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1=head1 NAME
2
3perlport - Writing portable Perl
4
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5=head1 DESCRIPTION
6
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7Perl runs on numerous operating systems. While most of them share
8much in common, they also have their own unique features.
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9
10This document is meant to help you to find out what constitutes portable
b7df3edc 11Perl code. That way once you make a decision to write portably,
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12you know where the lines are drawn, and you can stay within them.
13
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14There is a tradeoff between taking full advantage of one particular
15type of computer and taking advantage of a full range of them.
16Naturally, as you broaden your range and become more diverse, the
17common factors drop, and you are left with an increasingly smaller
18area of common ground in which you can operate to accomplish a
19particular task. Thus, when you begin attacking a problem, it is
20important to consider under which part of the tradeoff curve you
21want to operate. Specifically, you must decide whether it is
22important that the task that you are coding have the full generality
23of being portable, or whether to just get the job done right now.
24This is the hardest choice to be made. The rest is easy, because
25Perl provides many choices, whichever way you want to approach your
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26problem.
27
28Looking at it another way, writing portable code is usually about
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29willfully limiting your available choices. Naturally, it takes
30discipline and sacrifice to do that. The product of portability
31and convenience may be a constant. You have been warned.
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32
33Be aware of two important points:
34
35=over 4
36
37=item Not all Perl programs have to be portable
38
b7df3edc 39There is no reason you should not use Perl as a language to glue Unix
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40tools together, or to prototype a Macintosh application, or to manage the
41Windows registry. If it makes no sense to aim for portability for one
42reason or another in a given program, then don't bother.
43
b7df3edc 44=item Nearly all of Perl already I<is> portable
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45
46Don't be fooled into thinking that it is hard to create portable Perl
47code. It isn't. Perl tries its level-best to bridge the gaps between
48what's available on different platforms, and all the means available to
49use those features. Thus almost all Perl code runs on any machine
6ab3f9cb 50without modification. But there are some significant issues in
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51writing portable code, and this document is entirely about those issues.
52
53=back
54
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55Here's the general rule: When you approach a task commonly done
56using a whole range of platforms, think about writing portable
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57code. That way, you don't sacrifice much by way of the implementation
58choices you can avail yourself of, and at the same time you can give
59your users lots of platform choices. On the other hand, when you have to
60take advantage of some unique feature of a particular platform, as is
61often the case with systems programming (whether for Unix, Windows,
204ad8d5 62VMS, etc.), consider writing platform-specific code.
e41182b5 63
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64When the code will run on only two or three operating systems, you
65may need to consider only the differences of those particular systems.
66The important thing is to decide where the code will run and to be
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67deliberate in your decision.
68
69The material below is separated into three main sections: main issues of
7ee27b7c 70portability (L<"ISSUES">), platform-specific issues (L<"PLATFORMS">), and
b7df3edc 71built-in perl functions that behave differently on various ports
7ee27b7c 72(L<"FUNCTION IMPLEMENTATIONS">).
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73
74This information should not be considered complete; it includes possibly
b8099c3d 75transient information about idiosyncrasies of some of the ports, almost
b7df3edc 76all of which are in a state of constant evolution. Thus, this material
e41182b5 77should be considered a perpetual work in progress
cc07ed0b 78(C<< <IMG SRC="yellow_sign.gif" ALT="Under Construction"> >>).
e41182b5 79
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80=head1 ISSUES
81
82=head2 Newlines
83
638bc118 84In most operating systems, lines in files are terminated by newlines.
e41182b5 85Just what is used as a newline may vary from OS to OS. Unix
b7df3edc 86traditionally uses C<\012>, one type of DOSish I/O uses C<\015\012>,
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87and S<Mac OS> uses C<\015>.
88
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89Perl uses C<\n> to represent the "logical" newline, where what is
90logical may depend on the platform in use. In MacPerl, C<\n> always
51d9476f 91means C<\015>. In DOSish perls, C<\n> usually means C<\012>, but when
92accessing a file in "text" mode, perl uses the C<:crlf> layer that
93translates it to (or from) C<\015\012>, depending on whether you're
94reading or writing. Unix does the same thing on ttys in canonical
95mode. C<\015\012> is commonly referred to as CRLF.
b7df3edc 96
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97To trim trailing newlines from text lines use chomp(). With default
98settings that function looks for a trailing C<\n> character and thus
99trims in a portable way.
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100
101When dealing with binary files (or text files in binary mode) be sure
102to explicitly set $/ to the appropriate value for your file format
103before using chomp().
104
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105Because of the "text" mode translation, DOSish perls have limitations
106in using C<seek> and C<tell> on a file accessed in "text" mode.
107Stick to C<seek>-ing to locations you got from C<tell> (and no
108others), and you are usually free to use C<seek> and C<tell> even
109in "text" mode. Using C<seek> or C<tell> or other file operations
110may be non-portable. If you use C<binmode> on a file, however, you
111can usually C<seek> and C<tell> with arbitrary values in safety.
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112
113A common misconception in socket programming is that C<\n> eq C<\012>
0a47030a 114everywhere. When using protocols such as common Internet protocols,
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115C<\012> and C<\015> are called for specifically, and the values of
116the logical C<\n> and C<\r> (carriage return) are not reliable.
117
118 print SOCKET "Hi there, client!\r\n"; # WRONG
119 print SOCKET "Hi there, client!\015\012"; # RIGHT
120
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121However, using C<\015\012> (or C<\cM\cJ>, or C<\x0D\x0A>) can be tedious
122and unsightly, as well as confusing to those maintaining the code. As
6ab3f9cb 123such, the Socket module supplies the Right Thing for those who want it.
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124
125 use Socket qw(:DEFAULT :crlf);
126 print SOCKET "Hi there, client!$CRLF" # RIGHT
127
6ab3f9cb 128When reading from a socket, remember that the default input record
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129separator C<$/> is C<\n>, but robust socket code will recognize as
130either C<\012> or C<\015\012> as end of line:
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131
132 while (<SOCKET>) {
133 # ...
134 }
135
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136Because both CRLF and LF end in LF, the input record separator can
137be set to LF and any CR stripped later. Better to write:
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138
139 use Socket qw(:DEFAULT :crlf);
140 local($/) = LF; # not needed if $/ is already \012
141
142 while (<SOCKET>) {
143 s/$CR?$LF/\n/; # not sure if socket uses LF or CRLF, OK
144 # s/\015?\012/\n/; # same thing
145 }
146
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147This example is preferred over the previous one--even for Unix
148platforms--because now any C<\015>'s (C<\cM>'s) are stripped out
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149(and there was much rejoicing).
150
6ab3f9cb 151Similarly, functions that return text data--such as a function that
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152fetches a web page--should sometimes translate newlines before
153returning the data, if they've not yet been translated to the local
154newline representation. A single line of code will often suffice:
2ee0eb3c 155
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156 $data =~ s/\015?\012/\n/g;
157 return $data;
2ee0eb3c 158
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159Some of this may be confusing. Here's a handy reference to the ASCII CR
160and LF characters. You can print it out and stick it in your wallet.
161
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162 LF eq \012 eq \x0A eq \cJ eq chr(10) eq ASCII 10
163 CR eq \015 eq \x0D eq \cM eq chr(13) eq ASCII 13
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164
165 | Unix | DOS | Mac |
166 ---------------------------
167 \n | LF | LF | CR |
168 \r | CR | CR | LF |
169 \n * | LF | CRLF | CR |
170 \r * | CR | CR | LF |
171 ---------------------------
172 * text-mode STDIO
173
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174The Unix column assumes that you are not accessing a serial line
175(like a tty) in canonical mode. If you are, then CR on input becomes
176"\n", and "\n" on output becomes CRLF.
177
6ab3f9cb 178These are just the most common definitions of C<\n> and C<\r> in Perl.
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179There may well be others. For example, on an EBCDIC implementation
180such as z/OS (OS/390) or OS/400 (using the ILE, the PASE is ASCII-based)
181the above material is similar to "Unix" but the code numbers change:
74555b7a 182
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183 LF eq \025 eq \x15 eq \cU eq chr(21) eq CP-1047 21
184 LF eq \045 eq \x25 eq chr(37) eq CP-0037 37
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185 CR eq \015 eq \x0D eq \cM eq chr(13) eq CP-1047 13
186 CR eq \015 eq \x0D eq \cM eq chr(13) eq CP-0037 13
187
188 | z/OS | OS/400 |
189 ----------------------
190 \n | LF | LF |
191 \r | CR | CR |
192 \n * | LF | LF |
193 \r * | CR | CR |
194 ----------------------
195 * text-mode STDIO
6ab3f9cb 196
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197=head2 Numbers endianness and Width
198
199Different CPUs store integers and floating point numbers in different
200orders (called I<endianness>) and widths (32-bit and 64-bit being the
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201most common today). This affects your programs when they attempt to transfer
202numbers in binary format from one CPU architecture to another,
203usually either "live" via network connection, or by storing the
204numbers to secondary storage such as a disk file or tape.
322422de 205
b7df3edc 206Conflicting storage orders make utter mess out of the numbers. If a
d1e3b762 207little-endian host (Intel, VAX) stores 0x12345678 (305419896 in
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208decimal), a big-endian host (Motorola, Sparc, PA) reads it as
2090x78563412 (2018915346 in decimal). Alpha and MIPS can be either:
210Digital/Compaq used/uses them in little-endian mode; SGI/Cray uses
211them in big-endian mode. To avoid this problem in network (socket)
212connections use the C<pack> and C<unpack> formats C<n> and C<N>, the
213"network" orders. These are guaranteed to be portable.
322422de 214
7a4d2905 215As of perl 5.9.2, you can also use the C<E<gt>> and C<E<lt>> modifiers
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216to force big- or little-endian byte-order. This is useful if you want
217to store signed integers or 64-bit integers, for example.
218
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219You can explore the endianness of your platform by unpacking a
220data structure packed in native format such as:
221
222 print unpack("h*", pack("s2", 1, 2)), "\n";
223 # '10002000' on e.g. Intel x86 or Alpha 21064 in little-endian mode
224 # '00100020' on e.g. Motorola 68040
225
226If you need to distinguish between endian architectures you could use
227either of the variables set like so:
228
229 $is_big_endian = unpack("h*", pack("s", 1)) =~ /01/;
4375e838 230 $is_little_endian = unpack("h*", pack("s", 1)) =~ /^1/;
d1e3b762 231
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232Differing widths can cause truncation even between platforms of equal
233endianness. The platform of shorter width loses the upper parts of the
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234number. There is no good solution for this problem except to avoid
235transferring or storing raw binary numbers.
236
b7df3edc 237One can circumnavigate both these problems in two ways. Either
322422de 238transfer and store numbers always in text format, instead of raw
b7df3edc 239binary, or else consider using modules like Data::Dumper (included in
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240the standard distribution as of Perl 5.005) and Storable (included as
241of perl 5.8). Keeping all data as text significantly simplifies matters.
322422de 242
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243The v-strings are portable only up to v2147483647 (0x7FFFFFFF), that's
244how far EBCDIC, or more precisely UTF-EBCDIC will go.
245
433acd8a 246=head2 Files and Filesystems
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247
248Most platforms these days structure files in a hierarchical fashion.
b7df3edc 249So, it is reasonably safe to assume that all platforms support the
6ab3f9cb 250notion of a "path" to uniquely identify a file on the system. How
b7df3edc 251that path is really written, though, differs considerably.
e41182b5 252
4375e838 253Although similar, file path specifications differ between Unix,
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254Windows, S<Mac OS>, OS/2, VMS, VOS, S<RISC OS>, and probably others.
255Unix, for example, is one of the few OSes that has the elegant idea
256of a single root directory.
322422de 257
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258DOS, OS/2, VMS, VOS, and Windows can work similarly to Unix with C</>
259as path separator, or in their own idiosyncratic ways (such as having
260several root directories and various "unrooted" device files such NIL:
261and LPT:).
322422de 262
204ad8d5 263S<Mac OS> 9 and earlier used C<:> as a path separator instead of C</>.
322422de 264
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265The filesystem may support neither hard links (C<link>) nor
266symbolic links (C<symlink>, C<readlink>, C<lstat>).
433acd8a 267
6ab3f9cb 268The filesystem may support neither access timestamp nor change
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269timestamp (meaning that about the only portable timestamp is the
270modification timestamp), or one second granularity of any timestamps
271(e.g. the FAT filesystem limits the time granularity to two seconds).
272
74555b7a 273The "inode change timestamp" (the C<-C> filetest) may really be the
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274"creation timestamp" (which it is not in UNIX).
275
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276VOS perl can emulate Unix filenames with C</> as path separator. The
277native pathname characters greater-than, less-than, number-sign, and
278percent-sign are always accepted.
279
6ab3f9cb 280S<RISC OS> perl can emulate Unix filenames with C</> as path
322422de 281separator, or go native and use C<.> for path separator and C<:> to
6ab3f9cb 282signal filesystems and disk names.
e41182b5 283
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284Don't assume UNIX filesystem access semantics: that read, write,
285and execute are all the permissions there are, and even if they exist,
286that their semantics (for example what do r, w, and x mean on
287a directory) are the UNIX ones. The various UNIX/POSIX compatibility
288layers usually try to make interfaces like chmod() work, but sometimes
289there simply is no good mapping.
290
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291If all this is intimidating, have no (well, maybe only a little)
292fear. There are modules that can help. The File::Spec modules
293provide methods to do the Right Thing on whatever platform happens
294to be running the program.
e41182b5 295
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296 use File::Spec::Functions;
297 chdir(updir()); # go up one directory
298 $file = catfile(curdir(), 'temp', 'file.txt');
e41182b5 299 # on Unix and Win32, './temp/file.txt'
204ad8d5 300 # on Mac OS Classic, ':temp:file.txt'
d1e3b762 301 # on VMS, '[.temp]file.txt'
e41182b5 302
b7df3edc 303File::Spec is available in the standard distribution as of version
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3045.004_05. File::Spec::Functions is only in File::Spec 0.7 and later,
305and some versions of perl come with version 0.6. If File::Spec
306is not updated to 0.7 or later, you must use the object-oriented
307interface from File::Spec (or upgrade File::Spec).
e41182b5 308
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309In general, production code should not have file paths hardcoded.
310Making them user-supplied or read from a configuration file is
311better, keeping in mind that file path syntax varies on different
312machines.
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313
314This is especially noticeable in scripts like Makefiles and test suites,
315which often assume C</> as a path separator for subdirectories.
316
b7df3edc 317Also of use is File::Basename from the standard distribution, which
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318splits a pathname into pieces (base filename, full path to directory,
319and file suffix).
320
19799a22 321Even when on a single platform (if you can call Unix a single platform),
b7df3edc 322remember not to count on the existence or the contents of particular
3c075c7d 323system-specific files or directories, like F</etc/passwd>,
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324F</etc/sendmail.conf>, F</etc/resolv.conf>, or even F</tmp/>. For
325example, F</etc/passwd> may exist but not contain the encrypted
326passwords, because the system is using some form of enhanced security.
327Or it may not contain all the accounts, because the system is using NIS.
3c075c7d 328If code does need to rely on such a file, include a description of the
b7df3edc 329file and its format in the code's documentation, then make it easy for
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330the user to override the default location of the file.
331
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332Don't assume a text file will end with a newline. They should,
333but people forget.
e41182b5 334
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335Do not have two files or directories of the same name with different
336case, like F<test.pl> and F<Test.pl>, as many platforms have
337case-insensitive (or at least case-forgiving) filenames. Also, try
338not to have non-word characters (except for C<.>) in the names, and
339keep them to the 8.3 convention, for maximum portability, onerous a
340burden though this may appear.
dd9f0070 341
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342Likewise, when using the AutoSplit module, try to keep your functions to
3438.3 naming and case-insensitive conventions; or, at the least,
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344make it so the resulting files have a unique (case-insensitively)
345first 8 characters.
346
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347Whitespace in filenames is tolerated on most systems, but not all,
348and even on systems where it might be tolerated, some utilities
fe829689 349might become confused by such whitespace.
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351Many systems (DOS, VMS ODS-2) cannot have more than one C<.> in their
352filenames.
433acd8a 353
c47ff5f1 354Don't assume C<< > >> won't be the first character of a filename.
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355Always use C<< < >> explicitly to open a file for reading, or even
356better, use the three-arg version of open, unless you want the user to
357be able to specify a pipe open.
0a47030a 358
fe829689 359 open(FILE, '<', $existing_file) or die $!;
0a47030a 360
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361If filenames might use strange characters, it is safest to open it
362with C<sysopen> instead of C<open>. C<open> is magic and can
c47ff5f1 363translate characters like C<< > >>, C<< < >>, and C<|>, which may
b7df3edc 364be the wrong thing to do. (Sometimes, though, it's the right thing.)
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365Three-arg open can also help protect against this translation in cases
366where it is undesirable.
e41182b5 367
ec481373 368Don't use C<:> as a part of a filename since many systems use that for
8939ba94 369their own semantics (Mac OS Classic for separating pathname components,
ec481373 370many networking schemes and utilities for separating the nodename and
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371the pathname, and so on). For the same reasons, avoid C<@>, C<;> and
372C<|>.
ec481373 373
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374Don't assume that in pathnames you can collapse two leading slashes
375C<//> into one: some networking and clustering filesystems have special
376semantics for that. Let the operating system to sort it out.
377
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378The I<portable filename characters> as defined by ANSI C are
379
380 a b c d e f g h i j k l m n o p q r t u v w x y z
381 A B C D E F G H I J K L M N O P Q R T U V W X Y Z
382 0 1 2 3 4 5 6 7 8 9
383 . _ -
384
08fef530 385and the "-" shouldn't be the first character. If you want to be
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386hypercorrect, stay case-insensitive and within the 8.3 naming
387convention (all the files and directories have to be unique within one
388directory if their names are lowercased and truncated to eight
389characters before the C<.>, if any, and to three characters after the
390C<.>, if any). (And do not use C<.>s in directory names.)
ec481373 391
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392=head2 System Interaction
393
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394Not all platforms provide a command line. These are usually platforms
395that rely primarily on a Graphical User Interface (GUI) for user
396interaction. A program requiring a command line interface might
397not work everywhere. This is probably for the user of the program
398to deal with, so don't stay up late worrying about it.
e41182b5 399
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400Some platforms can't delete or rename files held open by the system,
401this limitation may also apply to changing filesystem metainformation
402like file permissions or owners. Remember to C<close> files when you
403are done with them. Don't C<unlink> or C<rename> an open file. Don't
404C<tie> or C<open> a file already tied or opened; C<untie> or C<close>
405it first.
e41182b5 406
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407Don't open the same file more than once at a time for writing, as some
408operating systems put mandatory locks on such files.
409
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410Don't assume that write/modify permission on a directory gives the
411right to add or delete files/directories in that directory. That is
412filesystem specific: in some filesystems you need write/modify
413permission also (or even just) in the file/directory itself. In some
414filesystems (AFS, DFS) the permission to add/delete directory entries
415is a completely separate permission.
416
417Don't assume that a single C<unlink> completely gets rid of the file:
418some filesystems (most notably the ones in VMS) have versioned
419filesystems, and unlink() removes only the most recent one (it doesn't
420remove all the versions because by default the native tools on those
421platforms remove just the most recent version, too). The portable
422idiom to remove all the versions of a file is
423
94bb614c 424 1 while unlink "file";
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425
426This will terminate if the file is undeleteable for some reason
427(protected, not there, and so on).
428
e41182b5 429Don't count on a specific environment variable existing in C<%ENV>.
0a47030a 430Don't count on C<%ENV> entries being case-sensitive, or even
4a0d0822 431case-preserving. Don't try to clear %ENV by saying C<%ENV = ();>, or,
6be8f7a6 432if you really have to, make it conditional on C<$^O ne 'VMS'> since in
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433VMS the C<%ENV> table is much more than a per-process key-value string
434table.
e41182b5 435
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436On VMS, some entries in the %ENV hash are dynamically created when
437their key is used on a read if they did not previously exist. The
438values for C<$ENV{HOME}>, C<$ENV{TERM}>, C<$ENV{HOME}>, and C<$ENV{USER}>,
439are known to be dynamically generated. The specific names that are
440dynamically generated may vary with the version of the C library on VMS,
441and more may exist than is documented.
442
443On VMS by default, changes to the %ENV hash are persistent after the process
444exits. This can cause unintended issues.
445
d1e3b762 446Don't count on signals or C<%SIG> for anything.
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447
448Don't count on filename globbing. Use C<opendir>, C<readdir>, and
449C<closedir> instead.
450
b8099c3d 451Don't count on per-program environment variables, or per-program current
dd9f0070 452directories.
b8099c3d 453
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454Don't count on specific values of C<$!>, neither numeric nor
455especially the strings values-- users may switch their locales causing
456error messages to be translated into their languages. If you can
457trust a POSIXish environment, you can portably use the symbols defined
458by the Errno module, like ENOENT. And don't trust on the values of C<$!>
459at all except immediately after a failed system call.
3c075c7d 460
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461=head2 Command names versus file pathnames
462
463Don't assume that the name used to invoke a command or program with
464C<system> or C<exec> can also be used to test for the existence of the
465file that holds the executable code for that command or program.
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466First, many systems have "internal" commands that are built-in to the
467shell or OS and while these commands can be invoked, there is no
468corresponding file. Second, some operating systems (e.g., Cygwin,
469DJGPP, OS/2, and VOS) have required suffixes for executable files;
470these suffixes are generally permitted on the command name but are not
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471required. Thus, a command like "perl" might exist in a file named
472"perl", "perl.exe", or "perl.pm", depending on the operating system.
473The variable "_exe" in the Config module holds the executable suffix,
68fb0eb7
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474if any. Third, the VMS port carefully sets up $^X and
475$Config{perlpath} so that no further processing is required. This is
476just as well, because the matching regular expression used below would
477then have to deal with a possible trailing version number in the VMS
478file name.
a10d74f3
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479
480To convert $^X to a file pathname, taking account of the requirements
481of the various operating system possibilities, say:
7ee27b7c 482
a10d74f3 483 use Config;
a10d74f3 484 $thisperl = $^X;
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485 if ($^O ne 'VMS')
486 {$thisperl .= $Config{_exe} unless $thisperl =~ m/$Config{_exe}$/i;}
a10d74f3
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487
488To convert $Config{perlpath} to a file pathname, say:
7ee27b7c 489
a10d74f3 490 use Config;
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491 $thisperl = $Config{perlpath};
492 if ($^O ne 'VMS')
493 {$thisperl .= $Config{_exe} unless $thisperl =~ m/$Config{_exe}$/i;}
a10d74f3 494
7137b697
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495=head2 Networking
496
497Don't assume that you can reach the public Internet.
498
499Don't assume that there is only one way to get through firewalls
500to the public Internet.
501
932f293e
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502Don't assume that you can reach outside world through any other port
503than 80, or some web proxy. ftp is blocked by many firewalls.
504
dbc6a9ce
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505Don't assume that you can send email by connecting to the local SMTP port.
506
7137b697 507Don't assume that you can reach yourself or any node by the name
dbc6a9ce 508'localhost'. The same goes for '127.0.0.1'. You will have to try both.
932f293e 509
86feb2c5
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510Don't assume that the host has only one network card, or that it
511can't bind to many virtual IP addresses.
932f293e
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512
513Don't assume a particular network device name.
7137b697 514
dbc6a9ce 515Don't assume a particular set of ioctl()s will work.
7137b697
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516
517Don't assume that you can ping hosts and get replies.
518
dbc6a9ce
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519Don't assume that any particular port (service) will respond.
520
7ee27b7c 521Don't assume that Sys::Hostname (or any other API or command)
dbc6a9ce
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522returns either a fully qualified hostname or a non-qualified hostname:
523it all depends on how the system had been configured. Also remember
524things like DHCP and NAT-- the hostname you get back might not be very
525useful.
526
932f293e
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527All the above "don't":s may look daunting, and they are -- but the key
528is to degrade gracefully if one cannot reach the particular network
529service one wants. Croaking or hanging do not look very professional.
530
e41182b5
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531=head2 Interprocess Communication (IPC)
532
b7df3edc
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533In general, don't directly access the system in code meant to be
534portable. That means, no C<system>, C<exec>, C<fork>, C<pipe>,
535C<``>, C<qx//>, C<open> with a C<|>, nor any of the other things
536that makes being a perl hacker worth being.
e41182b5
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537
538Commands that launch external processes are generally supported on
b7df3edc
GS
539most platforms (though many of them do not support any type of
540forking). The problem with using them arises from what you invoke
541them on. External tools are often named differently on different
4375e838 542platforms, may not be available in the same location, might accept
b7df3edc
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543different arguments, can behave differently, and often present their
544results in a platform-dependent way. Thus, you should seldom depend
545on them to produce consistent results. (Then again, if you're calling
546I<netstat -a>, you probably don't expect it to run on both Unix and CP/M.)
e41182b5 547
b7df3edc 548One especially common bit of Perl code is opening a pipe to B<sendmail>:
e41182b5 549
b7df3edc
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550 open(MAIL, '|/usr/lib/sendmail -t')
551 or die "cannot fork sendmail: $!";
e41182b5
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552
553This is fine for systems programming when sendmail is known to be
554available. But it is not fine for many non-Unix systems, and even
555some Unix systems that may not have sendmail installed. If a portable
b7df3edc
GS
556solution is needed, see the various distributions on CPAN that deal
557with it. Mail::Mailer and Mail::Send in the MailTools distribution are
558commonly used, and provide several mailing methods, including mail,
559sendmail, and direct SMTP (via Net::SMTP) if a mail transfer agent is
560not available. Mail::Sendmail is a standalone module that provides
561simple, platform-independent mailing.
562
563The Unix System V IPC (C<msg*(), sem*(), shm*()>) is not available
564even on all Unix platforms.
e41182b5 565
a81e5e2e
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566Do not use either the bare result of C<pack("N", 10, 20, 30, 40)> or
567bare v-strings (such as C<v10.20.30.40>) to represent IPv4 addresses:
568both forms just pack the four bytes into network order. That this
569would be equal to the C language C<in_addr> struct (which is what the
570socket code internally uses) is not guaranteed. To be portable use
571the routines of the Socket extension, such as C<inet_aton()>,
572C<inet_ntoa()>, and C<sockaddr_in()>.
6b2463a0 573
e41182b5 574The rule of thumb for portable code is: Do it all in portable Perl, or
0a47030a
GS
575use a module (that may internally implement it with platform-specific
576code, but expose a common interface).
e41182b5 577
e41182b5
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578=head2 External Subroutines (XS)
579
b7df3edc 580XS code can usually be made to work with any platform, but dependent
e41182b5
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581libraries, header files, etc., might not be readily available or
582portable, or the XS code itself might be platform-specific, just as Perl
583code might be. If the libraries and headers are portable, then it is
584normally reasonable to make sure the XS code is portable, too.
585
b7df3edc
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586A different type of portability issue arises when writing XS code:
587availability of a C compiler on the end-user's system. C brings
588with it its own portability issues, and writing XS code will expose
589you to some of those. Writing purely in Perl is an easier way to
e41182b5
GS
590achieve portability.
591
e41182b5
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592=head2 Standard Modules
593
594In general, the standard modules work across platforms. Notable
6ab3f9cb 595exceptions are the CPAN module (which currently makes connections to external
e41182b5 596programs that may not be available), platform-specific modules (like
6ab3f9cb 597ExtUtils::MM_VMS), and DBM modules.
e41182b5 598
b7df3edc 599There is no one DBM module available on all platforms.
6ab3f9cb
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600SDBM_File and the others are generally available on all Unix and DOSish
601ports, but not in MacPerl, where only NBDM_File and DB_File are
0a47030a 602available.
e41182b5
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603
604The good news is that at least some DBM module should be available, and
6ab3f9cb 605AnyDBM_File will use whichever module it can find. Of course, then
b7df3edc
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606the code needs to be fairly strict, dropping to the greatest common
607factor (e.g., not exceeding 1K for each record), so that it will
6ab3f9cb 608work with any DBM module. See L<AnyDBM_File> for more details.
e41182b5 609
e41182b5
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610=head2 Time and Date
611
0a47030a 612The system's notion of time of day and calendar date is controlled in
b7df3edc 613widely different ways. Don't assume the timezone is stored in C<$ENV{TZ}>,
0a47030a 614and even if it is, don't assume that you can control the timezone through
c87488a3
HS
615that variable. Don't assume anything about the three-letter timezone
616abbreviations (for example that MST would be the Mountain Standard Time,
617it's been known to stand for Moscow Standard Time). If you need to
618use timezones, express them in some unambiguous format like the
619exact number of minutes offset from UTC, or the POSIX timezone
620format.
e41182b5 621
322422de 622Don't assume that the epoch starts at 00:00:00, January 1, 1970,
c87488a3
HS
623because that is OS- and implementation-specific. It is better to
624store a date in an unambiguous representation. The ISO 8601 standard
625defines YYYY-MM-DD as the date format, or YYYY-MM-DDTHH-MM-SS
626(that's a literal "T" separating the date from the time).
627Please do use the ISO 8601 instead of making us to guess what
628date 02/03/04 might be. ISO 8601 even sorts nicely as-is.
629A text representation (like "1987-12-18") can be easily converted
630into an OS-specific value using a module like Date::Parse.
631An array of values, such as those returned by C<localtime>, can be
632converted to an OS-specific representation using Time::Local.
322422de 633
19799a22
GS
634When calculating specific times, such as for tests in time or date modules,
635it may be appropriate to calculate an offset for the epoch.
b7df3edc 636
19799a22
GS
637 require Time::Local;
638 $offset = Time::Local::timegm(0, 0, 0, 1, 0, 70);
b7df3edc 639
204ad8d5
JV
640The value for C<$offset> in Unix will be C<0>, but in Mac OS Classic
641will be some large number. C<$offset> can then be added to a Unix time
642value to get what should be the proper value on any system.
322422de
GS
643
644=head2 Character sets and character encoding
645
ec481373
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646Assume very little about character sets.
647
648Assume nothing about numerical values (C<ord>, C<chr>) of characters.
649Do not use explicit code point ranges (like \xHH-\xHH); use for
650example symbolic character classes like C<[:print:]>.
651
652Do not assume that the alphabetic characters are encoded contiguously
653(in the numeric sense). There may be gaps.
654
655Do not assume anything about the ordering of the characters.
656The lowercase letters may come before or after the uppercase letters;
b432a672
AL
657the lowercase and uppercase may be interlaced so that both "a" and "A"
658come before "b"; the accented and other international characters may
659be interlaced so that E<auml> comes before "b".
322422de
GS
660
661=head2 Internationalisation
662
b7df3edc
GS
663If you may assume POSIX (a rather large assumption), you may read
664more about the POSIX locale system from L<perllocale>. The locale
665system at least attempts to make things a little bit more portable,
666or at least more convenient and native-friendly for non-English
667users. The system affects character sets and encoding, and date
668and time formatting--amongst other things.
e41182b5 669
c87488a3
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670If you really want to be international, you should consider Unicode.
671See L<perluniintro> and L<perlunicode> for more information.
672
11264fdb
JH
673If you want to use non-ASCII bytes (outside the bytes 0x00..0x7f) in
674the "source code" of your code, to be portable you have to be explicit
675about what bytes they are. Someone might for example be using your
676code under a UTF-8 locale, in which case random native bytes might be
677illegal ("Malformed UTF-8 ...") This means that for example embedding
678ISO 8859-1 bytes beyond 0x7f into your strings might cause trouble
679later. If the bytes are native 8-bit bytes, you can use the C<bytes>
680pragma. If the bytes are in a string (regular expression being a
681curious string), you can often also use the C<\xHH> notation instead
2575c402
JW
682of embedding the bytes as-is. (If you want to write your code in UTF-8,
683you can use the C<utf8>.) The C<bytes> and C<utf8> pragmata are
684available since Perl 5.6.0.
11264fdb 685
e41182b5
GS
686=head2 System Resources
687
0a47030a
GS
688If your code is destined for systems with severely constrained (or
689missing!) virtual memory systems then you want to be I<especially> mindful
690of avoiding wasteful constructs such as:
e41182b5
GS
691
692 # NOTE: this is no longer "bad" in perl5.005
693 for (0..10000000) {} # bad
694 for (my $x = 0; $x <= 10000000; ++$x) {} # good
695
696 @lines = <VERY_LARGE_FILE>; # bad
697
698 while (<FILE>) {$file .= $_} # sometimes bad
0a47030a 699 $file = join('', <FILE>); # better
e41182b5 700
b7df3edc
GS
701The last two constructs may appear unintuitive to most people. The
702first repeatedly grows a string, whereas the second allocates a
703large chunk of memory in one go. On some systems, the second is
704more efficient that the first.
0a47030a 705
e41182b5
GS
706=head2 Security
707
b7df3edc
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708Most multi-user platforms provide basic levels of security, usually
709implemented at the filesystem level. Some, however, do
a1667ba3 710not-- unfortunately. Thus the notion of user id, or "home" directory,
b7df3edc
GS
711or even the state of being logged-in, may be unrecognizable on many
712platforms. If you write programs that are security-conscious, it
713is usually best to know what type of system you will be running
714under so that you can write code explicitly for that platform (or
715class of platforms).
0a47030a 716
a1667ba3
JH
717Don't assume the UNIX filesystem access semantics: the operating
718system or the filesystem may be using some ACL systems, which are
719richer languages than the usual rwx. Even if the rwx exist,
720their semantics might be different.
721
722(From security viewpoint testing for permissions before attempting to
723do something is silly anyway: if one tries this, there is potential
724for race conditions-- someone or something might change the
725permissions between the permissions check and the actual operation.
726Just try the operation.)
727
728Don't assume the UNIX user and group semantics: especially, don't
2edcc0d9 729expect the C<< $< >> and C<< $> >> (or the C<$(> and C<$)>) to work
a1667ba3
JH
730for switching identities (or memberships).
731
732Don't assume set-uid and set-gid semantics. (And even if you do,
733think twice: set-uid and set-gid are a known can of security worms.)
734
e41182b5
GS
735=head2 Style
736
737For those times when it is necessary to have platform-specific code,
738consider keeping the platform-specific code in one place, making porting
6ab3f9cb 739to other platforms easier. Use the Config module and the special
0a47030a
GS
740variable C<$^O> to differentiate platforms, as described in
741L<"PLATFORMS">.
e41182b5 742
b7df3edc
GS
743Be careful in the tests you supply with your module or programs.
744Module code may be fully portable, but its tests might not be. This
745often happens when tests spawn off other processes or call external
746programs to aid in the testing, or when (as noted above) the tests
c87488a3
HS
747assume certain things about the filesystem and paths. Be careful not
748to depend on a specific output style for errors, such as when checking
749C<$!> after a failed system call. Using C<$!> for anything else than
750displaying it as output is doubtful (though see the Errno module for
751testing reasonably portably for error value). Some platforms expect
752a certain output format, and Perl on those platforms may have been
753adjusted accordingly. Most specifically, don't anchor a regex when
754testing an error value.
e41182b5 755
0a47030a 756=head1 CPAN Testers
e41182b5 757
0a47030a
GS
758Modules uploaded to CPAN are tested by a variety of volunteers on
759different platforms. These CPAN testers are notified by mail of each
e41182b5 760new upload, and reply to the list with PASS, FAIL, NA (not applicable to
0a47030a 761this platform), or UNKNOWN (unknown), along with any relevant notations.
e41182b5
GS
762
763The purpose of the testing is twofold: one, to help developers fix any
0a47030a 764problems in their code that crop up because of lack of testing on other
b7df3edc 765platforms; two, to provide users with information about whether
0a47030a 766a given module works on a given platform.
e41182b5 767
7ee27b7c
AT
768Also see:
769
e41182b5
GS
770=over 4
771
7ee27b7c
AT
772=item *
773
774Mailing list: cpan-testers@perl.org
775
776=item *
e41182b5 777
7ee27b7c 778Testing results: http://testers.cpan.org/
e41182b5
GS
779
780=back
781
e41182b5
GS
782=head1 PLATFORMS
783
784As of version 5.002, Perl is built with a C<$^O> variable that
785indicates the operating system it was built on. This was implemented
b7df3edc
GS
786to help speed up code that would otherwise have to C<use Config>
787and use the value of C<$Config{osname}>. Of course, to get more
e41182b5
GS
788detailed information about the system, looking into C<%Config> is
789certainly recommended.
790
b7df3edc
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791C<%Config> cannot always be trusted, however, because it was built
792at compile time. If perl was built in one place, then transferred
793elsewhere, some values may be wrong. The values may even have been
794edited after the fact.
6ab3f9cb 795
e41182b5
GS
796=head2 Unix
797
798Perl works on a bewildering variety of Unix and Unix-like platforms (see
799e.g. most of the files in the F<hints/> directory in the source code kit).
800On most of these systems, the value of C<$^O> (hence C<$Config{'osname'}>,
d1e3b762
GS
801too) is determined either by lowercasing and stripping punctuation from the
802first field of the string returned by typing C<uname -a> (or a similar command)
803at the shell prompt or by testing the file system for the presence of
804uniquely named files such as a kernel or header file. Here, for example,
805are a few of the more popular Unix flavors:
e41182b5 806
b7df3edc 807 uname $^O $Config{'archname'}
6ab3f9cb 808 --------------------------------------------
b7df3edc 809 AIX aix aix
6ab3f9cb 810 BSD/OS bsdos i386-bsdos
e1516da7 811 Darwin darwin darwin
6ab3f9cb
GS
812 dgux dgux AViiON-dgux
813 DYNIX/ptx dynixptx i386-dynixptx
b7df3edc 814 FreeBSD freebsd freebsd-i386
df00ff3b 815 Haiku haiku BePC-haiku
d1e3b762 816 Linux linux arm-linux
b7df3edc 817 Linux linux i386-linux
6ab3f9cb
GS
818 Linux linux i586-linux
819 Linux linux ppc-linux
b7df3edc
GS
820 HP-UX hpux PA-RISC1.1
821 IRIX irix irix
b787fad4 822 Mac OS X darwin darwin
d1e3b762
GS
823 NeXT 3 next next-fat
824 NeXT 4 next OPENSTEP-Mach
6ab3f9cb 825 openbsd openbsd i386-openbsd
b7df3edc 826 OSF1 dec_osf alpha-dec_osf
6ab3f9cb
GS
827 reliantunix-n svr4 RM400-svr4
828 SCO_SV sco_sv i386-sco_sv
829 SINIX-N svr4 RM400-svr4
830 sn4609 unicos CRAY_C90-unicos
831 sn6521 unicosmk t3e-unicosmk
832 sn9617 unicos CRAY_J90-unicos
b7df3edc
GS
833 SunOS solaris sun4-solaris
834 SunOS solaris i86pc-solaris
835 SunOS4 sunos sun4-sunos
e41182b5 836
b7df3edc
GS
837Because the value of C<$Config{archname}> may depend on the
838hardware architecture, it can vary more than the value of C<$^O>.
6ab3f9cb 839
e41182b5
GS
840=head2 DOS and Derivatives
841
b7df3edc 842Perl has long been ported to Intel-style microcomputers running under
e41182b5
GS
843systems like PC-DOS, MS-DOS, OS/2, and most Windows platforms you can
844bring yourself to mention (except for Windows CE, if you count that).
b7df3edc 845Users familiar with I<COMMAND.COM> or I<CMD.EXE> style shells should
e41182b5
GS
846be aware that each of these file specifications may have subtle
847differences:
848
849 $filespec0 = "c:/foo/bar/file.txt";
850 $filespec1 = "c:\\foo\\bar\\file.txt";
851 $filespec2 = 'c:\foo\bar\file.txt';
852 $filespec3 = 'c:\\foo\\bar\\file.txt';
853
b7df3edc
GS
854System calls accept either C</> or C<\> as the path separator.
855However, many command-line utilities of DOS vintage treat C</> as
856the option prefix, so may get confused by filenames containing C</>.
857Aside from calling any external programs, C</> will work just fine,
858and probably better, as it is more consistent with popular usage,
859and avoids the problem of remembering what to backwhack and what
860not to.
e41182b5 861
b7df3edc
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862The DOS FAT filesystem can accommodate only "8.3" style filenames. Under
863the "case-insensitive, but case-preserving" HPFS (OS/2) and NTFS (NT)
0a47030a 864filesystems you may have to be careful about case returned with functions
e41182b5
GS
865like C<readdir> or used with functions like C<open> or C<opendir>.
866
b7df3edc
GS
867DOS also treats several filenames as special, such as AUX, PRN,
868NUL, CON, COM1, LPT1, LPT2, etc. Unfortunately, sometimes these
869filenames won't even work if you include an explicit directory
870prefix. It is best to avoid such filenames, if you want your code
871to be portable to DOS and its derivatives. It's hard to know what
872these all are, unfortunately.
e41182b5
GS
873
874Users of these operating systems may also wish to make use of
b7df3edc 875scripts such as I<pl2bat.bat> or I<pl2cmd> to
e41182b5
GS
876put wrappers around your scripts.
877
878Newline (C<\n>) is translated as C<\015\012> by STDIO when reading from
6ab3f9cb
GS
879and writing to files (see L<"Newlines">). C<binmode(FILEHANDLE)>
880will keep C<\n> translated as C<\012> for that filehandle. Since it is a
881no-op on other systems, C<binmode> should be used for cross-platform code
b7df3edc
GS
882that deals with binary data. That's assuming you realize in advance
883that your data is in binary. General-purpose programs should
884often assume nothing about their data.
e41182b5 885
b7df3edc 886The C<$^O> variable and the C<$Config{archname}> values for various
e41182b5
GS
887DOSish perls are as follows:
888
67ac489e
MS
889 OS $^O $Config{archname} ID Version
890 --------------------------------------------------------
891 MS-DOS dos ?
892 PC-DOS dos ?
893 OS/2 os2 ?
894 Windows 3.1 ? ? 0 3 01
895 Windows 95 MSWin32 MSWin32-x86 1 4 00
896 Windows 98 MSWin32 MSWin32-x86 1 4 10
897 Windows ME MSWin32 MSWin32-x86 1 ?
898 Windows NT MSWin32 MSWin32-x86 2 4 xx
899 Windows NT MSWin32 MSWin32-ALPHA 2 4 xx
900 Windows NT MSWin32 MSWin32-ppc 2 4 xx
7ee27b7c
AT
901 Windows 2000 MSWin32 MSWin32-x86 2 5 00
902 Windows XP MSWin32 MSWin32-x86 2 5 01
903 Windows 2003 MSWin32 MSWin32-x86 2 5 02
67ac489e 904 Windows CE MSWin32 ? 3
7ee27b7c 905 Cygwin cygwin cygwin
e41182b5 906
34aaaa84
PP
907The various MSWin32 Perl's can distinguish the OS they are running on
908via the value of the fifth element of the list returned from
909Win32::GetOSVersion(). For example:
910
911 if ($^O eq 'MSWin32') {
912 my @os_version_info = Win32::GetOSVersion();
913 print +('3.1','95','NT')[$os_version_info[4]],"\n";
914 }
915
7939d86b
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916There are also Win32::IsWinNT() and Win32::IsWin95(), try C<perldoc Win32>,
917and as of libwin32 0.19 (not part of the core Perl distribution)
918Win32::GetOSName(). The very portable POSIX::uname() will work too:
1d65be3a
JH
919
920 c:\> perl -MPOSIX -we "print join '|', uname"
921 Windows NT|moonru|5.0|Build 2195 (Service Pack 2)|x86
d99f392e 922
e41182b5
GS
923Also see:
924
925=over 4
926
c997b287 927=item *
e41182b5 928
c997b287
GS
929The djgpp environment for DOS, http://www.delorie.com/djgpp/
930and L<perldos>.
e41182b5 931
c997b287 932=item *
e41182b5 933
c997b287 934The EMX environment for DOS, OS/2, etc. emx@iaehv.nl,
f224927c 935ftp://hobbes.nmsu.edu/pub/os2/dev/emx/ Also L<perlos2>.
e41182b5 936
c997b287 937=item *
d1e3b762 938
c997b287
GS
939Build instructions for Win32 in L<perlwin32>, or under the Cygnus environment
940in L<perlcygwin>.
941
942=item *
943
944The C<Win32::*> modules in L<Win32>.
945
946=item *
947
948The ActiveState Pages, http://www.activestate.com/
949
950=item *
951
952The Cygwin environment for Win32; F<README.cygwin> (installed
47dafe4d 953as L<perlcygwin>), http://www.cygwin.com/
c997b287
GS
954
955=item *
956
957The U/WIN environment for Win32,
cea6626f 958http://www.research.att.com/sw/tools/uwin/
c997b287 959
cea6626f 960=item *
d1e3b762 961
cea6626f 962Build instructions for OS/2, L<perlos2>
d1e3b762 963
e41182b5
GS
964=back
965
e41182b5
GS
966=head2 VMS
967
c997b287 968Perl on VMS is discussed in L<perlvms> in the perl distribution.
016930a6
JM
969
970The official name of VMS as of this writing is OpenVMS.
971
b7df3edc 972Perl on VMS can accept either VMS- or Unix-style file
e41182b5
GS
973specifications as in either of the following:
974
975 $ perl -ne "print if /perl_setup/i" SYS$LOGIN:LOGIN.COM
976 $ perl -ne "print if /perl_setup/i" /sys$login/login.com
977
978but not a mixture of both as in:
979
980 $ perl -ne "print if /perl_setup/i" sys$login:/login.com
981 Can't open sys$login:/login.com: file specification syntax error
982
983Interacting with Perl from the Digital Command Language (DCL) shell
984often requires a different set of quotation marks than Unix shells do.
985For example:
986
987 $ perl -e "print ""Hello, world.\n"""
988 Hello, world.
989
b7df3edc 990There are several ways to wrap your perl scripts in DCL F<.COM> files, if
e41182b5
GS
991you are so inclined. For example:
992
993 $ write sys$output "Hello from DCL!"
994 $ if p1 .eqs. ""
995 $ then perl -x 'f$environment("PROCEDURE")
996 $ else perl -x - 'p1 'p2 'p3 'p4 'p5 'p6 'p7 'p8
997 $ deck/dollars="__END__"
998 #!/usr/bin/perl
999
1000 print "Hello from Perl!\n";
1001
1002 __END__
1003 $ endif
1004
1005Do take care with C<$ ASSIGN/nolog/user SYS$COMMAND: SYS$INPUT> if your
c47ff5f1 1006perl-in-DCL script expects to do things like C<< $read = <STDIN>; >>.
e41182b5 1007
016930a6
JM
1008The VMS operating system has two filesystems, known as ODS-2 and ODS-5.
1009
1010For ODS-2, filenames are in the format "name.extension;version". The
1011maximum length for filenames is 39 characters, and the maximum length for
e41182b5
GS
1012extensions is also 39 characters. Version is a number from 1 to
101332767. Valid characters are C</[A-Z0-9$_-]/>.
1014
016930a6
JM
1015The ODS-2 filesystem is case-insensitive and does not preserve case.
1016Perl simulates this by converting all filenames to lowercase internally.
1017
1018For ODS-5, filenames may have almost any character in them and can include
1019Unicode characters. Characters that could be misinterpreted by the DCL
1020shell or file parsing utilities need to be prefixed with the C<^>
1021character, or replaced with hexadecimal characters prefixed with the
1022C<^> character. Such prefixing is only needed with the pathnames are
1023in VMS format in applications. Programs that can accept the UNIX format
1024of pathnames do not need the escape characters. The maximum length for
1025filenames is 255 characters. The ODS-5 file system can handle both
1026a case preserved and a case sensitive mode.
1027
1028ODS-5 is only available on the OpenVMS for 64 bit platforms.
1029
1030Support for the extended file specifications is being done as optional
1031settings to preserve backward compatibility with Perl scripts that
1032assume the previous VMS limitations.
1033
1034In general routines on VMS that get a UNIX format file specification
1035should return it in a UNIX format, and when they get a VMS format
1036specification they should return a VMS format unless they are documented
1037to do a conversion.
1038
1039For routines that generate return a file specification, VMS allows setting
1040if the C library which Perl is built on if it will be returned in VMS
1041format or in UNIX format.
1042
1043With the ODS-2 file system, there is not much difference in syntax of
1044filenames without paths for VMS or UNIX. With the extended character
1045set available with ODS-5 there can be a significant difference.
1046
1047Because of this, existing Perl scripts written for VMS were sometimes
1048treating VMS and UNIX filenames interchangeably. Without the extended
1049character set enabled, this behavior will mostly be maintained for
1050backwards compatibility.
1051
1052When extended characters are enabled with ODS-5, the handling of
1053UNIX formatted file specifications is to that of a UNIX system.
1054
1055VMS file specifications without extensions have a trailing dot. An
1056equivalent UNIX file specification should not show the trailing dot.
1057
1058The result of all of this, is that for VMS, for portable scripts, you
1059can not depend on Perl to present the filenames in lowercase, to be
1060case sensitive, and that the filenames could be returned in either
1061UNIX or VMS format.
1062
1063And if a routine returns a file specification, unless it is intended to
1064convert it, it should return it in the same format as it found it.
1065
1066C<readdir> by default has traditionally returned lowercased filenames.
1067When the ODS-5 support is enabled, it will return the exact case of the
1068filename on the disk.
1069
1070Files without extensions have a trailing period on them, so doing a
1071C<readdir> in the default mode with a file named F<A.;5> will
1072return F<a.> when VMS is (though that file could be opened with
0a47030a 1073C<open(FH, 'A')>).
e41182b5 1074
016930a6
JM
1075With support for extended file specifications and if C<opendir> was
1076given a UNIX format directory, a file named F<A.;5> will return F<a>
1077and optionally in the exact case on the disk. When C<opendir> is given
1078a VMS format directory, then C<readdir> should return F<a.>, and
1079again with the optionally the exact case.
1080
f34d0673 1081RMS had an eight level limit on directory depths from any rooted logical
1089a9e3
CB
1082(allowing 16 levels overall) prior to VMS 7.2, and even with versions of
1083VMS on VAX up through 7.3. Hence C<PERL_ROOT:[LIB.2.3.4.5.6.7.8]> is a
1084valid directory specification but C<PERL_ROOT:[LIB.2.3.4.5.6.7.8.9]> is
1085not. F<Makefile.PL> authors might have to take this into account, but at
1086least they can refer to the former as C</PERL_ROOT/lib/2/3/4/5/6/7/8/>.
1087
1088Pumpkings and module integrators can easily see whether files with too many
1089directory levels have snuck into the core by running the following in the
1090top-level source directory:
1091
1092 $ perl -ne "$_=~s/\s+.*//; print if scalar(split /\//) > 8;" < MANIFEST
1093
e41182b5 1094
6ab3f9cb 1095The VMS::Filespec module, which gets installed as part of the build
0a47030a
GS
1096process on VMS, is a pure Perl module that can easily be installed on
1097non-VMS platforms and can be helpful for conversions to and from RMS
016930a6
JM
1098native formats. It is also now the only way that you should check to
1099see if VMS is in a case sensitive mode.
e41182b5 1100
5e12dbfa
PP
1101What C<\n> represents depends on the type of file opened. It usually
1102represents C<\012> but it could also be C<\015>, C<\012>, C<\015\012>,
fa11829f 1103C<\000>, C<\040>, or nothing depending on the file organization and
5e12dbfa
PP
1104record format. The VMS::Stdio module provides access to the
1105special fopen() requirements of files with unusual attributes on VMS.
e41182b5
GS
1106
1107TCP/IP stacks are optional on VMS, so socket routines might not be
1108implemented. UDP sockets may not be supported.
1109
016930a6
JM
1110The TCP/IP library support for all current versions of VMS is dynamically
1111loaded if present, so even if the routines are configured, they may
1112return a status indicating that they are not implemented.
1113
e41182b5
GS
1114The value of C<$^O> on OpenVMS is "VMS". To determine the architecture
1115that you are running on without resorting to loading all of C<%Config>
1116you can examine the content of the C<@INC> array like so:
1117
1118 if (grep(/VMS_AXP/, @INC)) {
1119 print "I'm on Alpha!\n";
6ab3f9cb 1120
e41182b5
GS
1121 } elsif (grep(/VMS_VAX/, @INC)) {
1122 print "I'm on VAX!\n";
6ab3f9cb 1123
016930a6
JM
1124 } elsif (grep(/VMS_IA64/, @INC)) {
1125 print "I'm on IA64!\n";
1126
e41182b5
GS
1127 } else {
1128 print "I'm not so sure about where $^O is...\n";
1129 }
1130
016930a6
JM
1131In general, the significant differences should only be if Perl is running
1132on VMS_VAX or one of the 64 bit OpenVMS platforms.
1133
b7df3edc
GS
1134On VMS, perl determines the UTC offset from the C<SYS$TIMEZONE_DIFFERENTIAL>
1135logical name. Although the VMS epoch began at 17-NOV-1858 00:00:00.00,
6ab3f9cb 1136calls to C<localtime> are adjusted to count offsets from
b7df3edc 113701-JAN-1970 00:00:00.00, just like Unix.
6ab3f9cb 1138
e41182b5
GS
1139Also see:
1140
1141=over 4
1142
c997b287
GS
1143=item *
1144
1145F<README.vms> (installed as L<README_vms>), L<perlvms>
1146
1147=item *
1148
1089a9e3 1149vmsperl list, vmsperl-subscribe@perl.org
e41182b5 1150
c997b287 1151=item *
e41182b5 1152
c997b287 1153vmsperl on the web, http://www.sidhe.org/vmsperl/index.html
e41182b5
GS
1154
1155=back
1156
495c5fdc
GP
1157=head2 VOS
1158
9a997319
JH
1159Perl on VOS is discussed in F<README.vos> in the perl distribution
1160(installed as L<perlvos>). Perl on VOS can accept either VOS- or
1161Unix-style file specifications as in either of the following:
495c5fdc 1162
ea8b8ad2
VP
1163 $ perl -ne "print if /perl_setup/i" >system>notices
1164 $ perl -ne "print if /perl_setup/i" /system/notices
495c5fdc
GP
1165
1166or even a mixture of both as in:
1167
ea8b8ad2 1168 $ perl -ne "print if /perl_setup/i" >system/notices
495c5fdc 1169
b7df3edc 1170Even though VOS allows the slash character to appear in object
495c5fdc
GP
1171names, because the VOS port of Perl interprets it as a pathname
1172delimiting character, VOS files, directories, or links whose names
1173contain a slash character cannot be processed. Such files must be
a3dfe201 1174renamed before they can be processed by Perl. Note that VOS limits
b449fc5b
NC
1175file names to 32 or fewer characters, file names cannot start with a
1176C<-> character, or contain any character matching C<< tr/ !%&'()*+;<>?// >>
495c5fdc 1177
495c5fdc
GP
1178The value of C<$^O> on VOS is "VOS". To determine the architecture that
1179you are running on without resorting to loading all of C<%Config> you
c997b287 1180can examine the content of the @INC array like so:
495c5fdc 1181
24e8e380 1182 if ($^O =~ /VOS/) {
495c5fdc
GP
1183 print "I'm on a Stratus box!\n";
1184 } else {
1185 print "I'm not on a Stratus box!\n";
1186 die;
1187 }
1188
495c5fdc
GP
1189Also see:
1190
1191=over 4
1192
c997b287 1193=item *
495c5fdc 1194
cc07ed0b 1195F<README.vos> (installed as L<perlvos>)
c997b287
GS
1196
1197=item *
1198
1199The VOS mailing list.
495c5fdc
GP
1200
1201There is no specific mailing list for Perl on VOS. You can post
1202comments to the comp.sys.stratus newsgroup, or subscribe to the general
cc07ed0b 1203Stratus mailing list. Send a letter with "subscribe Info-Stratus" in
495c5fdc
GP
1204the message body to majordomo@list.stratagy.com.
1205
c997b287
GS
1206=item *
1207
cc07ed0b 1208VOS Perl on the web at http://ftp.stratus.com/pub/vos/posix/posix.html
495c5fdc
GP
1209
1210=back
1211
e41182b5
GS
1212=head2 EBCDIC Platforms
1213
1214Recent versions of Perl have been ported to platforms such as OS/400 on
d1e3b762
GS
1215AS/400 minicomputers as well as OS/390, VM/ESA, and BS2000 for S/390
1216Mainframes. Such computers use EBCDIC character sets internally (usually
0cc436d0
GS
1217Character Code Set ID 0037 for OS/400 and either 1047 or POSIX-BC for S/390
1218systems). On the mainframe perl currently works under the "Unix system
1219services for OS/390" (formerly known as OpenEdition), VM/ESA OpenEdition, or
1220the BS200 POSIX-BC system (BS2000 is supported in perl 5.6 and greater).
522b859a
JH
1221See L<perlos390> for details. Note that for OS/400 there is also a port of
1222Perl 5.8.1/5.9.0 or later to the PASE which is ASCII-based (as opposed to
1223ILE which is EBCDIC-based), see L<perlos400>.
e41182b5 1224
7c5ffed3
JH
1225As of R2.5 of USS for OS/390 and Version 2.3 of VM/ESA these Unix
1226sub-systems do not support the C<#!> shebang trick for script invocation.
1227Hence, on OS/390 and VM/ESA perl scripts can be executed with a header
1228similar to the following simple script:
e41182b5
GS
1229
1230 : # use perl
1231 eval 'exec /usr/local/bin/perl -S $0 ${1+"$@"}'
1232 if 0;
1233 #!/usr/local/bin/perl # just a comment really
1234
1235 print "Hello from perl!\n";
1236
d1e3b762
GS
1237OS/390 will support the C<#!> shebang trick in release 2.8 and beyond.
1238Calls to C<system> and backticks can use POSIX shell syntax on all
1239S/390 systems.
1240
b7df3edc 1241On the AS/400, if PERL5 is in your library list, you may need
6ab3f9cb
GS
1242to wrap your perl scripts in a CL procedure to invoke them like so:
1243
1244 BEGIN
1245 CALL PGM(PERL5/PERL) PARM('/QOpenSys/hello.pl')
1246 ENDPGM
1247
1248This will invoke the perl script F<hello.pl> in the root of the
1249QOpenSys file system. On the AS/400 calls to C<system> or backticks
1250must use CL syntax.
1251
e41182b5 1252On these platforms, bear in mind that the EBCDIC character set may have
0a47030a
GS
1253an effect on what happens with some perl functions (such as C<chr>,
1254C<pack>, C<print>, C<printf>, C<ord>, C<sort>, C<sprintf>, C<unpack>), as
1255well as bit-fiddling with ASCII constants using operators like C<^>, C<&>
1256and C<|>, not to mention dealing with socket interfaces to ASCII computers
6ab3f9cb 1257(see L<"Newlines">).
e41182b5 1258
b7df3edc
GS
1259Fortunately, most web servers for the mainframe will correctly
1260translate the C<\n> in the following statement to its ASCII equivalent
1261(C<\r> is the same under both Unix and OS/390 & VM/ESA):
e41182b5
GS
1262
1263 print "Content-type: text/html\r\n\r\n";
1264
d1e3b762 1265The values of C<$^O> on some of these platforms includes:
e41182b5 1266
d1e3b762
GS
1267 uname $^O $Config{'archname'}
1268 --------------------------------------------
1269 OS/390 os390 os390
1270 OS400 os400 os400
1271 POSIX-BC posix-bc BS2000-posix-bc
1272 VM/ESA vmesa vmesa
3c075c7d 1273
e41182b5
GS
1274Some simple tricks for determining if you are running on an EBCDIC
1275platform could include any of the following (perhaps all):
1276
1277 if ("\t" eq "\05") { print "EBCDIC may be spoken here!\n"; }
1278
1279 if (ord('A') == 193) { print "EBCDIC may be spoken here!\n"; }
1280
1281 if (chr(169) eq 'z') { print "EBCDIC may be spoken here!\n"; }
1282
b7df3edc 1283One thing you may not want to rely on is the EBCDIC encoding
0a47030a
GS
1284of punctuation characters since these may differ from code page to code
1285page (and once your module or script is rumoured to work with EBCDIC,
1286folks will want it to work with all EBCDIC character sets).
e41182b5
GS
1287
1288Also see:
1289
1290=over 4
1291
c997b287
GS
1292=item *
1293
dc5c060f 1294L<perlos390>, F<README.os390>, F<perlbs2000>, F<README.vmesa>,
bb462878 1295L<perlebcdic>.
c997b287
GS
1296
1297=item *
e41182b5
GS
1298
1299The perl-mvs@perl.org list is for discussion of porting issues as well as
1300general usage issues for all EBCDIC Perls. Send a message body of
1301"subscribe perl-mvs" to majordomo@perl.org.
1302
7ee27b7c 1303=item *
c997b287
GS
1304
1305AS/400 Perl information at
b1866b2d 1306http://as400.rochester.ibm.com/
d1e3b762 1307as well as on CPAN in the F<ports/> directory.
e41182b5
GS
1308
1309=back
1310
b8099c3d
CN
1311=head2 Acorn RISC OS
1312
b7df3edc
GS
1313Because Acorns use ASCII with newlines (C<\n>) in text files as C<\012> like
1314Unix, and because Unix filename emulation is turned on by default,
1315most simple scripts will probably work "out of the box". The native
6ab3f9cb 1316filesystem is modular, and individual filesystems are free to be
0a47030a 1317case-sensitive or insensitive, and are usually case-preserving. Some
b7df3edc 1318native filesystems have name length limits, which file and directory
6ab3f9cb
GS
1319names are silently truncated to fit. Scripts should be aware that the
1320standard filesystem currently has a name length limit of B<10>
1321characters, with up to 77 items in a directory, but other filesystems
0a47030a 1322may not impose such limitations.
b8099c3d
CN
1323
1324Native filenames are of the form
1325
6ab3f9cb 1326 Filesystem#Special_Field::DiskName.$.Directory.Directory.File
dd9f0070 1327
b8099c3d
CN
1328where
1329
1330 Special_Field is not usually present, but may contain . and $ .
1331 Filesystem =~ m|[A-Za-z0-9_]|
1332 DsicName =~ m|[A-Za-z0-9_/]|
1333 $ represents the root directory
1334 . is the path separator
1335 @ is the current directory (per filesystem but machine global)
1336 ^ is the parent directory
1337 Directory and File =~ m|[^\0- "\.\$\%\&:\@\\^\|\177]+|
1338
1339The default filename translation is roughly C<tr|/.|./|;>
1340
6ab3f9cb 1341Note that C<"ADFS::HardDisk.$.File" ne 'ADFS::HardDisk.$.File'> and that
0a47030a
GS
1342the second stage of C<$> interpolation in regular expressions will fall
1343foul of the C<$.> if scripts are not careful.
1344
1345Logical paths specified by system variables containing comma-separated
b7df3edc 1346search lists are also allowed; hence C<System:Modules> is a valid
0a47030a 1347filename, and the filesystem will prefix C<Modules> with each section of
6ab3f9cb 1348C<System$Path> until a name is made that points to an object on disk.
b7df3edc 1349Writing to a new file C<System:Modules> would be allowed only if
0a47030a
GS
1350C<System$Path> contains a single item list. The filesystem will also
1351expand system variables in filenames if enclosed in angle brackets, so
c47ff5f1 1352C<< <System$Dir>.Modules >> would look for the file
0a47030a 1353S<C<$ENV{'System$Dir'} . 'Modules'>>. The obvious implication of this is
c47ff5f1 1354that B<fully qualified filenames can start with C<< <> >>> and should
0a47030a 1355be protected when C<open> is used for input.
b8099c3d
CN
1356
1357Because C<.> was in use as a directory separator and filenames could not
1358be assumed to be unique after 10 characters, Acorn implemented the C
1359compiler to strip the trailing C<.c> C<.h> C<.s> and C<.o> suffix from
1360filenames specified in source code and store the respective files in
b7df3edc 1361subdirectories named after the suffix. Hence files are translated:
b8099c3d
CN
1362
1363 foo.h h.foo
1364 C:foo.h C:h.foo (logical path variable)
1365 sys/os.h sys.h.os (C compiler groks Unix-speak)
1366 10charname.c c.10charname
1367 10charname.o o.10charname
1368 11charname_.c c.11charname (assuming filesystem truncates at 10)
1369
1370The Unix emulation library's translation of filenames to native assumes
b7df3edc
GS
1371that this sort of translation is required, and it allows a user-defined list
1372of known suffixes that it will transpose in this fashion. This may
1373seem transparent, but consider that with these rules C<foo/bar/baz.h>
0a47030a
GS
1374and C<foo/bar/h/baz> both map to C<foo.bar.h.baz>, and that C<readdir> and
1375C<glob> cannot and do not attempt to emulate the reverse mapping. Other
6ab3f9cb 1376C<.>'s in filenames are translated to C</>.
0a47030a 1377
b7df3edc 1378As implied above, the environment accessed through C<%ENV> is global, and
0a47030a 1379the convention is that program specific environment variables are of the
6ab3f9cb
GS
1380form C<Program$Name>. Each filesystem maintains a current directory,
1381and the current filesystem's current directory is the B<global> current
b7df3edc
GS
1382directory. Consequently, sociable programs don't change the current
1383directory but rely on full pathnames, and programs (and Makefiles) cannot
0a47030a
GS
1384assume that they can spawn a child process which can change the current
1385directory without affecting its parent (and everyone else for that
1386matter).
1387
b7df3edc
GS
1388Because native operating system filehandles are global and are currently
1389allocated down from 255, with 0 being a reserved value, the Unix emulation
0a47030a
GS
1390library emulates Unix filehandles. Consequently, you can't rely on
1391passing C<STDIN>, C<STDOUT>, or C<STDERR> to your children.
1392
1393The desire of users to express filenames of the form
c47ff5f1 1394C<< <Foo$Dir>.Bar >> on the command line unquoted causes problems,
0a47030a 1395too: C<``> command output capture has to perform a guessing game. It
c47ff5f1 1396assumes that a string C<< <[^<>]+\$[^<>]> >> is a
0a47030a 1397reference to an environment variable, whereas anything else involving
c47ff5f1 1398C<< < >> or C<< > >> is redirection, and generally manages to be 99%
0a47030a
GS
1399right. Of course, the problem remains that scripts cannot rely on any
1400Unix tools being available, or that any tools found have Unix-like command
1401line arguments.
1402
b7df3edc
GS
1403Extensions and XS are, in theory, buildable by anyone using free
1404tools. In practice, many don't, as users of the Acorn platform are
1405used to binary distributions. MakeMaker does run, but no available
1406make currently copes with MakeMaker's makefiles; even if and when
1407this should be fixed, the lack of a Unix-like shell will cause
1408problems with makefile rules, especially lines of the form C<cd
1409sdbm && make all>, and anything using quoting.
b8099c3d
CN
1410
1411"S<RISC OS>" is the proper name for the operating system, but the value
1412in C<$^O> is "riscos" (because we don't like shouting).
1413
e41182b5
GS
1414=head2 Other perls
1415
b7df3edc 1416Perl has been ported to many platforms that do not fit into any of
cd86ed9d
JV
1417the categories listed above. Some, such as AmigaOS, BeOS, HP MPE/iX,
1418QNX, Plan 9, and VOS, have been well-integrated into the standard
1419Perl source code kit. You may need to see the F<ports/> directory
1420on CPAN for information, and possibly binaries, for the likes of:
1421aos, Atari ST, lynxos, riscos, Novell Netware, Tandem Guardian,
1422I<etc.> (Yes, we know that some of these OSes may fall under the
1423Unix category, but we are not a standards body.)
e41182b5 1424
d1e3b762
GS
1425Some approximate operating system names and their C<$^O> values
1426in the "OTHER" category include:
1427
1428 OS $^O $Config{'archname'}
1429 ------------------------------------------
1430 Amiga DOS amigaos m68k-amigos
cec2c193 1431 BeOS beos
d1e3b762
GS
1432 MPE/iX mpeix PA-RISC1.1
1433
e41182b5
GS
1434See also:
1435
1436=over 4
1437
c997b287
GS
1438=item *
1439
1440Amiga, F<README.amiga> (installed as L<perlamiga>).
1441
1442=item *
d1e3b762 1443
c997b287 1444Be OS, F<README.beos>
e41182b5 1445
c997b287
GS
1446=item *
1447
1448HP 300 MPE/iX, F<README.mpeix> and Mark Bixby's web page
e59066d8 1449http://www.bixby.org/mark/porting.html
c997b287
GS
1450
1451=item *
e41182b5 1452
6ab3f9cb 1453A free perl5-based PERL.NLM for Novell Netware is available in
c997b287 1454precompiled binary and source code form from http://www.novell.com/
6ab3f9cb 1455as well as from CPAN.
e41182b5 1456
13a2d996 1457=item *
c997b287 1458
e6f03d26 1459S<Plan 9>, F<README.plan9>
d1e3b762 1460
e41182b5
GS
1461=back
1462
e41182b5
GS
1463=head1 FUNCTION IMPLEMENTATIONS
1464
b7df3edc
GS
1465Listed below are functions that are either completely unimplemented
1466or else have been implemented differently on various platforms.
1467Following each description will be, in parentheses, a list of
1468platforms that the description applies to.
e41182b5 1469
b7df3edc
GS
1470The list may well be incomplete, or even wrong in some places. When
1471in doubt, consult the platform-specific README files in the Perl
1472source distribution, and any other documentation resources accompanying
1473a given port.
e41182b5 1474
0a47030a 1475Be aware, moreover, that even among Unix-ish systems there are variations.
e41182b5 1476
b7df3edc
GS
1477For many functions, you can also query C<%Config>, exported by
1478default from the Config module. For example, to check whether the
1479platform has the C<lstat> call, check C<$Config{d_lstat}>. See
1480L<Config> for a full description of available variables.
e41182b5
GS
1481
1482=head2 Alphabetical Listing of Perl Functions
1483
1484=over 8
1485
e41182b5
GS
1486=item -X
1487
038ae9a4
SH
1488C<-w> only inspects the read-only file attribute (FILE_ATTRIBUTE_READONLY),
1489which determines whether the directory can be deleted, not whether it can
1490be written to. Directories always have read and write access unless denied
1491by discretionary access control lists (DACLs). (S<Win32>)
1492
b7df3edc
GS
1493C<-r>, C<-w>, C<-x>, and C<-o> tell whether the file is accessible,
1494which may not reflect UIC-based file protections. (VMS)
e41182b5 1495
b8099c3d
CN
1496C<-s> by name on an open file will return the space reserved on disk,
1497rather than the current extent. C<-s> on an open filehandle returns the
b7df3edc 1498current size. (S<RISC OS>)
b8099c3d 1499
e41182b5 1500C<-R>, C<-W>, C<-X>, C<-O> are indistinguishable from C<-r>, C<-w>,
204ad8d5 1501C<-x>, C<-o>. (Win32, VMS, S<RISC OS>)
e41182b5 1502
287a962e 1503C<-g>, C<-k>, C<-l>, C<-u>, C<-A> are not particularly meaningful.
b8099c3d 1504(Win32, VMS, S<RISC OS>)
e41182b5 1505
287a962e
JD
1506C<-p> is not particularly meaningful. (VMS, S<RISC OS>)
1507
e41182b5
GS
1508C<-d> is true if passed a device spec without an explicit directory.
1509(VMS)
1510
e41182b5 1511C<-x> (or C<-X>) determine if a file ends in one of the executable
b7df3edc 1512suffixes. C<-S> is meaningless. (Win32)
e41182b5 1513
b8099c3d
CN
1514C<-x> (or C<-X>) determine if a file has an executable file type.
1515(S<RISC OS>)
1516
47cd99a4 1517=item atan2
519bc777
RGS
1518
1519Due to issues with various CPUs, math libraries, compilers, and standards,
1520results for C<atan2()> may vary depending on any combination of the above.
1521Perl attempts to conform to the Open Group/IEEE standards for the results
1522returned from C<atan2()>, but cannot force the issue if the system Perl is
1523run on does not allow it. (Tru64, HP-UX 10.20)
1524
1525The current version of the standards for C<atan2()> is available at
1526L<http://www.opengroup.org/onlinepubs/009695399/functions/atan2.html>.
1527
47cd99a4 1528=item binmode
e41182b5 1529
204ad8d5 1530Meaningless. (S<RISC OS>)
e41182b5
GS
1531
1532Reopens file and restores pointer; if function fails, underlying
1533filehandle may be closed, or pointer may be in a different position.
1534(VMS)
1535
1536The value returned by C<tell> may be affected after the call, and
1537the filehandle may be flushed. (Win32)
1538
47cd99a4 1539=item chmod
e41182b5 1540
e41182b5
GS
1541Only good for changing "owner" read-write access, "group", and "other"
1542bits are meaningless. (Win32)
1543
b8099c3d
CN
1544Only good for changing "owner" and "other" read-write access. (S<RISC OS>)
1545
495c5fdc
GP
1546Access permissions are mapped onto VOS access-control list changes. (VOS)
1547
4e51f8e4 1548The actual permissions set depend on the value of the C<CYGWIN>
789f0d36 1549in the SYSTEM environment settings. (Cygwin)
4e51f8e4 1550
47cd99a4 1551=item chown
e41182b5 1552
204ad8d5 1553Not implemented. (Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1554
1555Does nothing, but won't fail. (Win32)
1556
3fd80bd6
PG
1557A little funky, because VOS's notion of ownership is a little funky (VOS).
1558
e41182b5
GS
1559=item chroot
1560
204ad8d5 1561Not implemented. (Win32, VMS, S<Plan 9>, S<RISC OS>, VOS, VM/ESA)
e41182b5 1562
47cd99a4 1563=item crypt
e41182b5
GS
1564
1565May not be available if library or source was not provided when building
b8099c3d 1566perl. (Win32)
e41182b5 1567
47cd99a4 1568=item dbmclose
e41182b5 1569
e6f03d26 1570Not implemented. (VMS, S<Plan 9>, VOS)
e41182b5 1571
47cd99a4 1572=item dbmopen
e41182b5 1573
e6f03d26 1574Not implemented. (VMS, S<Plan 9>, VOS)
e41182b5 1575
47cd99a4 1576=item dump
e41182b5 1577
204ad8d5 1578Not useful. (S<RISC OS>)
e41182b5 1579
84d78eb7 1580Not supported. (Cygwin, Win32)
e41182b5 1581
b8099c3d 1582Invokes VMS debugger. (VMS)
e41182b5 1583
47cd99a4 1584=item exec
e41182b5 1585
7c5ffed3 1586Implemented via Spawn. (VM/ESA)
3c075c7d 1587
0f897271
GS
1588Does not automatically flush output handles on some platforms.
1589(SunOS, Solaris, HP-UX)
1590
fe12c0e8
MS
1591=item exit
1592
1593Emulates UNIX exit() (which considers C<exit 1> to indicate an error) by
1594mapping the C<1> to SS$_ABORT (C<44>). This behavior may be overridden
1595with the pragma C<use vmsish 'exit'>. As with the CRTL's exit()
1596function, C<exit 0> is also mapped to an exit status of SS$_NORMAL
1597(C<1>); this mapping cannot be overridden. Any other argument to exit()
016930a6
JM
1598is used directly as Perl's exit status. On VMS, unless the future
1599POSIX_EXIT mode is enabled, the exit code should always be a valid
1600VMS exit code and not a generic number. When the POSIX_EXIT mode is
1601enabled, a generic number will be encoded in a method compatible with
1602the C library _POSIX_EXIT macro so that it can be decoded by other
1603programs, particularly ones written in C, like the GNV package. (VMS)
fe12c0e8 1604
47cd99a4 1605=item fcntl
e41182b5 1606
016930a6
JM
1607Not implemented. (Win32)
1608Some functions available based on the version of VMS. (VMS)
e41182b5 1609
47cd99a4 1610=item flock
e41182b5 1611
204ad8d5 1612Not implemented (VMS, S<RISC OS>, VOS).
e41182b5
GS
1613
1614Available only on Windows NT (not on Windows 95). (Win32)
1615
1616=item fork
1617
204ad8d5 1618Not implemented. (AmigaOS, S<RISC OS>, VM/ESA, VMS)
0f897271
GS
1619
1620Emulated using multiple interpreters. See L<perlfork>. (Win32)
1621
1622Does not automatically flush output handles on some platforms.
1623(SunOS, Solaris, HP-UX)
e41182b5
GS
1624
1625=item getlogin
1626
204ad8d5 1627Not implemented. (S<RISC OS>)
e41182b5 1628
47cd99a4 1629=item getpgrp
e41182b5 1630
204ad8d5 1631Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5
GS
1632
1633=item getppid
1634
204ad8d5 1635Not implemented. (Win32, S<RISC OS>)
e41182b5 1636
47cd99a4 1637=item getpriority
e41182b5 1638
204ad8d5 1639Not implemented. (Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5 1640
47cd99a4 1641=item getpwnam
e41182b5 1642
204ad8d5 1643Not implemented. (Win32)
e41182b5 1644
b8099c3d
CN
1645Not useful. (S<RISC OS>)
1646
47cd99a4 1647=item getgrnam
e41182b5 1648
204ad8d5 1649Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5 1650
47cd99a4 1651=item getnetbyname
e41182b5 1652
204ad8d5 1653Not implemented. (Win32, S<Plan 9>)
e41182b5 1654
47cd99a4 1655=item getpwuid
e41182b5 1656
204ad8d5 1657Not implemented. (Win32)
e41182b5 1658
b8099c3d
CN
1659Not useful. (S<RISC OS>)
1660
47cd99a4 1661=item getgrgid
e41182b5 1662
204ad8d5 1663Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5 1664
47cd99a4 1665=item getnetbyaddr
e41182b5 1666
204ad8d5 1667Not implemented. (Win32, S<Plan 9>)
e41182b5 1668
47cd99a4 1669=item getprotobynumber
e41182b5 1670
47cd99a4 1671=item getservbyport
e41182b5 1672
e41182b5
GS
1673=item getpwent
1674
204ad8d5 1675Not implemented. (Win32, VM/ESA)
e41182b5
GS
1676
1677=item getgrent
1678
204ad8d5 1679Not implemented. (Win32, VMS, VM/ESA)
e41182b5 1680
ef5a6dd7
JH
1681=item gethostbyname
1682
1683C<gethostbyname('localhost')> does not work everywhere: you may have
204ad8d5 1684to use C<gethostbyname('127.0.0.1')>. (S<Irix 5>)
ef5a6dd7 1685
e41182b5
GS
1686=item gethostent
1687
204ad8d5 1688Not implemented. (Win32)
e41182b5
GS
1689
1690=item getnetent
1691
204ad8d5 1692Not implemented. (Win32, S<Plan 9>)
e41182b5
GS
1693
1694=item getprotoent
1695
204ad8d5 1696Not implemented. (Win32, S<Plan 9>)
e41182b5
GS
1697
1698=item getservent
1699
e6f03d26 1700Not implemented. (Win32, S<Plan 9>)
e41182b5 1701
47cd99a4 1702=item sethostent
e41182b5 1703
204ad8d5 1704Not implemented. (Win32, S<Plan 9>, S<RISC OS>)
e41182b5 1705
47cd99a4 1706=item setnetent
e41182b5 1707
204ad8d5 1708Not implemented. (Win32, S<Plan 9>, S<RISC OS>)
e41182b5 1709
47cd99a4 1710=item setprotoent
e41182b5 1711
204ad8d5 1712Not implemented. (Win32, S<Plan 9>, S<RISC OS>)
e41182b5 1713
47cd99a4 1714=item setservent
e41182b5 1715
e6f03d26 1716Not implemented. (S<Plan 9>, Win32, S<RISC OS>)
e41182b5
GS
1717
1718=item endpwent
1719
204ad8d5 1720Not implemented. (MPE/iX, VM/ESA, Win32)
e41182b5
GS
1721
1722=item endgrent
1723
204ad8d5 1724Not implemented. (MPE/iX, S<RISC OS>, VM/ESA, VMS, Win32)
e41182b5
GS
1725
1726=item endhostent
1727
204ad8d5 1728Not implemented. (Win32)
e41182b5
GS
1729
1730=item endnetent
1731
204ad8d5 1732Not implemented. (Win32, S<Plan 9>)
e41182b5
GS
1733
1734=item endprotoent
1735
204ad8d5 1736Not implemented. (Win32, S<Plan 9>)
e41182b5
GS
1737
1738=item endservent
1739
e6f03d26 1740Not implemented. (S<Plan 9>, Win32)
e41182b5
GS
1741
1742=item getsockopt SOCKET,LEVEL,OPTNAME
1743
e6f03d26 1744Not implemented. (S<Plan 9>)
e41182b5 1745
e41182b5
GS
1746=item glob
1747
63f87e49
GS
1748This operator is implemented via the File::Glob extension on most
1749platforms. See L<File::Glob> for portability information.
b8099c3d 1750
62aa5637
MS
1751=item gmtime
1752
461d5a49
MS
1753In theory, gmtime() is reliable from -2**63 to 2**63-1. However,
1754because work arounds in the implementation use floating point numbers,
1755it will become inaccurate as the time gets larger. This is a bug and
1756will be fixed in the future.
62aa5637 1757
e41182b5
GS
1758=item ioctl FILEHANDLE,FUNCTION,SCALAR
1759
1760Not implemented. (VMS)
1761
1762Available only for socket handles, and it does what the ioctlsocket() call
1763in the Winsock API does. (Win32)
1764
b8099c3d
CN
1765Available only for socket handles. (S<RISC OS>)
1766
47cd99a4 1767=item kill
e41182b5 1768
862b5365 1769Not implemented, hence not useful for taint checking. (S<RISC OS>)
e41182b5 1770
63f87e49
GS
1771C<kill()> doesn't have the semantics of C<raise()>, i.e. it doesn't send
1772a signal to the identified process like it does on Unix platforms.
1773Instead C<kill($sig, $pid)> terminates the process identified by $pid,
1774and makes it exit immediately with exit status $sig. As in Unix, if
1775$sig is 0 and the specified process exists, it returns true without
1776actually terminating it. (Win32)
e41182b5 1777
d0302514
JD
1778C<kill(-9, $pid)> will terminate the process specified by $pid and
1779recursively all child processes owned by it. This is different from
1780the Unix semantics, where the signal will be delivered to all
1781processes in the same process group as the process specified by
1782$pid. (Win32)
1783
016930a6
JM
1784Is not supported for process identification number of 0 or negative
1785numbers. (VMS)
1786
47cd99a4 1787=item link
e41182b5 1788
204ad8d5 1789Not implemented. (MPE/iX, S<RISC OS>)
e41182b5 1790
433acd8a
JH
1791Link count not updated because hard links are not quite that hard
1792(They are sort of half-way between hard and soft links). (AmigaOS)
1793
63d6c08b
JD
1794Hard links are implemented on Win32 under NTFS only. They are
1795natively supported on Windows 2000 and later. On Windows NT they
1796are implemented using the Windows POSIX subsystem support and the
1797Perl process will need Administrator or Backup Operator privileges
1798to create hard links.
a3dfe201 1799
016930a6
JM
1800Available on 64 bit OpenVMS 8.2 and later. (VMS)
1801
62aa5637
MS
1802=item localtime
1803
dc164757
MS
1804localtime() has the same range as L<gmtime>, but because time zone
1805rules change its accuracy for historical and future times may degrade
1806but usually by no more than an hour.
62aa5637 1807
e41182b5
GS
1808=item lstat
1809
016930a6 1810Not implemented. (S<RISC OS>)
e41182b5 1811
63f87e49 1812Return values (especially for device and inode) may be bogus. (Win32)
e41182b5 1813
47cd99a4 1814=item msgctl
e41182b5 1815
47cd99a4 1816=item msgget
e41182b5 1817
47cd99a4 1818=item msgsnd
e41182b5 1819
47cd99a4 1820=item msgrcv
e41182b5 1821
204ad8d5 1822Not implemented. (Win32, VMS, S<Plan 9>, S<RISC OS>, VOS)
e41182b5 1823
47cd99a4 1824=item open
e41182b5 1825
204ad8d5 1826open to C<|-> and C<-|> are unsupported. (Win32, S<RISC OS>)
e41182b5 1827
0f897271
GS
1828Opening a process does not automatically flush output handles on some
1829platforms. (SunOS, Solaris, HP-UX)
1830
e41182b5
GS
1831=item readlink
1832
b8099c3d 1833Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5 1834
47cd99a4 1835=item rename
c9b2b9d4
SS
1836
1837Can't move directories between directories on different logical volumes. (Win32)
1838
47cd99a4 1839=item select
e41182b5 1840
689c5c24 1841Only implemented on sockets. (Win32, VMS)
e41182b5 1842
b8099c3d
CN
1843Only reliable on sockets. (S<RISC OS>)
1844
76e05f0b 1845Note that the C<select FILEHANDLE> form is generally portable.
63f87e49 1846
47cd99a4 1847=item semctl
e41182b5 1848
47cd99a4 1849=item semget
e41182b5 1850
47cd99a4 1851=item semop
e41182b5 1852
204ad8d5 1853Not implemented. ( Win32, VMS, S<RISC OS>, VOS)
e41182b5 1854
a3dfe201
GS
1855=item setgrent
1856
204ad8d5 1857Not implemented. (MPE/iX, VMS, Win32, S<RISC OS>, VOS)
a3dfe201 1858
47cd99a4 1859=item setpgrp
e41182b5 1860
204ad8d5 1861Not implemented. (Win32, VMS, S<RISC OS>, VOS)
e41182b5 1862
47cd99a4 1863=item setpriority
e41182b5 1864
204ad8d5 1865Not implemented. (Win32, VMS, S<RISC OS>, VOS)
e41182b5 1866
a3dfe201
GS
1867=item setpwent
1868
204ad8d5 1869Not implemented. (MPE/iX, Win32, S<RISC OS>, VOS)
a3dfe201 1870
47cd99a4 1871=item setsockopt
e41182b5 1872
e6f03d26 1873Not implemented. (S<Plan 9>)
e41182b5 1874
47cd99a4 1875=item shmctl
e41182b5 1876
47cd99a4 1877=item shmget
e41182b5 1878
47cd99a4 1879=item shmread
e41182b5 1880
47cd99a4 1881=item shmwrite
e41182b5 1882
204ad8d5 1883Not implemented. (Win32, VMS, S<RISC OS>, VOS)
e41182b5 1884
47cd99a4 1885=item sockatmark
80cbd5ad
JH
1886
1887A relatively recent addition to socket functions, may not
1888be implemented even in UNIX platforms.
1889
47cd99a4 1890=item socketpair
e41182b5 1891
f38e12df 1892Not implemented. (S<RISC OS>, VOS, VM/ESA)
016930a6
JM
1893
1894Available on 64 bit OpenVMS 8.2 and later. (VMS)
e41182b5 1895
e41182b5
GS
1896=item stat
1897
d62e1b7f
JH
1898Platforms that do not have rdev, blksize, or blocks will return these
1899as '', so numeric comparison or manipulation of these fields may cause
1900'not numeric' warnings.
1901
3f1f789b 1902ctime not supported on UFS (S<Mac OS X>).
e41182b5 1903
95a3fe12
MS
1904ctime is creation time instead of inode change time (Win32).
1905
e41182b5
GS
1906device and inode are not meaningful. (Win32)
1907
1908device and inode are not necessarily reliable. (VMS)
1909
b8099c3d
CN
1910mtime, atime and ctime all return the last modification time. Device and
1911inode are not necessarily reliable. (S<RISC OS>)
1912
d62e1b7f
JH
1913dev, rdev, blksize, and blocks are not available. inode is not
1914meaningful and will differ between stat calls on the same file. (os2)
1915
73e9292c
JH
1916some versions of cygwin when doing a stat("foo") and if not finding it
1917may then attempt to stat("foo.exe") (Cygwin)
1918
1fafdf34
JD
1919On Win32 stat() needs to open the file to determine the link count
1920and update attributes that may have been changed through hard links.
1921Setting ${^WIN32_SLOPPY_STAT} to a true value speeds up stat() by
1922not performing this operation. (Win32)
1923
47cd99a4 1924=item symlink
e41182b5 1925
c73b03b7
JM
1926Not implemented. (Win32, S<RISC OS>)
1927
1928Implemented on 64 bit VMS 8.3. VMS requires the symbolic link to be in Unix
1929syntax if it is intended to resolve to a valid path.
e41182b5 1930
47cd99a4 1931=item syscall
e41182b5 1932
204ad8d5 1933Not implemented. (Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5 1934
47cd99a4 1935=item sysopen
f34d0673 1936
dd9f0070 1937The traditional "0", "1", and "2" MODEs are implemented with different
322422de
GS
1938numeric values on some systems. The flags exported by C<Fcntl>
1939(O_RDONLY, O_WRONLY, O_RDWR) should work everywhere though. (S<Mac
7c5ffed3 1940OS>, OS/390, VM/ESA)
f34d0673 1941
47cd99a4 1942=item system
e41182b5 1943
e41182b5 1944As an optimization, may not call the command shell specified in
b7df3edc 1945C<$ENV{PERL5SHELL}>. C<system(1, @args)> spawns an external
e41182b5
GS
1946process and immediately returns its process designator, without
1947waiting for it to terminate. Return value may be used subsequently
63f87e49
GS
1948in C<wait> or C<waitpid>. Failure to spawn() a subprocess is indicated
1949by setting $? to "255 << 8". C<$?> is set in a way compatible with
1950Unix (i.e. the exitstatus of the subprocess is obtained by "$? >> 8",
1951as described in the documentation). (Win32)
e41182b5 1952
b8099c3d
CN
1953There is no shell to process metacharacters, and the native standard is
1954to pass a command line terminated by "\n" "\r" or "\0" to the spawned
c47ff5f1 1955program. Redirection such as C<< > foo >> is performed (if at all) by
b8099c3d
CN
1956the run time library of the spawned program. C<system> I<list> will call
1957the Unix emulation library's C<exec> emulation, which attempts to provide
1958emulation of the stdin, stdout, stderr in force in the parent, providing
1959the child program uses a compatible version of the emulation library.
1960I<scalar> will call the native command line direct and no such emulation
1961of a child Unix program will exists. Mileage B<will> vary. (S<RISC OS>)
1962
0f897271
GS
1963Does not automatically flush output handles on some platforms.
1964(SunOS, Solaris, HP-UX)
1965
9bc98430
CB
1966The return value is POSIX-like (shifted up by 8 bits), which only allows
1967room for a made-up value derived from the severity bits of the native
196832-bit condition code (unless overridden by C<use vmsish 'status'>).
016930a6
JM
1969If the native condition code is one that has a POSIX value encoded, the
1970POSIX value will be decoded to extract the expected exit value.
9bc98430
CB
1971For more details see L<perlvms/$?>. (VMS)
1972
e41182b5
GS
1973=item times
1974
63f87e49
GS
1975"cumulative" times will be bogus. On anything other than Windows NT
1976or Windows 2000, "system" time will be bogus, and "user" time is
1977actually the time returned by the clock() function in the C runtime
1978library. (Win32)
e41182b5 1979
b8099c3d
CN
1980Not useful. (S<RISC OS>)
1981
47cd99a4 1982=item truncate
e41182b5 1983
6d738113 1984Not implemented. (Older versions of VMS)
e41182b5 1985
3fd80bd6 1986Truncation to same-or-shorter lengths only. (VOS)
495c5fdc 1987
4cfdb94f 1988If a FILEHANDLE is supplied, it must be writable and opened in append
e71a7dc8 1989mode (i.e., use C<<< open(FH, '>>filename') >>>
4cfdb94f
GS
1990or C<sysopen(FH,...,O_APPEND|O_RDWR)>. If a filename is supplied, it
1991should not be held open elsewhere. (Win32)
1992
e41182b5
GS
1993=item umask
1994
1995Returns undef where unavailable, as of version 5.005.
1996
b7df3edc
GS
1997C<umask> works but the correct permissions are set only when the file
1998is finally closed. (AmigaOS)
433acd8a 1999
47cd99a4 2000=item utime
e41182b5 2001
204ad8d5 2002Only the modification time is updated. (S<BeOS>, VMS, S<RISC OS>)
e41182b5 2003
322422de
GS
2004May not behave as expected. Behavior depends on the C runtime
2005library's implementation of utime(), and the filesystem being
2006used. The FAT filesystem typically does not support an "access
2007time" field, and it may limit timestamps to a granularity of
2008two seconds. (Win32)
e41182b5
GS
2009
2010=item wait
2011
47cd99a4 2012=item waitpid
e41182b5 2013
e41182b5 2014Can only be applied to process handles returned for processes spawned
a6f858fb 2015using C<system(1, ...)> or pseudo processes created with C<fork()>. (Win32)
e41182b5 2016
b8099c3d
CN
2017Not useful. (S<RISC OS>)
2018
e41182b5
GS
2019=back
2020
2021
ba58ab26
JH
2022=head1 Supported Platforms
2023
522b859a 2024As of July 2002 (the Perl release 5.8.0), the following platforms are
cec2c193 2025able to build Perl from the standard source code distribution
e59066d8 2026available at http://www.cpan.org/src/
cec2c193
JH
2027
2028 AIX
2029 BeOS
6f683aa2 2030 BSD/OS (BSDi)
cec2c193
JH
2031 Cygwin
2032 DG/UX
811b48f2 2033 DOS DJGPP 1)
cec2c193
JH
2034 DYNIX/ptx
2035 EPOC R5
2036 FreeBSD
6f683aa2 2037 HI-UXMPP (Hitachi) (5.8.0 worked but we didn't know it)
cec2c193
JH
2038 HP-UX
2039 IRIX
2040 Linux
8939ba94 2041 Mac OS Classic
6f683aa2 2042 Mac OS X (Darwin)
cec2c193
JH
2043 MPE/iX
2044 NetBSD
2045 NetWare
2046 NonStop-UX
6f683aa2 2047 ReliantUNIX (formerly SINIX)
cec2c193 2048 OpenBSD
6f683aa2 2049 OpenVMS (formerly VMS)
3ebac25b 2050 Open UNIX (Unixware) (since Perl 5.8.1/5.9.0)
cec2c193 2051 OS/2
522b859a 2052 OS/400 (using the PASE) (since Perl 5.8.1/5.9.0)
70de81db 2053 PowerUX
6f683aa2 2054 POSIX-BC (formerly BS2000)
cec2c193
JH
2055 QNX
2056 Solaris
70de81db 2057 SunOS 4
6f683aa2
JH
2058 SUPER-UX (NEC)
2059 Tru64 UNIX (formerly DEC OSF/1, Digital UNIX)
cec2c193
JH
2060 UNICOS
2061 UNICOS/mk
2062 UTS
2063 VOS
811b48f2 2064 Win95/98/ME/2K/XP 2)
c40b5d1d 2065 WinCE
6f683aa2 2066 z/OS (formerly OS/390)
cec2c193 2067 VM/ESA
ba58ab26 2068
811b48f2
JH
2069 1) in DOS mode either the DOS or OS/2 ports can be used
2070 2) compilers: Borland, MinGW (GCC), VC6
cec2c193 2071
c40b5d1d 2072The following platforms worked with the previous releases (5.6 and
cec2c193
JH
20735.7), but we did not manage either to fix or to test these in time
2074for the 5.8.0 release. There is a very good chance that many of these
70de81db 2075will work fine with the 5.8.0.
cec2c193 2076
8da2b1be 2077 BSD/OS
cec2c193
JH
2078 DomainOS
2079 Hurd
2080 LynxOS
2081 MachTen
2082 PowerMAX
2083 SCO SV
cec2c193
JH
2084 SVR4
2085 Unixware
2086 Windows 3.1
ba58ab26 2087
70de81db
JH
2088Known to be broken for 5.8.0 (but 5.6.1 and 5.7.2 can be used):
2089
2090 AmigaOS
2091
ba58ab26 2092The following platforms have been known to build Perl from source in
fd46a41b
JH
2093the past (5.005_03 and earlier), but we haven't been able to verify
2094their status for the current release, either because the
2095hardware/software platforms are rare or because we don't have an
2096active champion on these platforms--or both. They used to work,
2097though, so go ahead and try compiling them, and let perlbug@perl.org
2098of any trouble.
ba58ab26 2099
cec2c193
JH
2100 3b1
2101 A/UX
cec2c193
JH
2102 ConvexOS
2103 CX/UX
2104 DC/OSx
2105 DDE SMES
2106 DOS EMX
2107 Dynix
2108 EP/IX
2109 ESIX
2110 FPS
2111 GENIX
2112 Greenhills
2113 ISC
2114 MachTen 68k
cec2c193
JH
2115 MPC
2116 NEWS-OS
2117 NextSTEP
2118 OpenSTEP
2119 Opus
2120 Plan 9
cec2c193 2121 RISC/os
8da2b1be 2122 SCO ODT/OSR
cec2c193
JH
2123 Stellar
2124 SVR2
2125 TI1500
2126 TitanOS
2127 Ultrix
2128 Unisys Dynix
ba58ab26
JH
2129
2130The following platforms have their own source code distributions and
1577cd80 2131binaries available via http://www.cpan.org/ports/
ba58ab26 2132
cec2c193 2133 Perl release
ba58ab26 2134
522b859a 2135 OS/400 (ILE) 5.005_02
cec2c193 2136 Tandem Guardian 5.004
ba58ab26
JH
2137
2138The following platforms have only binaries available via
a93751fa 2139http://www.cpan.org/ports/index.html :
ba58ab26 2140
cec2c193 2141 Perl release
ba58ab26 2142
cec2c193
JH
2143 Acorn RISCOS 5.005_02
2144 AOS 5.002
2145 LynxOS 5.004_02
ba58ab26
JH
2146
2147Although we do suggest that you always build your own Perl from
2148the source code, both for maximal configurability and for security,
2149in case you are in a hurry you can check
a93751fa 2150http://www.cpan.org/ports/index.html for binary distributions.
ba58ab26 2151
c997b287
GS
2152=head1 SEE ALSO
2153
cec2c193 2154L<perlaix>, L<perlamiga>, L<perlapollo>, L<perlbeos>, L<perlbs2000>,
18a271bd 2155L<perlce>, L<perlcygwin>, L<perldgux>, L<perldos>, L<perlepoc>,
469e7be4 2156L<perlebcdic>, L<perlfreebsd>, L<perlhurd>, L<perlhpux>, L<perlirix>,
e94c1c05 2157L<perlmacos>, L<perlmacosx>, L<perlmpeix>,
522b859a
JH
2158L<perlnetware>, L<perlos2>, L<perlos390>, L<perlos400>,
2159L<perlplan9>, L<perlqnx>, L<perlsolaris>, L<perltru64>,
2160L<perlunicode>, L<perlvmesa>, L<perlvms>, L<perlvos>,
2161L<perlwin32>, and L<Win32>.
c997b287 2162
e41182b5
GS
2163=head1 AUTHORS / CONTRIBUTORS
2164
06e9666b 2165Abigail <abigail@foad.org>,
c47ff5f1
GS
2166Charles Bailey <bailey@newman.upenn.edu>,
2167Graham Barr <gbarr@pobox.com>,
2168Tom Christiansen <tchrist@perl.com>,
06e9666b 2169Nicholas Clark <nick@ccl4.org>,
c47ff5f1 2170Thomas Dorner <Thomas.Dorner@start.de>,
06e9666b
A
2171Andy Dougherty <doughera@lafayette.edu>,
2172Dominic Dunlop <domo@computer.org>,
2173Neale Ferguson <neale@vma.tabnsw.com.au>,
c47ff5f1 2174David J. Fiander <davidf@mks.com>,
3fd80bd6 2175Paul Green <Paul.Green@stratus.com>,
06e9666b 2176M.J.T. Guy <mjtg@cam.ac.uk>,
61f30a5e 2177Jarkko Hietaniemi <jhi@iki.fi>,
c47ff5f1 2178Luther Huffman <lutherh@stratcom.com>,
06e9666b
A
2179Nick Ing-Simmons <nick@ing-simmons.net>,
2180Andreas J. KE<ouml>nig <a.koenig@mind.de>,
c47ff5f1
GS
2181Markus Laker <mlaker@contax.co.uk>,
2182Andrew M. Langmead <aml@world.std.com>,
2183Larry Moore <ljmoore@freespace.net>,
2184Paul Moore <Paul.Moore@uk.origin-it.com>,
2185Chris Nandor <pudge@pobox.com>,
1afc07ec 2186Matthias Neeracher <neeracher@mac.com>,
e71a7dc8 2187Philip Newton <pne@cpan.org>,
c47ff5f1
GS
2188Gary Ng <71564.1743@CompuServe.COM>,
2189Tom Phoenix <rootbeer@teleport.com>,
2190AndrE<eacute> Pirard <A.Pirard@ulg.ac.be>,
2191Peter Prymmer <pvhp@forte.com>,
2192Hugo van der Sanden <hv@crypt0.demon.co.uk>,
2193Gurusamy Sarathy <gsar@activestate.com>,
2194Paul J. Schinder <schinder@pobox.com>,
2195Michael G Schwern <schwern@pobox.com>,
06e9666b 2196Dan Sugalski <dan@sidhe.org>,
c47ff5f1 2197Nathan Torkington <gnat@frii.com>.
016930a6 2198John Malmberg <wb8tyw@qsl.net>