/software platforms are rare or because we don't have an
2234active champion on these platforms--or both. They used to work,
2235though, so go ahead and try compiling them, and let perlbug@perl.org
2236of any trouble.
ba58ab26 2237
cec2c193
JH
2238 3b1
2239 A/UX
cec2c193
JH
2240 ConvexOS
2241 CX/UX
2242 DC/OSx
2243 DDE SMES
2244 DOS EMX
2245 Dynix
2246 EP/IX
2247 ESIX
2248 FPS
2249 GENIX
2250 Greenhills
2251 ISC
2252 MachTen 68k
2253 MiNT
2254 MPC
2255 NEWS-OS
2256 NextSTEP
2257 OpenSTEP
2258 Opus
2259 Plan 9
cec2c193 2260 RISC/os
8da2b1be 2261 SCO ODT/OSR
cec2c193
JH
2262 Stellar
2263 SVR2
2264 TI1500
2265 TitanOS
2266 Ultrix
2267 Unisys Dynix
ba58ab26
JH
2268
2269The following platforms have their own source code distributions and
1577cd80 2270binaries available via http://www.cpan.org/ports/
ba58ab26 2271
cec2c193 2272 Perl release
ba58ab26 2273
522b859a 2274 OS/400 (ILE) 5.005_02
cec2c193 2275 Tandem Guardian 5.004
ba58ab26
JH
2276
2277The following platforms have only binaries available via
a93751fa 2278http://www.cpan.org/ports/index.html :
ba58ab26 2279
cec2c193 2280 Perl release
ba58ab26 2281
cec2c193
JH
2282 Acorn RISCOS 5.005_02
2283 AOS 5.002
2284 LynxOS 5.004_02
ba58ab26
JH
2285
2286Although we do suggest that you always build your own Perl from
2287the source code, both for maximal configurability and for security,
2288in case you are in a hurry you can check
a93751fa 2289http://www.cpan.org/ports/index.html for binary distributions.
ba58ab26 2290
c997b287
GS
2291=head1 SEE ALSO
2292
cec2c193 2293L<perlaix>, L<perlamiga>, L<perlapollo>, L<perlbeos>, L<perlbs2000>,
18a271bd 2294L<perlce>, L<perlcygwin>, L<perldgux>, L<perldos>, L<perlepoc>,
469e7be4 2295L<perlebcdic>, L<perlfreebsd>, L<perlhurd>, L<perlhpux>, L<perlirix>,
0d53b15f 2296L<perlmachten>, L<perlmacos>, L<perlmacosx>, L<perlmint>, L<perlmpeix>,
522b859a
JH
2297L<perlnetware>, L<perlos2>, L<perlos390>, L<perlos400>,
2298L<perlplan9>, L<perlqnx>, L<perlsolaris>, L<perltru64>,
2299L<perlunicode>, L<perlvmesa>, L<perlvms>, L<perlvos>,
2300L<perlwin32>, and L<Win32>.
c997b287 2301
e41182b5
GS
2302=head1 AUTHORS / CONTRIBUTORS
2303
06e9666b 2304Abigail <abigail@foad.org>,
c47ff5f1
GS
2305Charles Bailey <bailey@newman.upenn.edu>,
2306Graham Barr <gbarr@pobox.com>,
2307Tom Christiansen <tchrist@perl.com>,
06e9666b 2308Nicholas Clark <nick@ccl4.org>,
c47ff5f1 2309Thomas Dorner <Thomas.Dorner@start.de>,
06e9666b
A
2310Andy Dougherty <doughera@lafayette.edu>,
2311Dominic Dunlop <domo@computer.org>,
2312Neale Ferguson <neale@vma.tabnsw.com.au>,
c47ff5f1 2313David J. Fiander <davidf@mks.com>,
3fd80bd6 2314Paul Green <Paul.Green@stratus.com>,
06e9666b 2315M.J.T. Guy <mjtg@cam.ac.uk>,
61f30a5e 2316Jarkko Hietaniemi <jhi@iki.fi>,
c47ff5f1 2317Luther Huffman <lutherh@stratcom.com>,
06e9666b
A
2318Nick Ing-Simmons <nick@ing-simmons.net>,
2319Andreas J. KE<ouml>nig <a.koenig@mind.de>,
c47ff5f1
GS
2320Markus Laker <mlaker@contax.co.uk>,
2321Andrew M. Langmead <aml@world.std.com>,
2322Larry Moore <ljmoore@freespace.net>,
2323Paul Moore <Paul.Moore@uk.origin-it.com>,
2324Chris Nandor <pudge@pobox.com>,
1afc07ec 2325Matthias Neeracher <neeracher@mac.com>,
e71a7dc8 2326Philip Newton <pne@cpan.org>,
c47ff5f1
GS
2327Gary Ng <71564.1743@CompuServe.COM>,
2328Tom Phoenix <rootbeer@teleport.com>,
2329AndrE<eacute> Pirard <A.Pirard@ulg.ac.be>,
2330Peter Prymmer <pvhp@forte.com>,
2331Hugo van der Sanden <hv@crypt0.demon.co.uk>,
2332Gurusamy Sarathy <gsar@activestate.com>,
2333Paul J. Schinder <schinder@pobox.com>,
2334Michael G Schwern <schwern@pobox.com>,
06e9666b 2335Dan Sugalski <dan@sidhe.org>,
c47ff5f1 2336Nathan Torkington <gnat@frii.com>.
e41182b5 2337