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1=head1 NAME
2
3perlport - Writing portable Perl
4
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5=head1 DESCRIPTION
6
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7Perl runs on numerous operating systems. While most of them share
8much in common, they also have their own unique features.
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9
10This document is meant to help you to find out what constitutes portable
b7df3edc 11Perl code. That way once you make a decision to write portably,
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12you know where the lines are drawn, and you can stay within them.
13
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14There is a tradeoff between taking full advantage of one particular
15type of computer and taking advantage of a full range of them.
16Naturally, as you broaden your range and become more diverse, the
17common factors drop, and you are left with an increasingly smaller
18area of common ground in which you can operate to accomplish a
19particular task. Thus, when you begin attacking a problem, it is
20important to consider under which part of the tradeoff curve you
21want to operate. Specifically, you must decide whether it is
22important that the task that you are coding have the full generality
23of being portable, or whether to just get the job done right now.
24This is the hardest choice to be made. The rest is easy, because
25Perl provides many choices, whichever way you want to approach your
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26problem.
27
28Looking at it another way, writing portable code is usually about
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29willfully limiting your available choices. Naturally, it takes
30discipline and sacrifice to do that. The product of portability
31and convenience may be a constant. You have been warned.
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32
33Be aware of two important points:
34
35=over 4
36
37=item Not all Perl programs have to be portable
38
b7df3edc 39There is no reason you should not use Perl as a language to glue Unix
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40tools together, or to prototype a Macintosh application, or to manage the
41Windows registry. If it makes no sense to aim for portability for one
42reason or another in a given program, then don't bother.
43
b7df3edc 44=item Nearly all of Perl already I<is> portable
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45
46Don't be fooled into thinking that it is hard to create portable Perl
47code. It isn't. Perl tries its level-best to bridge the gaps between
48what's available on different platforms, and all the means available to
49use those features. Thus almost all Perl code runs on any machine
6ab3f9cb 50without modification. But there are some significant issues in
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51writing portable code, and this document is entirely about those issues.
52
53=back
54
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55Here's the general rule: When you approach a task commonly done
56using a whole range of platforms, think about writing portable
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57code. That way, you don't sacrifice much by way of the implementation
58choices you can avail yourself of, and at the same time you can give
59your users lots of platform choices. On the other hand, when you have to
60take advantage of some unique feature of a particular platform, as is
61often the case with systems programming (whether for Unix, Windows,
62S<Mac OS>, VMS, etc.), consider writing platform-specific code.
63
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64When the code will run on only two or three operating systems, you
65may need to consider only the differences of those particular systems.
66The important thing is to decide where the code will run and to be
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67deliberate in your decision.
68
69The material below is separated into three main sections: main issues of
70portability (L<"ISSUES">, platform-specific issues (L<"PLATFORMS">, and
b7df3edc 71built-in perl functions that behave differently on various ports
0a47030a 72(L<"FUNCTION IMPLEMENTATIONS">.
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73
74This information should not be considered complete; it includes possibly
b8099c3d 75transient information about idiosyncrasies of some of the ports, almost
b7df3edc 76all of which are in a state of constant evolution. Thus, this material
e41182b5 77should be considered a perpetual work in progress
cc07ed0b 78(C<< <IMG SRC="yellow_sign.gif" ALT="Under Construction"> >>).
e41182b5 79
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80=head1 ISSUES
81
82=head2 Newlines
83
638bc118 84In most operating systems, lines in files are terminated by newlines.
e41182b5 85Just what is used as a newline may vary from OS to OS. Unix
b7df3edc 86traditionally uses C<\012>, one type of DOSish I/O uses C<\015\012>,
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87and S<Mac OS> uses C<\015>.
88
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89Perl uses C<\n> to represent the "logical" newline, where what is
90logical may depend on the platform in use. In MacPerl, C<\n> always
91means C<\015>. In DOSish perls, C<\n> usually means C<\012>, but
92when accessing a file in "text" mode, STDIO translates it to (or
56d7751a 93from) C<\015\012>, depending on whether you're reading or writing.
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94Unix does the same thing on ttys in canonical mode. C<\015\012>
95is commonly referred to as CRLF.
96
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97A common cause of unportable programs is the misuse of chop() to trim
98newlines:
99
100 # XXX UNPORTABLE!
101 while(<FILE>) {
102 chop;
103 @array = split(/:/);
104 #...
105 }
106
8939ba94 107You can get away with this on Unix and Mac OS (they have a single
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108character end-of-line), but the same program will break under DOSish
109perls because you're only chop()ing half the end-of-line. Instead,
110chomp() should be used to trim newlines. The Dunce::Files module can
111help audit your code for misuses of chop().
112
113When dealing with binary files (or text files in binary mode) be sure
114to explicitly set $/ to the appropriate value for your file format
115before using chomp().
116
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117Because of the "text" mode translation, DOSish perls have limitations
118in using C<seek> and C<tell> on a file accessed in "text" mode.
119Stick to C<seek>-ing to locations you got from C<tell> (and no
120others), and you are usually free to use C<seek> and C<tell> even
121in "text" mode. Using C<seek> or C<tell> or other file operations
122may be non-portable. If you use C<binmode> on a file, however, you
123can usually C<seek> and C<tell> with arbitrary values in safety.
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124
125A common misconception in socket programming is that C<\n> eq C<\012>
0a47030a 126everywhere. When using protocols such as common Internet protocols,
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127C<\012> and C<\015> are called for specifically, and the values of
128the logical C<\n> and C<\r> (carriage return) are not reliable.
129
130 print SOCKET "Hi there, client!\r\n"; # WRONG
131 print SOCKET "Hi there, client!\015\012"; # RIGHT
132
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133However, using C<\015\012> (or C<\cM\cJ>, or C<\x0D\x0A>) can be tedious
134and unsightly, as well as confusing to those maintaining the code. As
6ab3f9cb 135such, the Socket module supplies the Right Thing for those who want it.
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136
137 use Socket qw(:DEFAULT :crlf);
138 print SOCKET "Hi there, client!$CRLF" # RIGHT
139
6ab3f9cb 140When reading from a socket, remember that the default input record
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141separator C<$/> is C<\n>, but robust socket code will recognize as
142either C<\012> or C<\015\012> as end of line:
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143
144 while (<SOCKET>) {
145 # ...
146 }
147
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148Because both CRLF and LF end in LF, the input record separator can
149be set to LF and any CR stripped later. Better to write:
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150
151 use Socket qw(:DEFAULT :crlf);
152 local($/) = LF; # not needed if $/ is already \012
153
154 while (<SOCKET>) {
155 s/$CR?$LF/\n/; # not sure if socket uses LF or CRLF, OK
156 # s/\015?\012/\n/; # same thing
157 }
158
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159This example is preferred over the previous one--even for Unix
160platforms--because now any C<\015>'s (C<\cM>'s) are stripped out
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161(and there was much rejoicing).
162
6ab3f9cb 163Similarly, functions that return text data--such as a function that
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164fetches a web page--should sometimes translate newlines before
165returning the data, if they've not yet been translated to the local
166newline representation. A single line of code will often suffice:
2ee0eb3c 167
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168 $data =~ s/\015?\012/\n/g;
169 return $data;
2ee0eb3c 170
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171Some of this may be confusing. Here's a handy reference to the ASCII CR
172and LF characters. You can print it out and stick it in your wallet.
173
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174 LF eq \012 eq \x0A eq \cJ eq chr(10) eq ASCII 10
175 CR eq \015 eq \x0D eq \cM eq chr(13) eq ASCII 13
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176
177 | Unix | DOS | Mac |
178 ---------------------------
179 \n | LF | LF | CR |
180 \r | CR | CR | LF |
181 \n * | LF | CRLF | CR |
182 \r * | CR | CR | LF |
183 ---------------------------
184 * text-mode STDIO
185
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186The Unix column assumes that you are not accessing a serial line
187(like a tty) in canonical mode. If you are, then CR on input becomes
188"\n", and "\n" on output becomes CRLF.
189
6ab3f9cb 190These are just the most common definitions of C<\n> and C<\r> in Perl.
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191There may well be others. For example, on an EBCDIC implementation
192such as z/OS (OS/390) or OS/400 (using the ILE, the PASE is ASCII-based)
193the above material is similar to "Unix" but the code numbers change:
74555b7a 194
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195 LF eq \025 eq \x15 eq \cU eq chr(21) eq CP-1047 21
196 LF eq \045 eq \x25 eq chr(37) eq CP-0037 37
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197 CR eq \015 eq \x0D eq \cM eq chr(13) eq CP-1047 13
198 CR eq \015 eq \x0D eq \cM eq chr(13) eq CP-0037 13
199
200 | z/OS | OS/400 |
201 ----------------------
202 \n | LF | LF |
203 \r | CR | CR |
204 \n * | LF | LF |
205 \r * | CR | CR |
206 ----------------------
207 * text-mode STDIO
6ab3f9cb 208
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209=head2 Numbers endianness and Width
210
211Different CPUs store integers and floating point numbers in different
212orders (called I<endianness>) and widths (32-bit and 64-bit being the
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213most common today). This affects your programs when they attempt to transfer
214numbers in binary format from one CPU architecture to another,
215usually either "live" via network connection, or by storing the
216numbers to secondary storage such as a disk file or tape.
322422de 217
b7df3edc 218Conflicting storage orders make utter mess out of the numbers. If a
d1e3b762 219little-endian host (Intel, VAX) stores 0x12345678 (305419896 in
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220decimal), a big-endian host (Motorola, Sparc, PA) reads it as
2210x78563412 (2018915346 in decimal). Alpha and MIPS can be either:
222Digital/Compaq used/uses them in little-endian mode; SGI/Cray uses
223them in big-endian mode. To avoid this problem in network (socket)
224connections use the C<pack> and C<unpack> formats C<n> and C<N>, the
225"network" orders. These are guaranteed to be portable.
322422de 226
7a4d2905 227As of perl 5.9.2, you can also use the C<E<gt>> and C<E<lt>> modifiers
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228to force big- or little-endian byte-order. This is useful if you want
229to store signed integers or 64-bit integers, for example.
230
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231You can explore the endianness of your platform by unpacking a
232data structure packed in native format such as:
233
234 print unpack("h*", pack("s2", 1, 2)), "\n";
235 # '10002000' on e.g. Intel x86 or Alpha 21064 in little-endian mode
236 # '00100020' on e.g. Motorola 68040
237
238If you need to distinguish between endian architectures you could use
239either of the variables set like so:
240
241 $is_big_endian = unpack("h*", pack("s", 1)) =~ /01/;
4375e838 242 $is_little_endian = unpack("h*", pack("s", 1)) =~ /^1/;
d1e3b762 243
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244Differing widths can cause truncation even between platforms of equal
245endianness. The platform of shorter width loses the upper parts of the
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246number. There is no good solution for this problem except to avoid
247transferring or storing raw binary numbers.
248
b7df3edc 249One can circumnavigate both these problems in two ways. Either
322422de 250transfer and store numbers always in text format, instead of raw
b7df3edc 251binary, or else consider using modules like Data::Dumper (included in
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252the standard distribution as of Perl 5.005) and Storable (included as
253of perl 5.8). Keeping all data as text significantly simplifies matters.
322422de 254
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255The v-strings are portable only up to v2147483647 (0x7FFFFFFF), that's
256how far EBCDIC, or more precisely UTF-EBCDIC will go.
257
433acd8a 258=head2 Files and Filesystems
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259
260Most platforms these days structure files in a hierarchical fashion.
b7df3edc 261So, it is reasonably safe to assume that all platforms support the
6ab3f9cb 262notion of a "path" to uniquely identify a file on the system. How
b7df3edc 263that path is really written, though, differs considerably.
e41182b5 264
4375e838 265Although similar, file path specifications differ between Unix,
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266Windows, S<Mac OS>, OS/2, VMS, VOS, S<RISC OS>, and probably others.
267Unix, for example, is one of the few OSes that has the elegant idea
268of a single root directory.
322422de 269
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270DOS, OS/2, VMS, VOS, and Windows can work similarly to Unix with C</>
271as path separator, or in their own idiosyncratic ways (such as having
272several root directories and various "unrooted" device files such NIL:
273and LPT:).
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274
275S<Mac OS> uses C<:> as a path separator instead of C</>.
276
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277The filesystem may support neither hard links (C<link>) nor
278symbolic links (C<symlink>, C<readlink>, C<lstat>).
433acd8a 279
6ab3f9cb 280The filesystem may support neither access timestamp nor change
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281timestamp (meaning that about the only portable timestamp is the
282modification timestamp), or one second granularity of any timestamps
283(e.g. the FAT filesystem limits the time granularity to two seconds).
284
74555b7a 285The "inode change timestamp" (the C<-C> filetest) may really be the
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286"creation timestamp" (which it is not in UNIX).
287
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288VOS perl can emulate Unix filenames with C</> as path separator. The
289native pathname characters greater-than, less-than, number-sign, and
290percent-sign are always accepted.
291
6ab3f9cb 292S<RISC OS> perl can emulate Unix filenames with C</> as path
322422de 293separator, or go native and use C<.> for path separator and C<:> to
6ab3f9cb 294signal filesystems and disk names.
e41182b5 295
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296Don't assume UNIX filesystem access semantics: that read, write,
297and execute are all the permissions there are, and even if they exist,
298that their semantics (for example what do r, w, and x mean on
299a directory) are the UNIX ones. The various UNIX/POSIX compatibility
300layers usually try to make interfaces like chmod() work, but sometimes
301there simply is no good mapping.
302
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303If all this is intimidating, have no (well, maybe only a little)
304fear. There are modules that can help. The File::Spec modules
305provide methods to do the Right Thing on whatever platform happens
306to be running the program.
e41182b5 307
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308 use File::Spec::Functions;
309 chdir(updir()); # go up one directory
310 $file = catfile(curdir(), 'temp', 'file.txt');
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311 # on Unix and Win32, './temp/file.txt'
312 # on Mac OS, ':temp:file.txt'
d1e3b762 313 # on VMS, '[.temp]file.txt'
e41182b5 314
b7df3edc 315File::Spec is available in the standard distribution as of version
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3165.004_05. File::Spec::Functions is only in File::Spec 0.7 and later,
317and some versions of perl come with version 0.6. If File::Spec
318is not updated to 0.7 or later, you must use the object-oriented
319interface from File::Spec (or upgrade File::Spec).
e41182b5 320
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321In general, production code should not have file paths hardcoded.
322Making them user-supplied or read from a configuration file is
323better, keeping in mind that file path syntax varies on different
324machines.
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325
326This is especially noticeable in scripts like Makefiles and test suites,
327which often assume C</> as a path separator for subdirectories.
328
b7df3edc 329Also of use is File::Basename from the standard distribution, which
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330splits a pathname into pieces (base filename, full path to directory,
331and file suffix).
332
19799a22 333Even when on a single platform (if you can call Unix a single platform),
b7df3edc 334remember not to count on the existence or the contents of particular
3c075c7d 335system-specific files or directories, like F</etc/passwd>,
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336F</etc/sendmail.conf>, F</etc/resolv.conf>, or even F</tmp/>. For
337example, F</etc/passwd> may exist but not contain the encrypted
338passwords, because the system is using some form of enhanced security.
339Or it may not contain all the accounts, because the system is using NIS.
3c075c7d 340If code does need to rely on such a file, include a description of the
b7df3edc 341file and its format in the code's documentation, then make it easy for
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342the user to override the default location of the file.
343
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344Don't assume a text file will end with a newline. They should,
345but people forget.
e41182b5 346
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347Do not have two files or directories of the same name with different
348case, like F<test.pl> and F<Test.pl>, as many platforms have
349case-insensitive (or at least case-forgiving) filenames. Also, try
350not to have non-word characters (except for C<.>) in the names, and
351keep them to the 8.3 convention, for maximum portability, onerous a
352burden though this may appear.
dd9f0070 353
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354Likewise, when using the AutoSplit module, try to keep your functions to
3558.3 naming and case-insensitive conventions; or, at the least,
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356make it so the resulting files have a unique (case-insensitively)
357first 8 characters.
358
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359Whitespace in filenames is tolerated on most systems, but not all,
360and even on systems where it might be tolerated, some utilities
fe829689 361might become confused by such whitespace.
ec481373 362
b7df3edc 363Many systems (DOS, VMS) cannot have more than one C<.> in their filenames.
433acd8a 364
c47ff5f1 365Don't assume C<< > >> won't be the first character of a filename.
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366Always use C<< < >> explicitly to open a file for reading, or even
367better, use the three-arg version of open, unless you want the user to
368be able to specify a pipe open.
0a47030a 369
fe829689 370 open(FILE, '<', $existing_file) or die $!;
0a47030a 371
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372If filenames might use strange characters, it is safest to open it
373with C<sysopen> instead of C<open>. C<open> is magic and can
c47ff5f1 374translate characters like C<< > >>, C<< < >>, and C<|>, which may
b7df3edc 375be the wrong thing to do. (Sometimes, though, it's the right thing.)
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376Three-arg open can also help protect against this translation in cases
377where it is undesirable.
e41182b5 378
ec481373 379Don't use C<:> as a part of a filename since many systems use that for
8939ba94 380their own semantics (Mac OS Classic for separating pathname components,
ec481373 381many networking schemes and utilities for separating the nodename and
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382the pathname, and so on). For the same reasons, avoid C<@>, C<;> and
383C<|>.
ec481373 384
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385Don't assume that in pathnames you can collapse two leading slashes
386C<//> into one: some networking and clustering filesystems have special
387semantics for that. Let the operating system to sort it out.
388
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389The I<portable filename characters> as defined by ANSI C are
390
391 a b c d e f g h i j k l m n o p q r t u v w x y z
392 A B C D E F G H I J K L M N O P Q R T U V W X Y Z
393 0 1 2 3 4 5 6 7 8 9
394 . _ -
395
08fef530 396and the "-" shouldn't be the first character. If you want to be
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397hypercorrect, stay case-insensitive and within the 8.3 naming
398convention (all the files and directories have to be unique within one
399directory if their names are lowercased and truncated to eight
400characters before the C<.>, if any, and to three characters after the
401C<.>, if any). (And do not use C<.>s in directory names.)
ec481373 402
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403=head2 System Interaction
404
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405Not all platforms provide a command line. These are usually platforms
406that rely primarily on a Graphical User Interface (GUI) for user
407interaction. A program requiring a command line interface might
408not work everywhere. This is probably for the user of the program
409to deal with, so don't stay up late worrying about it.
e41182b5 410
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411Some platforms can't delete or rename files held open by the system,
412this limitation may also apply to changing filesystem metainformation
413like file permissions or owners. Remember to C<close> files when you
414are done with them. Don't C<unlink> or C<rename> an open file. Don't
415C<tie> or C<open> a file already tied or opened; C<untie> or C<close>
416it first.
e41182b5 417
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418Don't open the same file more than once at a time for writing, as some
419operating systems put mandatory locks on such files.
420
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421Don't assume that write/modify permission on a directory gives the
422right to add or delete files/directories in that directory. That is
423filesystem specific: in some filesystems you need write/modify
424permission also (or even just) in the file/directory itself. In some
425filesystems (AFS, DFS) the permission to add/delete directory entries
426is a completely separate permission.
427
428Don't assume that a single C<unlink> completely gets rid of the file:
429some filesystems (most notably the ones in VMS) have versioned
430filesystems, and unlink() removes only the most recent one (it doesn't
431remove all the versions because by default the native tools on those
432platforms remove just the most recent version, too). The portable
433idiom to remove all the versions of a file is
434
94bb614c 435 1 while unlink "file";
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436
437This will terminate if the file is undeleteable for some reason
438(protected, not there, and so on).
439
e41182b5 440Don't count on a specific environment variable existing in C<%ENV>.
0a47030a 441Don't count on C<%ENV> entries being case-sensitive, or even
4a0d0822 442case-preserving. Don't try to clear %ENV by saying C<%ENV = ();>, or,
6be8f7a6 443if you really have to, make it conditional on C<$^O ne 'VMS'> since in
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444VMS the C<%ENV> table is much more than a per-process key-value string
445table.
e41182b5 446
d1e3b762 447Don't count on signals or C<%SIG> for anything.
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448
449Don't count on filename globbing. Use C<opendir>, C<readdir>, and
450C<closedir> instead.
451
b8099c3d 452Don't count on per-program environment variables, or per-program current
dd9f0070 453directories.
b8099c3d 454
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455Don't count on specific values of C<$!>, neither numeric nor
456especially the strings values-- users may switch their locales causing
457error messages to be translated into their languages. If you can
458trust a POSIXish environment, you can portably use the symbols defined
459by the Errno module, like ENOENT. And don't trust on the values of C<$!>
460at all except immediately after a failed system call.
3c075c7d 461
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462=head2 Command names versus file pathnames
463
464Don't assume that the name used to invoke a command or program with
465C<system> or C<exec> can also be used to test for the existence of the
466file that holds the executable code for that command or program.
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467First, many systems have "internal" commands that are built-in to the
468shell or OS and while these commands can be invoked, there is no
469corresponding file. Second, some operating systems (e.g., Cygwin,
470DJGPP, OS/2, and VOS) have required suffixes for executable files;
471these suffixes are generally permitted on the command name but are not
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472required. Thus, a command like "perl" might exist in a file named
473"perl", "perl.exe", or "perl.pm", depending on the operating system.
474The variable "_exe" in the Config module holds the executable suffix,
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475if any. Third, the VMS port carefully sets up $^X and
476$Config{perlpath} so that no further processing is required. This is
477just as well, because the matching regular expression used below would
478then have to deal with a possible trailing version number in the VMS
479file name.
a10d74f3
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480
481To convert $^X to a file pathname, taking account of the requirements
482of the various operating system possibilities, say:
483 use Config;
a10d74f3 484 $thisperl = $^X;
68fb0eb7
PG
485 if ($^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:
a10d74f3 489 use Config;
68fb0eb7
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490 $thisperl = $Config{perlpath};
491 if ($^O ne 'VMS')
492 {$thisperl .= $Config{_exe} unless $thisperl =~ m/$Config{_exe}$/i;}
a10d74f3 493
7137b697
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494=head2 Networking
495
496Don't assume that you can reach the public Internet.
497
498Don't assume that there is only one way to get through firewalls
499to the public Internet.
500
932f293e
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501Don't assume that you can reach outside world through any other port
502than 80, or some web proxy. ftp is blocked by many firewalls.
503
dbc6a9ce
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504Don't assume that you can send email by connecting to the local SMTP port.
505
7137b697 506Don't assume that you can reach yourself or any node by the name
dbc6a9ce 507'localhost'. The same goes for '127.0.0.1'. You will have to try both.
932f293e 508
86feb2c5
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509Don't assume that the host has only one network card, or that it
510can't bind to many virtual IP addresses.
932f293e
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511
512Don't assume a particular network device name.
7137b697 513
dbc6a9ce 514Don't assume a particular set of ioctl()s will work.
7137b697
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515
516Don't assume that you can ping hosts and get replies.
517
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518Don't assume that any particular port (service) will respond.
519
520Don't assume that Sys::Hostname() (or any other API or command)
521returns either a fully qualified hostname or a non-qualified hostname:
522it all depends on how the system had been configured. Also remember
523things like DHCP and NAT-- the hostname you get back might not be very
524useful.
525
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526All the above "don't":s may look daunting, and they are -- but the key
527is to degrade gracefully if one cannot reach the particular network
528service one wants. Croaking or hanging do not look very professional.
529
e41182b5
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530=head2 Interprocess Communication (IPC)
531
b7df3edc
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532In general, don't directly access the system in code meant to be
533portable. That means, no C<system>, C<exec>, C<fork>, C<pipe>,
534C<``>, C<qx//>, C<open> with a C<|>, nor any of the other things
535that makes being a perl hacker worth being.
e41182b5
GS
536
537Commands that launch external processes are generally supported on
b7df3edc
GS
538most platforms (though many of them do not support any type of
539forking). The problem with using them arises from what you invoke
540them on. External tools are often named differently on different
4375e838 541platforms, may not be available in the same location, might accept
b7df3edc
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542different arguments, can behave differently, and often present their
543results in a platform-dependent way. Thus, you should seldom depend
544on them to produce consistent results. (Then again, if you're calling
545I<netstat -a>, you probably don't expect it to run on both Unix and CP/M.)
e41182b5 546
b7df3edc 547One especially common bit of Perl code is opening a pipe to B<sendmail>:
e41182b5 548
b7df3edc
GS
549 open(MAIL, '|/usr/lib/sendmail -t')
550 or die "cannot fork sendmail: $!";
e41182b5
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551
552This is fine for systems programming when sendmail is known to be
553available. But it is not fine for many non-Unix systems, and even
554some Unix systems that may not have sendmail installed. If a portable
b7df3edc
GS
555solution is needed, see the various distributions on CPAN that deal
556with it. Mail::Mailer and Mail::Send in the MailTools distribution are
557commonly used, and provide several mailing methods, including mail,
558sendmail, and direct SMTP (via Net::SMTP) if a mail transfer agent is
559not available. Mail::Sendmail is a standalone module that provides
560simple, platform-independent mailing.
561
562The Unix System V IPC (C<msg*(), sem*(), shm*()>) is not available
563even on all Unix platforms.
e41182b5 564
a81e5e2e
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565Do not use either the bare result of C<pack("N", 10, 20, 30, 40)> or
566bare v-strings (such as C<v10.20.30.40>) to represent IPv4 addresses:
567both forms just pack the four bytes into network order. That this
568would be equal to the C language C<in_addr> struct (which is what the
569socket code internally uses) is not guaranteed. To be portable use
570the routines of the Socket extension, such as C<inet_aton()>,
571C<inet_ntoa()>, and C<sockaddr_in()>.
6b2463a0 572
e41182b5 573The rule of thumb for portable code is: Do it all in portable Perl, or
0a47030a
GS
574use a module (that may internally implement it with platform-specific
575code, but expose a common interface).
e41182b5 576
e41182b5
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577=head2 External Subroutines (XS)
578
b7df3edc 579XS code can usually be made to work with any platform, but dependent
e41182b5
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580libraries, header files, etc., might not be readily available or
581portable, or the XS code itself might be platform-specific, just as Perl
582code might be. If the libraries and headers are portable, then it is
583normally reasonable to make sure the XS code is portable, too.
584
b7df3edc
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585A different type of portability issue arises when writing XS code:
586availability of a C compiler on the end-user's system. C brings
587with it its own portability issues, and writing XS code will expose
588you to some of those. Writing purely in Perl is an easier way to
e41182b5
GS
589achieve portability.
590
e41182b5
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591=head2 Standard Modules
592
593In general, the standard modules work across platforms. Notable
6ab3f9cb 594exceptions are the CPAN module (which currently makes connections to external
e41182b5 595programs that may not be available), platform-specific modules (like
6ab3f9cb 596ExtUtils::MM_VMS), and DBM modules.
e41182b5 597
b7df3edc 598There is no one DBM module available on all platforms.
6ab3f9cb
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599SDBM_File and the others are generally available on all Unix and DOSish
600ports, but not in MacPerl, where only NBDM_File and DB_File are
0a47030a 601available.
e41182b5
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602
603The good news is that at least some DBM module should be available, and
6ab3f9cb 604AnyDBM_File will use whichever module it can find. Of course, then
b7df3edc
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605the code needs to be fairly strict, dropping to the greatest common
606factor (e.g., not exceeding 1K for each record), so that it will
6ab3f9cb 607work with any DBM module. See L<AnyDBM_File> for more details.
e41182b5 608
e41182b5
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609=head2 Time and Date
610
0a47030a 611The system's notion of time of day and calendar date is controlled in
b7df3edc 612widely different ways. Don't assume the timezone is stored in C<$ENV{TZ}>,
0a47030a 613and even if it is, don't assume that you can control the timezone through
c87488a3
HS
614that variable. Don't assume anything about the three-letter timezone
615abbreviations (for example that MST would be the Mountain Standard Time,
616it's been known to stand for Moscow Standard Time). If you need to
617use timezones, express them in some unambiguous format like the
618exact number of minutes offset from UTC, or the POSIX timezone
619format.
e41182b5 620
322422de 621Don't assume that the epoch starts at 00:00:00, January 1, 1970,
c87488a3
HS
622because that is OS- and implementation-specific. It is better to
623store a date in an unambiguous representation. The ISO 8601 standard
624defines YYYY-MM-DD as the date format, or YYYY-MM-DDTHH-MM-SS
625(that's a literal "T" separating the date from the time).
626Please do use the ISO 8601 instead of making us to guess what
627date 02/03/04 might be. ISO 8601 even sorts nicely as-is.
628A text representation (like "1987-12-18") can be easily converted
629into an OS-specific value using a module like Date::Parse.
630An array of values, such as those returned by C<localtime>, can be
631converted to an OS-specific representation using Time::Local.
322422de 632
19799a22
GS
633When calculating specific times, such as for tests in time or date modules,
634it may be appropriate to calculate an offset for the epoch.
b7df3edc 635
19799a22
GS
636 require Time::Local;
637 $offset = Time::Local::timegm(0, 0, 0, 1, 0, 70);
b7df3edc 638
19799a22
GS
639The value for C<$offset> in Unix will be C<0>, but in Mac OS will be
640some large number. C<$offset> can then be added to a Unix time value
641to get what should be the proper value on any system.
322422de 642
bbac04ed
RGS
643On Windows (at least), you shouldn't pass a negative value to C<gmtime> or
644C<localtime>.
645
322422de
GS
646=head2 Character sets and character encoding
647
ec481373
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648Assume very little about character sets.
649
650Assume nothing about numerical values (C<ord>, C<chr>) of characters.
651Do not use explicit code point ranges (like \xHH-\xHH); use for
652example symbolic character classes like C<[:print:]>.
653
654Do not assume that the alphabetic characters are encoded contiguously
655(in the numeric sense). There may be gaps.
656
657Do not assume anything about the ordering of the characters.
658The lowercase letters may come before or after the uppercase letters;
659the lowercase and uppercase may be interlaced so that both `a' and `A'
660come before `b'; the accented and other international characters may
661be interlaced so that E<auml> comes before `b'.
322422de
GS
662
663=head2 Internationalisation
664
b7df3edc
GS
665If you may assume POSIX (a rather large assumption), you may read
666more about the POSIX locale system from L<perllocale>. The locale
667system at least attempts to make things a little bit more portable,
668or at least more convenient and native-friendly for non-English
669users. The system affects character sets and encoding, and date
670and time formatting--amongst other things.
e41182b5 671
c87488a3
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672If you really want to be international, you should consider Unicode.
673See L<perluniintro> and L<perlunicode> for more information.
674
11264fdb
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675If you want to use non-ASCII bytes (outside the bytes 0x00..0x7f) in
676the "source code" of your code, to be portable you have to be explicit
677about what bytes they are. Someone might for example be using your
678code under a UTF-8 locale, in which case random native bytes might be
679illegal ("Malformed UTF-8 ...") This means that for example embedding
680ISO 8859-1 bytes beyond 0x7f into your strings might cause trouble
681later. If the bytes are native 8-bit bytes, you can use the C<bytes>
682pragma. If the bytes are in a string (regular expression being a
683curious string), you can often also use the C<\xHH> notation instead
684of embedding the bytes as-is. If they are in some particular legacy
685encoding (ether single-byte or something more complicated), you can
686use the C<encoding> pragma. (If you want to write your code in UTF-8,
687you can use either the C<utf8> pragma, or the C<encoding> pragma.)
688The C<bytes> and C<utf8> pragmata are available since Perl 5.6.0, and
689the C<encoding> pragma since Perl 5.8.0.
690
e41182b5
GS
691=head2 System Resources
692
0a47030a
GS
693If your code is destined for systems with severely constrained (or
694missing!) virtual memory systems then you want to be I<especially> mindful
695of avoiding wasteful constructs such as:
e41182b5
GS
696
697 # NOTE: this is no longer "bad" in perl5.005
698 for (0..10000000) {} # bad
699 for (my $x = 0; $x <= 10000000; ++$x) {} # good
700
701 @lines = <VERY_LARGE_FILE>; # bad
702
703 while (<FILE>) {$file .= $_} # sometimes bad
0a47030a 704 $file = join('', <FILE>); # better
e41182b5 705
b7df3edc
GS
706The last two constructs may appear unintuitive to most people. The
707first repeatedly grows a string, whereas the second allocates a
708large chunk of memory in one go. On some systems, the second is
709more efficient that the first.
0a47030a 710
e41182b5
GS
711=head2 Security
712
b7df3edc
GS
713Most multi-user platforms provide basic levels of security, usually
714implemented at the filesystem level. Some, however, do
a1667ba3 715not-- unfortunately. Thus the notion of user id, or "home" directory,
b7df3edc
GS
716or even the state of being logged-in, may be unrecognizable on many
717platforms. If you write programs that are security-conscious, it
718is usually best to know what type of system you will be running
719under so that you can write code explicitly for that platform (or
720class of platforms).
0a47030a 721
a1667ba3
JH
722Don't assume the UNIX filesystem access semantics: the operating
723system or the filesystem may be using some ACL systems, which are
724richer languages than the usual rwx. Even if the rwx exist,
725their semantics might be different.
726
727(From security viewpoint testing for permissions before attempting to
728do something is silly anyway: if one tries this, there is potential
729for race conditions-- someone or something might change the
730permissions between the permissions check and the actual operation.
731Just try the operation.)
732
733Don't assume the UNIX user and group semantics: especially, don't
2edcc0d9 734expect the C<< $< >> and C<< $> >> (or the C<$(> and C<$)>) to work
a1667ba3
JH
735for switching identities (or memberships).
736
737Don't assume set-uid and set-gid semantics. (And even if you do,
738think twice: set-uid and set-gid are a known can of security worms.)
739
e41182b5
GS
740=head2 Style
741
742For those times when it is necessary to have platform-specific code,
743consider keeping the platform-specific code in one place, making porting
6ab3f9cb 744to other platforms easier. Use the Config module and the special
0a47030a
GS
745variable C<$^O> to differentiate platforms, as described in
746L<"PLATFORMS">.
e41182b5 747
b7df3edc
GS
748Be careful in the tests you supply with your module or programs.
749Module code may be fully portable, but its tests might not be. This
750often happens when tests spawn off other processes or call external
751programs to aid in the testing, or when (as noted above) the tests
c87488a3
HS
752assume certain things about the filesystem and paths. Be careful not
753to depend on a specific output style for errors, such as when checking
754C<$!> after a failed system call. Using C<$!> for anything else than
755displaying it as output is doubtful (though see the Errno module for
756testing reasonably portably for error value). Some platforms expect
757a certain output format, and Perl on those platforms may have been
758adjusted accordingly. Most specifically, don't anchor a regex when
759testing an error value.
e41182b5 760
0a47030a 761=head1 CPAN Testers
e41182b5 762
0a47030a
GS
763Modules uploaded to CPAN are tested by a variety of volunteers on
764different platforms. These CPAN testers are notified by mail of each
e41182b5 765new upload, and reply to the list with PASS, FAIL, NA (not applicable to
0a47030a 766this platform), or UNKNOWN (unknown), along with any relevant notations.
e41182b5
GS
767
768The purpose of the testing is twofold: one, to help developers fix any
0a47030a 769problems in their code that crop up because of lack of testing on other
b7df3edc 770platforms; two, to provide users with information about whether
0a47030a 771a given module works on a given platform.
e41182b5
GS
772
773=over 4
774
775=item Mailing list: cpan-testers@perl.org
776
c997b287 777=item Testing results: http://testers.cpan.org/
e41182b5
GS
778
779=back
780
e41182b5
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781=head1 PLATFORMS
782
783As of version 5.002, Perl is built with a C<$^O> variable that
784indicates the operating system it was built on. This was implemented
b7df3edc
GS
785to help speed up code that would otherwise have to C<use Config>
786and use the value of C<$Config{osname}>. Of course, to get more
e41182b5
GS
787detailed information about the system, looking into C<%Config> is
788certainly recommended.
789
b7df3edc
GS
790C<%Config> cannot always be trusted, however, because it was built
791at compile time. If perl was built in one place, then transferred
792elsewhere, some values may be wrong. The values may even have been
793edited after the fact.
6ab3f9cb 794
e41182b5
GS
795=head2 Unix
796
797Perl works on a bewildering variety of Unix and Unix-like platforms (see
798e.g. most of the files in the F<hints/> directory in the source code kit).
799On most of these systems, the value of C<$^O> (hence C<$Config{'osname'}>,
d1e3b762
GS
800too) is determined either by lowercasing and stripping punctuation from the
801first field of the string returned by typing C<uname -a> (or a similar command)
802at the shell prompt or by testing the file system for the presence of
803uniquely named files such as a kernel or header file. Here, for example,
804are a few of the more popular Unix flavors:
e41182b5 805
b7df3edc 806 uname $^O $Config{'archname'}
6ab3f9cb 807 --------------------------------------------
b7df3edc 808 AIX aix aix
6ab3f9cb 809 BSD/OS bsdos i386-bsdos
e1516da7 810 Darwin darwin darwin
6ab3f9cb
GS
811 dgux dgux AViiON-dgux
812 DYNIX/ptx dynixptx i386-dynixptx
b7df3edc 813 FreeBSD freebsd freebsd-i386
d1e3b762 814 Linux linux arm-linux
b7df3edc 815 Linux linux i386-linux
6ab3f9cb
GS
816 Linux linux i586-linux
817 Linux linux ppc-linux
b7df3edc
GS
818 HP-UX hpux PA-RISC1.1
819 IRIX irix irix
b787fad4 820 Mac OS X darwin darwin
d1e3b762
GS
821 MachTen PPC machten powerpc-machten
822 NeXT 3 next next-fat
823 NeXT 4 next OPENSTEP-Mach
6ab3f9cb 824 openbsd openbsd i386-openbsd
b7df3edc 825 OSF1 dec_osf alpha-dec_osf
6ab3f9cb
GS
826 reliantunix-n svr4 RM400-svr4
827 SCO_SV sco_sv i386-sco_sv
828 SINIX-N svr4 RM400-svr4
829 sn4609 unicos CRAY_C90-unicos
830 sn6521 unicosmk t3e-unicosmk
831 sn9617 unicos CRAY_J90-unicos
b7df3edc
GS
832 SunOS solaris sun4-solaris
833 SunOS solaris i86pc-solaris
834 SunOS4 sunos sun4-sunos
e41182b5 835
b7df3edc
GS
836Because the value of C<$Config{archname}> may depend on the
837hardware architecture, it can vary more than the value of C<$^O>.
6ab3f9cb 838
e41182b5
GS
839=head2 DOS and Derivatives
840
b7df3edc 841Perl has long been ported to Intel-style microcomputers running under
e41182b5
GS
842systems like PC-DOS, MS-DOS, OS/2, and most Windows platforms you can
843bring yourself to mention (except for Windows CE, if you count that).
b7df3edc 844Users familiar with I<COMMAND.COM> or I<CMD.EXE> style shells should
e41182b5
GS
845be aware that each of these file specifications may have subtle
846differences:
847
848 $filespec0 = "c:/foo/bar/file.txt";
849 $filespec1 = "c:\\foo\\bar\\file.txt";
850 $filespec2 = 'c:\foo\bar\file.txt';
851 $filespec3 = 'c:\\foo\\bar\\file.txt';
852
b7df3edc
GS
853System calls accept either C</> or C<\> as the path separator.
854However, many command-line utilities of DOS vintage treat C</> as
855the option prefix, so may get confused by filenames containing C</>.
856Aside from calling any external programs, C</> will work just fine,
857and probably better, as it is more consistent with popular usage,
858and avoids the problem of remembering what to backwhack and what
859not to.
e41182b5 860
b7df3edc
GS
861The DOS FAT filesystem can accommodate only "8.3" style filenames. Under
862the "case-insensitive, but case-preserving" HPFS (OS/2) and NTFS (NT)
0a47030a 863filesystems you may have to be careful about case returned with functions
e41182b5
GS
864like C<readdir> or used with functions like C<open> or C<opendir>.
865
b7df3edc
GS
866DOS also treats several filenames as special, such as AUX, PRN,
867NUL, CON, COM1, LPT1, LPT2, etc. Unfortunately, sometimes these
868filenames won't even work if you include an explicit directory
869prefix. It is best to avoid such filenames, if you want your code
870to be portable to DOS and its derivatives. It's hard to know what
871these all are, unfortunately.
e41182b5
GS
872
873Users of these operating systems may also wish to make use of
b7df3edc 874scripts such as I<pl2bat.bat> or I<pl2cmd> to
e41182b5
GS
875put wrappers around your scripts.
876
877Newline (C<\n>) is translated as C<\015\012> by STDIO when reading from
6ab3f9cb
GS
878and writing to files (see L<"Newlines">). C<binmode(FILEHANDLE)>
879will keep C<\n> translated as C<\012> for that filehandle. Since it is a
880no-op on other systems, C<binmode> should be used for cross-platform code
b7df3edc
GS
881that deals with binary data. That's assuming you realize in advance
882that your data is in binary. General-purpose programs should
883often assume nothing about their data.
e41182b5 884
b7df3edc 885The C<$^O> variable and the C<$Config{archname}> values for various
e41182b5
GS
886DOSish perls are as follows:
887
67ac489e
MS
888 OS $^O $Config{archname} ID Version
889 --------------------------------------------------------
890 MS-DOS dos ?
891 PC-DOS dos ?
892 OS/2 os2 ?
893 Windows 3.1 ? ? 0 3 01
894 Windows 95 MSWin32 MSWin32-x86 1 4 00
895 Windows 98 MSWin32 MSWin32-x86 1 4 10
896 Windows ME MSWin32 MSWin32-x86 1 ?
897 Windows NT MSWin32 MSWin32-x86 2 4 xx
898 Windows NT MSWin32 MSWin32-ALPHA 2 4 xx
899 Windows NT MSWin32 MSWin32-ppc 2 4 xx
900 Windows 2000 MSWin32 MSWin32-x86 2 5 xx
901 Windows XP MSWin32 MSWin32-x86 2 ?
902 Windows CE MSWin32 ? 3
903 Cygwin cygwin ?
e41182b5 904
34aaaa84
PP
905The various MSWin32 Perl's can distinguish the OS they are running on
906via the value of the fifth element of the list returned from
907Win32::GetOSVersion(). For example:
908
909 if ($^O eq 'MSWin32') {
910 my @os_version_info = Win32::GetOSVersion();
911 print +('3.1','95','NT')[$os_version_info[4]],"\n";
912 }
913
7939d86b
JH
914There are also Win32::IsWinNT() and Win32::IsWin95(), try C<perldoc Win32>,
915and as of libwin32 0.19 (not part of the core Perl distribution)
916Win32::GetOSName(). The very portable POSIX::uname() will work too:
1d65be3a
JH
917
918 c:\> perl -MPOSIX -we "print join '|', uname"
919 Windows NT|moonru|5.0|Build 2195 (Service Pack 2)|x86
d99f392e 920
e41182b5
GS
921Also see:
922
923=over 4
924
c997b287 925=item *
e41182b5 926
c997b287
GS
927The djgpp environment for DOS, http://www.delorie.com/djgpp/
928and L<perldos>.
e41182b5 929
c997b287 930=item *
e41182b5 931
c997b287
GS
932The EMX environment for DOS, OS/2, etc. emx@iaehv.nl,
933http://www.leo.org/pub/comp/os/os2/leo/gnu/emx+gcc/index.html or
f224927c 934ftp://hobbes.nmsu.edu/pub/os2/dev/emx/ Also L<perlos2>.
e41182b5 935
c997b287 936=item *
d1e3b762 937
c997b287
GS
938Build instructions for Win32 in L<perlwin32>, or under the Cygnus environment
939in L<perlcygwin>.
940
941=item *
942
943The C<Win32::*> modules in L<Win32>.
944
945=item *
946
947The ActiveState Pages, http://www.activestate.com/
948
949=item *
950
951The Cygwin environment for Win32; F<README.cygwin> (installed
47dafe4d 952as L<perlcygwin>), http://www.cygwin.com/
c997b287
GS
953
954=item *
955
956The U/WIN environment for Win32,
cea6626f 957http://www.research.att.com/sw/tools/uwin/
c997b287 958
cea6626f 959=item *
d1e3b762 960
cea6626f 961Build instructions for OS/2, L<perlos2>
d1e3b762 962
e41182b5
GS
963=back
964
dd9f0070 965=head2 S<Mac OS>
e41182b5
GS
966
967Any module requiring XS compilation is right out for most people, because
968MacPerl is built using non-free (and non-cheap!) compilers. Some XS
969modules that can work with MacPerl are built and distributed in binary
6ab3f9cb 970form on CPAN.
e41182b5
GS
971
972Directories are specified as:
973
974 volume:folder:file for absolute pathnames
975 volume:folder: for absolute pathnames
976 :folder:file for relative pathnames
977 :folder: for relative pathnames
978 :file for relative pathnames
979 file for relative pathnames
980
b7df3edc 981Files are stored in the directory in alphabetical order. Filenames are
6ab3f9cb 982limited to 31 characters, and may include any character except for
b7df3edc 983null and C<:>, which is reserved as the path separator.
e41182b5 984
0a47030a 985Instead of C<flock>, see C<FSpSetFLock> and C<FSpRstFLock> in the
6ab3f9cb 986Mac::Files module, or C<chmod(0444, ...)> and C<chmod(0666, ...)>.
e41182b5
GS
987
988In the MacPerl application, you can't run a program from the command line;
989programs that expect C<@ARGV> to be populated can be edited with something
990like the following, which brings up a dialog box asking for the command
991line arguments.
992
993 if (!@ARGV) {
994 @ARGV = split /\s+/, MacPerl::Ask('Arguments?');
995 }
996
b7df3edc 997A MacPerl script saved as a "droplet" will populate C<@ARGV> with the full
e41182b5
GS
998pathnames of the files dropped onto the script.
999
b7df3edc
GS
1000Mac users can run programs under a type of command line interface
1001under MPW (Macintosh Programmer's Workshop, a free development
1002environment from Apple). MacPerl was first introduced as an MPW
1003tool, and MPW can be used like a shell:
e41182b5
GS
1004
1005 perl myscript.plx some arguments
1006
1007ToolServer is another app from Apple that provides access to MPW tools
0a47030a 1008from MPW and the MacPerl app, which allows MacPerl programs to use
e41182b5
GS
1009C<system>, backticks, and piped C<open>.
1010
1011"S<Mac OS>" is the proper name for the operating system, but the value
1012in C<$^O> is "MacOS". To determine architecture, version, or whether
1013the application or MPW tool version is running, check:
1014
1015 $is_app = $MacPerl::Version =~ /App/;
1016 $is_tool = $MacPerl::Version =~ /MPW/;
1017 ($version) = $MacPerl::Version =~ /^(\S+)/;
1018 $is_ppc = $MacPerl::Architecture eq 'MacPPC';
1019 $is_68k = $MacPerl::Architecture eq 'Mac68K';
1020
b787fad4
JH
1021S<Mac OS X>, based on NeXT's OpenStep OS, runs MacPerl natively, under the
1022"Classic" environment. There is no "Carbon" version of MacPerl to run
1023under the primary Mac OS X environment. S<Mac OS X> and its Open Source
1024version, Darwin, both run Unix perl natively.
6ab3f9cb 1025
e41182b5
GS
1026Also see:
1027
1028=over 4
1029
c997b287
GS
1030=item *
1031
862b5365 1032MacPerl Development, http://dev.macperl.org/ .
c997b287
GS
1033
1034=item *
1035
862b5365 1036The MacPerl Pages, http://www.macperl.com/ .
e41182b5 1037
c997b287 1038=item *
6ab3f9cb 1039
862b5365 1040The MacPerl mailing lists, http://lists.perl.org/ .
e41182b5
GS
1041
1042=back
1043
e41182b5
GS
1044=head2 VMS
1045
c997b287 1046Perl on VMS is discussed in L<perlvms> in the perl distribution.
b7df3edc 1047Perl on VMS can accept either VMS- or Unix-style file
e41182b5
GS
1048specifications as in either of the following:
1049
1050 $ perl -ne "print if /perl_setup/i" SYS$LOGIN:LOGIN.COM
1051 $ perl -ne "print if /perl_setup/i" /sys$login/login.com
1052
1053but not a mixture of both as in:
1054
1055 $ perl -ne "print if /perl_setup/i" sys$login:/login.com
1056 Can't open sys$login:/login.com: file specification syntax error
1057
1058Interacting with Perl from the Digital Command Language (DCL) shell
1059often requires a different set of quotation marks than Unix shells do.
1060For example:
1061
1062 $ perl -e "print ""Hello, world.\n"""
1063 Hello, world.
1064
b7df3edc 1065There are several ways to wrap your perl scripts in DCL F<.COM> files, if
e41182b5
GS
1066you are so inclined. For example:
1067
1068 $ write sys$output "Hello from DCL!"
1069 $ if p1 .eqs. ""
1070 $ then perl -x 'f$environment("PROCEDURE")
1071 $ else perl -x - 'p1 'p2 'p3 'p4 'p5 'p6 'p7 'p8
1072 $ deck/dollars="__END__"
1073 #!/usr/bin/perl
1074
1075 print "Hello from Perl!\n";
1076
1077 __END__
1078 $ endif
1079
1080Do take care with C<$ ASSIGN/nolog/user SYS$COMMAND: SYS$INPUT> if your
c47ff5f1 1081perl-in-DCL script expects to do things like C<< $read = <STDIN>; >>.
e41182b5
GS
1082
1083Filenames are in the format "name.extension;version". The maximum
1084length for filenames is 39 characters, and the maximum length for
1085extensions is also 39 characters. Version is a number from 1 to
108632767. Valid characters are C</[A-Z0-9$_-]/>.
1087
b7df3edc 1088VMS's RMS filesystem is case-insensitive and does not preserve case.
e41182b5 1089C<readdir> returns lowercased filenames, but specifying a file for
b7df3edc 1090opening remains case-insensitive. Files without extensions have a
e41182b5 1091trailing period on them, so doing a C<readdir> with a file named F<A.;5>
0a47030a
GS
1092will return F<a.> (though that file could be opened with
1093C<open(FH, 'A')>).
e41182b5 1094
f34d0673 1095RMS had an eight level limit on directory depths from any rooted logical
dd9f0070
CN
1096(allowing 16 levels overall) prior to VMS 7.2. Hence
1097C<PERL_ROOT:[LIB.2.3.4.5.6.7.8]> is a valid directory specification but
1098C<PERL_ROOT:[LIB.2.3.4.5.6.7.8.9]> is not. F<Makefile.PL> authors might
1099have to take this into account, but at least they can refer to the former
f34d0673 1100as C</PERL_ROOT/lib/2/3/4/5/6/7/8/>.
e41182b5 1101
6ab3f9cb 1102The VMS::Filespec module, which gets installed as part of the build
0a47030a
GS
1103process on VMS, is a pure Perl module that can easily be installed on
1104non-VMS platforms and can be helpful for conversions to and from RMS
1105native formats.
e41182b5 1106
5e12dbfa
PP
1107What C<\n> represents depends on the type of file opened. It usually
1108represents C<\012> but it could also be C<\015>, C<\012>, C<\015\012>,
fa11829f 1109C<\000>, C<\040>, or nothing depending on the file organization and
5e12dbfa
PP
1110record format. The VMS::Stdio module provides access to the
1111special fopen() requirements of files with unusual attributes on VMS.
e41182b5
GS
1112
1113TCP/IP stacks are optional on VMS, so socket routines might not be
1114implemented. UDP sockets may not be supported.
1115
1116The value of C<$^O> on OpenVMS is "VMS". To determine the architecture
1117that you are running on without resorting to loading all of C<%Config>
1118you can examine the content of the C<@INC> array like so:
1119
1120 if (grep(/VMS_AXP/, @INC)) {
1121 print "I'm on Alpha!\n";
6ab3f9cb 1122
e41182b5
GS
1123 } elsif (grep(/VMS_VAX/, @INC)) {
1124 print "I'm on VAX!\n";
6ab3f9cb 1125
e41182b5
GS
1126 } else {
1127 print "I'm not so sure about where $^O is...\n";
1128 }
1129
b7df3edc
GS
1130On VMS, perl determines the UTC offset from the C<SYS$TIMEZONE_DIFFERENTIAL>
1131logical name. Although the VMS epoch began at 17-NOV-1858 00:00:00.00,
6ab3f9cb 1132calls to C<localtime> are adjusted to count offsets from
b7df3edc 113301-JAN-1970 00:00:00.00, just like Unix.
6ab3f9cb 1134
e41182b5
GS
1135Also see:
1136
1137=over 4
1138
c997b287
GS
1139=item *
1140
1141F<README.vms> (installed as L<README_vms>), L<perlvms>
1142
1143=item *
1144
1145vmsperl list, majordomo@perl.org
e41182b5 1146
c997b287 1147(Put the words C<subscribe vmsperl> in message body.)
e41182b5 1148
c997b287 1149=item *
e41182b5 1150
c997b287 1151vmsperl on the web, http://www.sidhe.org/vmsperl/index.html
e41182b5
GS
1152
1153=back
1154
495c5fdc
GP
1155=head2 VOS
1156
9a997319
JH
1157Perl on VOS is discussed in F<README.vos> in the perl distribution
1158(installed as L<perlvos>). Perl on VOS can accept either VOS- or
1159Unix-style file specifications as in either of the following:
495c5fdc 1160
cc07ed0b
PG
1161 C<< $ perl -ne "print if /perl_setup/i" >system>notices >>
1162 C<< $ perl -ne "print if /perl_setup/i" /system/notices >>
495c5fdc
GP
1163
1164or even a mixture of both as in:
1165
cc07ed0b 1166 C<< $ perl -ne "print if /perl_setup/i" >system/notices >>
495c5fdc 1167
b7df3edc 1168Even though VOS allows the slash character to appear in object
495c5fdc
GP
1169names, because the VOS port of Perl interprets it as a pathname
1170delimiting character, VOS files, directories, or links whose names
1171contain a slash character cannot be processed. Such files must be
a3dfe201
GS
1172renamed before they can be processed by Perl. Note that VOS limits
1173file names to 32 or fewer characters.
495c5fdc 1174
495c5fdc
GP
1175The value of C<$^O> on VOS is "VOS". To determine the architecture that
1176you are running on without resorting to loading all of C<%Config> you
c997b287 1177can examine the content of the @INC array like so:
495c5fdc 1178
24e8e380 1179 if ($^O =~ /VOS/) {
495c5fdc
GP
1180 print "I'm on a Stratus box!\n";
1181 } else {
1182 print "I'm not on a Stratus box!\n";
1183 die;
1184 }
1185
495c5fdc
GP
1186Also see:
1187
1188=over 4
1189
c997b287 1190=item *
495c5fdc 1191
cc07ed0b 1192F<README.vos> (installed as L<perlvos>)
c997b287
GS
1193
1194=item *
1195
1196The VOS mailing list.
495c5fdc
GP
1197
1198There is no specific mailing list for Perl on VOS. You can post
1199comments to the comp.sys.stratus newsgroup, or subscribe to the general
cc07ed0b 1200Stratus mailing list. Send a letter with "subscribe Info-Stratus" in
495c5fdc
GP
1201the message body to majordomo@list.stratagy.com.
1202
c997b287
GS
1203=item *
1204
cc07ed0b 1205VOS Perl on the web at http://ftp.stratus.com/pub/vos/posix/posix.html
495c5fdc
GP
1206
1207=back
1208
e41182b5
GS
1209=head2 EBCDIC Platforms
1210
1211Recent versions of Perl have been ported to platforms such as OS/400 on
d1e3b762
GS
1212AS/400 minicomputers as well as OS/390, VM/ESA, and BS2000 for S/390
1213Mainframes. Such computers use EBCDIC character sets internally (usually
0cc436d0
GS
1214Character Code Set ID 0037 for OS/400 and either 1047 or POSIX-BC for S/390
1215systems). On the mainframe perl currently works under the "Unix system
1216services for OS/390" (formerly known as OpenEdition), VM/ESA OpenEdition, or
1217the BS200 POSIX-BC system (BS2000 is supported in perl 5.6 and greater).
522b859a
JH
1218See L<perlos390> for details. Note that for OS/400 there is also a port of
1219Perl 5.8.1/5.9.0 or later to the PASE which is ASCII-based (as opposed to
1220ILE which is EBCDIC-based), see L<perlos400>.
e41182b5 1221
7c5ffed3
JH
1222As of R2.5 of USS for OS/390 and Version 2.3 of VM/ESA these Unix
1223sub-systems do not support the C<#!> shebang trick for script invocation.
1224Hence, on OS/390 and VM/ESA perl scripts can be executed with a header
1225similar to the following simple script:
e41182b5
GS
1226
1227 : # use perl
1228 eval 'exec /usr/local/bin/perl -S $0 ${1+"$@"}'
1229 if 0;
1230 #!/usr/local/bin/perl # just a comment really
1231
1232 print "Hello from perl!\n";
1233
d1e3b762
GS
1234OS/390 will support the C<#!> shebang trick in release 2.8 and beyond.
1235Calls to C<system> and backticks can use POSIX shell syntax on all
1236S/390 systems.
1237
b7df3edc 1238On the AS/400, if PERL5 is in your library list, you may need
6ab3f9cb
GS
1239to wrap your perl scripts in a CL procedure to invoke them like so:
1240
1241 BEGIN
1242 CALL PGM(PERL5/PERL) PARM('/QOpenSys/hello.pl')
1243 ENDPGM
1244
1245This will invoke the perl script F<hello.pl> in the root of the
1246QOpenSys file system. On the AS/400 calls to C<system> or backticks
1247must use CL syntax.
1248
e41182b5 1249On these platforms, bear in mind that the EBCDIC character set may have
0a47030a
GS
1250an effect on what happens with some perl functions (such as C<chr>,
1251C<pack>, C<print>, C<printf>, C<ord>, C<sort>, C<sprintf>, C<unpack>), as
1252well as bit-fiddling with ASCII constants using operators like C<^>, C<&>
1253and C<|>, not to mention dealing with socket interfaces to ASCII computers
6ab3f9cb 1254(see L<"Newlines">).
e41182b5 1255
b7df3edc
GS
1256Fortunately, most web servers for the mainframe will correctly
1257translate the C<\n> in the following statement to its ASCII equivalent
1258(C<\r> is the same under both Unix and OS/390 & VM/ESA):
e41182b5
GS
1259
1260 print "Content-type: text/html\r\n\r\n";
1261
d1e3b762 1262The values of C<$^O> on some of these platforms includes:
e41182b5 1263
d1e3b762
GS
1264 uname $^O $Config{'archname'}
1265 --------------------------------------------
1266 OS/390 os390 os390
1267 OS400 os400 os400
1268 POSIX-BC posix-bc BS2000-posix-bc
1269 VM/ESA vmesa vmesa
3c075c7d 1270
e41182b5
GS
1271Some simple tricks for determining if you are running on an EBCDIC
1272platform could include any of the following (perhaps all):
1273
1274 if ("\t" eq "\05") { print "EBCDIC may be spoken here!\n"; }
1275
1276 if (ord('A') == 193) { print "EBCDIC may be spoken here!\n"; }
1277
1278 if (chr(169) eq 'z') { print "EBCDIC may be spoken here!\n"; }
1279
b7df3edc 1280One thing you may not want to rely on is the EBCDIC encoding
0a47030a
GS
1281of punctuation characters since these may differ from code page to code
1282page (and once your module or script is rumoured to work with EBCDIC,
1283folks will want it to work with all EBCDIC character sets).
e41182b5
GS
1284
1285Also see:
1286
1287=over 4
1288
c997b287
GS
1289=item *
1290
1291*
d1e3b762 1292
dc5c060f 1293L<perlos390>, F<README.os390>, F<perlbs2000>, F<README.vmesa>,
bb462878 1294L<perlebcdic>.
c997b287
GS
1295
1296=item *
e41182b5
GS
1297
1298The perl-mvs@perl.org list is for discussion of porting issues as well as
1299general usage issues for all EBCDIC Perls. Send a message body of
1300"subscribe perl-mvs" to majordomo@perl.org.
1301
c997b287
GS
1302=item *
1303
1304AS/400 Perl information at
b1866b2d 1305http://as400.rochester.ibm.com/
d1e3b762 1306as well as on CPAN in the F<ports/> directory.
e41182b5
GS
1307
1308=back
1309
b8099c3d
CN
1310=head2 Acorn RISC OS
1311
b7df3edc
GS
1312Because Acorns use ASCII with newlines (C<\n>) in text files as C<\012> like
1313Unix, and because Unix filename emulation is turned on by default,
1314most simple scripts will probably work "out of the box". The native
6ab3f9cb 1315filesystem is modular, and individual filesystems are free to be
0a47030a 1316case-sensitive or insensitive, and are usually case-preserving. Some
b7df3edc 1317native filesystems have name length limits, which file and directory
6ab3f9cb
GS
1318names are silently truncated to fit. Scripts should be aware that the
1319standard filesystem currently has a name length limit of B<10>
1320characters, with up to 77 items in a directory, but other filesystems
0a47030a 1321may not impose such limitations.
b8099c3d
CN
1322
1323Native filenames are of the form
1324
6ab3f9cb 1325 Filesystem#Special_Field::DiskName.$.Directory.Directory.File
dd9f0070 1326
b8099c3d
CN
1327where
1328
1329 Special_Field is not usually present, but may contain . and $ .
1330 Filesystem =~ m|[A-Za-z0-9_]|
1331 DsicName =~ m|[A-Za-z0-9_/]|
1332 $ represents the root directory
1333 . is the path separator
1334 @ is the current directory (per filesystem but machine global)
1335 ^ is the parent directory
1336 Directory and File =~ m|[^\0- "\.\$\%\&:\@\\^\|\177]+|
1337
1338The default filename translation is roughly C<tr|/.|./|;>
1339
6ab3f9cb 1340Note that C<"ADFS::HardDisk.$.File" ne 'ADFS::HardDisk.$.File'> and that
0a47030a
GS
1341the second stage of C<$> interpolation in regular expressions will fall
1342foul of the C<$.> if scripts are not careful.
1343
1344Logical paths specified by system variables containing comma-separated
b7df3edc 1345search lists are also allowed; hence C<System:Modules> is a valid
0a47030a 1346filename, and the filesystem will prefix C<Modules> with each section of
6ab3f9cb 1347C<System$Path> until a name is made that points to an object on disk.
b7df3edc 1348Writing to a new file C<System:Modules> would be allowed only if
0a47030a
GS
1349C<System$Path> contains a single item list. The filesystem will also
1350expand system variables in filenames if enclosed in angle brackets, so
c47ff5f1 1351C<< <System$Dir>.Modules >> would look for the file
0a47030a 1352S<C<$ENV{'System$Dir'} . 'Modules'>>. The obvious implication of this is
c47ff5f1 1353that B<fully qualified filenames can start with C<< <> >>> and should
0a47030a 1354be protected when C<open> is used for input.
b8099c3d
CN
1355
1356Because C<.> was in use as a directory separator and filenames could not
1357be assumed to be unique after 10 characters, Acorn implemented the C
1358compiler to strip the trailing C<.c> C<.h> C<.s> and C<.o> suffix from
1359filenames specified in source code and store the respective files in
b7df3edc 1360subdirectories named after the suffix. Hence files are translated:
b8099c3d
CN
1361
1362 foo.h h.foo
1363 C:foo.h C:h.foo (logical path variable)
1364 sys/os.h sys.h.os (C compiler groks Unix-speak)
1365 10charname.c c.10charname
1366 10charname.o o.10charname
1367 11charname_.c c.11charname (assuming filesystem truncates at 10)
1368
1369The Unix emulation library's translation of filenames to native assumes
b7df3edc
GS
1370that this sort of translation is required, and it allows a user-defined list
1371of known suffixes that it will transpose in this fashion. This may
1372seem transparent, but consider that with these rules C<foo/bar/baz.h>
0a47030a
GS
1373and C<foo/bar/h/baz> both map to C<foo.bar.h.baz>, and that C<readdir> and
1374C<glob> cannot and do not attempt to emulate the reverse mapping. Other
6ab3f9cb 1375C<.>'s in filenames are translated to C</>.
0a47030a 1376
b7df3edc 1377As implied above, the environment accessed through C<%ENV> is global, and
0a47030a 1378the convention is that program specific environment variables are of the
6ab3f9cb
GS
1379form C<Program$Name>. Each filesystem maintains a current directory,
1380and the current filesystem's current directory is the B<global> current
b7df3edc
GS
1381directory. Consequently, sociable programs don't change the current
1382directory but rely on full pathnames, and programs (and Makefiles) cannot
0a47030a
GS
1383assume that they can spawn a child process which can change the current
1384directory without affecting its parent (and everyone else for that
1385matter).
1386
b7df3edc
GS
1387Because native operating system filehandles are global and are currently
1388allocated down from 255, with 0 being a reserved value, the Unix emulation
0a47030a
GS
1389library emulates Unix filehandles. Consequently, you can't rely on
1390passing C<STDIN>, C<STDOUT>, or C<STDERR> to your children.
1391
1392The desire of users to express filenames of the form
c47ff5f1 1393C<< <Foo$Dir>.Bar >> on the command line unquoted causes problems,
0a47030a 1394too: C<``> command output capture has to perform a guessing game. It
c47ff5f1 1395assumes that a string C<< <[^<>]+\$[^<>]> >> is a
0a47030a 1396reference to an environment variable, whereas anything else involving
c47ff5f1 1397C<< < >> or C<< > >> is redirection, and generally manages to be 99%
0a47030a
GS
1398right. Of course, the problem remains that scripts cannot rely on any
1399Unix tools being available, or that any tools found have Unix-like command
1400line arguments.
1401
b7df3edc
GS
1402Extensions and XS are, in theory, buildable by anyone using free
1403tools. In practice, many don't, as users of the Acorn platform are
1404used to binary distributions. MakeMaker does run, but no available
1405make currently copes with MakeMaker's makefiles; even if and when
1406this should be fixed, the lack of a Unix-like shell will cause
1407problems with makefile rules, especially lines of the form C<cd
1408sdbm && make all>, and anything using quoting.
b8099c3d
CN
1409
1410"S<RISC OS>" is the proper name for the operating system, but the value
1411in C<$^O> is "riscos" (because we don't like shouting).
1412
e41182b5
GS
1413=head2 Other perls
1414
b7df3edc
GS
1415Perl has been ported to many platforms that do not fit into any of
1416the categories listed above. Some, such as AmigaOS, Atari MiNT,
1417BeOS, HP MPE/iX, QNX, Plan 9, and VOS, have been well-integrated
1418into the standard Perl source code kit. You may need to see the
1419F<ports/> directory on CPAN for information, and possibly binaries,
1420for the likes of: aos, Atari ST, lynxos, riscos, Novell Netware,
1421Tandem Guardian, I<etc.> (Yes, we know that some of these OSes may
1422fall under the Unix category, but we are not a standards body.)
e41182b5 1423
d1e3b762
GS
1424Some approximate operating system names and their C<$^O> values
1425in the "OTHER" category include:
1426
1427 OS $^O $Config{'archname'}
1428 ------------------------------------------
1429 Amiga DOS amigaos m68k-amigos
cec2c193 1430 BeOS beos
d1e3b762
GS
1431 MPE/iX mpeix PA-RISC1.1
1432
e41182b5
GS
1433See also:
1434
1435=over 4
1436
c997b287
GS
1437=item *
1438
1439Amiga, F<README.amiga> (installed as L<perlamiga>).
1440
1441=item *
d1e3b762 1442
c997b287
GS
1443Atari, F<README.mint> and Guido Flohr's web page
1444http://stud.uni-sb.de/~gufl0000/
e41182b5 1445
c997b287 1446=item *
d1e3b762 1447
c997b287 1448Be OS, F<README.beos>
e41182b5 1449
c997b287
GS
1450=item *
1451
1452HP 300 MPE/iX, F<README.mpeix> and Mark Bixby's web page
34aaaa84 1453http://www.bixby.org/mark/perlix.html
c997b287
GS
1454
1455=item *
e41182b5 1456
6ab3f9cb 1457A free perl5-based PERL.NLM for Novell Netware is available in
c997b287 1458precompiled binary and source code form from http://www.novell.com/
6ab3f9cb 1459as well as from CPAN.
e41182b5 1460
13a2d996 1461=item *
c997b287 1462
e6f03d26 1463S<Plan 9>, F<README.plan9>
d1e3b762 1464
e41182b5
GS
1465=back
1466
e41182b5
GS
1467=head1 FUNCTION IMPLEMENTATIONS
1468
b7df3edc
GS
1469Listed below are functions that are either completely unimplemented
1470or else have been implemented differently on various platforms.
1471Following each description will be, in parentheses, a list of
1472platforms that the description applies to.
e41182b5 1473
b7df3edc
GS
1474The list may well be incomplete, or even wrong in some places. When
1475in doubt, consult the platform-specific README files in the Perl
1476source distribution, and any other documentation resources accompanying
1477a given port.
e41182b5 1478
0a47030a 1479Be aware, moreover, that even among Unix-ish systems there are variations.
e41182b5 1480
b7df3edc
GS
1481For many functions, you can also query C<%Config>, exported by
1482default from the Config module. For example, to check whether the
1483platform has the C<lstat> call, check C<$Config{d_lstat}>. See
1484L<Config> for a full description of available variables.
e41182b5
GS
1485
1486=head2 Alphabetical Listing of Perl Functions
1487
1488=over 8
1489
1490=item -X FILEHANDLE
1491
1492=item -X EXPR
1493
1494=item -X
1495
b7df3edc 1496C<-r>, C<-w>, and C<-x> have a limited meaning only; directories
e41182b5 1497and applications are executable, and there are no uid/gid
b7df3edc 1498considerations. C<-o> is not supported. (S<Mac OS>)
e41182b5 1499
b7df3edc
GS
1500C<-r>, C<-w>, C<-x>, and C<-o> tell whether the file is accessible,
1501which may not reflect UIC-based file protections. (VMS)
e41182b5 1502
b8099c3d
CN
1503C<-s> returns the size of the data fork, not the total size of data fork
1504plus resource fork. (S<Mac OS>).
1505
1506C<-s> by name on an open file will return the space reserved on disk,
1507rather than the current extent. C<-s> on an open filehandle returns the
b7df3edc 1508current size. (S<RISC OS>)
b8099c3d 1509
e41182b5 1510C<-R>, C<-W>, C<-X>, C<-O> are indistinguishable from C<-r>, C<-w>,
b8099c3d 1511C<-x>, C<-o>. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1512
1513C<-b>, C<-c>, C<-k>, C<-g>, C<-p>, C<-u>, C<-A> are not implemented.
1514(S<Mac OS>)
1515
1516C<-g>, C<-k>, C<-l>, C<-p>, C<-u>, C<-A> are not particularly meaningful.
b8099c3d 1517(Win32, VMS, S<RISC OS>)
e41182b5
GS
1518
1519C<-d> is true if passed a device spec without an explicit directory.
1520(VMS)
1521
1522C<-T> and C<-B> are implemented, but might misclassify Mac text files
0a47030a 1523with foreign characters; this is the case will all platforms, but may
b7df3edc 1524affect S<Mac OS> often. (S<Mac OS>)
e41182b5
GS
1525
1526C<-x> (or C<-X>) determine if a file ends in one of the executable
b7df3edc 1527suffixes. C<-S> is meaningless. (Win32)
e41182b5 1528
b8099c3d
CN
1529C<-x> (or C<-X>) determine if a file has an executable file type.
1530(S<RISC OS>)
1531
e41182b5
GS
1532=item binmode FILEHANDLE
1533
b7df3edc 1534Meaningless. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1535
1536Reopens file and restores pointer; if function fails, underlying
1537filehandle may be closed, or pointer may be in a different position.
1538(VMS)
1539
1540The value returned by C<tell> may be affected after the call, and
1541the filehandle may be flushed. (Win32)
1542
1543=item chmod LIST
1544
b7df3edc 1545Only limited meaning. Disabling/enabling write permission is mapped to
e41182b5
GS
1546locking/unlocking the file. (S<Mac OS>)
1547
1548Only good for changing "owner" read-write access, "group", and "other"
1549bits are meaningless. (Win32)
1550
b8099c3d
CN
1551Only good for changing "owner" and "other" read-write access. (S<RISC OS>)
1552
495c5fdc
GP
1553Access permissions are mapped onto VOS access-control list changes. (VOS)
1554
4e51f8e4 1555The actual permissions set depend on the value of the C<CYGWIN>
789f0d36 1556in the SYSTEM environment settings. (Cygwin)
4e51f8e4 1557
e41182b5
GS
1558=item chown LIST
1559
3fd80bd6 1560Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1561
1562Does nothing, but won't fail. (Win32)
1563
3fd80bd6
PG
1564A little funky, because VOS's notion of ownership is a little funky (VOS).
1565
e41182b5
GS
1566=item chroot FILENAME
1567
1568=item chroot
1569
e6f03d26 1570Not implemented. (S<Mac OS>, Win32, VMS, S<Plan 9>, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1571
1572=item crypt PLAINTEXT,SALT
1573
1574May not be available if library or source was not provided when building
b8099c3d 1575perl. (Win32)
e41182b5
GS
1576
1577=item dbmclose HASH
1578
e6f03d26 1579Not implemented. (VMS, S<Plan 9>, VOS)
e41182b5
GS
1580
1581=item dbmopen HASH,DBNAME,MODE
1582
e6f03d26 1583Not implemented. (VMS, S<Plan 9>, VOS)
e41182b5
GS
1584
1585=item dump LABEL
1586
b8099c3d 1587Not useful. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1588
1589Not implemented. (Win32)
1590
b8099c3d 1591Invokes VMS debugger. (VMS)
e41182b5
GS
1592
1593=item exec LIST
1594
1595Not implemented. (S<Mac OS>)
1596
7c5ffed3 1597Implemented via Spawn. (VM/ESA)
3c075c7d 1598
0f897271
GS
1599Does not automatically flush output handles on some platforms.
1600(SunOS, Solaris, HP-UX)
1601
fe12c0e8
MS
1602=item exit EXPR
1603
1604=item exit
1605
1606Emulates UNIX exit() (which considers C<exit 1> to indicate an error) by
1607mapping the C<1> to SS$_ABORT (C<44>). This behavior may be overridden
1608with the pragma C<use vmsish 'exit'>. As with the CRTL's exit()
1609function, C<exit 0> is also mapped to an exit status of SS$_NORMAL
1610(C<1>); this mapping cannot be overridden. Any other argument to exit()
1611is used directly as Perl's exit status. (VMS)
1612
e41182b5
GS
1613=item fcntl FILEHANDLE,FUNCTION,SCALAR
1614
1615Not implemented. (Win32, VMS)
1616
1617=item flock FILEHANDLE,OPERATION
1618
495c5fdc 1619Not implemented (S<Mac OS>, VMS, S<RISC OS>, VOS).
e41182b5
GS
1620
1621Available only on Windows NT (not on Windows 95). (Win32)
1622
1623=item fork
1624
3fd80bd6 1625Not implemented. (S<Mac OS>, AmigaOS, S<RISC OS>, VM/ESA, VMS)
0f897271
GS
1626
1627Emulated using multiple interpreters. See L<perlfork>. (Win32)
1628
1629Does not automatically flush output handles on some platforms.
1630(SunOS, Solaris, HP-UX)
e41182b5
GS
1631
1632=item getlogin
1633
b8099c3d 1634Not implemented. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1635
1636=item getpgrp PID
1637
3fd80bd6 1638Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1639
1640=item getppid
1641
41cbbefa 1642Not implemented. (S<Mac OS>, Win32, S<RISC OS>)
e41182b5
GS
1643
1644=item getpriority WHICH,WHO
1645
7c5ffed3 1646Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1647
1648=item getpwnam NAME
1649
1650Not implemented. (S<Mac OS>, Win32)
1651
b8099c3d
CN
1652Not useful. (S<RISC OS>)
1653
e41182b5
GS
1654=item getgrnam NAME
1655
b8099c3d 1656Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1657
1658=item getnetbyname NAME
1659
e6f03d26 1660Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1661
1662=item getpwuid UID
1663
1664Not implemented. (S<Mac OS>, Win32)
1665
b8099c3d
CN
1666Not useful. (S<RISC OS>)
1667
e41182b5
GS
1668=item getgrgid GID
1669
b8099c3d 1670Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1671
1672=item getnetbyaddr ADDR,ADDRTYPE
1673
e6f03d26 1674Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1675
1676=item getprotobynumber NUMBER
1677
1678Not implemented. (S<Mac OS>)
1679
1680=item getservbyport PORT,PROTO
1681
1682Not implemented. (S<Mac OS>)
1683
1684=item getpwent
1685
7c5ffed3 1686Not implemented. (S<Mac OS>, Win32, VM/ESA)
e41182b5
GS
1687
1688=item getgrent
1689
7c5ffed3 1690Not implemented. (S<Mac OS>, Win32, VMS, VM/ESA)
e41182b5 1691
ef5a6dd7
JH
1692=item gethostbyname
1693
1694C<gethostbyname('localhost')> does not work everywhere: you may have
1695to use C<gethostbyname('127.0.0.1')>. (S<Mac OS>, S<Irix 5>)
1696
e41182b5
GS
1697=item gethostent
1698
1699Not implemented. (S<Mac OS>, Win32)
1700
1701=item getnetent
1702
e6f03d26 1703Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1704
1705=item getprotoent
1706
e6f03d26 1707Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1708
1709=item getservent
1710
e6f03d26 1711Not implemented. (Win32, S<Plan 9>)
e41182b5 1712
e41182b5
GS
1713=item sethostent STAYOPEN
1714
e6f03d26 1715Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1716
1717=item setnetent STAYOPEN
1718
e6f03d26 1719Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1720
1721=item setprotoent STAYOPEN
1722
e6f03d26 1723Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1724
1725=item setservent STAYOPEN
1726
e6f03d26 1727Not implemented. (S<Plan 9>, Win32, S<RISC OS>)
e41182b5
GS
1728
1729=item endpwent
1730
a3dfe201 1731Not implemented. (S<Mac OS>, MPE/iX, VM/ESA, Win32)
e41182b5
GS
1732
1733=item endgrent
1734
a3dfe201 1735Not implemented. (S<Mac OS>, MPE/iX, S<RISC OS>, VM/ESA, VMS, Win32)
e41182b5
GS
1736
1737=item endhostent
1738
1739Not implemented. (S<Mac OS>, Win32)
1740
1741=item endnetent
1742
e6f03d26 1743Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1744
1745=item endprotoent
1746
e6f03d26 1747Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1748
1749=item endservent
1750
e6f03d26 1751Not implemented. (S<Plan 9>, Win32)
e41182b5
GS
1752
1753=item getsockopt SOCKET,LEVEL,OPTNAME
1754
e6f03d26 1755Not implemented. (S<Plan 9>)
e41182b5
GS
1756
1757=item glob EXPR
1758
1759=item glob
1760
63f87e49
GS
1761This operator is implemented via the File::Glob extension on most
1762platforms. See L<File::Glob> for portability information.
b8099c3d 1763
e41182b5
GS
1764=item ioctl FILEHANDLE,FUNCTION,SCALAR
1765
1766Not implemented. (VMS)
1767
1768Available only for socket handles, and it does what the ioctlsocket() call
1769in the Winsock API does. (Win32)
1770
b8099c3d
CN
1771Available only for socket handles. (S<RISC OS>)
1772
b350dd2f 1773=item kill SIGNAL, LIST
e41182b5 1774
862b5365
JH
1775C<kill(0, LIST)> is implemented for the sake of taint checking;
1776use with other signals is unimplemented. (S<Mac OS>)
1777
1778Not implemented, hence not useful for taint checking. (S<RISC OS>)
e41182b5 1779
63f87e49
GS
1780C<kill()> doesn't have the semantics of C<raise()>, i.e. it doesn't send
1781a signal to the identified process like it does on Unix platforms.
1782Instead C<kill($sig, $pid)> terminates the process identified by $pid,
1783and makes it exit immediately with exit status $sig. As in Unix, if
1784$sig is 0 and the specified process exists, it returns true without
1785actually terminating it. (Win32)
e41182b5
GS
1786
1787=item link OLDFILE,NEWFILE
1788
a3dfe201 1789Not implemented. (S<Mac OS>, MPE/iX, VMS, 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
a3dfe201
GS
1794Hard links are implemented on Win32 (Windows NT and Windows 2000)
1795under NTFS only.
1796
e41182b5
GS
1797=item lstat FILEHANDLE
1798
1799=item lstat EXPR
1800
1801=item lstat
1802
b8099c3d 1803Not implemented. (VMS, S<RISC OS>)
e41182b5 1804
63f87e49 1805Return values (especially for device and inode) may be bogus. (Win32)
e41182b5
GS
1806
1807=item msgctl ID,CMD,ARG
1808
1809=item msgget KEY,FLAGS
1810
1811=item msgsnd ID,MSG,FLAGS
1812
1813=item msgrcv ID,VAR,SIZE,TYPE,FLAGS
1814
e6f03d26 1815Not implemented. (S<Mac OS>, Win32, VMS, S<Plan 9>, S<RISC OS>, VOS)
e41182b5
GS
1816
1817=item open FILEHANDLE,EXPR
1818
1819=item open FILEHANDLE
1820
b7df3edc 1821The C<|> variants are supported only if ToolServer is installed.
e41182b5
GS
1822(S<Mac OS>)
1823
c47ff5f1 1824open to C<|-> and C<-|> are unsupported. (S<Mac OS>, Win32, S<RISC OS>)
e41182b5 1825
0f897271
GS
1826Opening a process does not automatically flush output handles on some
1827platforms. (SunOS, Solaris, HP-UX)
1828
e41182b5
GS
1829=item pipe READHANDLE,WRITEHANDLE
1830
433acd8a
JH
1831Very limited functionality. (MiNT)
1832
e41182b5
GS
1833=item readlink EXPR
1834
1835=item readlink
1836
b8099c3d 1837Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5 1838
c9b2b9d4
SS
1839=item rename OLDNAME,NEWNAME
1840
1841Can't move directories between directories on different logical volumes. (Win32)
1842
e41182b5
GS
1843=item select RBITS,WBITS,EBITS,TIMEOUT
1844
689c5c24 1845Only implemented on sockets. (Win32, VMS)
e41182b5 1846
b8099c3d
CN
1847Only reliable on sockets. (S<RISC OS>)
1848
76e05f0b 1849Note that the C<select FILEHANDLE> form is generally portable.
63f87e49 1850
e41182b5
GS
1851=item semctl ID,SEMNUM,CMD,ARG
1852
1853=item semget KEY,NSEMS,FLAGS
1854
1855=item semop KEY,OPSTRING
1856
495c5fdc 1857Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1858
a3dfe201
GS
1859=item setgrent
1860
3fd80bd6 1861Not implemented. (S<Mac OS>, MPE/iX, VMS, Win32, S<RISC OS>, VOS)
a3dfe201 1862
e41182b5
GS
1863=item setpgrp PID,PGRP
1864
495c5fdc 1865Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5
GS
1866
1867=item setpriority WHICH,WHO,PRIORITY
1868
495c5fdc 1869Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1870
a3dfe201
GS
1871=item setpwent
1872
3fd80bd6 1873Not implemented. (S<Mac OS>, MPE/iX, Win32, S<RISC OS>, VOS)
a3dfe201 1874
e41182b5
GS
1875=item setsockopt SOCKET,LEVEL,OPTNAME,OPTVAL
1876
e6f03d26 1877Not implemented. (S<Plan 9>)
e41182b5
GS
1878
1879=item shmctl ID,CMD,ARG
1880
1881=item shmget KEY,SIZE,FLAGS
1882
1883=item shmread ID,VAR,POS,SIZE
1884
1885=item shmwrite ID,STRING,POS,SIZE
1886
495c5fdc 1887Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1888
80cbd5ad
JH
1889=item sockatmark SOCKET
1890
1891A relatively recent addition to socket functions, may not
1892be implemented even in UNIX platforms.
1893
e41182b5
GS
1894=item socketpair SOCKET1,SOCKET2,DOMAIN,TYPE,PROTOCOL
1895
862b5365 1896Not implemented. (Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1897
1898=item stat FILEHANDLE
1899
1900=item stat EXPR
1901
1902=item stat
1903
d62e1b7f
JH
1904Platforms that do not have rdev, blksize, or blocks will return these
1905as '', so numeric comparison or manipulation of these fields may cause
1906'not numeric' warnings.
1907
e41182b5 1908mtime and atime are the same thing, and ctime is creation time instead of
3f1f789b
JH
1909inode change time. (S<Mac OS>).
1910
1911ctime not supported on UFS (S<Mac OS X>).
e41182b5 1912
95a3fe12
MS
1913ctime is creation time instead of inode change time (Win32).
1914
e41182b5
GS
1915device and inode are not meaningful. (Win32)
1916
1917device and inode are not necessarily reliable. (VMS)
1918
b8099c3d
CN
1919mtime, atime and ctime all return the last modification time. Device and
1920inode are not necessarily reliable. (S<RISC OS>)
1921
d62e1b7f
JH
1922dev, rdev, blksize, and blocks are not available. inode is not
1923meaningful and will differ between stat calls on the same file. (os2)
1924
73e9292c
JH
1925some versions of cygwin when doing a stat("foo") and if not finding it
1926may then attempt to stat("foo.exe") (Cygwin)
1927
e41182b5
GS
1928=item symlink OLDFILE,NEWFILE
1929
b8099c3d 1930Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5
GS
1931
1932=item syscall LIST
1933
7c5ffed3 1934Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5 1935
f34d0673
GS
1936=item sysopen FILEHANDLE,FILENAME,MODE,PERMS
1937
dd9f0070 1938The traditional "0", "1", and "2" MODEs are implemented with different
322422de
GS
1939numeric values on some systems. The flags exported by C<Fcntl>
1940(O_RDONLY, O_WRONLY, O_RDWR) should work everywhere though. (S<Mac
7c5ffed3 1941OS>, OS/390, VM/ESA)
f34d0673 1942
e41182b5
GS
1943=item system LIST
1944
9d6eb86e 1945In general, do not assume the UNIX/POSIX semantics that you can shift
7717d0e7 1946C<$?> right by eight to get the exit value, or that C<$? & 127>
9d6eb86e
JH
1947would give you the number of the signal that terminated the program,
1948or that C<$? & 128> would test true if the program was terminated by a
1949coredump. Instead, use the POSIX W*() interfaces: for example, use
74555b7a
PP
1950WIFEXITED($?) and WEXITVALUE($?) to test for a normal exit and the exit
1951value, WIFSIGNALED($?) and WTERMSIG($?) for a signal exit and the
7717d0e7 1952signal. Core dumping is not a portable concept, so there's no portable
9d6eb86e
JH
1953way to test for that.
1954
e41182b5
GS
1955Only implemented if ToolServer is installed. (S<Mac OS>)
1956
1957As an optimization, may not call the command shell specified in
b7df3edc 1958C<$ENV{PERL5SHELL}>. C<system(1, @args)> spawns an external
e41182b5
GS
1959process and immediately returns its process designator, without
1960waiting for it to terminate. Return value may be used subsequently
63f87e49
GS
1961in C<wait> or C<waitpid>. Failure to spawn() a subprocess is indicated
1962by setting $? to "255 << 8". C<$?> is set in a way compatible with
1963Unix (i.e. the exitstatus of the subprocess is obtained by "$? >> 8",
1964as described in the documentation). (Win32)
e41182b5 1965
b8099c3d
CN
1966There is no shell to process metacharacters, and the native standard is
1967to pass a command line terminated by "\n" "\r" or "\0" to the spawned
c47ff5f1 1968program. Redirection such as C<< > foo >> is performed (if at all) by
b8099c3d
CN
1969the run time library of the spawned program. C<system> I<list> will call
1970the Unix emulation library's C<exec> emulation, which attempts to provide
1971emulation of the stdin, stdout, stderr in force in the parent, providing
1972the child program uses a compatible version of the emulation library.
1973I<scalar> will call the native command line direct and no such emulation
1974of a child Unix program will exists. Mileage B<will> vary. (S<RISC OS>)
1975
433acd8a
JH
1976Far from being POSIX compliant. Because there may be no underlying
1977/bin/sh tries to work around the problem by forking and execing the
9b63e9ec 1978first token in its argument string. Handles basic redirection
c47ff5f1 1979("<" or ">") on its own behalf. (MiNT)
433acd8a 1980
0f897271
GS
1981Does not automatically flush output handles on some platforms.
1982(SunOS, Solaris, HP-UX)
1983
9bc98430
CB
1984The return value is POSIX-like (shifted up by 8 bits), which only allows
1985room for a made-up value derived from the severity bits of the native
198632-bit condition code (unless overridden by C<use vmsish 'status'>).
1987For more details see L<perlvms/$?>. (VMS)
1988
e41182b5
GS
1989=item times
1990
1991Only the first entry returned is nonzero. (S<Mac OS>)
1992
63f87e49
GS
1993"cumulative" times will be bogus. On anything other than Windows NT
1994or Windows 2000, "system" time will be bogus, and "user" time is
1995actually the time returned by the clock() function in the C runtime
1996library. (Win32)
e41182b5 1997
b8099c3d
CN
1998Not useful. (S<RISC OS>)
1999
e41182b5
GS
2000=item truncate FILEHANDLE,LENGTH
2001
2002=item truncate EXPR,LENGTH
2003
6d738113 2004Not implemented. (Older versions of VMS)
e41182b5 2005
3fd80bd6 2006Truncation to same-or-shorter lengths only. (VOS)
495c5fdc 2007
4cfdb94f 2008If a FILEHANDLE is supplied, it must be writable and opened in append
e71a7dc8 2009mode (i.e., use C<<< open(FH, '>>filename') >>>
4cfdb94f
GS
2010or C<sysopen(FH,...,O_APPEND|O_RDWR)>. If a filename is supplied, it
2011should not be held open elsewhere. (Win32)
2012
e41182b5
GS
2013=item umask EXPR
2014
2015=item umask
2016
2017Returns undef where unavailable, as of version 5.005.
2018
b7df3edc
GS
2019C<umask> works but the correct permissions are set only when the file
2020is finally closed. (AmigaOS)
433acd8a 2021
e41182b5
GS
2022=item utime LIST
2023
15c65113 2024Only the modification time is updated. (S<BeOS>, S<Mac OS>, VMS, S<RISC OS>)
e41182b5 2025
322422de
GS
2026May not behave as expected. Behavior depends on the C runtime
2027library's implementation of utime(), and the filesystem being
2028used. The FAT filesystem typically does not support an "access
2029time" field, and it may limit timestamps to a granularity of
2030two seconds. (Win32)
e41182b5
GS
2031
2032=item wait
2033
2034=item waitpid PID,FLAGS
2035
3fd80bd6 2036Not implemented. (S<Mac OS>)
e41182b5
GS
2037
2038Can only be applied to process handles returned for processes spawned
a6f858fb 2039using C<system(1, ...)> or pseudo processes created with C<fork()>. (Win32)
e41182b5 2040
b8099c3d
CN
2041Not useful. (S<RISC OS>)
2042
e41182b5
GS
2043=back
2044
b8099c3d
CN
2045=head1 CHANGES
2046
2047=over 4
2048
3fd80bd6
PG
2049=item v1.49, 12 August 2002
2050
2051Updates for VOS from Paul Green.
2052
fd46a41b
JH
2053=item v1.48, 02 February 2001
2054
2055Various updates from perl5-porters over the past year, supported
2056platforms update from Jarkko Hietaniemi.
2057
c997b287
GS
2058=item v1.47, 22 March 2000
2059
2060Various cleanups from Tom Christiansen, including migration of
2061long platform listings from L<perl>.
2062
56d7751a
GS
2063=item v1.46, 12 February 2000
2064
2065Updates for VOS and MPE/iX. (Peter Prymmer) Other small changes.
2066
0cc436d0
GS
2067=item v1.45, 20 December 1999
2068
2069Small changes from 5.005_63 distribution, more changes to EBCDIC info.
2070
d1e3b762
GS
2071=item v1.44, 19 July 1999
2072
2073A bunch of updates from Peter Prymmer for C<$^O> values,
2074endianness, File::Spec, VMS, BS2000, OS/400.
2075
b7df3edc
GS
2076=item v1.43, 24 May 1999
2077
2078Added a lot of cleaning up from Tom Christiansen.
2079
19799a22 2080=item v1.42, 22 May 1999
b7df3edc 2081
19799a22 2082Added notes about tests, sprintf/printf, and epoch offsets.
b7df3edc 2083
6ab3f9cb
GS
2084=item v1.41, 19 May 1999
2085
2086Lots more little changes to formatting and content.
2087
d1e3b762 2088Added a bunch of C<$^O> and related values
6ab3f9cb
GS
2089for various platforms; fixed mail and web addresses, and added
2090and changed miscellaneous notes. (Peter Prymmer)
2091
2092=item v1.40, 11 April 1999
2093
2094Miscellaneous changes.
2095
2096=item v1.39, 11 February 1999
2ee0eb3c
CN
2097
2098Changes from Jarkko and EMX URL fixes Michael Schwern. Additional
2099note about newlines added.
2100
9b63e9ec
CN
2101=item v1.38, 31 December 1998
2102
2103More changes from Jarkko.
2104
3c075c7d
CN
2105=item v1.37, 19 December 1998
2106
2107More minor changes. Merge two separate version 1.35 documents.
2108
2109=item v1.36, 9 September 1998
2110
2111Updated for Stratus VOS. Also known as version 1.35.
2112
2113=item v1.35, 13 August 1998
495c5fdc 2114
3c075c7d
CN
2115Integrate more minor changes, plus addition of new sections under
2116L<"ISSUES">: L<"Numbers endianness and Width">,
2117L<"Character sets and character encoding">,
2118L<"Internationalisation">.
495c5fdc 2119
3c075c7d 2120=item v1.33, 06 August 1998
0a47030a
GS
2121
2122Integrate more minor changes.
2123
3c075c7d 2124=item v1.32, 05 August 1998
dd9f0070
CN
2125
2126Integrate more minor changes.
2127
3c075c7d 2128=item v1.30, 03 August 1998
b8099c3d
CN
2129
2130Major update for RISC OS, other minor changes.
2131
3c075c7d 2132=item v1.23, 10 July 1998
b8099c3d
CN
2133
2134First public release with perl5.005.
2135
2136=back
e41182b5 2137
ba58ab26
JH
2138=head1 Supported Platforms
2139
522b859a 2140As of July 2002 (the Perl release 5.8.0), the following platforms are
cec2c193
JH
2141able to build Perl from the standard source code distribution
2142available at http://www.cpan.org/src/index.html
2143
2144 AIX
2145 BeOS
6f683aa2 2146 BSD/OS (BSDi)
cec2c193
JH
2147 Cygwin
2148 DG/UX
811b48f2 2149 DOS DJGPP 1)
cec2c193
JH
2150 DYNIX/ptx
2151 EPOC R5
2152 FreeBSD
6f683aa2 2153 HI-UXMPP (Hitachi) (5.8.0 worked but we didn't know it)
cec2c193
JH
2154 HP-UX
2155 IRIX
2156 Linux
8939ba94 2157 Mac OS Classic
6f683aa2 2158 Mac OS X (Darwin)
cec2c193
JH
2159 MPE/iX
2160 NetBSD
2161 NetWare
2162 NonStop-UX
6f683aa2 2163 ReliantUNIX (formerly SINIX)
cec2c193 2164 OpenBSD
6f683aa2 2165 OpenVMS (formerly VMS)
3ebac25b 2166 Open UNIX (Unixware) (since Perl 5.8.1/5.9.0)
cec2c193 2167 OS/2
522b859a 2168 OS/400 (using the PASE) (since Perl 5.8.1/5.9.0)
70de81db 2169 PowerUX
6f683aa2 2170 POSIX-BC (formerly BS2000)
cec2c193
JH
2171 QNX
2172 Solaris
70de81db 2173 SunOS 4
6f683aa2
JH
2174 SUPER-UX (NEC)
2175 Tru64 UNIX (formerly DEC OSF/1, Digital UNIX)
cec2c193
JH
2176 UNICOS
2177 UNICOS/mk
2178 UTS
2179 VOS
811b48f2 2180 Win95/98/ME/2K/XP 2)
c40b5d1d 2181 WinCE
6f683aa2 2182 z/OS (formerly OS/390)
cec2c193 2183 VM/ESA
ba58ab26 2184
811b48f2
JH
2185 1) in DOS mode either the DOS or OS/2 ports can be used
2186 2) compilers: Borland, MinGW (GCC), VC6
cec2c193 2187
c40b5d1d 2188The following platforms worked with the previous releases (5.6 and
cec2c193
JH
21895.7), but we did not manage either to fix or to test these in time
2190for the 5.8.0 release. There is a very good chance that many of these
70de81db 2191will work fine with the 5.8.0.
cec2c193 2192
8da2b1be 2193 BSD/OS
cec2c193
JH
2194 DomainOS
2195 Hurd
2196 LynxOS
2197 MachTen
2198 PowerMAX
2199 SCO SV
cec2c193
JH
2200 SVR4
2201 Unixware
2202 Windows 3.1
ba58ab26 2203
70de81db
JH
2204Known to be broken for 5.8.0 (but 5.6.1 and 5.7.2 can be used):
2205
2206 AmigaOS
2207
ba58ab26 2208The following platforms have been known to build Perl from source in
fd46a41b
JH
2209the past (5.005_03 and earlier), but we haven't been able to verify
2210their status for the current release, either because the
2211hardware/software platforms are rare or because we don't have an
2212active champion on these platforms--or both. They used to work,
2213though, so go ahead and try compiling them, and let perlbug@perl.org
2214of any trouble.
ba58ab26 2215
cec2c193
JH
2216 3b1
2217 A/UX
cec2c193
JH
2218 ConvexOS
2219 CX/UX
2220 DC/OSx
2221 DDE SMES
2222 DOS EMX
2223 Dynix
2224 EP/IX
2225 ESIX
2226 FPS
2227 GENIX
2228 Greenhills
2229 ISC
2230 MachTen 68k
2231 MiNT
2232 MPC
2233 NEWS-OS
2234 NextSTEP
2235 OpenSTEP
2236 Opus
2237 Plan 9
cec2c193 2238 RISC/os
8da2b1be 2239 SCO ODT/OSR
cec2c193
JH
2240 Stellar
2241 SVR2
2242 TI1500
2243 TitanOS
2244 Ultrix
2245 Unisys Dynix
ba58ab26
JH
2246
2247The following platforms have their own source code distributions and
1577cd80 2248binaries available via http://www.cpan.org/ports/
ba58ab26 2249
cec2c193 2250 Perl release
ba58ab26 2251
522b859a 2252 OS/400 (ILE) 5.005_02
cec2c193 2253 Tandem Guardian 5.004
ba58ab26
JH
2254
2255The following platforms have only binaries available via
a93751fa 2256http://www.cpan.org/ports/index.html :
ba58ab26 2257
cec2c193 2258 Perl release
ba58ab26 2259
cec2c193
JH
2260 Acorn RISCOS 5.005_02
2261 AOS 5.002
2262 LynxOS 5.004_02
ba58ab26
JH
2263
2264Although we do suggest that you always build your own Perl from
2265the source code, both for maximal configurability and for security,
2266in case you are in a hurry you can check
a93751fa 2267http://www.cpan.org/ports/index.html for binary distributions.
ba58ab26 2268
c997b287
GS
2269=head1 SEE ALSO
2270
cec2c193 2271L<perlaix>, L<perlamiga>, L<perlapollo>, L<perlbeos>, L<perlbs2000>,
18a271bd 2272L<perlce>, L<perlcygwin>, L<perldgux>, L<perldos>, L<perlepoc>,
469e7be4 2273L<perlebcdic>, L<perlfreebsd>, L<perlhurd>, L<perlhpux>, L<perlirix>,
0d53b15f 2274L<perlmachten>, L<perlmacos>, L<perlmacosx>, L<perlmint>, L<perlmpeix>,
522b859a
JH
2275L<perlnetware>, L<perlos2>, L<perlos390>, L<perlos400>,
2276L<perlplan9>, L<perlqnx>, L<perlsolaris>, L<perltru64>,
2277L<perlunicode>, L<perlvmesa>, L<perlvms>, L<perlvos>,
2278L<perlwin32>, and L<Win32>.
c997b287 2279
e41182b5
GS
2280=head1 AUTHORS / CONTRIBUTORS
2281
06e9666b 2282Abigail <abigail@foad.org>,
c47ff5f1
GS
2283Charles Bailey <bailey@newman.upenn.edu>,
2284Graham Barr <gbarr@pobox.com>,
2285Tom Christiansen <tchrist@perl.com>,
06e9666b 2286Nicholas Clark <nick@ccl4.org>,
c47ff5f1 2287Thomas Dorner <Thomas.Dorner@start.de>,
06e9666b
A
2288Andy Dougherty <doughera@lafayette.edu>,
2289Dominic Dunlop <domo@computer.org>,
2290Neale Ferguson <neale@vma.tabnsw.com.au>,
c47ff5f1 2291David J. Fiander <davidf@mks.com>,
3fd80bd6 2292Paul Green <Paul.Green@stratus.com>,
06e9666b 2293M.J.T. Guy <mjtg@cam.ac.uk>,
61f30a5e 2294Jarkko Hietaniemi <jhi@iki.fi>,
c47ff5f1 2295Luther Huffman <lutherh@stratcom.com>,
06e9666b
A
2296Nick Ing-Simmons <nick@ing-simmons.net>,
2297Andreas J. KE<ouml>nig <a.koenig@mind.de>,
c47ff5f1
GS
2298Markus Laker <mlaker@contax.co.uk>,
2299Andrew M. Langmead <aml@world.std.com>,
2300Larry Moore <ljmoore@freespace.net>,
2301Paul Moore <Paul.Moore@uk.origin-it.com>,
2302Chris Nandor <pudge@pobox.com>,
1afc07ec 2303Matthias Neeracher <neeracher@mac.com>,
e71a7dc8 2304Philip Newton <pne@cpan.org>,
c47ff5f1
GS
2305Gary Ng <71564.1743@CompuServe.COM>,
2306Tom Phoenix <rootbeer@teleport.com>,
2307AndrE<eacute> Pirard <A.Pirard@ulg.ac.be>,
2308Peter Prymmer <pvhp@forte.com>,
2309Hugo van der Sanden <hv@crypt0.demon.co.uk>,
2310Gurusamy Sarathy <gsar@activestate.com>,
2311Paul J. Schinder <schinder@pobox.com>,
2312Michael G Schwern <schwern@pobox.com>,
06e9666b 2313Dan Sugalski <dan@sidhe.org>,
c47ff5f1 2314Nathan Torkington <gnat@frii.com>.
e41182b5 2315