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1=head1 NAME
2
3perlport - Writing portable Perl
4
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5=head1 DESCRIPTION
6
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7Perl runs on numerous operating systems. While most of them share
8much in common, they also have their own unique features.
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9
10This document is meant to help you to find out what constitutes portable
b7df3edc 11Perl code. That way once you make a decision to write portably,
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12you know where the lines are drawn, and you can stay within them.
13
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14There is a tradeoff between taking full advantage of one particular
15type of computer and taking advantage of a full range of them.
16Naturally, as you broaden your range and become more diverse, the
17common factors drop, and you are left with an increasingly smaller
18area of common ground in which you can operate to accomplish a
19particular task. Thus, when you begin attacking a problem, it is
20important to consider under which part of the tradeoff curve you
21want to operate. Specifically, you must decide whether it is
22important that the task that you are coding have the full generality
23of being portable, or whether to just get the job done right now.
24This is the hardest choice to be made. The rest is easy, because
25Perl provides many choices, whichever way you want to approach your
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26problem.
27
28Looking at it another way, writing portable code is usually about
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29willfully limiting your available choices. Naturally, it takes
30discipline and sacrifice to do that. The product of portability
31and convenience may be a constant. You have been warned.
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32
33Be aware of two important points:
34
35=over 4
36
37=item Not all Perl programs have to be portable
38
b7df3edc 39There is no reason you should not use Perl as a language to glue Unix
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40tools together, or to prototype a Macintosh application, or to manage the
41Windows registry. If it makes no sense to aim for portability for one
42reason or another in a given program, then don't bother.
43
b7df3edc 44=item Nearly all of Perl already I<is> portable
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45
46Don't be fooled into thinking that it is hard to create portable Perl
47code. It isn't. Perl tries its level-best to bridge the gaps between
48what's available on different platforms, and all the means available to
49use those features. Thus almost all Perl code runs on any machine
6ab3f9cb 50without modification. But there are some significant issues in
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51writing portable code, and this document is entirely about those issues.
52
53=back
54
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55Here's the general rule: When you approach a task commonly done
56using a whole range of platforms, think about writing portable
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57code. That way, you don't sacrifice much by way of the implementation
58choices you can avail yourself of, and at the same time you can give
59your users lots of platform choices. On the other hand, when you have to
60take advantage of some unique feature of a particular platform, as is
61often the case with systems programming (whether for Unix, Windows,
62S<Mac OS>, VMS, etc.), consider writing platform-specific code.
63
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64When the code will run on only two or three operating systems, you
65may need to consider only the differences of those particular systems.
66The important thing is to decide where the code will run and to be
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67deliberate in your decision.
68
69The material below is separated into three main sections: main issues of
70portability (L<"ISSUES">, platform-specific issues (L<"PLATFORMS">, and
b7df3edc 71built-in perl functions that behave differently on various ports
0a47030a 72(L<"FUNCTION IMPLEMENTATIONS">.
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73
74This information should not be considered complete; it includes possibly
b8099c3d 75transient information about idiosyncrasies of some of the ports, almost
b7df3edc 76all of which are in a state of constant evolution. Thus, this material
e41182b5 77should be considered a perpetual work in progress
cc07ed0b 78(C<< <IMG SRC="yellow_sign.gif" ALT="Under Construction"> >>).
e41182b5 79
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80=head1 ISSUES
81
82=head2 Newlines
83
638bc118 84In most operating systems, lines in files are terminated by newlines.
e41182b5 85Just what is used as a newline may vary from OS to OS. Unix
b7df3edc 86traditionally uses C<\012>, one type of DOSish I/O uses C<\015\012>,
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87and S<Mac OS> uses C<\015>.
88
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89Perl uses C<\n> to represent the "logical" newline, where what is
90logical may depend on the platform in use. In MacPerl, C<\n> always
91means C<\015>. In DOSish perls, C<\n> usually means C<\012>, but
92when accessing a file in "text" mode, STDIO translates it to (or
56d7751a 93from) C<\015\012>, depending on whether you're reading or writing.
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94Unix does the same thing on ttys in canonical mode. C<\015\012>
95is commonly referred to as CRLF.
96
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97A common cause of unportable programs is the misuse of chop() to trim
98newlines:
99
100 # XXX UNPORTABLE!
101 while(<FILE>) {
102 chop;
103 @array = split(/:/);
104 #...
105 }
106
8939ba94 107You can get away with this on Unix and Mac OS (they have a single
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108character end-of-line), but the same program will break under DOSish
109perls because you're only chop()ing half the end-of-line. Instead,
110chomp() should be used to trim newlines. The Dunce::Files module can
111help audit your code for misuses of chop().
112
113When dealing with binary files (or text files in binary mode) be sure
114to explicitly set $/ to the appropriate value for your file format
115before using chomp().
116
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117Because of the "text" mode translation, DOSish perls have limitations
118in using C<seek> and C<tell> on a file accessed in "text" mode.
119Stick to C<seek>-ing to locations you got from C<tell> (and no
120others), and you are usually free to use C<seek> and C<tell> even
121in "text" mode. Using C<seek> or C<tell> or other file operations
122may be non-portable. If you use C<binmode> on a file, however, you
123can usually C<seek> and C<tell> with arbitrary values in safety.
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124
125A common misconception in socket programming is that C<\n> eq C<\012>
0a47030a 126everywhere. When using protocols such as common Internet protocols,
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127C<\012> and C<\015> are called for specifically, and the values of
128the logical C<\n> and C<\r> (carriage return) are not reliable.
129
130 print SOCKET "Hi there, client!\r\n"; # WRONG
131 print SOCKET "Hi there, client!\015\012"; # RIGHT
132
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133However, using C<\015\012> (or C<\cM\cJ>, or C<\x0D\x0A>) can be tedious
134and unsightly, as well as confusing to those maintaining the code. As
6ab3f9cb 135such, the Socket module supplies the Right Thing for those who want it.
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136
137 use Socket qw(:DEFAULT :crlf);
138 print SOCKET "Hi there, client!$CRLF" # RIGHT
139
6ab3f9cb 140When reading from a socket, remember that the default input record
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141separator C<$/> is C<\n>, but robust socket code will recognize as
142either C<\012> or C<\015\012> as end of line:
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143
144 while (<SOCKET>) {
145 # ...
146 }
147
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148Because both CRLF and LF end in LF, the input record separator can
149be set to LF and any CR stripped later. Better to write:
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150
151 use Socket qw(:DEFAULT :crlf);
152 local($/) = LF; # not needed if $/ is already \012
153
154 while (<SOCKET>) {
155 s/$CR?$LF/\n/; # not sure if socket uses LF or CRLF, OK
156 # s/\015?\012/\n/; # same thing
157 }
158
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159This example is preferred over the previous one--even for Unix
160platforms--because now any C<\015>'s (C<\cM>'s) are stripped out
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161(and there was much rejoicing).
162
6ab3f9cb 163Similarly, functions that return text data--such as a function that
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164fetches a web page--should sometimes translate newlines before
165returning the data, if they've not yet been translated to the local
166newline representation. A single line of code will often suffice:
2ee0eb3c 167
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168 $data =~ s/\015?\012/\n/g;
169 return $data;
2ee0eb3c 170
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171Some of this may be confusing. Here's a handy reference to the ASCII CR
172and LF characters. You can print it out and stick it in your wallet.
173
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174 LF eq \012 eq \x0A eq \cJ eq chr(10) eq ASCII 10
175 CR eq \015 eq \x0D eq \cM eq chr(13) eq ASCII 13
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176
177 | Unix | DOS | Mac |
178 ---------------------------
179 \n | LF | LF | CR |
180 \r | CR | CR | LF |
181 \n * | LF | CRLF | CR |
182 \r * | CR | CR | LF |
183 ---------------------------
184 * text-mode STDIO
185
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186The Unix column assumes that you are not accessing a serial line
187(like a tty) in canonical mode. If you are, then CR on input becomes
188"\n", and "\n" on output becomes CRLF.
189
6ab3f9cb 190These are just the most common definitions of C<\n> and C<\r> in Perl.
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191There may well be others. For example, on an EBCDIC implementation
192such as z/OS (OS/390) or OS/400 (using the ILE, the PASE is ASCII-based)
193the above material is similar to "Unix" but the code numbers change:
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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
GS
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.
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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
GS
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
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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.
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587
588=head2 Character sets and character encoding
589
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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
0a47030a
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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
b7df3edc
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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<$Config{osname}>. Of course, to get more
e41182b5
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708detailed information about the system, looking into C<%Config> is
709certainly recommended.
710
b7df3edc
GS
711C<%Config> cannot always be trusted, however, because it was built
712at compile time. If perl was built in one place, then transferred
713elsewhere, some values may be wrong. The values may even have been
714edited after the fact.
6ab3f9cb 715
e41182b5
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716=head2 Unix
717
718Perl works on a bewildering variety of Unix and Unix-like platforms (see
719e.g. most of the files in the F<hints/> directory in the source code kit).
720On most of these systems, the value of C<$^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
7939d86b
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835There are also Win32::IsWinNT() and Win32::IsWin95(), try C<perldoc Win32>,
836and as of libwin32 0.19 (not part of the core Perl distribution)
837Win32::GetOSName(). The very portable POSIX::uname() will work too:
1d65be3a
JH
838
839 c:\> perl -MPOSIX -we "print join '|', uname"
840 Windows NT|moonru|5.0|Build 2195 (Service Pack 2)|x86
d99f392e 841
e41182b5
GS
842Also see:
843
844=over 4
845
c997b287 846=item *
e41182b5 847
c997b287
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848The djgpp environment for DOS, http://www.delorie.com/djgpp/
849and L<perldos>.
e41182b5 850
c997b287 851=item *
e41182b5 852
c997b287
GS
853The EMX environment for DOS, OS/2, etc. emx@iaehv.nl,
854http://www.leo.org/pub/comp/os/os2/leo/gnu/emx+gcc/index.html or
f224927c 855ftp://hobbes.nmsu.edu/pub/os2/dev/emx/ Also L<perlos2>.
e41182b5 856
c997b287 857=item *
d1e3b762 858
c997b287
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859Build instructions for Win32 in L<perlwin32>, or under the Cygnus environment
860in L<perlcygwin>.
861
862=item *
863
864The C<Win32::*> modules in L<Win32>.
865
866=item *
867
868The ActiveState Pages, http://www.activestate.com/
869
870=item *
871
872The Cygwin environment for Win32; F<README.cygwin> (installed
47dafe4d 873as L<perlcygwin>), http://www.cygwin.com/
c997b287
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874
875=item *
876
877The U/WIN environment for Win32,
cea6626f 878http://www.research.att.com/sw/tools/uwin/
c997b287 879
cea6626f 880=item *
d1e3b762 881
cea6626f 882Build instructions for OS/2, L<perlos2>
d1e3b762 883
e41182b5
GS
884=back
885
dd9f0070 886=head2 S<Mac OS>
e41182b5
GS
887
888Any module requiring XS compilation is right out for most people, because
889MacPerl is built using non-free (and non-cheap!) compilers. Some XS
890modules that can work with MacPerl are built and distributed in binary
6ab3f9cb 891form on CPAN.
e41182b5
GS
892
893Directories are specified as:
894
895 volume:folder:file for absolute pathnames
896 volume:folder: for absolute pathnames
897 :folder:file for relative pathnames
898 :folder: for relative pathnames
899 :file for relative pathnames
900 file for relative pathnames
901
b7df3edc 902Files are stored in the directory in alphabetical order. Filenames are
6ab3f9cb 903limited to 31 characters, and may include any character except for
b7df3edc 904null and C<:>, which is reserved as the path separator.
e41182b5 905
0a47030a 906Instead of C<flock>, see C<FSpSetFLock> and C<FSpRstFLock> in the
6ab3f9cb 907Mac::Files module, or C<chmod(0444, ...)> and C<chmod(0666, ...)>.
e41182b5
GS
908
909In the MacPerl application, you can't run a program from the command line;
910programs that expect C<@ARGV> to be populated can be edited with something
911like the following, which brings up a dialog box asking for the command
912line arguments.
913
914 if (!@ARGV) {
915 @ARGV = split /\s+/, MacPerl::Ask('Arguments?');
916 }
917
b7df3edc 918A MacPerl script saved as a "droplet" will populate C<@ARGV> with the full
e41182b5
GS
919pathnames of the files dropped onto the script.
920
b7df3edc
GS
921Mac users can run programs under a type of command line interface
922under MPW (Macintosh Programmer's Workshop, a free development
923environment from Apple). MacPerl was first introduced as an MPW
924tool, and MPW can be used like a shell:
e41182b5
GS
925
926 perl myscript.plx some arguments
927
928ToolServer is another app from Apple that provides access to MPW tools
0a47030a 929from MPW and the MacPerl app, which allows MacPerl programs to use
e41182b5
GS
930C<system>, backticks, and piped C<open>.
931
932"S<Mac OS>" is the proper name for the operating system, but the value
933in C<$^O> is "MacOS". To determine architecture, version, or whether
934the application or MPW tool version is running, check:
935
936 $is_app = $MacPerl::Version =~ /App/;
937 $is_tool = $MacPerl::Version =~ /MPW/;
938 ($version) = $MacPerl::Version =~ /^(\S+)/;
939 $is_ppc = $MacPerl::Architecture eq 'MacPPC';
940 $is_68k = $MacPerl::Architecture eq 'Mac68K';
941
b787fad4
JH
942S<Mac OS X>, based on NeXT's OpenStep OS, runs MacPerl natively, under the
943"Classic" environment. There is no "Carbon" version of MacPerl to run
944under the primary Mac OS X environment. S<Mac OS X> and its Open Source
945version, Darwin, both run Unix perl natively.
6ab3f9cb 946
e41182b5
GS
947Also see:
948
949=over 4
950
c997b287
GS
951=item *
952
862b5365 953MacPerl Development, http://dev.macperl.org/ .
c997b287
GS
954
955=item *
956
862b5365 957The MacPerl Pages, http://www.macperl.com/ .
e41182b5 958
c997b287 959=item *
6ab3f9cb 960
862b5365 961The MacPerl mailing lists, http://lists.perl.org/ .
e41182b5
GS
962
963=back
964
e41182b5
GS
965=head2 VMS
966
c997b287 967Perl on VMS is discussed in L<perlvms> in the perl distribution.
b7df3edc 968Perl on VMS can accept either VMS- or Unix-style file
e41182b5
GS
969specifications as in either of the following:
970
971 $ perl -ne "print if /perl_setup/i" SYS$LOGIN:LOGIN.COM
972 $ perl -ne "print if /perl_setup/i" /sys$login/login.com
973
974but not a mixture of both as in:
975
976 $ perl -ne "print if /perl_setup/i" sys$login:/login.com
977 Can't open sys$login:/login.com: file specification syntax error
978
979Interacting with Perl from the Digital Command Language (DCL) shell
980often requires a different set of quotation marks than Unix shells do.
981For example:
982
983 $ perl -e "print ""Hello, world.\n"""
984 Hello, world.
985
b7df3edc 986There are several ways to wrap your perl scripts in DCL F<.COM> files, if
e41182b5
GS
987you are so inclined. For example:
988
989 $ write sys$output "Hello from DCL!"
990 $ if p1 .eqs. ""
991 $ then perl -x 'f$environment("PROCEDURE")
992 $ else perl -x - 'p1 'p2 'p3 'p4 'p5 'p6 'p7 'p8
993 $ deck/dollars="__END__"
994 #!/usr/bin/perl
995
996 print "Hello from Perl!\n";
997
998 __END__
999 $ endif
1000
1001Do take care with C<$ ASSIGN/nolog/user SYS$COMMAND: SYS$INPUT> if your
c47ff5f1 1002perl-in-DCL script expects to do things like C<< $read = <STDIN>; >>.
e41182b5
GS
1003
1004Filenames are in the format "name.extension;version". The maximum
1005length for filenames is 39 characters, and the maximum length for
1006extensions is also 39 characters. Version is a number from 1 to
100732767. Valid characters are C</[A-Z0-9$_-]/>.
1008
b7df3edc 1009VMS's RMS filesystem is case-insensitive and does not preserve case.
e41182b5 1010C<readdir> returns lowercased filenames, but specifying a file for
b7df3edc 1011opening remains case-insensitive. Files without extensions have a
e41182b5 1012trailing period on them, so doing a C<readdir> with a file named F<A.;5>
0a47030a
GS
1013will return F<a.> (though that file could be opened with
1014C<open(FH, 'A')>).
e41182b5 1015
f34d0673 1016RMS had an eight level limit on directory depths from any rooted logical
dd9f0070
CN
1017(allowing 16 levels overall) prior to VMS 7.2. Hence
1018C<PERL_ROOT:[LIB.2.3.4.5.6.7.8]> is a valid directory specification but
1019C<PERL_ROOT:[LIB.2.3.4.5.6.7.8.9]> is not. F<Makefile.PL> authors might
1020have to take this into account, but at least they can refer to the former
f34d0673 1021as C</PERL_ROOT/lib/2/3/4/5/6/7/8/>.
e41182b5 1022
6ab3f9cb 1023The VMS::Filespec module, which gets installed as part of the build
0a47030a
GS
1024process on VMS, is a pure Perl module that can easily be installed on
1025non-VMS platforms and can be helpful for conversions to and from RMS
1026native formats.
e41182b5 1027
5e12dbfa
PP
1028What C<\n> represents depends on the type of file opened. It usually
1029represents C<\012> but it could also be C<\015>, C<\012>, C<\015\012>,
1030C<\000>, C<\040>, or nothing depending on the file organiztion and
1031record format. The VMS::Stdio module provides access to the
1032special fopen() requirements of files with unusual attributes on VMS.
e41182b5
GS
1033
1034TCP/IP stacks are optional on VMS, so socket routines might not be
1035implemented. UDP sockets may not be supported.
1036
1037The value of C<$^O> on OpenVMS is "VMS". To determine the architecture
1038that you are running on without resorting to loading all of C<%Config>
1039you can examine the content of the C<@INC> array like so:
1040
1041 if (grep(/VMS_AXP/, @INC)) {
1042 print "I'm on Alpha!\n";
6ab3f9cb 1043
e41182b5
GS
1044 } elsif (grep(/VMS_VAX/, @INC)) {
1045 print "I'm on VAX!\n";
6ab3f9cb 1046
e41182b5
GS
1047 } else {
1048 print "I'm not so sure about where $^O is...\n";
1049 }
1050
b7df3edc
GS
1051On VMS, perl determines the UTC offset from the C<SYS$TIMEZONE_DIFFERENTIAL>
1052logical name. Although the VMS epoch began at 17-NOV-1858 00:00:00.00,
6ab3f9cb 1053calls to C<localtime> are adjusted to count offsets from
b7df3edc 105401-JAN-1970 00:00:00.00, just like Unix.
6ab3f9cb 1055
e41182b5
GS
1056Also see:
1057
1058=over 4
1059
c997b287
GS
1060=item *
1061
1062F<README.vms> (installed as L<README_vms>), L<perlvms>
1063
1064=item *
1065
1066vmsperl list, majordomo@perl.org
e41182b5 1067
c997b287 1068(Put the words C<subscribe vmsperl> in message body.)
e41182b5 1069
c997b287 1070=item *
e41182b5 1071
c997b287 1072vmsperl on the web, http://www.sidhe.org/vmsperl/index.html
e41182b5
GS
1073
1074=back
1075
495c5fdc
GP
1076=head2 VOS
1077
9a997319
JH
1078Perl on VOS is discussed in F<README.vos> in the perl distribution
1079(installed as L<perlvos>). Perl on VOS can accept either VOS- or
1080Unix-style file specifications as in either of the following:
495c5fdc 1081
cc07ed0b
PG
1082 C<< $ perl -ne "print if /perl_setup/i" >system>notices >>
1083 C<< $ perl -ne "print if /perl_setup/i" /system/notices >>
495c5fdc
GP
1084
1085or even a mixture of both as in:
1086
cc07ed0b 1087 C<< $ perl -ne "print if /perl_setup/i" >system/notices >>
495c5fdc 1088
b7df3edc 1089Even though VOS allows the slash character to appear in object
495c5fdc
GP
1090names, because the VOS port of Perl interprets it as a pathname
1091delimiting character, VOS files, directories, or links whose names
1092contain a slash character cannot be processed. Such files must be
a3dfe201
GS
1093renamed before they can be processed by Perl. Note that VOS limits
1094file names to 32 or fewer characters.
495c5fdc 1095
495c5fdc
GP
1096The value of C<$^O> on VOS is "VOS". To determine the architecture that
1097you are running on without resorting to loading all of C<%Config> you
c997b287 1098can examine the content of the @INC array like so:
495c5fdc 1099
24e8e380 1100 if ($^O =~ /VOS/) {
495c5fdc
GP
1101 print "I'm on a Stratus box!\n";
1102 } else {
1103 print "I'm not on a Stratus box!\n";
1104 die;
1105 }
1106
495c5fdc
GP
1107Also see:
1108
1109=over 4
1110
c997b287 1111=item *
495c5fdc 1112
cc07ed0b 1113F<README.vos> (installed as L<perlvos>)
c997b287
GS
1114
1115=item *
1116
1117The VOS mailing list.
495c5fdc
GP
1118
1119There is no specific mailing list for Perl on VOS. You can post
1120comments to the comp.sys.stratus newsgroup, or subscribe to the general
cc07ed0b 1121Stratus mailing list. Send a letter with "subscribe Info-Stratus" in
495c5fdc
GP
1122the message body to majordomo@list.stratagy.com.
1123
c997b287
GS
1124=item *
1125
cc07ed0b 1126VOS Perl on the web at http://ftp.stratus.com/pub/vos/posix/posix.html
495c5fdc
GP
1127
1128=back
1129
e41182b5
GS
1130=head2 EBCDIC Platforms
1131
1132Recent versions of Perl have been ported to platforms such as OS/400 on
d1e3b762
GS
1133AS/400 minicomputers as well as OS/390, VM/ESA, and BS2000 for S/390
1134Mainframes. Such computers use EBCDIC character sets internally (usually
0cc436d0
GS
1135Character Code Set ID 0037 for OS/400 and either 1047 or POSIX-BC for S/390
1136systems). On the mainframe perl currently works under the "Unix system
1137services for OS/390" (formerly known as OpenEdition), VM/ESA OpenEdition, or
1138the BS200 POSIX-BC system (BS2000 is supported in perl 5.6 and greater).
522b859a
JH
1139See L<perlos390> for details. Note that for OS/400 there is also a port of
1140Perl 5.8.1/5.9.0 or later to the PASE which is ASCII-based (as opposed to
1141ILE which is EBCDIC-based), see L<perlos400>.
e41182b5 1142
7c5ffed3
JH
1143As of R2.5 of USS for OS/390 and Version 2.3 of VM/ESA these Unix
1144sub-systems do not support the C<#!> shebang trick for script invocation.
1145Hence, on OS/390 and VM/ESA perl scripts can be executed with a header
1146similar to the following simple script:
e41182b5
GS
1147
1148 : # use perl
1149 eval 'exec /usr/local/bin/perl -S $0 ${1+"$@"}'
1150 if 0;
1151 #!/usr/local/bin/perl # just a comment really
1152
1153 print "Hello from perl!\n";
1154
d1e3b762
GS
1155OS/390 will support the C<#!> shebang trick in release 2.8 and beyond.
1156Calls to C<system> and backticks can use POSIX shell syntax on all
1157S/390 systems.
1158
b7df3edc 1159On the AS/400, if PERL5 is in your library list, you may need
6ab3f9cb
GS
1160to wrap your perl scripts in a CL procedure to invoke them like so:
1161
1162 BEGIN
1163 CALL PGM(PERL5/PERL) PARM('/QOpenSys/hello.pl')
1164 ENDPGM
1165
1166This will invoke the perl script F<hello.pl> in the root of the
1167QOpenSys file system. On the AS/400 calls to C<system> or backticks
1168must use CL syntax.
1169
e41182b5 1170On these platforms, bear in mind that the EBCDIC character set may have
0a47030a
GS
1171an effect on what happens with some perl functions (such as C<chr>,
1172C<pack>, C<print>, C<printf>, C<ord>, C<sort>, C<sprintf>, C<unpack>), as
1173well as bit-fiddling with ASCII constants using operators like C<^>, C<&>
1174and C<|>, not to mention dealing with socket interfaces to ASCII computers
6ab3f9cb 1175(see L<"Newlines">).
e41182b5 1176
b7df3edc
GS
1177Fortunately, most web servers for the mainframe will correctly
1178translate the C<\n> in the following statement to its ASCII equivalent
1179(C<\r> is the same under both Unix and OS/390 & VM/ESA):
e41182b5
GS
1180
1181 print "Content-type: text/html\r\n\r\n";
1182
d1e3b762 1183The values of C<$^O> on some of these platforms includes:
e41182b5 1184
d1e3b762
GS
1185 uname $^O $Config{'archname'}
1186 --------------------------------------------
1187 OS/390 os390 os390
1188 OS400 os400 os400
1189 POSIX-BC posix-bc BS2000-posix-bc
1190 VM/ESA vmesa vmesa
3c075c7d 1191
e41182b5
GS
1192Some simple tricks for determining if you are running on an EBCDIC
1193platform could include any of the following (perhaps all):
1194
1195 if ("\t" eq "\05") { print "EBCDIC may be spoken here!\n"; }
1196
1197 if (ord('A') == 193) { print "EBCDIC may be spoken here!\n"; }
1198
1199 if (chr(169) eq 'z') { print "EBCDIC may be spoken here!\n"; }
1200
b7df3edc 1201One thing you may not want to rely on is the EBCDIC encoding
0a47030a
GS
1202of punctuation characters since these may differ from code page to code
1203page (and once your module or script is rumoured to work with EBCDIC,
1204folks will want it to work with all EBCDIC character sets).
e41182b5
GS
1205
1206Also see:
1207
1208=over 4
1209
c997b287
GS
1210=item *
1211
1212*
d1e3b762 1213
dc5c060f 1214L<perlos390>, F<README.os390>, F<perlbs2000>, F<README.vmesa>,
bb462878 1215L<perlebcdic>.
c997b287
GS
1216
1217=item *
e41182b5
GS
1218
1219The perl-mvs@perl.org list is for discussion of porting issues as well as
1220general usage issues for all EBCDIC Perls. Send a message body of
1221"subscribe perl-mvs" to majordomo@perl.org.
1222
c997b287
GS
1223=item *
1224
1225AS/400 Perl information at
b1866b2d 1226http://as400.rochester.ibm.com/
d1e3b762 1227as well as on CPAN in the F<ports/> directory.
e41182b5
GS
1228
1229=back
1230
b8099c3d
CN
1231=head2 Acorn RISC OS
1232
b7df3edc
GS
1233Because Acorns use ASCII with newlines (C<\n>) in text files as C<\012> like
1234Unix, and because Unix filename emulation is turned on by default,
1235most simple scripts will probably work "out of the box". The native
6ab3f9cb 1236filesystem is modular, and individual filesystems are free to be
0a47030a 1237case-sensitive or insensitive, and are usually case-preserving. Some
b7df3edc 1238native filesystems have name length limits, which file and directory
6ab3f9cb
GS
1239names are silently truncated to fit. Scripts should be aware that the
1240standard filesystem currently has a name length limit of B<10>
1241characters, with up to 77 items in a directory, but other filesystems
0a47030a 1242may not impose such limitations.
b8099c3d
CN
1243
1244Native filenames are of the form
1245
6ab3f9cb 1246 Filesystem#Special_Field::DiskName.$.Directory.Directory.File
dd9f0070 1247
b8099c3d
CN
1248where
1249
1250 Special_Field is not usually present, but may contain . and $ .
1251 Filesystem =~ m|[A-Za-z0-9_]|
1252 DsicName =~ m|[A-Za-z0-9_/]|
1253 $ represents the root directory
1254 . is the path separator
1255 @ is the current directory (per filesystem but machine global)
1256 ^ is the parent directory
1257 Directory and File =~ m|[^\0- "\.\$\%\&:\@\\^\|\177]+|
1258
1259The default filename translation is roughly C<tr|/.|./|;>
1260
6ab3f9cb 1261Note that C<"ADFS::HardDisk.$.File" ne 'ADFS::HardDisk.$.File'> and that
0a47030a
GS
1262the second stage of C<$> interpolation in regular expressions will fall
1263foul of the C<$.> if scripts are not careful.
1264
1265Logical paths specified by system variables containing comma-separated
b7df3edc 1266search lists are also allowed; hence C<System:Modules> is a valid
0a47030a 1267filename, and the filesystem will prefix C<Modules> with each section of
6ab3f9cb 1268C<System$Path> until a name is made that points to an object on disk.
b7df3edc 1269Writing to a new file C<System:Modules> would be allowed only if
0a47030a
GS
1270C<System$Path> contains a single item list. The filesystem will also
1271expand system variables in filenames if enclosed in angle brackets, so
c47ff5f1 1272C<< <System$Dir>.Modules >> would look for the file
0a47030a 1273S<C<$ENV{'System$Dir'} . 'Modules'>>. The obvious implication of this is
c47ff5f1 1274that B<fully qualified filenames can start with C<< <> >>> and should
0a47030a 1275be protected when C<open> is used for input.
b8099c3d
CN
1276
1277Because C<.> was in use as a directory separator and filenames could not
1278be assumed to be unique after 10 characters, Acorn implemented the C
1279compiler to strip the trailing C<.c> C<.h> C<.s> and C<.o> suffix from
1280filenames specified in source code and store the respective files in
b7df3edc 1281subdirectories named after the suffix. Hence files are translated:
b8099c3d
CN
1282
1283 foo.h h.foo
1284 C:foo.h C:h.foo (logical path variable)
1285 sys/os.h sys.h.os (C compiler groks Unix-speak)
1286 10charname.c c.10charname
1287 10charname.o o.10charname
1288 11charname_.c c.11charname (assuming filesystem truncates at 10)
1289
1290The Unix emulation library's translation of filenames to native assumes
b7df3edc
GS
1291that this sort of translation is required, and it allows a user-defined list
1292of known suffixes that it will transpose in this fashion. This may
1293seem transparent, but consider that with these rules C<foo/bar/baz.h>
0a47030a
GS
1294and C<foo/bar/h/baz> both map to C<foo.bar.h.baz>, and that C<readdir> and
1295C<glob> cannot and do not attempt to emulate the reverse mapping. Other
6ab3f9cb 1296C<.>'s in filenames are translated to C</>.
0a47030a 1297
b7df3edc 1298As implied above, the environment accessed through C<%ENV> is global, and
0a47030a 1299the convention is that program specific environment variables are of the
6ab3f9cb
GS
1300form C<Program$Name>. Each filesystem maintains a current directory,
1301and the current filesystem's current directory is the B<global> current
b7df3edc
GS
1302directory. Consequently, sociable programs don't change the current
1303directory but rely on full pathnames, and programs (and Makefiles) cannot
0a47030a
GS
1304assume that they can spawn a child process which can change the current
1305directory without affecting its parent (and everyone else for that
1306matter).
1307
b7df3edc
GS
1308Because native operating system filehandles are global and are currently
1309allocated down from 255, with 0 being a reserved value, the Unix emulation
0a47030a
GS
1310library emulates Unix filehandles. Consequently, you can't rely on
1311passing C<STDIN>, C<STDOUT>, or C<STDERR> to your children.
1312
1313The desire of users to express filenames of the form
c47ff5f1 1314C<< <Foo$Dir>.Bar >> on the command line unquoted causes problems,
0a47030a 1315too: C<``> command output capture has to perform a guessing game. It
c47ff5f1 1316assumes that a string C<< <[^<>]+\$[^<>]> >> is a
0a47030a 1317reference to an environment variable, whereas anything else involving
c47ff5f1 1318C<< < >> or C<< > >> is redirection, and generally manages to be 99%
0a47030a
GS
1319right. Of course, the problem remains that scripts cannot rely on any
1320Unix tools being available, or that any tools found have Unix-like command
1321line arguments.
1322
b7df3edc
GS
1323Extensions and XS are, in theory, buildable by anyone using free
1324tools. In practice, many don't, as users of the Acorn platform are
1325used to binary distributions. MakeMaker does run, but no available
1326make currently copes with MakeMaker's makefiles; even if and when
1327this should be fixed, the lack of a Unix-like shell will cause
1328problems with makefile rules, especially lines of the form C<cd
1329sdbm && make all>, and anything using quoting.
b8099c3d
CN
1330
1331"S<RISC OS>" is the proper name for the operating system, but the value
1332in C<$^O> is "riscos" (because we don't like shouting).
1333
e41182b5
GS
1334=head2 Other perls
1335
b7df3edc
GS
1336Perl has been ported to many platforms that do not fit into any of
1337the categories listed above. Some, such as AmigaOS, Atari MiNT,
1338BeOS, HP MPE/iX, QNX, Plan 9, and VOS, have been well-integrated
1339into the standard Perl source code kit. You may need to see the
1340F<ports/> directory on CPAN for information, and possibly binaries,
1341for the likes of: aos, Atari ST, lynxos, riscos, Novell Netware,
1342Tandem Guardian, I<etc.> (Yes, we know that some of these OSes may
1343fall under the Unix category, but we are not a standards body.)
e41182b5 1344
d1e3b762
GS
1345Some approximate operating system names and their C<$^O> values
1346in the "OTHER" category include:
1347
1348 OS $^O $Config{'archname'}
1349 ------------------------------------------
1350 Amiga DOS amigaos m68k-amigos
cec2c193 1351 BeOS beos
d1e3b762
GS
1352 MPE/iX mpeix PA-RISC1.1
1353
e41182b5
GS
1354See also:
1355
1356=over 4
1357
c997b287
GS
1358=item *
1359
1360Amiga, F<README.amiga> (installed as L<perlamiga>).
1361
1362=item *
d1e3b762 1363
c997b287
GS
1364Atari, F<README.mint> and Guido Flohr's web page
1365http://stud.uni-sb.de/~gufl0000/
e41182b5 1366
c997b287 1367=item *
d1e3b762 1368
c997b287 1369Be OS, F<README.beos>
e41182b5 1370
c997b287
GS
1371=item *
1372
1373HP 300 MPE/iX, F<README.mpeix> and Mark Bixby's web page
34aaaa84 1374http://www.bixby.org/mark/perlix.html
c997b287
GS
1375
1376=item *
e41182b5 1377
6ab3f9cb 1378A free perl5-based PERL.NLM for Novell Netware is available in
c997b287 1379precompiled binary and source code form from http://www.novell.com/
6ab3f9cb 1380as well as from CPAN.
e41182b5 1381
13a2d996 1382=item *
c997b287 1383
e6f03d26 1384S<Plan 9>, F<README.plan9>
d1e3b762 1385
e41182b5
GS
1386=back
1387
e41182b5
GS
1388=head1 FUNCTION IMPLEMENTATIONS
1389
b7df3edc
GS
1390Listed below are functions that are either completely unimplemented
1391or else have been implemented differently on various platforms.
1392Following each description will be, in parentheses, a list of
1393platforms that the description applies to.
e41182b5 1394
b7df3edc
GS
1395The list may well be incomplete, or even wrong in some places. When
1396in doubt, consult the platform-specific README files in the Perl
1397source distribution, and any other documentation resources accompanying
1398a given port.
e41182b5 1399
0a47030a 1400Be aware, moreover, that even among Unix-ish systems there are variations.
e41182b5 1401
b7df3edc
GS
1402For many functions, you can also query C<%Config>, exported by
1403default from the Config module. For example, to check whether the
1404platform has the C<lstat> call, check C<$Config{d_lstat}>. See
1405L<Config> for a full description of available variables.
e41182b5
GS
1406
1407=head2 Alphabetical Listing of Perl Functions
1408
1409=over 8
1410
1411=item -X FILEHANDLE
1412
1413=item -X EXPR
1414
1415=item -X
1416
b7df3edc 1417C<-r>, C<-w>, and C<-x> have a limited meaning only; directories
e41182b5 1418and applications are executable, and there are no uid/gid
b7df3edc 1419considerations. C<-o> is not supported. (S<Mac OS>)
e41182b5 1420
b7df3edc
GS
1421C<-r>, C<-w>, C<-x>, and C<-o> tell whether the file is accessible,
1422which may not reflect UIC-based file protections. (VMS)
e41182b5 1423
b8099c3d
CN
1424C<-s> returns the size of the data fork, not the total size of data fork
1425plus resource fork. (S<Mac OS>).
1426
1427C<-s> by name on an open file will return the space reserved on disk,
1428rather than the current extent. C<-s> on an open filehandle returns the
b7df3edc 1429current size. (S<RISC OS>)
b8099c3d 1430
e41182b5 1431C<-R>, C<-W>, C<-X>, C<-O> are indistinguishable from C<-r>, C<-w>,
b8099c3d 1432C<-x>, C<-o>. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1433
1434C<-b>, C<-c>, C<-k>, C<-g>, C<-p>, C<-u>, C<-A> are not implemented.
1435(S<Mac OS>)
1436
1437C<-g>, C<-k>, C<-l>, C<-p>, C<-u>, C<-A> are not particularly meaningful.
b8099c3d 1438(Win32, VMS, S<RISC OS>)
e41182b5
GS
1439
1440C<-d> is true if passed a device spec without an explicit directory.
1441(VMS)
1442
1443C<-T> and C<-B> are implemented, but might misclassify Mac text files
0a47030a 1444with foreign characters; this is the case will all platforms, but may
b7df3edc 1445affect S<Mac OS> often. (S<Mac OS>)
e41182b5
GS
1446
1447C<-x> (or C<-X>) determine if a file ends in one of the executable
b7df3edc 1448suffixes. C<-S> is meaningless. (Win32)
e41182b5 1449
b8099c3d
CN
1450C<-x> (or C<-X>) determine if a file has an executable file type.
1451(S<RISC OS>)
1452
63f87e49
GS
1453=item alarm SECONDS
1454
1455=item alarm
1456
1457Not implemented. (Win32)
1458
e41182b5
GS
1459=item binmode FILEHANDLE
1460
b7df3edc 1461Meaningless. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1462
1463Reopens file and restores pointer; if function fails, underlying
1464filehandle may be closed, or pointer may be in a different position.
1465(VMS)
1466
1467The value returned by C<tell> may be affected after the call, and
1468the filehandle may be flushed. (Win32)
1469
1470=item chmod LIST
1471
b7df3edc 1472Only limited meaning. Disabling/enabling write permission is mapped to
e41182b5
GS
1473locking/unlocking the file. (S<Mac OS>)
1474
1475Only good for changing "owner" read-write access, "group", and "other"
1476bits are meaningless. (Win32)
1477
b8099c3d
CN
1478Only good for changing "owner" and "other" read-write access. (S<RISC OS>)
1479
495c5fdc
GP
1480Access permissions are mapped onto VOS access-control list changes. (VOS)
1481
4e51f8e4 1482The actual permissions set depend on the value of the C<CYGWIN>
789f0d36 1483in the SYSTEM environment settings. (Cygwin)
4e51f8e4 1484
e41182b5
GS
1485=item chown LIST
1486
3fd80bd6 1487Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1488
1489Does nothing, but won't fail. (Win32)
1490
3fd80bd6
PG
1491A little funky, because VOS's notion of ownership is a little funky (VOS).
1492
e41182b5
GS
1493=item chroot FILENAME
1494
1495=item chroot
1496
e6f03d26 1497Not implemented. (S<Mac OS>, Win32, VMS, S<Plan 9>, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1498
1499=item crypt PLAINTEXT,SALT
1500
1501May not be available if library or source was not provided when building
b8099c3d 1502perl. (Win32)
e41182b5
GS
1503
1504=item dbmclose HASH
1505
e6f03d26 1506Not implemented. (VMS, S<Plan 9>, VOS)
e41182b5
GS
1507
1508=item dbmopen HASH,DBNAME,MODE
1509
e6f03d26 1510Not implemented. (VMS, S<Plan 9>, VOS)
e41182b5
GS
1511
1512=item dump LABEL
1513
b8099c3d 1514Not useful. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1515
1516Not implemented. (Win32)
1517
b8099c3d 1518Invokes VMS debugger. (VMS)
e41182b5
GS
1519
1520=item exec LIST
1521
1522Not implemented. (S<Mac OS>)
1523
7c5ffed3 1524Implemented via Spawn. (VM/ESA)
3c075c7d 1525
0f897271
GS
1526Does not automatically flush output handles on some platforms.
1527(SunOS, Solaris, HP-UX)
1528
fe12c0e8
MS
1529=item exit EXPR
1530
1531=item exit
1532
1533Emulates UNIX exit() (which considers C<exit 1> to indicate an error) by
1534mapping the C<1> to SS$_ABORT (C<44>). This behavior may be overridden
1535with the pragma C<use vmsish 'exit'>. As with the CRTL's exit()
1536function, C<exit 0> is also mapped to an exit status of SS$_NORMAL
1537(C<1>); this mapping cannot be overridden. Any other argument to exit()
1538is used directly as Perl's exit status. (VMS)
1539
e41182b5
GS
1540=item fcntl FILEHANDLE,FUNCTION,SCALAR
1541
1542Not implemented. (Win32, VMS)
1543
1544=item flock FILEHANDLE,OPERATION
1545
495c5fdc 1546Not implemented (S<Mac OS>, VMS, S<RISC OS>, VOS).
e41182b5
GS
1547
1548Available only on Windows NT (not on Windows 95). (Win32)
1549
1550=item fork
1551
3fd80bd6 1552Not implemented. (S<Mac OS>, AmigaOS, S<RISC OS>, VM/ESA, VMS)
0f897271
GS
1553
1554Emulated using multiple interpreters. See L<perlfork>. (Win32)
1555
1556Does not automatically flush output handles on some platforms.
1557(SunOS, Solaris, HP-UX)
e41182b5
GS
1558
1559=item getlogin
1560
b8099c3d 1561Not implemented. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1562
1563=item getpgrp PID
1564
3fd80bd6 1565Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1566
1567=item getppid
1568
41cbbefa 1569Not implemented. (S<Mac OS>, Win32, S<RISC OS>)
e41182b5
GS
1570
1571=item getpriority WHICH,WHO
1572
7c5ffed3 1573Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1574
1575=item getpwnam NAME
1576
1577Not implemented. (S<Mac OS>, Win32)
1578
b8099c3d
CN
1579Not useful. (S<RISC OS>)
1580
e41182b5
GS
1581=item getgrnam NAME
1582
b8099c3d 1583Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1584
1585=item getnetbyname NAME
1586
e6f03d26 1587Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1588
1589=item getpwuid UID
1590
1591Not implemented. (S<Mac OS>, Win32)
1592
b8099c3d
CN
1593Not useful. (S<RISC OS>)
1594
e41182b5
GS
1595=item getgrgid GID
1596
b8099c3d 1597Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1598
1599=item getnetbyaddr ADDR,ADDRTYPE
1600
e6f03d26 1601Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1602
1603=item getprotobynumber NUMBER
1604
1605Not implemented. (S<Mac OS>)
1606
1607=item getservbyport PORT,PROTO
1608
1609Not implemented. (S<Mac OS>)
1610
1611=item getpwent
1612
7c5ffed3 1613Not implemented. (S<Mac OS>, Win32, VM/ESA)
e41182b5
GS
1614
1615=item getgrent
1616
7c5ffed3 1617Not implemented. (S<Mac OS>, Win32, VMS, VM/ESA)
e41182b5
GS
1618
1619=item gethostent
1620
1621Not implemented. (S<Mac OS>, Win32)
1622
1623=item getnetent
1624
e6f03d26 1625Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1626
1627=item getprotoent
1628
e6f03d26 1629Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1630
1631=item getservent
1632
e6f03d26 1633Not implemented. (Win32, S<Plan 9>)
e41182b5 1634
e41182b5
GS
1635=item sethostent STAYOPEN
1636
e6f03d26 1637Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1638
1639=item setnetent STAYOPEN
1640
e6f03d26 1641Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1642
1643=item setprotoent STAYOPEN
1644
e6f03d26 1645Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1646
1647=item setservent STAYOPEN
1648
e6f03d26 1649Not implemented. (S<Plan 9>, Win32, S<RISC OS>)
e41182b5
GS
1650
1651=item endpwent
1652
a3dfe201 1653Not implemented. (S<Mac OS>, MPE/iX, VM/ESA, Win32)
e41182b5
GS
1654
1655=item endgrent
1656
a3dfe201 1657Not implemented. (S<Mac OS>, MPE/iX, S<RISC OS>, VM/ESA, VMS, Win32)
e41182b5
GS
1658
1659=item endhostent
1660
1661Not implemented. (S<Mac OS>, Win32)
1662
1663=item endnetent
1664
e6f03d26 1665Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1666
1667=item endprotoent
1668
e6f03d26 1669Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1670
1671=item endservent
1672
e6f03d26 1673Not implemented. (S<Plan 9>, Win32)
e41182b5
GS
1674
1675=item getsockopt SOCKET,LEVEL,OPTNAME
1676
e6f03d26 1677Not implemented. (S<Plan 9>)
e41182b5
GS
1678
1679=item glob EXPR
1680
1681=item glob
1682
63f87e49
GS
1683This operator is implemented via the File::Glob extension on most
1684platforms. See L<File::Glob> for portability information.
b8099c3d 1685
e41182b5
GS
1686=item ioctl FILEHANDLE,FUNCTION,SCALAR
1687
1688Not implemented. (VMS)
1689
1690Available only for socket handles, and it does what the ioctlsocket() call
1691in the Winsock API does. (Win32)
1692
b8099c3d
CN
1693Available only for socket handles. (S<RISC OS>)
1694
b350dd2f 1695=item kill SIGNAL, LIST
e41182b5 1696
862b5365
JH
1697C<kill(0, LIST)> is implemented for the sake of taint checking;
1698use with other signals is unimplemented. (S<Mac OS>)
1699
1700Not implemented, hence not useful for taint checking. (S<RISC OS>)
e41182b5 1701
63f87e49
GS
1702C<kill()> doesn't have the semantics of C<raise()>, i.e. it doesn't send
1703a signal to the identified process like it does on Unix platforms.
1704Instead C<kill($sig, $pid)> terminates the process identified by $pid,
1705and makes it exit immediately with exit status $sig. As in Unix, if
1706$sig is 0 and the specified process exists, it returns true without
1707actually terminating it. (Win32)
e41182b5
GS
1708
1709=item link OLDFILE,NEWFILE
1710
a3dfe201 1711Not implemented. (S<Mac OS>, MPE/iX, VMS, S<RISC OS>)
e41182b5 1712
433acd8a
JH
1713Link count not updated because hard links are not quite that hard
1714(They are sort of half-way between hard and soft links). (AmigaOS)
1715
a3dfe201
GS
1716Hard links are implemented on Win32 (Windows NT and Windows 2000)
1717under NTFS only.
1718
e41182b5
GS
1719=item lstat FILEHANDLE
1720
1721=item lstat EXPR
1722
1723=item lstat
1724
b8099c3d 1725Not implemented. (VMS, S<RISC OS>)
e41182b5 1726
63f87e49 1727Return values (especially for device and inode) may be bogus. (Win32)
e41182b5
GS
1728
1729=item msgctl ID,CMD,ARG
1730
1731=item msgget KEY,FLAGS
1732
1733=item msgsnd ID,MSG,FLAGS
1734
1735=item msgrcv ID,VAR,SIZE,TYPE,FLAGS
1736
e6f03d26 1737Not implemented. (S<Mac OS>, Win32, VMS, S<Plan 9>, S<RISC OS>, VOS)
e41182b5
GS
1738
1739=item open FILEHANDLE,EXPR
1740
1741=item open FILEHANDLE
1742
b7df3edc 1743The C<|> variants are supported only if ToolServer is installed.
e41182b5
GS
1744(S<Mac OS>)
1745
c47ff5f1 1746open to C<|-> and C<-|> are unsupported. (S<Mac OS>, Win32, S<RISC OS>)
e41182b5 1747
0f897271
GS
1748Opening a process does not automatically flush output handles on some
1749platforms. (SunOS, Solaris, HP-UX)
1750
e41182b5
GS
1751=item pipe READHANDLE,WRITEHANDLE
1752
433acd8a
JH
1753Very limited functionality. (MiNT)
1754
e41182b5
GS
1755=item readlink EXPR
1756
1757=item readlink
1758
b8099c3d 1759Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5
GS
1760
1761=item select RBITS,WBITS,EBITS,TIMEOUT
1762
689c5c24 1763Only implemented on sockets. (Win32, VMS)
e41182b5 1764
b8099c3d
CN
1765Only reliable on sockets. (S<RISC OS>)
1766
76e05f0b 1767Note that the C<select FILEHANDLE> form is generally portable.
63f87e49 1768
e41182b5
GS
1769=item semctl ID,SEMNUM,CMD,ARG
1770
1771=item semget KEY,NSEMS,FLAGS
1772
1773=item semop KEY,OPSTRING
1774
495c5fdc 1775Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1776
a3dfe201
GS
1777=item setgrent
1778
3fd80bd6 1779Not implemented. (S<Mac OS>, MPE/iX, VMS, Win32, S<RISC OS>, VOS)
a3dfe201 1780
e41182b5
GS
1781=item setpgrp PID,PGRP
1782
495c5fdc 1783Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5
GS
1784
1785=item setpriority WHICH,WHO,PRIORITY
1786
495c5fdc 1787Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1788
a3dfe201
GS
1789=item setpwent
1790
3fd80bd6 1791Not implemented. (S<Mac OS>, MPE/iX, Win32, S<RISC OS>, VOS)
a3dfe201 1792
e41182b5
GS
1793=item setsockopt SOCKET,LEVEL,OPTNAME,OPTVAL
1794
e6f03d26 1795Not implemented. (S<Plan 9>)
e41182b5
GS
1796
1797=item shmctl ID,CMD,ARG
1798
1799=item shmget KEY,SIZE,FLAGS
1800
1801=item shmread ID,VAR,POS,SIZE
1802
1803=item shmwrite ID,STRING,POS,SIZE
1804
495c5fdc 1805Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1806
80cbd5ad
JH
1807=item sockatmark SOCKET
1808
1809A relatively recent addition to socket functions, may not
1810be implemented even in UNIX platforms.
1811
e41182b5
GS
1812=item socketpair SOCKET1,SOCKET2,DOMAIN,TYPE,PROTOCOL
1813
862b5365 1814Not implemented. (Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1815
1816=item stat FILEHANDLE
1817
1818=item stat EXPR
1819
1820=item stat
1821
d62e1b7f
JH
1822Platforms that do not have rdev, blksize, or blocks will return these
1823as '', so numeric comparison or manipulation of these fields may cause
1824'not numeric' warnings.
1825
e41182b5 1826mtime and atime are the same thing, and ctime is creation time instead of
3f1f789b
JH
1827inode change time. (S<Mac OS>).
1828
1829ctime not supported on UFS (S<Mac OS X>).
e41182b5 1830
95a3fe12
MS
1831ctime is creation time instead of inode change time (Win32).
1832
e41182b5
GS
1833device and inode are not meaningful. (Win32)
1834
1835device and inode are not necessarily reliable. (VMS)
1836
b8099c3d
CN
1837mtime, atime and ctime all return the last modification time. Device and
1838inode are not necessarily reliable. (S<RISC OS>)
1839
d62e1b7f
JH
1840dev, rdev, blksize, and blocks are not available. inode is not
1841meaningful and will differ between stat calls on the same file. (os2)
1842
73e9292c
JH
1843some versions of cygwin when doing a stat("foo") and if not finding it
1844may then attempt to stat("foo.exe") (Cygwin)
1845
e41182b5
GS
1846=item symlink OLDFILE,NEWFILE
1847
b8099c3d 1848Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5
GS
1849
1850=item syscall LIST
1851
7c5ffed3 1852Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5 1853
f34d0673
GS
1854=item sysopen FILEHANDLE,FILENAME,MODE,PERMS
1855
dd9f0070 1856The traditional "0", "1", and "2" MODEs are implemented with different
322422de
GS
1857numeric values on some systems. The flags exported by C<Fcntl>
1858(O_RDONLY, O_WRONLY, O_RDWR) should work everywhere though. (S<Mac
7c5ffed3 1859OS>, OS/390, VM/ESA)
f34d0673 1860
e41182b5
GS
1861=item system LIST
1862
9d6eb86e 1863In general, do not assume the UNIX/POSIX semantics that you can shift
7717d0e7 1864C<$?> right by eight to get the exit value, or that C<$? & 127>
9d6eb86e
JH
1865would give you the number of the signal that terminated the program,
1866or that C<$? & 128> would test true if the program was terminated by a
1867coredump. Instead, use the POSIX W*() interfaces: for example, use
74555b7a
PP
1868WIFEXITED($?) and WEXITVALUE($?) to test for a normal exit and the exit
1869value, WIFSIGNALED($?) and WTERMSIG($?) for a signal exit and the
7717d0e7 1870signal. Core dumping is not a portable concept, so there's no portable
9d6eb86e
JH
1871way to test for that.
1872
e41182b5
GS
1873Only implemented if ToolServer is installed. (S<Mac OS>)
1874
1875As an optimization, may not call the command shell specified in
b7df3edc 1876C<$ENV{PERL5SHELL}>. C<system(1, @args)> spawns an external
e41182b5
GS
1877process and immediately returns its process designator, without
1878waiting for it to terminate. Return value may be used subsequently
63f87e49
GS
1879in C<wait> or C<waitpid>. Failure to spawn() a subprocess is indicated
1880by setting $? to "255 << 8". C<$?> is set in a way compatible with
1881Unix (i.e. the exitstatus of the subprocess is obtained by "$? >> 8",
1882as described in the documentation). (Win32)
e41182b5 1883
b8099c3d
CN
1884There is no shell to process metacharacters, and the native standard is
1885to pass a command line terminated by "\n" "\r" or "\0" to the spawned
c47ff5f1 1886program. Redirection such as C<< > foo >> is performed (if at all) by
b8099c3d
CN
1887the run time library of the spawned program. C<system> I<list> will call
1888the Unix emulation library's C<exec> emulation, which attempts to provide
1889emulation of the stdin, stdout, stderr in force in the parent, providing
1890the child program uses a compatible version of the emulation library.
1891I<scalar> will call the native command line direct and no such emulation
1892of a child Unix program will exists. Mileage B<will> vary. (S<RISC OS>)
1893
433acd8a
JH
1894Far from being POSIX compliant. Because there may be no underlying
1895/bin/sh tries to work around the problem by forking and execing the
9b63e9ec 1896first token in its argument string. Handles basic redirection
c47ff5f1 1897("<" or ">") on its own behalf. (MiNT)
433acd8a 1898
0f897271
GS
1899Does not automatically flush output handles on some platforms.
1900(SunOS, Solaris, HP-UX)
1901
9bc98430
CB
1902The return value is POSIX-like (shifted up by 8 bits), which only allows
1903room for a made-up value derived from the severity bits of the native
190432-bit condition code (unless overridden by C<use vmsish 'status'>).
1905For more details see L<perlvms/$?>. (VMS)
1906
e41182b5
GS
1907=item times
1908
1909Only the first entry returned is nonzero. (S<Mac OS>)
1910
63f87e49
GS
1911"cumulative" times will be bogus. On anything other than Windows NT
1912or Windows 2000, "system" time will be bogus, and "user" time is
1913actually the time returned by the clock() function in the C runtime
1914library. (Win32)
e41182b5 1915
b8099c3d
CN
1916Not useful. (S<RISC OS>)
1917
e41182b5
GS
1918=item truncate FILEHANDLE,LENGTH
1919
1920=item truncate EXPR,LENGTH
1921
6d738113 1922Not implemented. (Older versions of VMS)
e41182b5 1923
3fd80bd6 1924Truncation to same-or-shorter lengths only. (VOS)
495c5fdc 1925
4cfdb94f 1926If a FILEHANDLE is supplied, it must be writable and opened in append
e71a7dc8 1927mode (i.e., use C<<< open(FH, '>>filename') >>>
4cfdb94f
GS
1928or C<sysopen(FH,...,O_APPEND|O_RDWR)>. If a filename is supplied, it
1929should not be held open elsewhere. (Win32)
1930
e41182b5
GS
1931=item umask EXPR
1932
1933=item umask
1934
1935Returns undef where unavailable, as of version 5.005.
1936
b7df3edc
GS
1937C<umask> works but the correct permissions are set only when the file
1938is finally closed. (AmigaOS)
433acd8a 1939
e41182b5
GS
1940=item utime LIST
1941
15c65113 1942Only the modification time is updated. (S<BeOS>, S<Mac OS>, VMS, S<RISC OS>)
e41182b5 1943
322422de
GS
1944May not behave as expected. Behavior depends on the C runtime
1945library's implementation of utime(), and the filesystem being
1946used. The FAT filesystem typically does not support an "access
1947time" field, and it may limit timestamps to a granularity of
1948two seconds. (Win32)
e41182b5
GS
1949
1950=item wait
1951
1952=item waitpid PID,FLAGS
1953
3fd80bd6 1954Not implemented. (S<Mac OS>)
e41182b5
GS
1955
1956Can only be applied to process handles returned for processes spawned
a6f858fb 1957using C<system(1, ...)> or pseudo processes created with C<fork()>. (Win32)
e41182b5 1958
b8099c3d
CN
1959Not useful. (S<RISC OS>)
1960
e41182b5
GS
1961=back
1962
b8099c3d
CN
1963=head1 CHANGES
1964
1965=over 4
1966
3fd80bd6
PG
1967=item v1.49, 12 August 2002
1968
1969Updates for VOS from Paul Green.
1970
fd46a41b
JH
1971=item v1.48, 02 February 2001
1972
1973Various updates from perl5-porters over the past year, supported
1974platforms update from Jarkko Hietaniemi.
1975
c997b287
GS
1976=item v1.47, 22 March 2000
1977
1978Various cleanups from Tom Christiansen, including migration of
1979long platform listings from L<perl>.
1980
56d7751a
GS
1981=item v1.46, 12 February 2000
1982
1983Updates for VOS and MPE/iX. (Peter Prymmer) Other small changes.
1984
0cc436d0
GS
1985=item v1.45, 20 December 1999
1986
1987Small changes from 5.005_63 distribution, more changes to EBCDIC info.
1988
d1e3b762
GS
1989=item v1.44, 19 July 1999
1990
1991A bunch of updates from Peter Prymmer for C<$^O> values,
1992endianness, File::Spec, VMS, BS2000, OS/400.
1993
b7df3edc
GS
1994=item v1.43, 24 May 1999
1995
1996Added a lot of cleaning up from Tom Christiansen.
1997
19799a22 1998=item v1.42, 22 May 1999
b7df3edc 1999
19799a22 2000Added notes about tests, sprintf/printf, and epoch offsets.
b7df3edc 2001
6ab3f9cb
GS
2002=item v1.41, 19 May 1999
2003
2004Lots more little changes to formatting and content.
2005
d1e3b762 2006Added a bunch of C<$^O> and related values
6ab3f9cb
GS
2007for various platforms; fixed mail and web addresses, and added
2008and changed miscellaneous notes. (Peter Prymmer)
2009
2010=item v1.40, 11 April 1999
2011
2012Miscellaneous changes.
2013
2014=item v1.39, 11 February 1999
2ee0eb3c
CN
2015
2016Changes from Jarkko and EMX URL fixes Michael Schwern. Additional
2017note about newlines added.
2018
9b63e9ec
CN
2019=item v1.38, 31 December 1998
2020
2021More changes from Jarkko.
2022
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2023=item v1.37, 19 December 1998
2024
2025More minor changes. Merge two separate version 1.35 documents.
2026
2027=item v1.36, 9 September 1998
2028
2029Updated for Stratus VOS. Also known as version 1.35.
2030
2031=item v1.35, 13 August 1998
495c5fdc 2032
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2033Integrate more minor changes, plus addition of new sections under
2034L<"ISSUES">: L<"Numbers endianness and Width">,
2035L<"Character sets and character encoding">,
2036L<"Internationalisation">.
495c5fdc 2037
3c075c7d 2038=item v1.33, 06 August 1998
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2039
2040Integrate more minor changes.
2041
3c075c7d 2042=item v1.32, 05 August 1998
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CN
2043
2044Integrate more minor changes.
2045
3c075c7d 2046=item v1.30, 03 August 1998
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2047
2048Major update for RISC OS, other minor changes.
2049
3c075c7d 2050=item v1.23, 10 July 1998
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CN
2051
2052First public release with perl5.005.
2053
2054=back
e41182b5 2055
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2056=head1 Supported Platforms
2057
522b859a 2058As of July 2002 (the Perl release 5.8.0), the following platforms are
cec2c193
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2059able to build Perl from the standard source code distribution
2060available at http://www.cpan.org/src/index.html
2061
2062 AIX
2063 BeOS
2064 Cygwin
2065 DG/UX
811b48f2 2066 DOS DJGPP 1)
cec2c193
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2067 DYNIX/ptx
2068 EPOC R5
2069 FreeBSD
2070 HP-UX
2071 IRIX
2072 Linux
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2073 Mac OS Classic
2074 Mac OS X (Darwin)
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2075 MPE/iX
2076 NetBSD
2077 NetWare
2078 NonStop-UX
2079 ReliantUNIX (SINIX)
2080 OpenBSD
2081 OpenVMS (VMS)
2082 OS/2
522b859a 2083 OS/400 (using the PASE) (since Perl 5.8.1/5.9.0)
70de81db 2084 PowerUX
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2085 POSIX-BC (BS2000)
2086 QNX
2087 Solaris
70de81db 2088 SunOS 4
bb5ad0af 2089 SUPER-UX
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2090 Tru64 UNIX (DEC OSF/1, Digital UNIX)
2091 UNICOS
2092 UNICOS/mk
2093 UTS
2094 VOS
811b48f2 2095 Win95/98/ME/2K/XP 2)
c40b5d1d 2096 WinCE
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2097 z/OS (OS/390)
2098 VM/ESA
ba58ab26 2099
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2100 1) in DOS mode either the DOS or OS/2 ports can be used
2101 2) compilers: Borland, MinGW (GCC), VC6
cec2c193 2102
c40b5d1d 2103The following platforms worked with the previous releases (5.6 and
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21045.7), but we did not manage either to fix or to test these in time
2105for the 5.8.0 release. There is a very good chance that many of these
70de81db 2106will work fine with the 5.8.0.
cec2c193 2107
8da2b1be 2108 BSD/OS
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2109 DomainOS
2110 Hurd
2111 LynxOS
2112 MachTen
2113 PowerMAX
2114 SCO SV
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2115 SVR4
2116 Unixware
2117 Windows 3.1
ba58ab26 2118
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2119Known to be broken for 5.8.0 (but 5.6.1 and 5.7.2 can be used):
2120
2121 AmigaOS
2122
ba58ab26 2123The following platforms have been known to build Perl from source in
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2124the past (5.005_03 and earlier), but we haven't been able to verify
2125their status for the current release, either because the
2126hardware/software platforms are rare or because we don't have an
2127active champion on these platforms--or both. They used to work,
2128though, so go ahead and try compiling them, and let perlbug@perl.org
2129of any trouble.
ba58ab26 2130
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2131 3b1
2132 A/UX
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2133 ConvexOS
2134 CX/UX
2135 DC/OSx
2136 DDE SMES
2137 DOS EMX
2138 Dynix
2139 EP/IX
2140 ESIX
2141 FPS
2142 GENIX
2143 Greenhills
2144 ISC
2145 MachTen 68k
2146 MiNT
2147 MPC
2148 NEWS-OS
2149 NextSTEP
2150 OpenSTEP
2151 Opus
2152 Plan 9
cec2c193 2153 RISC/os
8da2b1be 2154 SCO ODT/OSR
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2155 Stellar
2156 SVR2
2157 TI1500
2158 TitanOS
2159 Ultrix
2160 Unisys Dynix
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2161
2162The following platforms have their own source code distributions and
1577cd80 2163binaries available via http://www.cpan.org/ports/
ba58ab26 2164
cec2c193 2165 Perl release
ba58ab26 2166
522b859a 2167 OS/400 (ILE) 5.005_02
cec2c193 2168 Tandem Guardian 5.004
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2169
2170The following platforms have only binaries available via
a93751fa 2171http://www.cpan.org/ports/index.html :
ba58ab26 2172
cec2c193 2173 Perl release
ba58ab26 2174
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2175 Acorn RISCOS 5.005_02
2176 AOS 5.002
2177 LynxOS 5.004_02
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2178
2179Although we do suggest that you always build your own Perl from
2180the source code, both for maximal configurability and for security,
2181in case you are in a hurry you can check
a93751fa 2182http://www.cpan.org/ports/index.html for binary distributions.
ba58ab26 2183
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2184=head1 SEE ALSO
2185
cec2c193 2186L<perlaix>, L<perlamiga>, L<perlapollo>, L<perlbeos>, L<perlbs2000>,
18a271bd 2187L<perlce>, L<perlcygwin>, L<perldgux>, L<perldos>, L<perlepoc>,
469e7be4 2188L<perlebcdic>, L<perlfreebsd>, L<perlhurd>, L<perlhpux>, L<perlirix>,
18a271bd 2189L<perlmachten>, L<perlmacos>, L<perlmint>, L<perlmpeix>,
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2190L<perlnetware>, L<perlos2>, L<perlos390>, L<perlos400>,
2191L<perlplan9>, L<perlqnx>, L<perlsolaris>, L<perltru64>,
2192L<perlunicode>, L<perlvmesa>, L<perlvms>, L<perlvos>,
2193L<perlwin32>, and L<Win32>.
c997b287 2194
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2195=head1 AUTHORS / CONTRIBUTORS
2196
06e9666b 2197Abigail <abigail@foad.org>,
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2198Charles Bailey <bailey@newman.upenn.edu>,
2199Graham Barr <gbarr@pobox.com>,
2200Tom Christiansen <tchrist@perl.com>,
06e9666b 2201Nicholas Clark <nick@ccl4.org>,
c47ff5f1 2202Thomas Dorner <Thomas.Dorner@start.de>,
06e9666b
A
2203Andy Dougherty <doughera@lafayette.edu>,
2204Dominic Dunlop <domo@computer.org>,
2205Neale Ferguson <neale@vma.tabnsw.com.au>,
c47ff5f1 2206David J. Fiander <davidf@mks.com>,
3fd80bd6 2207Paul Green <Paul.Green@stratus.com>,
06e9666b 2208M.J.T. Guy <mjtg@cam.ac.uk>,
61f30a5e 2209Jarkko Hietaniemi <jhi@iki.fi>,
c47ff5f1 2210Luther Huffman <lutherh@stratcom.com>,
06e9666b
A
2211Nick Ing-Simmons <nick@ing-simmons.net>,
2212Andreas J. KE<ouml>nig <a.koenig@mind.de>,
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2213Markus Laker <mlaker@contax.co.uk>,
2214Andrew M. Langmead <aml@world.std.com>,
2215Larry Moore <ljmoore@freespace.net>,
2216Paul Moore <Paul.Moore@uk.origin-it.com>,
2217Chris Nandor <pudge@pobox.com>,
1afc07ec 2218Matthias Neeracher <neeracher@mac.com>,
e71a7dc8 2219Philip Newton <pne@cpan.org>,
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2220Gary Ng <71564.1743@CompuServe.COM>,
2221Tom Phoenix <rootbeer@teleport.com>,
2222AndrE<eacute> Pirard <A.Pirard@ulg.ac.be>,
2223Peter Prymmer <pvhp@forte.com>,
2224Hugo van der Sanden <hv@crypt0.demon.co.uk>,
2225Gurusamy Sarathy <gsar@activestate.com>,
2226Paul J. Schinder <schinder@pobox.com>,
2227Michael G Schwern <schwern@pobox.com>,
06e9666b 2228Dan Sugalski <dan@sidhe.org>,
c47ff5f1 2229Nathan Torkington <gnat@frii.com>.
e41182b5 2230