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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.
aa7f90d3 191There may well be others. For example, on an EBCDIC implementation such
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192as z/OS or OS/400 the above material is similar to "Unix" but the code
193numbers change:
194
195 LF eq \025 eq \x15 eq chr(21) eq CP-1047 21
196 LF eq \045 eq \x25 eq \cU eq chr(37) eq CP-0037 37
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
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227You can explore the endianness of your platform by unpacking a
228data structure packed in native format such as:
229
230 print unpack("h*", pack("s2", 1, 2)), "\n";
231 # '10002000' on e.g. Intel x86 or Alpha 21064 in little-endian mode
232 # '00100020' on e.g. Motorola 68040
233
234If you need to distinguish between endian architectures you could use
235either of the variables set like so:
236
237 $is_big_endian = unpack("h*", pack("s", 1)) =~ /01/;
4375e838 238 $is_little_endian = unpack("h*", pack("s", 1)) =~ /^1/;
d1e3b762 239
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240Differing widths can cause truncation even between platforms of equal
241endianness. The platform of shorter width loses the upper parts of the
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242number. There is no good solution for this problem except to avoid
243transferring or storing raw binary numbers.
244
b7df3edc 245One can circumnavigate both these problems in two ways. Either
322422de 246transfer and store numbers always in text format, instead of raw
b7df3edc 247binary, or else consider using modules like Data::Dumper (included in
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248the standard distribution as of Perl 5.005) and Storable (included as
249of perl 5.8). Keeping all data as text significantly simplifies matters.
322422de 250
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251The v-strings are portable only up to v2147483647 (0x7FFFFFFF), that's
252how far EBCDIC, or more precisely UTF-EBCDIC will go.
253
433acd8a 254=head2 Files and Filesystems
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255
256Most platforms these days structure files in a hierarchical fashion.
b7df3edc 257So, it is reasonably safe to assume that all platforms support the
6ab3f9cb 258notion of a "path" to uniquely identify a file on the system. How
b7df3edc 259that path is really written, though, differs considerably.
e41182b5 260
4375e838 261Although similar, file path specifications differ between Unix,
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262Windows, S<Mac OS>, OS/2, VMS, VOS, S<RISC OS>, and probably others.
263Unix, for example, is one of the few OSes that has the elegant idea
264of a single root directory.
322422de 265
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266DOS, OS/2, VMS, VOS, and Windows can work similarly to Unix with C</>
267as path separator, or in their own idiosyncratic ways (such as having
268several root directories and various "unrooted" device files such NIL:
269and LPT:).
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270
271S<Mac OS> uses C<:> as a path separator instead of C</>.
272
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273The filesystem may support neither hard links (C<link>) nor
274symbolic links (C<symlink>, C<readlink>, C<lstat>).
433acd8a 275
6ab3f9cb 276The filesystem may support neither access timestamp nor change
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277timestamp (meaning that about the only portable timestamp is the
278modification timestamp), or one second granularity of any timestamps
279(e.g. the FAT filesystem limits the time granularity to two seconds).
280
74555b7a 281The "inode change timestamp" (the C<-C> filetest) may really be the
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282"creation timestamp" (which it is not in UNIX).
283
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284VOS perl can emulate Unix filenames with C</> as path separator. The
285native pathname characters greater-than, less-than, number-sign, and
286percent-sign are always accepted.
287
6ab3f9cb 288S<RISC OS> perl can emulate Unix filenames with C</> as path
322422de 289separator, or go native and use C<.> for path separator and C<:> to
6ab3f9cb 290signal filesystems and disk names.
e41182b5 291
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292Don't assume UNIX filesystem access semantics: that read, write,
293and execute are all the permissions there are, and even if they exist,
294that their semantics (for example what do r, w, and x mean on
295a directory) are the UNIX ones. The various UNIX/POSIX compatibility
296layers usually try to make interfaces like chmod() work, but sometimes
297there simply is no good mapping.
298
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299If all this is intimidating, have no (well, maybe only a little)
300fear. There are modules that can help. The File::Spec modules
301provide methods to do the Right Thing on whatever platform happens
302to be running the program.
e41182b5 303
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304 use File::Spec::Functions;
305 chdir(updir()); # go up one directory
306 $file = catfile(curdir(), 'temp', 'file.txt');
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307 # on Unix and Win32, './temp/file.txt'
308 # on Mac OS, ':temp:file.txt'
d1e3b762 309 # on VMS, '[.temp]file.txt'
e41182b5 310
b7df3edc 311File::Spec is available in the standard distribution as of version
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3125.004_05. File::Spec::Functions is only in File::Spec 0.7 and later,
313and some versions of perl come with version 0.6. If File::Spec
314is not updated to 0.7 or later, you must use the object-oriented
315interface from File::Spec (or upgrade File::Spec).
e41182b5 316
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317In general, production code should not have file paths hardcoded.
318Making them user-supplied or read from a configuration file is
319better, keeping in mind that file path syntax varies on different
320machines.
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321
322This is especially noticeable in scripts like Makefiles and test suites,
323which often assume C</> as a path separator for subdirectories.
324
b7df3edc 325Also of use is File::Basename from the standard distribution, which
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326splits a pathname into pieces (base filename, full path to directory,
327and file suffix).
328
19799a22 329Even when on a single platform (if you can call Unix a single platform),
b7df3edc 330remember not to count on the existence or the contents of particular
3c075c7d 331system-specific files or directories, like F</etc/passwd>,
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332F</etc/sendmail.conf>, F</etc/resolv.conf>, or even F</tmp/>. For
333example, F</etc/passwd> may exist but not contain the encrypted
334passwords, because the system is using some form of enhanced security.
335Or it may not contain all the accounts, because the system is using NIS.
3c075c7d 336If code does need to rely on such a file, include a description of the
b7df3edc 337file and its format in the code's documentation, then make it easy for
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338the user to override the default location of the file.
339
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340Don't assume a text file will end with a newline. They should,
341but people forget.
e41182b5 342
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343Do not have two files or directories of the same name with different
344case, like F<test.pl> and F<Test.pl>, as many platforms have
345case-insensitive (or at least case-forgiving) filenames. Also, try
346not to have non-word characters (except for C<.>) in the names, and
347keep them to the 8.3 convention, for maximum portability, onerous a
348burden though this may appear.
dd9f0070 349
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350Likewise, when using the AutoSplit module, try to keep your functions to
3518.3 naming and case-insensitive conventions; or, at the least,
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352make it so the resulting files have a unique (case-insensitively)
353first 8 characters.
354
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355Whitespace in filenames is tolerated on most systems, but not all,
356and even on systems where it might be tolerated, some utilities
fe829689 357might become confused by such whitespace.
ec481373 358
b7df3edc 359Many systems (DOS, VMS) cannot have more than one C<.> in their filenames.
433acd8a 360
c47ff5f1 361Don't assume C<< > >> won't be the first character of a filename.
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362Always use C<< < >> explicitly to open a file for reading, or even
363better, use the three-arg version of open, unless you want the user to
364be able to specify a pipe open.
0a47030a 365
fe829689 366 open(FILE, '<', $existing_file) or die $!;
0a47030a 367
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368If filenames might use strange characters, it is safest to open it
369with C<sysopen> instead of C<open>. C<open> is magic and can
c47ff5f1 370translate characters like C<< > >>, C<< < >>, and C<|>, which may
b7df3edc 371be the wrong thing to do. (Sometimes, though, it's the right thing.)
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372Three-arg open can also help protect against this translation in cases
373where it is undesirable.
e41182b5 374
ec481373 375Don't use C<:> as a part of a filename since many systems use that for
8939ba94 376their own semantics (Mac OS Classic for separating pathname components,
ec481373 377many networking schemes and utilities for separating the nodename and
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378the pathname, and so on). For the same reasons, avoid C<@>, C<;> and
379C<|>.
ec481373 380
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381Don't assume that in pathnames you can collapse two leading slashes
382C<//> into one: some networking and clustering filesystems have special
383semantics for that. Let the operating system to sort it out.
384
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385The I<portable filename characters> as defined by ANSI C are
386
387 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
388 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
389 0 1 2 3 4 5 6 7 8 9
390 . _ -
391
08fef530 392and the "-" shouldn't be the first character. If you want to be
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393hypercorrect, stay case-insensitive and within the 8.3 naming
394convention (all the files and directories have to be unique within one
395directory if their names are lowercased and truncated to eight
396characters before the C<.>, if any, and to three characters after the
397C<.>, if any). (And do not use C<.>s in directory names.)
ec481373 398
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399=head2 System Interaction
400
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401Not all platforms provide a command line. These are usually platforms
402that rely primarily on a Graphical User Interface (GUI) for user
403interaction. A program requiring a command line interface might
404not work everywhere. This is probably for the user of the program
405to deal with, so don't stay up late worrying about it.
e41182b5 406
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407Some platforms can't delete or rename files held open by the system.
408Remember to C<close> files when you are done with them. Don't
409C<unlink> or C<rename> an open file. Don't C<tie> or C<open> a
410file already tied or opened; C<untie> or C<close> it first.
e41182b5 411
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412Don't open the same file more than once at a time for writing, as some
413operating systems put mandatory locks on such files.
414
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415Don't assume that write/modify permission on a directory gives the
416right to add or delete files/directories in that directory. That is
417filesystem specific: in some filesystems you need write/modify
418permission also (or even just) in the file/directory itself. In some
419filesystems (AFS, DFS) the permission to add/delete directory entries
420is a completely separate permission.
421
422Don't assume that a single C<unlink> completely gets rid of the file:
423some filesystems (most notably the ones in VMS) have versioned
424filesystems, and unlink() removes only the most recent one (it doesn't
425remove all the versions because by default the native tools on those
426platforms remove just the most recent version, too). The portable
427idiom to remove all the versions of a file is
428
94bb614c 429 1 while unlink "file";
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430
431This will terminate if the file is undeleteable for some reason
432(protected, not there, and so on).
433
e41182b5 434Don't count on a specific environment variable existing in C<%ENV>.
0a47030a 435Don't count on C<%ENV> entries being case-sensitive, or even
4a0d0822 436case-preserving. Don't try to clear %ENV by saying C<%ENV = ();>, or,
6be8f7a6 437if you really have to, make it conditional on C<$^O ne 'VMS'> since in
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438VMS the C<%ENV> table is much more than a per-process key-value string
439table.
e41182b5 440
d1e3b762 441Don't count on signals or C<%SIG> for anything.
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442
443Don't count on filename globbing. Use C<opendir>, C<readdir>, and
444C<closedir> instead.
445
b8099c3d 446Don't count on per-program environment variables, or per-program current
dd9f0070 447directories.
b8099c3d 448
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449Don't count on specific values of C<$!>.
450
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451=head2 Command names versus file pathnames
452
453Don't assume that the name used to invoke a command or program with
454C<system> or C<exec> can also be used to test for the existence of the
455file that holds the executable code for that command or program.
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456First, many systems have "internal" commands that are built-in to the
457shell or OS and while these commands can be invoked, there is no
458corresponding file. Second, some operating systems (e.g., Cygwin,
459DJGPP, OS/2, and VOS) have required suffixes for executable files;
460these suffixes are generally permitted on the command name but are not
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461required. Thus, a command like "perl" might exist in a file named
462"perl", "perl.exe", or "perl.pm", depending on the operating system.
463The variable "_exe" in the Config module holds the executable suffix,
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464if any. Third, the VMS port carefully sets up $^X and
465$Config{perlpath} so that no further processing is required. This is
466just as well, because the matching regular expression used below would
467then have to deal with a possible trailing version number in the VMS
468file name.
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469
470To convert $^X to a file pathname, taking account of the requirements
471of the various operating system possibilities, say:
472 use Config;
a10d74f3 473 $thisperl = $^X;
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474 if ($^O ne 'VMS')
475 {$thisperl .= $Config{_exe} unless $thisperl =~ m/$Config{_exe}$/i;}
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476
477To convert $Config{perlpath} to a file pathname, say:
a10d74f3 478 use Config;
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479 $thisperl = $Config{perlpath};
480 if ($^O ne 'VMS')
481 {$thisperl .= $Config{_exe} unless $thisperl =~ m/$Config{_exe}$/i;}
a10d74f3 482
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483=head2 Interprocess Communication (IPC)
484
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485In general, don't directly access the system in code meant to be
486portable. That means, no C<system>, C<exec>, C<fork>, C<pipe>,
487C<``>, C<qx//>, C<open> with a C<|>, nor any of the other things
488that makes being a perl hacker worth being.
e41182b5
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489
490Commands that launch external processes are generally supported on
b7df3edc
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491most platforms (though many of them do not support any type of
492forking). The problem with using them arises from what you invoke
493them on. External tools are often named differently on different
4375e838 494platforms, may not be available in the same location, might accept
b7df3edc
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495different arguments, can behave differently, and often present their
496results in a platform-dependent way. Thus, you should seldom depend
497on them to produce consistent results. (Then again, if you're calling
498I<netstat -a>, you probably don't expect it to run on both Unix and CP/M.)
e41182b5 499
b7df3edc 500One especially common bit of Perl code is opening a pipe to B<sendmail>:
e41182b5 501
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502 open(MAIL, '|/usr/lib/sendmail -t')
503 or die "cannot fork sendmail: $!";
e41182b5
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504
505This is fine for systems programming when sendmail is known to be
506available. But it is not fine for many non-Unix systems, and even
507some Unix systems that may not have sendmail installed. If a portable
b7df3edc
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508solution is needed, see the various distributions on CPAN that deal
509with it. Mail::Mailer and Mail::Send in the MailTools distribution are
510commonly used, and provide several mailing methods, including mail,
511sendmail, and direct SMTP (via Net::SMTP) if a mail transfer agent is
512not available. Mail::Sendmail is a standalone module that provides
513simple, platform-independent mailing.
514
515The Unix System V IPC (C<msg*(), sem*(), shm*()>) is not available
516even on all Unix platforms.
e41182b5 517
a81e5e2e
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518Do not use either the bare result of C<pack("N", 10, 20, 30, 40)> or
519bare v-strings (such as C<v10.20.30.40>) to represent IPv4 addresses:
520both forms just pack the four bytes into network order. That this
521would be equal to the C language C<in_addr> struct (which is what the
522socket code internally uses) is not guaranteed. To be portable use
523the routines of the Socket extension, such as C<inet_aton()>,
524C<inet_ntoa()>, and C<sockaddr_in()>.
6b2463a0 525
e41182b5 526The rule of thumb for portable code is: Do it all in portable Perl, or
0a47030a
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527use a module (that may internally implement it with platform-specific
528code, but expose a common interface).
e41182b5 529
e41182b5
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530=head2 External Subroutines (XS)
531
b7df3edc 532XS code can usually be made to work with any platform, but dependent
e41182b5
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533libraries, header files, etc., might not be readily available or
534portable, or the XS code itself might be platform-specific, just as Perl
535code might be. If the libraries and headers are portable, then it is
536normally reasonable to make sure the XS code is portable, too.
537
b7df3edc
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538A different type of portability issue arises when writing XS code:
539availability of a C compiler on the end-user's system. C brings
540with it its own portability issues, and writing XS code will expose
541you to some of those. Writing purely in Perl is an easier way to
e41182b5
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542achieve portability.
543
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544=head2 Standard Modules
545
546In general, the standard modules work across platforms. Notable
6ab3f9cb 547exceptions are the CPAN module (which currently makes connections to external
e41182b5 548programs that may not be available), platform-specific modules (like
6ab3f9cb 549ExtUtils::MM_VMS), and DBM modules.
e41182b5 550
b7df3edc 551There is no one DBM module available on all platforms.
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552SDBM_File and the others are generally available on all Unix and DOSish
553ports, but not in MacPerl, where only NBDM_File and DB_File are
0a47030a 554available.
e41182b5
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555
556The good news is that at least some DBM module should be available, and
6ab3f9cb 557AnyDBM_File will use whichever module it can find. Of course, then
b7df3edc
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558the code needs to be fairly strict, dropping to the greatest common
559factor (e.g., not exceeding 1K for each record), so that it will
6ab3f9cb 560work with any DBM module. See L<AnyDBM_File> for more details.
e41182b5 561
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562=head2 Time and Date
563
0a47030a 564The system's notion of time of day and calendar date is controlled in
b7df3edc 565widely different ways. Don't assume the timezone is stored in C<$ENV{TZ}>,
0a47030a
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566and even if it is, don't assume that you can control the timezone through
567that variable.
e41182b5 568
322422de 569Don't assume that the epoch starts at 00:00:00, January 1, 1970,
6ab3f9cb
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570because that is OS- and implementation-specific. It is better to store a date
571in an unambiguous representation. The ISO-8601 standard defines
572"YYYY-MM-DD" as the date format. A text representation (like "1987-12-18")
573can be easily converted into an OS-specific value using a module like
574Date::Parse. An array of values, such as those returned by
322422de 575C<localtime>, can be converted to an OS-specific representation using
6ab3f9cb 576Time::Local.
322422de 577
19799a22
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578When calculating specific times, such as for tests in time or date modules,
579it may be appropriate to calculate an offset for the epoch.
b7df3edc 580
19799a22
GS
581 require Time::Local;
582 $offset = Time::Local::timegm(0, 0, 0, 1, 0, 70);
b7df3edc 583
19799a22
GS
584The value for C<$offset> in Unix will be C<0>, but in Mac OS will be
585some large number. C<$offset> can then be added to a Unix time value
586to get what should be the proper value on any system.
322422de
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587
588=head2 Character sets and character encoding
589
ec481373
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590Assume very little about character sets.
591
592Assume nothing about numerical values (C<ord>, C<chr>) of characters.
593Do not use explicit code point ranges (like \xHH-\xHH); use for
594example symbolic character classes like C<[:print:]>.
595
596Do not assume that the alphabetic characters are encoded contiguously
597(in the numeric sense). There may be gaps.
598
599Do not assume anything about the ordering of the characters.
600The lowercase letters may come before or after the uppercase letters;
601the lowercase and uppercase may be interlaced so that both `a' and `A'
602come before `b'; the accented and other international characters may
603be interlaced so that E<auml> comes before `b'.
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604
605=head2 Internationalisation
606
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607If you may assume POSIX (a rather large assumption), you may read
608more about the POSIX locale system from L<perllocale>. The locale
609system at least attempts to make things a little bit more portable,
610or at least more convenient and native-friendly for non-English
611users. The system affects character sets and encoding, and date
612and time formatting--amongst other things.
e41182b5
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613
614=head2 System Resources
615
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616If your code is destined for systems with severely constrained (or
617missing!) virtual memory systems then you want to be I<especially> mindful
618of avoiding wasteful constructs such as:
e41182b5
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619
620 # NOTE: this is no longer "bad" in perl5.005
621 for (0..10000000) {} # bad
622 for (my $x = 0; $x <= 10000000; ++$x) {} # good
623
624 @lines = <VERY_LARGE_FILE>; # bad
625
626 while (<FILE>) {$file .= $_} # sometimes bad
0a47030a 627 $file = join('', <FILE>); # better
e41182b5 628
b7df3edc
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629The last two constructs may appear unintuitive to most people. The
630first repeatedly grows a string, whereas the second allocates a
631large chunk of memory in one go. On some systems, the second is
632more efficient that the first.
0a47030a 633
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634=head2 Security
635
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636Most multi-user platforms provide basic levels of security, usually
637implemented at the filesystem level. Some, however, do
a1667ba3 638not-- unfortunately. Thus the notion of user id, or "home" directory,
b7df3edc
GS
639or even the state of being logged-in, may be unrecognizable on many
640platforms. If you write programs that are security-conscious, it
641is usually best to know what type of system you will be running
642under so that you can write code explicitly for that platform (or
643class of platforms).
0a47030a 644
a1667ba3
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645Don't assume the UNIX filesystem access semantics: the operating
646system or the filesystem may be using some ACL systems, which are
647richer languages than the usual rwx. Even if the rwx exist,
648their semantics might be different.
649
650(From security viewpoint testing for permissions before attempting to
651do something is silly anyway: if one tries this, there is potential
652for race conditions-- someone or something might change the
653permissions between the permissions check and the actual operation.
654Just try the operation.)
655
656Don't assume the UNIX user and group semantics: especially, don't
2edcc0d9 657expect the C<< $< >> and C<< $> >> (or the C<$(> and C<$)>) to work
a1667ba3
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658for switching identities (or memberships).
659
660Don't assume set-uid and set-gid semantics. (And even if you do,
661think twice: set-uid and set-gid are a known can of security worms.)
662
e41182b5
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663=head2 Style
664
665For those times when it is necessary to have platform-specific code,
666consider keeping the platform-specific code in one place, making porting
6ab3f9cb 667to other platforms easier. Use the Config module and the special
0a47030a
GS
668variable C<$^O> to differentiate platforms, as described in
669L<"PLATFORMS">.
e41182b5 670
b7df3edc
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671Be careful in the tests you supply with your module or programs.
672Module code may be fully portable, but its tests might not be. This
673often happens when tests spawn off other processes or call external
674programs to aid in the testing, or when (as noted above) the tests
675assume certain things about the filesystem and paths. Be careful
676not to depend on a specific output style for errors, such as when
d1be9408 677checking C<$!> after a system call. Some platforms expect a certain
b7df3edc
GS
678output format, and perl on those platforms may have been adjusted
679accordingly. Most specifically, don't anchor a regex when testing
680an error value.
e41182b5 681
0a47030a 682=head1 CPAN Testers
e41182b5 683
0a47030a
GS
684Modules uploaded to CPAN are tested by a variety of volunteers on
685different platforms. These CPAN testers are notified by mail of each
e41182b5 686new upload, and reply to the list with PASS, FAIL, NA (not applicable to
0a47030a 687this platform), or UNKNOWN (unknown), along with any relevant notations.
e41182b5
GS
688
689The purpose of the testing is twofold: one, to help developers fix any
0a47030a 690problems in their code that crop up because of lack of testing on other
b7df3edc 691platforms; two, to provide users with information about whether
0a47030a 692a given module works on a given platform.
e41182b5
GS
693
694=over 4
695
696=item Mailing list: cpan-testers@perl.org
697
c997b287 698=item Testing results: http://testers.cpan.org/
e41182b5
GS
699
700=back
701
e41182b5
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702=head1 PLATFORMS
703
704As of version 5.002, Perl is built with a C<$^O> variable that
705indicates the operating system it was built on. This was implemented
b7df3edc
GS
706to help speed up code that would otherwise have to C<use Config>
707and use the value of C<$Config{osname}>. Of course, to get more
e41182b5
GS
708detailed information about the system, looking into C<%Config> is
709certainly recommended.
710
b7df3edc
GS
711C<%Config> cannot always be trusted, however, because it was built
712at compile time. If perl was built in one place, then transferred
713elsewhere, some values may be wrong. The values may even have been
714edited after the fact.
6ab3f9cb 715
e41182b5
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716=head2 Unix
717
718Perl works on a bewildering variety of Unix and Unix-like platforms (see
719e.g. most of the files in the F<hints/> directory in the source code kit).
720On most of these systems, the value of C<$^O> (hence C<$Config{'osname'}>,
d1e3b762
GS
721too) is determined either by lowercasing and stripping punctuation from the
722first field of the string returned by typing C<uname -a> (or a similar command)
723at the shell prompt or by testing the file system for the presence of
724uniquely named files such as a kernel or header file. Here, for example,
725are a few of the more popular Unix flavors:
e41182b5 726
b7df3edc 727 uname $^O $Config{'archname'}
6ab3f9cb 728 --------------------------------------------
b7df3edc 729 AIX aix aix
6ab3f9cb 730 BSD/OS bsdos i386-bsdos
e1516da7 731 Darwin darwin darwin
6ab3f9cb
GS
732 dgux dgux AViiON-dgux
733 DYNIX/ptx dynixptx i386-dynixptx
b7df3edc 734 FreeBSD freebsd freebsd-i386
d1e3b762 735 Linux linux arm-linux
b7df3edc 736 Linux linux i386-linux
6ab3f9cb
GS
737 Linux linux i586-linux
738 Linux linux ppc-linux
b7df3edc
GS
739 HP-UX hpux PA-RISC1.1
740 IRIX irix irix
b787fad4 741 Mac OS X darwin darwin
d1e3b762
GS
742 MachTen PPC machten powerpc-machten
743 NeXT 3 next next-fat
744 NeXT 4 next OPENSTEP-Mach
6ab3f9cb 745 openbsd openbsd i386-openbsd
b7df3edc 746 OSF1 dec_osf alpha-dec_osf
6ab3f9cb
GS
747 reliantunix-n svr4 RM400-svr4
748 SCO_SV sco_sv i386-sco_sv
749 SINIX-N svr4 RM400-svr4
750 sn4609 unicos CRAY_C90-unicos
751 sn6521 unicosmk t3e-unicosmk
752 sn9617 unicos CRAY_J90-unicos
b7df3edc
GS
753 SunOS solaris sun4-solaris
754 SunOS solaris i86pc-solaris
755 SunOS4 sunos sun4-sunos
e41182b5 756
b7df3edc
GS
757Because the value of C<$Config{archname}> may depend on the
758hardware architecture, it can vary more than the value of C<$^O>.
6ab3f9cb 759
e41182b5
GS
760=head2 DOS and Derivatives
761
b7df3edc 762Perl has long been ported to Intel-style microcomputers running under
e41182b5
GS
763systems like PC-DOS, MS-DOS, OS/2, and most Windows platforms you can
764bring yourself to mention (except for Windows CE, if you count that).
b7df3edc 765Users familiar with I<COMMAND.COM> or I<CMD.EXE> style shells should
e41182b5
GS
766be aware that each of these file specifications may have subtle
767differences:
768
769 $filespec0 = "c:/foo/bar/file.txt";
770 $filespec1 = "c:\\foo\\bar\\file.txt";
771 $filespec2 = 'c:\foo\bar\file.txt';
772 $filespec3 = 'c:\\foo\\bar\\file.txt';
773
b7df3edc
GS
774System calls accept either C</> or C<\> as the path separator.
775However, many command-line utilities of DOS vintage treat C</> as
776the option prefix, so may get confused by filenames containing C</>.
777Aside from calling any external programs, C</> will work just fine,
778and probably better, as it is more consistent with popular usage,
779and avoids the problem of remembering what to backwhack and what
780not to.
e41182b5 781
b7df3edc
GS
782The DOS FAT filesystem can accommodate only "8.3" style filenames. Under
783the "case-insensitive, but case-preserving" HPFS (OS/2) and NTFS (NT)
0a47030a 784filesystems you may have to be careful about case returned with functions
e41182b5
GS
785like C<readdir> or used with functions like C<open> or C<opendir>.
786
b7df3edc
GS
787DOS also treats several filenames as special, such as AUX, PRN,
788NUL, CON, COM1, LPT1, LPT2, etc. Unfortunately, sometimes these
789filenames won't even work if you include an explicit directory
790prefix. It is best to avoid such filenames, if you want your code
791to be portable to DOS and its derivatives. It's hard to know what
792these all are, unfortunately.
e41182b5
GS
793
794Users of these operating systems may also wish to make use of
b7df3edc 795scripts such as I<pl2bat.bat> or I<pl2cmd> to
e41182b5
GS
796put wrappers around your scripts.
797
798Newline (C<\n>) is translated as C<\015\012> by STDIO when reading from
6ab3f9cb
GS
799and writing to files (see L<"Newlines">). C<binmode(FILEHANDLE)>
800will keep C<\n> translated as C<\012> for that filehandle. Since it is a
801no-op on other systems, C<binmode> should be used for cross-platform code
b7df3edc
GS
802that deals with binary data. That's assuming you realize in advance
803that your data is in binary. General-purpose programs should
804often assume nothing about their data.
e41182b5 805
b7df3edc 806The C<$^O> variable and the C<$Config{archname}> values for various
e41182b5
GS
807DOSish perls are as follows:
808
67ac489e
MS
809 OS $^O $Config{archname} ID Version
810 --------------------------------------------------------
811 MS-DOS dos ?
812 PC-DOS dos ?
813 OS/2 os2 ?
814 Windows 3.1 ? ? 0 3 01
815 Windows 95 MSWin32 MSWin32-x86 1 4 00
816 Windows 98 MSWin32 MSWin32-x86 1 4 10
817 Windows ME MSWin32 MSWin32-x86 1 ?
818 Windows NT MSWin32 MSWin32-x86 2 4 xx
819 Windows NT MSWin32 MSWin32-ALPHA 2 4 xx
820 Windows NT MSWin32 MSWin32-ppc 2 4 xx
821 Windows 2000 MSWin32 MSWin32-x86 2 5 xx
822 Windows XP MSWin32 MSWin32-x86 2 ?
823 Windows CE MSWin32 ? 3
824 Cygwin cygwin ?
e41182b5 825
34aaaa84
PP
826The various MSWin32 Perl's can distinguish the OS they are running on
827via the value of the fifth element of the list returned from
828Win32::GetOSVersion(). For example:
829
830 if ($^O eq 'MSWin32') {
831 my @os_version_info = Win32::GetOSVersion();
832 print +('3.1','95','NT')[$os_version_info[4]],"\n";
833 }
834
443f6d01
PN
835There are also Win32::IsWinNT() and Win32::IsWin95(), try
836C<perldoc Win32>. The very portable POSIX::uname() will work too:
1d65be3a
JH
837
838 c:\> perl -MPOSIX -we "print join '|', uname"
839 Windows NT|moonru|5.0|Build 2195 (Service Pack 2)|x86
d99f392e 840
e41182b5
GS
841Also see:
842
843=over 4
844
c997b287 845=item *
e41182b5 846
c997b287
GS
847The djgpp environment for DOS, http://www.delorie.com/djgpp/
848and L<perldos>.
e41182b5 849
c997b287 850=item *
e41182b5 851
c997b287
GS
852The EMX environment for DOS, OS/2, etc. emx@iaehv.nl,
853http://www.leo.org/pub/comp/os/os2/leo/gnu/emx+gcc/index.html or
f224927c 854ftp://hobbes.nmsu.edu/pub/os2/dev/emx/ Also L<perlos2>.
e41182b5 855
c997b287 856=item *
d1e3b762 857
c997b287
GS
858Build instructions for Win32 in L<perlwin32>, or under the Cygnus environment
859in L<perlcygwin>.
860
861=item *
862
863The C<Win32::*> modules in L<Win32>.
864
865=item *
866
867The ActiveState Pages, http://www.activestate.com/
868
869=item *
870
871The Cygwin environment for Win32; F<README.cygwin> (installed
47dafe4d 872as L<perlcygwin>), http://www.cygwin.com/
c997b287
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873
874=item *
875
876The U/WIN environment for Win32,
cea6626f 877http://www.research.att.com/sw/tools/uwin/
c997b287 878
cea6626f 879=item *
d1e3b762 880
cea6626f 881Build instructions for OS/2, L<perlos2>
d1e3b762 882
e41182b5
GS
883=back
884
dd9f0070 885=head2 S<Mac OS>
e41182b5
GS
886
887Any module requiring XS compilation is right out for most people, because
888MacPerl is built using non-free (and non-cheap!) compilers. Some XS
889modules that can work with MacPerl are built and distributed in binary
6ab3f9cb 890form on CPAN.
e41182b5
GS
891
892Directories are specified as:
893
894 volume:folder:file for absolute pathnames
895 volume:folder: for absolute pathnames
896 :folder:file for relative pathnames
897 :folder: for relative pathnames
898 :file for relative pathnames
899 file for relative pathnames
900
b7df3edc 901Files are stored in the directory in alphabetical order. Filenames are
6ab3f9cb 902limited to 31 characters, and may include any character except for
b7df3edc 903null and C<:>, which is reserved as the path separator.
e41182b5 904
0a47030a 905Instead of C<flock>, see C<FSpSetFLock> and C<FSpRstFLock> in the
6ab3f9cb 906Mac::Files module, or C<chmod(0444, ...)> and C<chmod(0666, ...)>.
e41182b5
GS
907
908In the MacPerl application, you can't run a program from the command line;
909programs that expect C<@ARGV> to be populated can be edited with something
910like the following, which brings up a dialog box asking for the command
911line arguments.
912
913 if (!@ARGV) {
914 @ARGV = split /\s+/, MacPerl::Ask('Arguments?');
915 }
916
b7df3edc 917A MacPerl script saved as a "droplet" will populate C<@ARGV> with the full
e41182b5
GS
918pathnames of the files dropped onto the script.
919
b7df3edc
GS
920Mac users can run programs under a type of command line interface
921under MPW (Macintosh Programmer's Workshop, a free development
922environment from Apple). MacPerl was first introduced as an MPW
923tool, and MPW can be used like a shell:
e41182b5
GS
924
925 perl myscript.plx some arguments
926
927ToolServer is another app from Apple that provides access to MPW tools
0a47030a 928from MPW and the MacPerl app, which allows MacPerl programs to use
e41182b5
GS
929C<system>, backticks, and piped C<open>.
930
931"S<Mac OS>" is the proper name for the operating system, but the value
932in C<$^O> is "MacOS". To determine architecture, version, or whether
933the application or MPW tool version is running, check:
934
935 $is_app = $MacPerl::Version =~ /App/;
936 $is_tool = $MacPerl::Version =~ /MPW/;
937 ($version) = $MacPerl::Version =~ /^(\S+)/;
938 $is_ppc = $MacPerl::Architecture eq 'MacPPC';
939 $is_68k = $MacPerl::Architecture eq 'Mac68K';
940
b787fad4
JH
941S<Mac OS X>, based on NeXT's OpenStep OS, runs MacPerl natively, under the
942"Classic" environment. There is no "Carbon" version of MacPerl to run
943under the primary Mac OS X environment. S<Mac OS X> and its Open Source
944version, Darwin, both run Unix perl natively.
6ab3f9cb 945
e41182b5
GS
946Also see:
947
948=over 4
949
c997b287
GS
950=item *
951
862b5365 952MacPerl Development, http://dev.macperl.org/ .
c997b287
GS
953
954=item *
955
862b5365 956The MacPerl Pages, http://www.macperl.com/ .
e41182b5 957
c997b287 958=item *
6ab3f9cb 959
862b5365 960The MacPerl mailing lists, http://lists.perl.org/ .
e41182b5
GS
961
962=back
963
e41182b5
GS
964=head2 VMS
965
c997b287 966Perl on VMS is discussed in L<perlvms> in the perl distribution.
b7df3edc 967Perl on VMS can accept either VMS- or Unix-style file
e41182b5
GS
968specifications as in either of the following:
969
970 $ perl -ne "print if /perl_setup/i" SYS$LOGIN:LOGIN.COM
971 $ perl -ne "print if /perl_setup/i" /sys$login/login.com
972
973but not a mixture of both as in:
974
975 $ perl -ne "print if /perl_setup/i" sys$login:/login.com
976 Can't open sys$login:/login.com: file specification syntax error
977
978Interacting with Perl from the Digital Command Language (DCL) shell
979often requires a different set of quotation marks than Unix shells do.
980For example:
981
982 $ perl -e "print ""Hello, world.\n"""
983 Hello, world.
984
b7df3edc 985There are several ways to wrap your perl scripts in DCL F<.COM> files, if
e41182b5
GS
986you are so inclined. For example:
987
988 $ write sys$output "Hello from DCL!"
989 $ if p1 .eqs. ""
990 $ then perl -x 'f$environment("PROCEDURE")
991 $ else perl -x - 'p1 'p2 'p3 'p4 'p5 'p6 'p7 'p8
992 $ deck/dollars="__END__"
993 #!/usr/bin/perl
994
995 print "Hello from Perl!\n";
996
997 __END__
998 $ endif
999
1000Do take care with C<$ ASSIGN/nolog/user SYS$COMMAND: SYS$INPUT> if your
c47ff5f1 1001perl-in-DCL script expects to do things like C<< $read = <STDIN>; >>.
e41182b5
GS
1002
1003Filenames are in the format "name.extension;version". The maximum
1004length for filenames is 39 characters, and the maximum length for
1005extensions is also 39 characters. Version is a number from 1 to
100632767. Valid characters are C</[A-Z0-9$_-]/>.
1007
b7df3edc 1008VMS's RMS filesystem is case-insensitive and does not preserve case.
e41182b5 1009C<readdir> returns lowercased filenames, but specifying a file for
b7df3edc 1010opening remains case-insensitive. Files without extensions have a
e41182b5 1011trailing period on them, so doing a C<readdir> with a file named F<A.;5>
0a47030a
GS
1012will return F<a.> (though that file could be opened with
1013C<open(FH, 'A')>).
e41182b5 1014
f34d0673 1015RMS had an eight level limit on directory depths from any rooted logical
dd9f0070
CN
1016(allowing 16 levels overall) prior to VMS 7.2. Hence
1017C<PERL_ROOT:[LIB.2.3.4.5.6.7.8]> is a valid directory specification but
1018C<PERL_ROOT:[LIB.2.3.4.5.6.7.8.9]> is not. F<Makefile.PL> authors might
1019have to take this into account, but at least they can refer to the former
f34d0673 1020as C</PERL_ROOT/lib/2/3/4/5/6/7/8/>.
e41182b5 1021
6ab3f9cb 1022The VMS::Filespec module, which gets installed as part of the build
0a47030a
GS
1023process on VMS, is a pure Perl module that can easily be installed on
1024non-VMS platforms and can be helpful for conversions to and from RMS
1025native formats.
e41182b5 1026
5e12dbfa
PP
1027What C<\n> represents depends on the type of file opened. It usually
1028represents C<\012> but it could also be C<\015>, C<\012>, C<\015\012>,
1029C<\000>, C<\040>, or nothing depending on the file organiztion and
1030record format. The VMS::Stdio module provides access to the
1031special fopen() requirements of files with unusual attributes on VMS.
e41182b5
GS
1032
1033TCP/IP stacks are optional on VMS, so socket routines might not be
1034implemented. UDP sockets may not be supported.
1035
1036The value of C<$^O> on OpenVMS is "VMS". To determine the architecture
1037that you are running on without resorting to loading all of C<%Config>
1038you can examine the content of the C<@INC> array like so:
1039
1040 if (grep(/VMS_AXP/, @INC)) {
1041 print "I'm on Alpha!\n";
6ab3f9cb 1042
e41182b5
GS
1043 } elsif (grep(/VMS_VAX/, @INC)) {
1044 print "I'm on VAX!\n";
6ab3f9cb 1045
e41182b5
GS
1046 } else {
1047 print "I'm not so sure about where $^O is...\n";
1048 }
1049
b7df3edc
GS
1050On VMS, perl determines the UTC offset from the C<SYS$TIMEZONE_DIFFERENTIAL>
1051logical name. Although the VMS epoch began at 17-NOV-1858 00:00:00.00,
6ab3f9cb 1052calls to C<localtime> are adjusted to count offsets from
b7df3edc 105301-JAN-1970 00:00:00.00, just like Unix.
6ab3f9cb 1054
e41182b5
GS
1055Also see:
1056
1057=over 4
1058
c997b287
GS
1059=item *
1060
1061F<README.vms> (installed as L<README_vms>), L<perlvms>
1062
1063=item *
1064
1065vmsperl list, majordomo@perl.org
e41182b5 1066
c997b287 1067(Put the words C<subscribe vmsperl> in message body.)
e41182b5 1068
c997b287 1069=item *
e41182b5 1070
c997b287 1071vmsperl on the web, http://www.sidhe.org/vmsperl/index.html
e41182b5
GS
1072
1073=back
1074
495c5fdc
PG
1075=head2 VOS
1076
9a997319
JH
1077Perl on VOS is discussed in F<README.vos> in the perl distribution
1078(installed as L<perlvos>). Perl on VOS can accept either VOS- or
1079Unix-style file specifications as in either of the following:
495c5fdc 1080
cc07ed0b
PG
1081 C<< $ perl -ne "print if /perl_setup/i" >system>notices >>
1082 C<< $ perl -ne "print if /perl_setup/i" /system/notices >>
495c5fdc
PG
1083
1084or even a mixture of both as in:
1085
cc07ed0b 1086 C<< $ perl -ne "print if /perl_setup/i" >system/notices >>
495c5fdc 1087
b7df3edc 1088Even though VOS allows the slash character to appear in object
495c5fdc
PG
1089names, because the VOS port of Perl interprets it as a pathname
1090delimiting character, VOS files, directories, or links whose names
1091contain a slash character cannot be processed. Such files must be
a3dfe201
GS
1092renamed before they can be processed by Perl. Note that VOS limits
1093file names to 32 or fewer characters.
495c5fdc 1094
cc07ed0b
PG
1095Perl on VOS can be built using two different compilers and two different
1096versions of the POSIX runtime. The recommended method for building full
1097Perl is with the GNU C compiler and the generally-available version of
1098VOS POSIX support. See F<README.vos> (installed as L<perlvos>) for
1099restrictions that apply when Perl is built using the VOS Standard C
1100compiler or the alpha version of VOS POSIX support.
495c5fdc
PG
1101
1102The value of C<$^O> on VOS is "VOS". To determine the architecture that
1103you are running on without resorting to loading all of C<%Config> you
c997b287 1104can examine the content of the @INC array like so:
495c5fdc 1105
24e8e380 1106 if ($^O =~ /VOS/) {
495c5fdc
PG
1107 print "I'm on a Stratus box!\n";
1108 } else {
1109 print "I'm not on a Stratus box!\n";
1110 die;
1111 }
1112
1113 if (grep(/860/, @INC)) {
1114 print "This box is a Stratus XA/R!\n";
6ab3f9cb 1115
495c5fdc 1116 } elsif (grep(/7100/, @INC)) {
24e8e380 1117 print "This box is a Stratus HP 7100 or 8xxx!\n";
6ab3f9cb 1118
495c5fdc 1119 } elsif (grep(/8000/, @INC)) {
24e8e380 1120 print "This box is a Stratus HP 8xxx!\n";
6ab3f9cb 1121
495c5fdc 1122 } else {
24e8e380 1123 print "This box is a Stratus 68K!\n";
495c5fdc
PG
1124 }
1125
1126Also see:
1127
1128=over 4
1129
c997b287 1130=item *
495c5fdc 1131
cc07ed0b 1132F<README.vos> (installed as L<perlvos>)
c997b287
GS
1133
1134=item *
1135
1136The VOS mailing list.
495c5fdc
PG
1137
1138There is no specific mailing list for Perl on VOS. You can post
1139comments to the comp.sys.stratus newsgroup, or subscribe to the general
cc07ed0b 1140Stratus mailing list. Send a letter with "subscribe Info-Stratus" in
495c5fdc
PG
1141the message body to majordomo@list.stratagy.com.
1142
c997b287
GS
1143=item *
1144
cc07ed0b 1145VOS Perl on the web at http://ftp.stratus.com/pub/vos/posix/posix.html
495c5fdc
PG
1146
1147=back
1148
e41182b5
GS
1149=head2 EBCDIC Platforms
1150
1151Recent versions of Perl have been ported to platforms such as OS/400 on
d1e3b762
GS
1152AS/400 minicomputers as well as OS/390, VM/ESA, and BS2000 for S/390
1153Mainframes. Such computers use EBCDIC character sets internally (usually
0cc436d0
GS
1154Character Code Set ID 0037 for OS/400 and either 1047 or POSIX-BC for S/390
1155systems). On the mainframe perl currently works under the "Unix system
1156services for OS/390" (formerly known as OpenEdition), VM/ESA OpenEdition, or
1157the BS200 POSIX-BC system (BS2000 is supported in perl 5.6 and greater).
c997b287 1158See L<perlos390> for details.
e41182b5 1159
7c5ffed3
JH
1160As of R2.5 of USS for OS/390 and Version 2.3 of VM/ESA these Unix
1161sub-systems do not support the C<#!> shebang trick for script invocation.
1162Hence, on OS/390 and VM/ESA perl scripts can be executed with a header
1163similar to the following simple script:
e41182b5
GS
1164
1165 : # use perl
1166 eval 'exec /usr/local/bin/perl -S $0 ${1+"$@"}'
1167 if 0;
1168 #!/usr/local/bin/perl # just a comment really
1169
1170 print "Hello from perl!\n";
1171
d1e3b762
GS
1172OS/390 will support the C<#!> shebang trick in release 2.8 and beyond.
1173Calls to C<system> and backticks can use POSIX shell syntax on all
1174S/390 systems.
1175
b7df3edc 1176On the AS/400, if PERL5 is in your library list, you may need
6ab3f9cb
GS
1177to wrap your perl scripts in a CL procedure to invoke them like so:
1178
1179 BEGIN
1180 CALL PGM(PERL5/PERL) PARM('/QOpenSys/hello.pl')
1181 ENDPGM
1182
1183This will invoke the perl script F<hello.pl> in the root of the
1184QOpenSys file system. On the AS/400 calls to C<system> or backticks
1185must use CL syntax.
1186
e41182b5 1187On these platforms, bear in mind that the EBCDIC character set may have
0a47030a
GS
1188an effect on what happens with some perl functions (such as C<chr>,
1189C<pack>, C<print>, C<printf>, C<ord>, C<sort>, C<sprintf>, C<unpack>), as
1190well as bit-fiddling with ASCII constants using operators like C<^>, C<&>
1191and C<|>, not to mention dealing with socket interfaces to ASCII computers
6ab3f9cb 1192(see L<"Newlines">).
e41182b5 1193
b7df3edc
GS
1194Fortunately, most web servers for the mainframe will correctly
1195translate the C<\n> in the following statement to its ASCII equivalent
1196(C<\r> is the same under both Unix and OS/390 & VM/ESA):
e41182b5
GS
1197
1198 print "Content-type: text/html\r\n\r\n";
1199
d1e3b762 1200The values of C<$^O> on some of these platforms includes:
e41182b5 1201
d1e3b762
GS
1202 uname $^O $Config{'archname'}
1203 --------------------------------------------
1204 OS/390 os390 os390
1205 OS400 os400 os400
1206 POSIX-BC posix-bc BS2000-posix-bc
1207 VM/ESA vmesa vmesa
3c075c7d 1208
e41182b5
GS
1209Some simple tricks for determining if you are running on an EBCDIC
1210platform could include any of the following (perhaps all):
1211
1212 if ("\t" eq "\05") { print "EBCDIC may be spoken here!\n"; }
1213
1214 if (ord('A') == 193) { print "EBCDIC may be spoken here!\n"; }
1215
1216 if (chr(169) eq 'z') { print "EBCDIC may be spoken here!\n"; }
1217
b7df3edc 1218One thing you may not want to rely on is the EBCDIC encoding
0a47030a
GS
1219of punctuation characters since these may differ from code page to code
1220page (and once your module or script is rumoured to work with EBCDIC,
1221folks will want it to work with all EBCDIC character sets).
e41182b5
GS
1222
1223Also see:
1224
1225=over 4
1226
c997b287
GS
1227=item *
1228
1229*
d1e3b762 1230
dc5c060f 1231L<perlos390>, F<README.os390>, F<perlbs2000>, F<README.vmesa>,
bb462878 1232L<perlebcdic>.
c997b287
GS
1233
1234=item *
e41182b5
GS
1235
1236The perl-mvs@perl.org list is for discussion of porting issues as well as
1237general usage issues for all EBCDIC Perls. Send a message body of
1238"subscribe perl-mvs" to majordomo@perl.org.
1239
c997b287
GS
1240=item *
1241
1242AS/400 Perl information at
b1866b2d 1243http://as400.rochester.ibm.com/
d1e3b762 1244as well as on CPAN in the F<ports/> directory.
e41182b5
GS
1245
1246=back
1247
b8099c3d
CN
1248=head2 Acorn RISC OS
1249
b7df3edc
GS
1250Because Acorns use ASCII with newlines (C<\n>) in text files as C<\012> like
1251Unix, and because Unix filename emulation is turned on by default,
1252most simple scripts will probably work "out of the box". The native
6ab3f9cb 1253filesystem is modular, and individual filesystems are free to be
0a47030a 1254case-sensitive or insensitive, and are usually case-preserving. Some
b7df3edc 1255native filesystems have name length limits, which file and directory
6ab3f9cb
GS
1256names are silently truncated to fit. Scripts should be aware that the
1257standard filesystem currently has a name length limit of B<10>
1258characters, with up to 77 items in a directory, but other filesystems
0a47030a 1259may not impose such limitations.
b8099c3d
CN
1260
1261Native filenames are of the form
1262
6ab3f9cb 1263 Filesystem#Special_Field::DiskName.$.Directory.Directory.File
dd9f0070 1264
b8099c3d
CN
1265where
1266
1267 Special_Field is not usually present, but may contain . and $ .
1268 Filesystem =~ m|[A-Za-z0-9_]|
1269 DsicName =~ m|[A-Za-z0-9_/]|
1270 $ represents the root directory
1271 . is the path separator
1272 @ is the current directory (per filesystem but machine global)
1273 ^ is the parent directory
1274 Directory and File =~ m|[^\0- "\.\$\%\&:\@\\^\|\177]+|
1275
1276The default filename translation is roughly C<tr|/.|./|;>
1277
6ab3f9cb 1278Note that C<"ADFS::HardDisk.$.File" ne 'ADFS::HardDisk.$.File'> and that
0a47030a
GS
1279the second stage of C<$> interpolation in regular expressions will fall
1280foul of the C<$.> if scripts are not careful.
1281
1282Logical paths specified by system variables containing comma-separated
b7df3edc 1283search lists are also allowed; hence C<System:Modules> is a valid
0a47030a 1284filename, and the filesystem will prefix C<Modules> with each section of
6ab3f9cb 1285C<System$Path> until a name is made that points to an object on disk.
b7df3edc 1286Writing to a new file C<System:Modules> would be allowed only if
0a47030a
GS
1287C<System$Path> contains a single item list. The filesystem will also
1288expand system variables in filenames if enclosed in angle brackets, so
c47ff5f1 1289C<< <System$Dir>.Modules >> would look for the file
0a47030a 1290S<C<$ENV{'System$Dir'} . 'Modules'>>. The obvious implication of this is
c47ff5f1 1291that B<fully qualified filenames can start with C<< <> >>> and should
0a47030a 1292be protected when C<open> is used for input.
b8099c3d
CN
1293
1294Because C<.> was in use as a directory separator and filenames could not
1295be assumed to be unique after 10 characters, Acorn implemented the C
1296compiler to strip the trailing C<.c> C<.h> C<.s> and C<.o> suffix from
1297filenames specified in source code and store the respective files in
b7df3edc 1298subdirectories named after the suffix. Hence files are translated:
b8099c3d
CN
1299
1300 foo.h h.foo
1301 C:foo.h C:h.foo (logical path variable)
1302 sys/os.h sys.h.os (C compiler groks Unix-speak)
1303 10charname.c c.10charname
1304 10charname.o o.10charname
1305 11charname_.c c.11charname (assuming filesystem truncates at 10)
1306
1307The Unix emulation library's translation of filenames to native assumes
b7df3edc
GS
1308that this sort of translation is required, and it allows a user-defined list
1309of known suffixes that it will transpose in this fashion. This may
1310seem transparent, but consider that with these rules C<foo/bar/baz.h>
0a47030a
GS
1311and C<foo/bar/h/baz> both map to C<foo.bar.h.baz>, and that C<readdir> and
1312C<glob> cannot and do not attempt to emulate the reverse mapping. Other
6ab3f9cb 1313C<.>'s in filenames are translated to C</>.
0a47030a 1314
b7df3edc 1315As implied above, the environment accessed through C<%ENV> is global, and
0a47030a 1316the convention is that program specific environment variables are of the
6ab3f9cb
GS
1317form C<Program$Name>. Each filesystem maintains a current directory,
1318and the current filesystem's current directory is the B<global> current
b7df3edc
GS
1319directory. Consequently, sociable programs don't change the current
1320directory but rely on full pathnames, and programs (and Makefiles) cannot
0a47030a
GS
1321assume that they can spawn a child process which can change the current
1322directory without affecting its parent (and everyone else for that
1323matter).
1324
b7df3edc
GS
1325Because native operating system filehandles are global and are currently
1326allocated down from 255, with 0 being a reserved value, the Unix emulation
0a47030a
GS
1327library emulates Unix filehandles. Consequently, you can't rely on
1328passing C<STDIN>, C<STDOUT>, or C<STDERR> to your children.
1329
1330The desire of users to express filenames of the form
c47ff5f1 1331C<< <Foo$Dir>.Bar >> on the command line unquoted causes problems,
0a47030a 1332too: C<``> command output capture has to perform a guessing game. It
c47ff5f1 1333assumes that a string C<< <[^<>]+\$[^<>]> >> is a
0a47030a 1334reference to an environment variable, whereas anything else involving
c47ff5f1 1335C<< < >> or C<< > >> is redirection, and generally manages to be 99%
0a47030a
GS
1336right. Of course, the problem remains that scripts cannot rely on any
1337Unix tools being available, or that any tools found have Unix-like command
1338line arguments.
1339
b7df3edc
GS
1340Extensions and XS are, in theory, buildable by anyone using free
1341tools. In practice, many don't, as users of the Acorn platform are
1342used to binary distributions. MakeMaker does run, but no available
1343make currently copes with MakeMaker's makefiles; even if and when
1344this should be fixed, the lack of a Unix-like shell will cause
1345problems with makefile rules, especially lines of the form C<cd
1346sdbm && make all>, and anything using quoting.
b8099c3d
CN
1347
1348"S<RISC OS>" is the proper name for the operating system, but the value
1349in C<$^O> is "riscos" (because we don't like shouting).
1350
e41182b5
GS
1351=head2 Other perls
1352
b7df3edc
GS
1353Perl has been ported to many platforms that do not fit into any of
1354the categories listed above. Some, such as AmigaOS, Atari MiNT,
1355BeOS, HP MPE/iX, QNX, Plan 9, and VOS, have been well-integrated
1356into the standard Perl source code kit. You may need to see the
1357F<ports/> directory on CPAN for information, and possibly binaries,
1358for the likes of: aos, Atari ST, lynxos, riscos, Novell Netware,
1359Tandem Guardian, I<etc.> (Yes, we know that some of these OSes may
1360fall under the Unix category, but we are not a standards body.)
e41182b5 1361
d1e3b762
GS
1362Some approximate operating system names and their C<$^O> values
1363in the "OTHER" category include:
1364
1365 OS $^O $Config{'archname'}
1366 ------------------------------------------
1367 Amiga DOS amigaos m68k-amigos
cec2c193 1368 BeOS beos
d1e3b762
GS
1369 MPE/iX mpeix PA-RISC1.1
1370
e41182b5
GS
1371See also:
1372
1373=over 4
1374
c997b287
GS
1375=item *
1376
1377Amiga, F<README.amiga> (installed as L<perlamiga>).
1378
1379=item *
d1e3b762 1380
c997b287
GS
1381Atari, F<README.mint> and Guido Flohr's web page
1382http://stud.uni-sb.de/~gufl0000/
e41182b5 1383
c997b287 1384=item *
d1e3b762 1385
c997b287 1386Be OS, F<README.beos>
e41182b5 1387
c997b287
GS
1388=item *
1389
1390HP 300 MPE/iX, F<README.mpeix> and Mark Bixby's web page
34aaaa84 1391http://www.bixby.org/mark/perlix.html
c997b287
GS
1392
1393=item *
e41182b5 1394
6ab3f9cb 1395A free perl5-based PERL.NLM for Novell Netware is available in
c997b287 1396precompiled binary and source code form from http://www.novell.com/
6ab3f9cb 1397as well as from CPAN.
e41182b5 1398
13a2d996 1399=item *
c997b287
GS
1400
1401Plan 9, F<README.plan9>
d1e3b762 1402
e41182b5
GS
1403=back
1404
e41182b5
GS
1405=head1 FUNCTION IMPLEMENTATIONS
1406
b7df3edc
GS
1407Listed below are functions that are either completely unimplemented
1408or else have been implemented differently on various platforms.
1409Following each description will be, in parentheses, a list of
1410platforms that the description applies to.
e41182b5 1411
b7df3edc
GS
1412The list may well be incomplete, or even wrong in some places. When
1413in doubt, consult the platform-specific README files in the Perl
1414source distribution, and any other documentation resources accompanying
1415a given port.
e41182b5 1416
0a47030a 1417Be aware, moreover, that even among Unix-ish systems there are variations.
e41182b5 1418
b7df3edc
GS
1419For many functions, you can also query C<%Config>, exported by
1420default from the Config module. For example, to check whether the
1421platform has the C<lstat> call, check C<$Config{d_lstat}>. See
1422L<Config> for a full description of available variables.
e41182b5
GS
1423
1424=head2 Alphabetical Listing of Perl Functions
1425
1426=over 8
1427
1428=item -X FILEHANDLE
1429
1430=item -X EXPR
1431
1432=item -X
1433
b7df3edc 1434C<-r>, C<-w>, and C<-x> have a limited meaning only; directories
e41182b5 1435and applications are executable, and there are no uid/gid
b7df3edc 1436considerations. C<-o> is not supported. (S<Mac OS>)
e41182b5 1437
b7df3edc
GS
1438C<-r>, C<-w>, C<-x>, and C<-o> tell whether the file is accessible,
1439which may not reflect UIC-based file protections. (VMS)
e41182b5 1440
b8099c3d
CN
1441C<-s> returns the size of the data fork, not the total size of data fork
1442plus resource fork. (S<Mac OS>).
1443
1444C<-s> by name on an open file will return the space reserved on disk,
1445rather than the current extent. C<-s> on an open filehandle returns the
b7df3edc 1446current size. (S<RISC OS>)
b8099c3d 1447
e41182b5 1448C<-R>, C<-W>, C<-X>, C<-O> are indistinguishable from C<-r>, C<-w>,
b8099c3d 1449C<-x>, C<-o>. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1450
1451C<-b>, C<-c>, C<-k>, C<-g>, C<-p>, C<-u>, C<-A> are not implemented.
1452(S<Mac OS>)
1453
1454C<-g>, C<-k>, C<-l>, C<-p>, C<-u>, C<-A> are not particularly meaningful.
b8099c3d 1455(Win32, VMS, S<RISC OS>)
e41182b5
GS
1456
1457C<-d> is true if passed a device spec without an explicit directory.
1458(VMS)
1459
1460C<-T> and C<-B> are implemented, but might misclassify Mac text files
0a47030a 1461with foreign characters; this is the case will all platforms, but may
b7df3edc 1462affect S<Mac OS> often. (S<Mac OS>)
e41182b5
GS
1463
1464C<-x> (or C<-X>) determine if a file ends in one of the executable
b7df3edc 1465suffixes. C<-S> is meaningless. (Win32)
e41182b5 1466
b8099c3d
CN
1467C<-x> (or C<-X>) determine if a file has an executable file type.
1468(S<RISC OS>)
1469
63f87e49
GS
1470=item alarm SECONDS
1471
1472=item alarm
1473
1474Not implemented. (Win32)
1475
e41182b5
GS
1476=item binmode FILEHANDLE
1477
b7df3edc 1478Meaningless. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1479
1480Reopens file and restores pointer; if function fails, underlying
1481filehandle may be closed, or pointer may be in a different position.
1482(VMS)
1483
1484The value returned by C<tell> may be affected after the call, and
1485the filehandle may be flushed. (Win32)
1486
1487=item chmod LIST
1488
b7df3edc 1489Only limited meaning. Disabling/enabling write permission is mapped to
e41182b5
GS
1490locking/unlocking the file. (S<Mac OS>)
1491
1492Only good for changing "owner" read-write access, "group", and "other"
1493bits are meaningless. (Win32)
1494
b8099c3d
CN
1495Only good for changing "owner" and "other" read-write access. (S<RISC OS>)
1496
495c5fdc
PG
1497Access permissions are mapped onto VOS access-control list changes. (VOS)
1498
4e51f8e4 1499The actual permissions set depend on the value of the C<CYGWIN>
789f0d36 1500in the SYSTEM environment settings. (Cygwin)
4e51f8e4 1501
e41182b5
GS
1502=item chown LIST
1503
495c5fdc 1504Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>, VOS)
e41182b5
GS
1505
1506Does nothing, but won't fail. (Win32)
1507
1508=item chroot FILENAME
1509
1510=item chroot
1511
7c5ffed3 1512Not implemented. (S<Mac OS>, Win32, VMS, Plan9, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1513
1514=item crypt PLAINTEXT,SALT
1515
1516May not be available if library or source was not provided when building
b8099c3d 1517perl. (Win32)
e41182b5 1518
495c5fdc
PG
1519Not implemented. (VOS)
1520
e41182b5
GS
1521=item dbmclose HASH
1522
495c5fdc 1523Not implemented. (VMS, Plan9, VOS)
e41182b5
GS
1524
1525=item dbmopen HASH,DBNAME,MODE
1526
495c5fdc 1527Not implemented. (VMS, Plan9, VOS)
e41182b5
GS
1528
1529=item dump LABEL
1530
b8099c3d 1531Not useful. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1532
1533Not implemented. (Win32)
1534
b8099c3d 1535Invokes VMS debugger. (VMS)
e41182b5
GS
1536
1537=item exec LIST
1538
1539Not implemented. (S<Mac OS>)
1540
7c5ffed3 1541Implemented via Spawn. (VM/ESA)
3c075c7d 1542
0f897271
GS
1543Does not automatically flush output handles on some platforms.
1544(SunOS, Solaris, HP-UX)
1545
fe12c0e8
MS
1546=item exit EXPR
1547
1548=item exit
1549
1550Emulates UNIX exit() (which considers C<exit 1> to indicate an error) by
1551mapping the C<1> to SS$_ABORT (C<44>). This behavior may be overridden
1552with the pragma C<use vmsish 'exit'>. As with the CRTL's exit()
1553function, C<exit 0> is also mapped to an exit status of SS$_NORMAL
1554(C<1>); this mapping cannot be overridden. Any other argument to exit()
1555is used directly as Perl's exit status. (VMS)
1556
e41182b5
GS
1557=item fcntl FILEHANDLE,FUNCTION,SCALAR
1558
1559Not implemented. (Win32, VMS)
1560
1561=item flock FILEHANDLE,OPERATION
1562
495c5fdc 1563Not implemented (S<Mac OS>, VMS, S<RISC OS>, VOS).
e41182b5
GS
1564
1565Available only on Windows NT (not on Windows 95). (Win32)
1566
1567=item fork
1568
0f897271
GS
1569Not implemented. (S<Mac OS>, AmigaOS, S<RISC OS>, VOS, VM/ESA)
1570
1571Emulated using multiple interpreters. See L<perlfork>. (Win32)
1572
1573Does not automatically flush output handles on some platforms.
1574(SunOS, Solaris, HP-UX)
e41182b5
GS
1575
1576=item getlogin
1577
b8099c3d 1578Not implemented. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1579
1580=item getpgrp PID
1581
495c5fdc 1582Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5
GS
1583
1584=item getppid
1585
b8099c3d 1586Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1587
1588=item getpriority WHICH,WHO
1589
7c5ffed3 1590Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1591
1592=item getpwnam NAME
1593
1594Not implemented. (S<Mac OS>, Win32)
1595
b8099c3d
CN
1596Not useful. (S<RISC OS>)
1597
e41182b5
GS
1598=item getgrnam NAME
1599
b8099c3d 1600Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1601
1602=item getnetbyname NAME
1603
1604Not implemented. (S<Mac OS>, Win32, Plan9)
1605
1606=item getpwuid UID
1607
1608Not implemented. (S<Mac OS>, Win32)
1609
b8099c3d
CN
1610Not useful. (S<RISC OS>)
1611
e41182b5
GS
1612=item getgrgid GID
1613
b8099c3d 1614Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1615
1616=item getnetbyaddr ADDR,ADDRTYPE
1617
1618Not implemented. (S<Mac OS>, Win32, Plan9)
1619
1620=item getprotobynumber NUMBER
1621
1622Not implemented. (S<Mac OS>)
1623
1624=item getservbyport PORT,PROTO
1625
1626Not implemented. (S<Mac OS>)
1627
1628=item getpwent
1629
7c5ffed3 1630Not implemented. (S<Mac OS>, Win32, VM/ESA)
e41182b5
GS
1631
1632=item getgrent
1633
7c5ffed3 1634Not implemented. (S<Mac OS>, Win32, VMS, VM/ESA)
e41182b5
GS
1635
1636=item gethostent
1637
1638Not implemented. (S<Mac OS>, Win32)
1639
1640=item getnetent
1641
1642Not implemented. (S<Mac OS>, Win32, Plan9)
1643
1644=item getprotoent
1645
1646Not implemented. (S<Mac OS>, Win32, Plan9)
1647
1648=item getservent
1649
1650Not implemented. (Win32, Plan9)
1651
e41182b5
GS
1652=item sethostent STAYOPEN
1653
b8099c3d 1654Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>)
e41182b5
GS
1655
1656=item setnetent STAYOPEN
1657
b8099c3d 1658Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>)
e41182b5
GS
1659
1660=item setprotoent STAYOPEN
1661
b8099c3d 1662Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>)
e41182b5
GS
1663
1664=item setservent STAYOPEN
1665
b8099c3d 1666Not implemented. (Plan9, Win32, S<RISC OS>)
e41182b5
GS
1667
1668=item endpwent
1669
a3dfe201 1670Not implemented. (S<Mac OS>, MPE/iX, VM/ESA, Win32)
e41182b5
GS
1671
1672=item endgrent
1673
a3dfe201 1674Not implemented. (S<Mac OS>, MPE/iX, S<RISC OS>, VM/ESA, VMS, Win32)
e41182b5
GS
1675
1676=item endhostent
1677
1678Not implemented. (S<Mac OS>, Win32)
1679
1680=item endnetent
1681
1682Not implemented. (S<Mac OS>, Win32, Plan9)
1683
1684=item endprotoent
1685
1686Not implemented. (S<Mac OS>, Win32, Plan9)
1687
1688=item endservent
1689
1690Not implemented. (Plan9, Win32)
1691
1692=item getsockopt SOCKET,LEVEL,OPTNAME
1693
97c10e77 1694Not implemented. (Plan9)
e41182b5
GS
1695
1696=item glob EXPR
1697
1698=item glob
1699
63f87e49
GS
1700This operator is implemented via the File::Glob extension on most
1701platforms. See L<File::Glob> for portability information.
b8099c3d 1702
e41182b5
GS
1703=item ioctl FILEHANDLE,FUNCTION,SCALAR
1704
1705Not implemented. (VMS)
1706
1707Available only for socket handles, and it does what the ioctlsocket() call
1708in the Winsock API does. (Win32)
1709
b8099c3d
CN
1710Available only for socket handles. (S<RISC OS>)
1711
b350dd2f 1712=item kill SIGNAL, LIST
e41182b5 1713
862b5365
JH
1714C<kill(0, LIST)> is implemented for the sake of taint checking;
1715use with other signals is unimplemented. (S<Mac OS>)
1716
1717Not implemented, hence not useful for taint checking. (S<RISC OS>)
e41182b5 1718
63f87e49
GS
1719C<kill()> doesn't have the semantics of C<raise()>, i.e. it doesn't send
1720a signal to the identified process like it does on Unix platforms.
1721Instead C<kill($sig, $pid)> terminates the process identified by $pid,
1722and makes it exit immediately with exit status $sig. As in Unix, if
1723$sig is 0 and the specified process exists, it returns true without
1724actually terminating it. (Win32)
e41182b5
GS
1725
1726=item link OLDFILE,NEWFILE
1727
a3dfe201 1728Not implemented. (S<Mac OS>, MPE/iX, VMS, S<RISC OS>)
e41182b5 1729
433acd8a
JH
1730Link count not updated because hard links are not quite that hard
1731(They are sort of half-way between hard and soft links). (AmigaOS)
1732
a3dfe201
GS
1733Hard links are implemented on Win32 (Windows NT and Windows 2000)
1734under NTFS only.
1735
e41182b5
GS
1736=item lstat FILEHANDLE
1737
1738=item lstat EXPR
1739
1740=item lstat
1741
b8099c3d 1742Not implemented. (VMS, S<RISC OS>)
e41182b5 1743
63f87e49 1744Return values (especially for device and inode) may be bogus. (Win32)
e41182b5
GS
1745
1746=item msgctl ID,CMD,ARG
1747
1748=item msgget KEY,FLAGS
1749
1750=item msgsnd ID,MSG,FLAGS
1751
1752=item msgrcv ID,VAR,SIZE,TYPE,FLAGS
1753
495c5fdc 1754Not implemented. (S<Mac OS>, Win32, VMS, Plan9, S<RISC OS>, VOS)
e41182b5
GS
1755
1756=item open FILEHANDLE,EXPR
1757
1758=item open FILEHANDLE
1759
b7df3edc 1760The C<|> variants are supported only if ToolServer is installed.
e41182b5
GS
1761(S<Mac OS>)
1762
c47ff5f1 1763open to C<|-> and C<-|> are unsupported. (S<Mac OS>, Win32, S<RISC OS>)
e41182b5 1764
0f897271
GS
1765Opening a process does not automatically flush output handles on some
1766platforms. (SunOS, Solaris, HP-UX)
1767
e41182b5
GS
1768=item pipe READHANDLE,WRITEHANDLE
1769
433acd8a
JH
1770Very limited functionality. (MiNT)
1771
e41182b5
GS
1772=item readlink EXPR
1773
1774=item readlink
1775
b8099c3d 1776Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5
GS
1777
1778=item select RBITS,WBITS,EBITS,TIMEOUT
1779
689c5c24 1780Only implemented on sockets. (Win32, VMS)
e41182b5 1781
b8099c3d
CN
1782Only reliable on sockets. (S<RISC OS>)
1783
76e05f0b 1784Note that the C<select FILEHANDLE> form is generally portable.
63f87e49 1785
e41182b5
GS
1786=item semctl ID,SEMNUM,CMD,ARG
1787
1788=item semget KEY,NSEMS,FLAGS
1789
1790=item semop KEY,OPSTRING
1791
495c5fdc 1792Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1793
a3dfe201
GS
1794=item setgrent
1795
74555b7a 1796Not implemented. (S<Mac OS>, MPE/iX, VMS, Win32, VMS, S<RISC OS>)
a3dfe201 1797
e41182b5
GS
1798=item setpgrp PID,PGRP
1799
495c5fdc 1800Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5
GS
1801
1802=item setpriority WHICH,WHO,PRIORITY
1803
495c5fdc 1804Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1805
a3dfe201
GS
1806=item setpwent
1807
74555b7a 1808Not implemented. (S<Mac OS>, MPE/iX, Win32, S<RISC OS>)
a3dfe201 1809
e41182b5
GS
1810=item setsockopt SOCKET,LEVEL,OPTNAME,OPTVAL
1811
97c10e77 1812Not implemented. (Plan9)
e41182b5
GS
1813
1814=item shmctl ID,CMD,ARG
1815
1816=item shmget KEY,SIZE,FLAGS
1817
1818=item shmread ID,VAR,POS,SIZE
1819
1820=item shmwrite ID,STRING,POS,SIZE
1821
495c5fdc 1822Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1823
80cbd5ad
JH
1824=item sockatmark SOCKET
1825
1826A relatively recent addition to socket functions, may not
1827be implemented even in UNIX platforms.
1828
e41182b5
GS
1829=item socketpair SOCKET1,SOCKET2,DOMAIN,TYPE,PROTOCOL
1830
862b5365 1831Not implemented. (Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1832
1833=item stat FILEHANDLE
1834
1835=item stat EXPR
1836
1837=item stat
1838
d62e1b7f
JH
1839Platforms that do not have rdev, blksize, or blocks will return these
1840as '', so numeric comparison or manipulation of these fields may cause
1841'not numeric' warnings.
1842
e41182b5 1843mtime and atime are the same thing, and ctime is creation time instead of
3f1f789b
JH
1844inode change time. (S<Mac OS>).
1845
1846ctime not supported on UFS (S<Mac OS X>).
e41182b5 1847
95a3fe12
MS
1848ctime is creation time instead of inode change time (Win32).
1849
e41182b5
GS
1850device and inode are not meaningful. (Win32)
1851
1852device and inode are not necessarily reliable. (VMS)
1853
b8099c3d
CN
1854mtime, atime and ctime all return the last modification time. Device and
1855inode are not necessarily reliable. (S<RISC OS>)
1856
d62e1b7f
JH
1857dev, rdev, blksize, and blocks are not available. inode is not
1858meaningful and will differ between stat calls on the same file. (os2)
1859
73e9292c
JH
1860some versions of cygwin when doing a stat("foo") and if not finding it
1861may then attempt to stat("foo.exe") (Cygwin)
1862
e41182b5
GS
1863=item symlink OLDFILE,NEWFILE
1864
b8099c3d 1865Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5
GS
1866
1867=item syscall LIST
1868
7c5ffed3 1869Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5 1870
f34d0673
GS
1871=item sysopen FILEHANDLE,FILENAME,MODE,PERMS
1872
dd9f0070 1873The traditional "0", "1", and "2" MODEs are implemented with different
322422de
GS
1874numeric values on some systems. The flags exported by C<Fcntl>
1875(O_RDONLY, O_WRONLY, O_RDWR) should work everywhere though. (S<Mac
7c5ffed3 1876OS>, OS/390, VM/ESA)
f34d0673 1877
e41182b5
GS
1878=item system LIST
1879
9d6eb86e 1880In general, do not assume the UNIX/POSIX semantics that you can shift
7717d0e7 1881C<$?> right by eight to get the exit value, or that C<$? & 127>
9d6eb86e
JH
1882would give you the number of the signal that terminated the program,
1883or that C<$? & 128> would test true if the program was terminated by a
1884coredump. Instead, use the POSIX W*() interfaces: for example, use
74555b7a
PP
1885WIFEXITED($?) and WEXITVALUE($?) to test for a normal exit and the exit
1886value, WIFSIGNALED($?) and WTERMSIG($?) for a signal exit and the
7717d0e7 1887signal. Core dumping is not a portable concept, so there's no portable
9d6eb86e
JH
1888way to test for that.
1889
e41182b5
GS
1890Only implemented if ToolServer is installed. (S<Mac OS>)
1891
1892As an optimization, may not call the command shell specified in
b7df3edc 1893C<$ENV{PERL5SHELL}>. C<system(1, @args)> spawns an external
e41182b5
GS
1894process and immediately returns its process designator, without
1895waiting for it to terminate. Return value may be used subsequently
63f87e49
GS
1896in C<wait> or C<waitpid>. Failure to spawn() a subprocess is indicated
1897by setting $? to "255 << 8". C<$?> is set in a way compatible with
1898Unix (i.e. the exitstatus of the subprocess is obtained by "$? >> 8",
1899as described in the documentation). (Win32)
e41182b5 1900
b8099c3d
CN
1901There is no shell to process metacharacters, and the native standard is
1902to pass a command line terminated by "\n" "\r" or "\0" to the spawned
c47ff5f1 1903program. Redirection such as C<< > foo >> is performed (if at all) by
b8099c3d
CN
1904the run time library of the spawned program. C<system> I<list> will call
1905the Unix emulation library's C<exec> emulation, which attempts to provide
1906emulation of the stdin, stdout, stderr in force in the parent, providing
1907the child program uses a compatible version of the emulation library.
1908I<scalar> will call the native command line direct and no such emulation
1909of a child Unix program will exists. Mileage B<will> vary. (S<RISC OS>)
1910
433acd8a
JH
1911Far from being POSIX compliant. Because there may be no underlying
1912/bin/sh tries to work around the problem by forking and execing the
9b63e9ec 1913first token in its argument string. Handles basic redirection
c47ff5f1 1914("<" or ">") on its own behalf. (MiNT)
433acd8a 1915
0f897271
GS
1916Does not automatically flush output handles on some platforms.
1917(SunOS, Solaris, HP-UX)
1918
9bc98430
CB
1919The return value is POSIX-like (shifted up by 8 bits), which only allows
1920room for a made-up value derived from the severity bits of the native
192132-bit condition code (unless overridden by C<use vmsish 'status'>).
1922For more details see L<perlvms/$?>. (VMS)
1923
e41182b5
GS
1924=item times
1925
1926Only the first entry returned is nonzero. (S<Mac OS>)
1927
63f87e49
GS
1928"cumulative" times will be bogus. On anything other than Windows NT
1929or Windows 2000, "system" time will be bogus, and "user" time is
1930actually the time returned by the clock() function in the C runtime
1931library. (Win32)
e41182b5 1932
b8099c3d
CN
1933Not useful. (S<RISC OS>)
1934
e41182b5
GS
1935=item truncate FILEHANDLE,LENGTH
1936
1937=item truncate EXPR,LENGTH
1938
6d738113 1939Not implemented. (Older versions of VMS)
e41182b5 1940
495c5fdc
PG
1941Truncation to zero-length only. (VOS)
1942
4cfdb94f 1943If a FILEHANDLE is supplied, it must be writable and opened in append
e71a7dc8 1944mode (i.e., use C<<< open(FH, '>>filename') >>>
4cfdb94f
GS
1945or C<sysopen(FH,...,O_APPEND|O_RDWR)>. If a filename is supplied, it
1946should not be held open elsewhere. (Win32)
1947
e41182b5
GS
1948=item umask EXPR
1949
1950=item umask
1951
1952Returns undef where unavailable, as of version 5.005.
1953
b7df3edc
GS
1954C<umask> works but the correct permissions are set only when the file
1955is finally closed. (AmigaOS)
433acd8a 1956
e41182b5
GS
1957=item utime LIST
1958
15c65113 1959Only the modification time is updated. (S<BeOS>, S<Mac OS>, VMS, S<RISC OS>)
e41182b5 1960
322422de
GS
1961May not behave as expected. Behavior depends on the C runtime
1962library's implementation of utime(), and the filesystem being
1963used. The FAT filesystem typically does not support an "access
1964time" field, and it may limit timestamps to a granularity of
1965two seconds. (Win32)
e41182b5
GS
1966
1967=item wait
1968
1969=item waitpid PID,FLAGS
1970
495c5fdc 1971Not implemented. (S<Mac OS>, VOS)
e41182b5
GS
1972
1973Can only be applied to process handles returned for processes spawned
a6f858fb 1974using C<system(1, ...)> or pseudo processes created with C<fork()>. (Win32)
e41182b5 1975
b8099c3d
CN
1976Not useful. (S<RISC OS>)
1977
e41182b5
GS
1978=back
1979
b8099c3d
CN
1980=head1 CHANGES
1981
1982=over 4
1983
fd46a41b
JH
1984=item v1.48, 02 February 2001
1985
1986Various updates from perl5-porters over the past year, supported
1987platforms update from Jarkko Hietaniemi.
1988
c997b287
GS
1989=item v1.47, 22 March 2000
1990
1991Various cleanups from Tom Christiansen, including migration of
1992long platform listings from L<perl>.
1993
56d7751a
GS
1994=item v1.46, 12 February 2000
1995
1996Updates for VOS and MPE/iX. (Peter Prymmer) Other small changes.
1997
0cc436d0
GS
1998=item v1.45, 20 December 1999
1999
2000Small changes from 5.005_63 distribution, more changes to EBCDIC info.
2001
d1e3b762
GS
2002=item v1.44, 19 July 1999
2003
2004A bunch of updates from Peter Prymmer for C<$^O> values,
2005endianness, File::Spec, VMS, BS2000, OS/400.
2006
b7df3edc
GS
2007=item v1.43, 24 May 1999
2008
2009Added a lot of cleaning up from Tom Christiansen.
2010
19799a22 2011=item v1.42, 22 May 1999
b7df3edc 2012
19799a22 2013Added notes about tests, sprintf/printf, and epoch offsets.
b7df3edc 2014
6ab3f9cb
GS
2015=item v1.41, 19 May 1999
2016
2017Lots more little changes to formatting and content.
2018
d1e3b762 2019Added a bunch of C<$^O> and related values
6ab3f9cb
GS
2020for various platforms; fixed mail and web addresses, and added
2021and changed miscellaneous notes. (Peter Prymmer)
2022
2023=item v1.40, 11 April 1999
2024
2025Miscellaneous changes.
2026
2027=item v1.39, 11 February 1999
2ee0eb3c
CN
2028
2029Changes from Jarkko and EMX URL fixes Michael Schwern. Additional
2030note about newlines added.
2031
9b63e9ec
CN
2032=item v1.38, 31 December 1998
2033
2034More changes from Jarkko.
2035
3c075c7d
CN
2036=item v1.37, 19 December 1998
2037
2038More minor changes. Merge two separate version 1.35 documents.
2039
2040=item v1.36, 9 September 1998
2041
2042Updated for Stratus VOS. Also known as version 1.35.
2043
2044=item v1.35, 13 August 1998
495c5fdc 2045
3c075c7d
CN
2046Integrate more minor changes, plus addition of new sections under
2047L<"ISSUES">: L<"Numbers endianness and Width">,
2048L<"Character sets and character encoding">,
2049L<"Internationalisation">.
495c5fdc 2050
3c075c7d 2051=item v1.33, 06 August 1998
0a47030a
GS
2052
2053Integrate more minor changes.
2054
3c075c7d 2055=item v1.32, 05 August 1998
dd9f0070
CN
2056
2057Integrate more minor changes.
2058
3c075c7d 2059=item v1.30, 03 August 1998
b8099c3d
CN
2060
2061Major update for RISC OS, other minor changes.
2062
3c075c7d 2063=item v1.23, 10 July 1998
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CN
2064
2065First public release with perl5.005.
2066
2067=back
e41182b5 2068
ba58ab26
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2069=head1 Supported Platforms
2070
cec2c193
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2071As of June 2002 (the Perl release 5.8.0), the following platforms are
2072able to build Perl from the standard source code distribution
2073available at http://www.cpan.org/src/index.html
2074
2075 AIX
2076 BeOS
2077 Cygwin
2078 DG/UX
2079 DOS DJGPP 1)
2080 DYNIX/ptx
2081 EPOC R5
2082 FreeBSD
2083 HP-UX
2084 IRIX
2085 Linux
8939ba94
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2086 Mac OS Classic
2087 Mac OS X (Darwin)
cec2c193
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2088 MPE/iX
2089 NetBSD
2090 NetWare
2091 NonStop-UX
2092 ReliantUNIX (SINIX)
2093 OpenBSD
2094 OpenVMS (VMS)
2095 OS/2
2096 POSIX-BC (BS2000)
2097 QNX
2098 Solaris
bb5ad0af 2099 SUPER-UX
cec2c193
JH
2100 Tru64 UNIX (DEC OSF/1, Digital UNIX)
2101 UNICOS
2102 UNICOS/mk
2103 UTS
2104 VOS
bb5ad0af 2105 Win95/98/ME/2K/XP 2)
c40b5d1d 2106 WinCE
cec2c193
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2107 z/OS (OS/390)
2108 VM/ESA
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2109
2110 1) in DOS mode either the DOS or OS/2 ports can be used
c40b5d1d 2111 2) compilers: Borland, Cygwin (GCC), MinGW (GCC), VC6
cec2c193 2112
c40b5d1d 2113The following platforms worked with the previous releases (5.6 and
cec2c193
JH
21145.7), but we did not manage either to fix or to test these in time
2115for the 5.8.0 release. There is a very good chance that many of these
2116will work fine with the 5.8.0. The only one known for certain to be
2117broken for 5.8.0 is the AmigaOS.
2118
2119 AmigaOS
2120 DomainOS
2121 Hurd
2122 LynxOS
2123 MachTen
2124 PowerMAX
2125 SCO SV
2126 SunOS 4
2127 SVR4
2128 Unixware
2129 Windows 3.1
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2130
2131The following platforms have been known to build Perl from source in
fd46a41b
JH
2132the past (5.005_03 and earlier), but we haven't been able to verify
2133their status for the current release, either because the
2134hardware/software platforms are rare or because we don't have an
2135active champion on these platforms--or both. They used to work,
2136though, so go ahead and try compiling them, and let perlbug@perl.org
2137of any trouble.
ba58ab26 2138
cec2c193
JH
2139 3b1
2140 A/UX
2141 BSD/OS
2142 ConvexOS
2143 CX/UX
2144 DC/OSx
2145 DDE SMES
2146 DOS EMX
2147 Dynix
2148 EP/IX
2149 ESIX
2150 FPS
2151 GENIX
2152 Greenhills
2153 ISC
2154 MachTen 68k
2155 MiNT
2156 MPC
2157 NEWS-OS
2158 NextSTEP
2159 OpenSTEP
2160 Opus
2161 Plan 9
2162 PowerUX
2163 RISC/os
2164 SCO ODT/OSR
2165 Stellar
2166 SVR2
2167 TI1500
2168 TitanOS
2169 Ultrix
2170 Unisys Dynix
2171 Unixware
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2172
2173The following platforms have their own source code distributions and
1577cd80 2174binaries available via http://www.cpan.org/ports/
ba58ab26 2175
cec2c193 2176 Perl release
ba58ab26 2177
cec2c193
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2178 OS/400 5.005_02
2179 Tandem Guardian 5.004
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2180
2181The following platforms have only binaries available via
a93751fa 2182http://www.cpan.org/ports/index.html :
ba58ab26 2183
cec2c193 2184 Perl release
ba58ab26 2185
cec2c193
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2186 Acorn RISCOS 5.005_02
2187 AOS 5.002
2188 LynxOS 5.004_02
ba58ab26
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2189
2190Although we do suggest that you always build your own Perl from
2191the source code, both for maximal configurability and for security,
2192in case you are in a hurry you can check
a93751fa 2193http://www.cpan.org/ports/index.html for binary distributions.
ba58ab26 2194
c997b287
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2195=head1 SEE ALSO
2196
cec2c193 2197L<perlaix>, L<perlamiga>, L<perlapollo>, L<perlbeos>, L<perlbs2000>,
a1f19229 2198L<perlce>, L<perlcygwin>, L<perldgux>, L<perldos>, L<perlepoc>, L<perlebcdic>,
a83b6f46 2199L<perlhurd>, L<perlhpux>, L<perlmachten>, L<perlmacos>, L<perlmint>,
9038e305
JH
2200L<perlmpeix>, L<perlnetware>, L<perlos2>, L<perlos390>, L<perlplan9>,
2201L<perlqnx>, L<perlsolaris>, L<perltru64>, L<perlunicode>,
2202L<perlvmesa>, L<perlvms>, L<perlvos>, L<perlwin32>, and L<Win32>.
c997b287 2203
e41182b5
GS
2204=head1 AUTHORS / CONTRIBUTORS
2205
06e9666b 2206Abigail <abigail@foad.org>,
c47ff5f1
GS
2207Charles Bailey <bailey@newman.upenn.edu>,
2208Graham Barr <gbarr@pobox.com>,
2209Tom Christiansen <tchrist@perl.com>,
06e9666b 2210Nicholas Clark <nick@ccl4.org>,
c47ff5f1 2211Thomas Dorner <Thomas.Dorner@start.de>,
06e9666b
A
2212Andy Dougherty <doughera@lafayette.edu>,
2213Dominic Dunlop <domo@computer.org>,
2214Neale Ferguson <neale@vma.tabnsw.com.au>,
c47ff5f1
GS
2215David J. Fiander <davidf@mks.com>,
2216Paul Green <Paul_Green@stratus.com>,
06e9666b 2217M.J.T. Guy <mjtg@cam.ac.uk>,
61f30a5e 2218Jarkko Hietaniemi <jhi@iki.fi>,
c47ff5f1 2219Luther Huffman <lutherh@stratcom.com>,
06e9666b
A
2220Nick Ing-Simmons <nick@ing-simmons.net>,
2221Andreas J. KE<ouml>nig <a.koenig@mind.de>,
c47ff5f1
GS
2222Markus Laker <mlaker@contax.co.uk>,
2223Andrew M. Langmead <aml@world.std.com>,
2224Larry Moore <ljmoore@freespace.net>,
2225Paul Moore <Paul.Moore@uk.origin-it.com>,
2226Chris Nandor <pudge@pobox.com>,
1afc07ec 2227Matthias Neeracher <neeracher@mac.com>,
e71a7dc8 2228Philip Newton <pne@cpan.org>,
c47ff5f1
GS
2229Gary Ng <71564.1743@CompuServe.COM>,
2230Tom Phoenix <rootbeer@teleport.com>,
2231AndrE<eacute> Pirard <A.Pirard@ulg.ac.be>,
2232Peter Prymmer <pvhp@forte.com>,
2233Hugo van der Sanden <hv@crypt0.demon.co.uk>,
2234Gurusamy Sarathy <gsar@activestate.com>,
2235Paul J. Schinder <schinder@pobox.com>,
2236Michael G Schwern <schwern@pobox.com>,
06e9666b 2237Dan Sugalski <dan@sidhe.org>,
c47ff5f1 2238Nathan Torkington <gnat@frii.com>.
e41182b5 2239