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1=head1 NAME
2
3perlport - Writing portable Perl
4
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5=head1 DESCRIPTION
6
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7Perl runs on numerous operating systems. While most of them share
8much in common, they also have their own unique features.
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9
10This document is meant to help you to find out what constitutes portable
b7df3edc 11Perl code. That way once you make a decision to write portably,
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12you know where the lines are drawn, and you can stay within them.
13
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14There is a tradeoff between taking full advantage of one particular
15type of computer and taking advantage of a full range of them.
16Naturally, as you broaden your range and become more diverse, the
17common factors drop, and you are left with an increasingly smaller
18area of common ground in which you can operate to accomplish a
19particular task. Thus, when you begin attacking a problem, it is
20important to consider under which part of the tradeoff curve you
21want to operate. Specifically, you must decide whether it is
22important that the task that you are coding have the full generality
23of being portable, or whether to just get the job done right now.
24This is the hardest choice to be made. The rest is easy, because
25Perl provides many choices, whichever way you want to approach your
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26problem.
27
28Looking at it another way, writing portable code is usually about
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29willfully limiting your available choices. Naturally, it takes
30discipline and sacrifice to do that. The product of portability
31and convenience may be a constant. You have been warned.
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32
33Be aware of two important points:
34
35=over 4
36
37=item Not all Perl programs have to be portable
38
b7df3edc 39There is no reason you should not use Perl as a language to glue Unix
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40tools together, or to prototype a Macintosh application, or to manage the
41Windows registry. If it makes no sense to aim for portability for one
42reason or another in a given program, then don't bother.
43
b7df3edc 44=item Nearly all of Perl already I<is> portable
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45
46Don't be fooled into thinking that it is hard to create portable Perl
47code. It isn't. Perl tries its level-best to bridge the gaps between
48what's available on different platforms, and all the means available to
49use those features. Thus almost all Perl code runs on any machine
6ab3f9cb 50without modification. But there are some significant issues in
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51writing portable code, and this document is entirely about those issues.
52
53=back
54
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55Here's the general rule: When you approach a task commonly done
56using a whole range of platforms, think about writing portable
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57code. That way, you don't sacrifice much by way of the implementation
58choices you can avail yourself of, and at the same time you can give
59your users lots of platform choices. On the other hand, when you have to
60take advantage of some unique feature of a particular platform, as is
61often the case with systems programming (whether for Unix, Windows,
62S<Mac OS>, VMS, etc.), consider writing platform-specific code.
63
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64When the code will run on only two or three operating systems, you
65may need to consider only the differences of those particular systems.
66The important thing is to decide where the code will run and to be
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67deliberate in your decision.
68
69The material below is separated into three main sections: main issues of
70portability (L<"ISSUES">, platform-specific issues (L<"PLATFORMS">, and
b7df3edc 71built-in perl functions that behave differently on various ports
0a47030a 72(L<"FUNCTION IMPLEMENTATIONS">.
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73
74This information should not be considered complete; it includes possibly
b8099c3d 75transient information about idiosyncrasies of some of the ports, almost
b7df3edc 76all of which are in a state of constant evolution. Thus, this material
e41182b5 77should be considered a perpetual work in progress
cc07ed0b 78(C<< <IMG SRC="yellow_sign.gif" ALT="Under Construction"> >>).
e41182b5 79
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80=head1 ISSUES
81
82=head2 Newlines
83
638bc118 84In most operating systems, lines in files are terminated by newlines.
e41182b5 85Just what is used as a newline may vary from OS to OS. Unix
b7df3edc 86traditionally uses C<\012>, one type of DOSish I/O uses C<\015\012>,
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87and S<Mac OS> uses C<\015>.
88
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89Perl uses C<\n> to represent the "logical" newline, where what is
90logical may depend on the platform in use. In MacPerl, C<\n> always
91means C<\015>. In DOSish perls, C<\n> usually means C<\012>, but
92when accessing a file in "text" mode, STDIO translates it to (or
56d7751a 93from) C<\015\012>, depending on whether you're reading or writing.
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94Unix does the same thing on ttys in canonical mode. C<\015\012>
95is commonly referred to as CRLF.
96
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97A common cause of unportable programs is the misuse of chop() to trim
98newlines:
99
100 # XXX UNPORTABLE!
101 while(<FILE>) {
102 chop;
103 @array = split(/:/);
104 #...
105 }
106
8939ba94 107You can get away with this on Unix and Mac OS (they have a single
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108character end-of-line), but the same program will break under DOSish
109perls because you're only chop()ing half the end-of-line. Instead,
110chomp() should be used to trim newlines. The Dunce::Files module can
111help audit your code for misuses of chop().
112
113When dealing with binary files (or text files in binary mode) be sure
114to explicitly set $/ to the appropriate value for your file format
115before using chomp().
116
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117Because of the "text" mode translation, DOSish perls have limitations
118in using C<seek> and C<tell> on a file accessed in "text" mode.
119Stick to C<seek>-ing to locations you got from C<tell> (and no
120others), and you are usually free to use C<seek> and C<tell> even
121in "text" mode. Using C<seek> or C<tell> or other file operations
122may be non-portable. If you use C<binmode> on a file, however, you
123can usually C<seek> and C<tell> with arbitrary values in safety.
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124
125A common misconception in socket programming is that C<\n> eq C<\012>
0a47030a 126everywhere. When using protocols such as common Internet protocols,
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127C<\012> and C<\015> are called for specifically, and the values of
128the logical C<\n> and C<\r> (carriage return) are not reliable.
129
130 print SOCKET "Hi there, client!\r\n"; # WRONG
131 print SOCKET "Hi there, client!\015\012"; # RIGHT
132
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133However, using C<\015\012> (or C<\cM\cJ>, or C<\x0D\x0A>) can be tedious
134and unsightly, as well as confusing to those maintaining the code. As
6ab3f9cb 135such, the Socket module supplies the Right Thing for those who want it.
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136
137 use Socket qw(:DEFAULT :crlf);
138 print SOCKET "Hi there, client!$CRLF" # RIGHT
139
6ab3f9cb 140When reading from a socket, remember that the default input record
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141separator C<$/> is C<\n>, but robust socket code will recognize as
142either C<\012> or C<\015\012> as end of line:
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143
144 while (<SOCKET>) {
145 # ...
146 }
147
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148Because both CRLF and LF end in LF, the input record separator can
149be set to LF and any CR stripped later. Better to write:
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150
151 use Socket qw(:DEFAULT :crlf);
152 local($/) = LF; # not needed if $/ is already \012
153
154 while (<SOCKET>) {
155 s/$CR?$LF/\n/; # not sure if socket uses LF or CRLF, OK
156 # s/\015?\012/\n/; # same thing
157 }
158
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159This example is preferred over the previous one--even for Unix
160platforms--because now any C<\015>'s (C<\cM>'s) are stripped out
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161(and there was much rejoicing).
162
6ab3f9cb 163Similarly, functions that return text data--such as a function that
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164fetches a web page--should sometimes translate newlines before
165returning the data, if they've not yet been translated to the local
166newline representation. A single line of code will often suffice:
2ee0eb3c 167
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168 $data =~ s/\015?\012/\n/g;
169 return $data;
2ee0eb3c 170
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171Some of this may be confusing. Here's a handy reference to the ASCII CR
172and LF characters. You can print it out and stick it in your wallet.
173
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174 LF eq \012 eq \x0A eq \cJ eq chr(10) eq ASCII 10
175 CR eq \015 eq \x0D eq \cM eq chr(13) eq ASCII 13
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176
177 | Unix | DOS | Mac |
178 ---------------------------
179 \n | LF | LF | CR |
180 \r | CR | CR | LF |
181 \n * | LF | CRLF | CR |
182 \r * | CR | CR | LF |
183 ---------------------------
184 * text-mode STDIO
185
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186The Unix column assumes that you are not accessing a serial line
187(like a tty) in canonical mode. If you are, then CR on input becomes
188"\n", and "\n" on output becomes CRLF.
189
6ab3f9cb 190These are just the most common definitions of C<\n> and C<\r> in Perl.
aa7f90d3 191There may well be others. For example, on an EBCDIC implementation such
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192as z/OS or OS/400 the above material is similar to "Unix" but the code
193numbers change:
194
195 LF eq \025 eq \x15 eq chr(21) eq CP-1047 21
196 LF eq \045 eq \x25 eq \cU eq chr(37) eq CP-0037 37
197 CR eq \015 eq \x0D eq \cM eq chr(13) eq CP-1047 13
198 CR eq \015 eq \x0D eq \cM eq chr(13) eq CP-0037 13
199
200 | z/OS | OS/400 |
201 ----------------------
202 \n | LF | LF |
203 \r | CR | CR |
204 \n * | LF | LF |
205 \r * | CR | CR |
206 ----------------------
207 * text-mode STDIO
6ab3f9cb 208
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209=head2 Numbers endianness and Width
210
211Different CPUs store integers and floating point numbers in different
212orders (called I<endianness>) and widths (32-bit and 64-bit being the
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213most common today). This affects your programs when they attempt to transfer
214numbers in binary format from one CPU architecture to another,
215usually either "live" via network connection, or by storing the
216numbers to secondary storage such as a disk file or tape.
322422de 217
b7df3edc 218Conflicting storage orders make utter mess out of the numbers. If a
d1e3b762 219little-endian host (Intel, VAX) stores 0x12345678 (305419896 in
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220decimal), a big-endian host (Motorola, Sparc, PA) reads it as
2210x78563412 (2018915346 in decimal). Alpha and MIPS can be either:
222Digital/Compaq used/uses them in little-endian mode; SGI/Cray uses
223them in big-endian mode. To avoid this problem in network (socket)
224connections use the C<pack> and C<unpack> formats C<n> and C<N>, the
225"network" orders. These are guaranteed to be portable.
322422de 226
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227You can explore the endianness of your platform by unpacking a
228data structure packed in native format such as:
229
230 print unpack("h*", pack("s2", 1, 2)), "\n";
231 # '10002000' on e.g. Intel x86 or Alpha 21064 in little-endian mode
232 # '00100020' on e.g. Motorola 68040
233
234If you need to distinguish between endian architectures you could use
235either of the variables set like so:
236
237 $is_big_endian = unpack("h*", pack("s", 1)) =~ /01/;
4375e838 238 $is_little_endian = unpack("h*", pack("s", 1)) =~ /^1/;
d1e3b762 239
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240Differing widths can cause truncation even between platforms of equal
241endianness. The platform of shorter width loses the upper parts of the
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242number. There is no good solution for this problem except to avoid
243transferring or storing raw binary numbers.
244
b7df3edc 245One can circumnavigate both these problems in two ways. Either
322422de 246transfer and store numbers always in text format, instead of raw
b7df3edc 247binary, or else consider using modules like Data::Dumper (included in
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248the standard distribution as of Perl 5.005) and Storable (included as
249of perl 5.8). Keeping all data as text significantly simplifies matters.
322422de 250
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251The v-strings are portable only up to v2147483647 (0x7FFFFFFF), that's
252how far EBCDIC, or more precisely UTF-EBCDIC will go.
253
433acd8a 254=head2 Files and Filesystems
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255
256Most platforms these days structure files in a hierarchical fashion.
b7df3edc 257So, it is reasonably safe to assume that all platforms support the
6ab3f9cb 258notion of a "path" to uniquely identify a file on the system. How
b7df3edc 259that path is really written, though, differs considerably.
e41182b5 260
4375e838 261Although similar, file path specifications differ between Unix,
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262Windows, S<Mac OS>, OS/2, VMS, VOS, S<RISC OS>, and probably others.
263Unix, for example, is one of the few OSes that has the elegant idea
264of a single root directory.
322422de 265
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266DOS, OS/2, VMS, VOS, and Windows can work similarly to Unix with C</>
267as path separator, or in their own idiosyncratic ways (such as having
268several root directories and various "unrooted" device files such NIL:
269and LPT:).
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270
271S<Mac OS> uses C<:> as a path separator instead of C</>.
272
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273The filesystem may support neither hard links (C<link>) nor
274symbolic links (C<symlink>, C<readlink>, C<lstat>).
433acd8a 275
6ab3f9cb 276The filesystem may support neither access timestamp nor change
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277timestamp (meaning that about the only portable timestamp is the
278modification timestamp), or one second granularity of any timestamps
279(e.g. the FAT filesystem limits the time granularity to two seconds).
280
74555b7a 281The "inode change timestamp" (the C<-C> filetest) may really be the
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282"creation timestamp" (which it is not in UNIX).
283
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284VOS perl can emulate Unix filenames with C</> as path separator. The
285native pathname characters greater-than, less-than, number-sign, and
286percent-sign are always accepted.
287
6ab3f9cb 288S<RISC OS> perl can emulate Unix filenames with C</> as path
322422de 289separator, or go native and use C<.> for path separator and C<:> to
6ab3f9cb 290signal filesystems and disk names.
e41182b5 291
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292Don't assume UNIX filesystem access semantics: that read, write,
293and execute are all the permissions there are, and even if they exist,
294that their semantics (for example what do r, w, and x mean on
295a directory) are the UNIX ones. The various UNIX/POSIX compatibility
296layers usually try to make interfaces like chmod() work, but sometimes
297there simply is no good mapping.
298
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299If all this is intimidating, have no (well, maybe only a little)
300fear. There are modules that can help. The File::Spec modules
301provide methods to do the Right Thing on whatever platform happens
302to be running the program.
e41182b5 303
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304 use File::Spec::Functions;
305 chdir(updir()); # go up one directory
306 $file = catfile(curdir(), 'temp', 'file.txt');
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307 # on Unix and Win32, './temp/file.txt'
308 # on Mac OS, ':temp:file.txt'
d1e3b762 309 # on VMS, '[.temp]file.txt'
e41182b5 310
b7df3edc 311File::Spec is available in the standard distribution as of version
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3125.004_05. File::Spec::Functions is only in File::Spec 0.7 and later,
313and some versions of perl come with version 0.6. If File::Spec
314is not updated to 0.7 or later, you must use the object-oriented
315interface from File::Spec (or upgrade File::Spec).
e41182b5 316
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317In general, production code should not have file paths hardcoded.
318Making them user-supplied or read from a configuration file is
319better, keeping in mind that file path syntax varies on different
320machines.
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321
322This is especially noticeable in scripts like Makefiles and test suites,
323which often assume C</> as a path separator for subdirectories.
324
b7df3edc 325Also of use is File::Basename from the standard distribution, which
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326splits a pathname into pieces (base filename, full path to directory,
327and file suffix).
328
19799a22 329Even when on a single platform (if you can call Unix a single platform),
b7df3edc 330remember not to count on the existence or the contents of particular
3c075c7d 331system-specific files or directories, like F</etc/passwd>,
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332F</etc/sendmail.conf>, F</etc/resolv.conf>, or even F</tmp/>. For
333example, F</etc/passwd> may exist but not contain the encrypted
334passwords, because the system is using some form of enhanced security.
335Or it may not contain all the accounts, because the system is using NIS.
3c075c7d 336If code does need to rely on such a file, include a description of the
b7df3edc 337file and its format in the code's documentation, then make it easy for
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338the user to override the default location of the file.
339
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340Don't assume a text file will end with a newline. They should,
341but people forget.
e41182b5 342
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343Do not have two files or directories of the same name with different
344case, like F<test.pl> and F<Test.pl>, as many platforms have
345case-insensitive (or at least case-forgiving) filenames. Also, try
346not to have non-word characters (except for C<.>) in the names, and
347keep them to the 8.3 convention, for maximum portability, onerous a
348burden though this may appear.
dd9f0070 349
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350Likewise, when using the AutoSplit module, try to keep your functions to
3518.3 naming and case-insensitive conventions; or, at the least,
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352make it so the resulting files have a unique (case-insensitively)
353first 8 characters.
354
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355Whitespace in filenames is tolerated on most systems, but not all,
356and even on systems where it might be tolerated, some utilities
fe829689 357might become confused by such whitespace.
ec481373 358
b7df3edc 359Many systems (DOS, VMS) cannot have more than one C<.> in their filenames.
433acd8a 360
c47ff5f1 361Don't assume C<< > >> won't be the first character of a filename.
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362Always use C<< < >> explicitly to open a file for reading, or even
363better, use the three-arg version of open, unless you want the user to
364be able to specify a pipe open.
0a47030a 365
fe829689 366 open(FILE, '<', $existing_file) or die $!;
0a47030a 367
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368If filenames might use strange characters, it is safest to open it
369with C<sysopen> instead of C<open>. C<open> is magic and can
c47ff5f1 370translate characters like C<< > >>, C<< < >>, and C<|>, which may
b7df3edc 371be the wrong thing to do. (Sometimes, though, it's the right thing.)
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372Three-arg open can also help protect against this translation in cases
373where it is undesirable.
e41182b5 374
ec481373 375Don't use C<:> as a part of a filename since many systems use that for
8939ba94 376their own semantics (Mac OS Classic for separating pathname components,
ec481373 377many networking schemes and utilities for separating the nodename and
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378the pathname, and so on). For the same reasons, avoid C<@>, C<;> and
379C<|>.
ec481373 380
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381Don't assume that in pathnames you can collapse two leading slashes
382C<//> into one: some networking and clustering filesystems have special
383semantics for that. Let the operating system to sort it out.
384
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385The I<portable filename characters> as defined by ANSI C are
386
387 a b c d e f g h i j k l m n o p q r t u v w x y z
388 A B C D E F G H I J K L M N O P Q R T U V W X Y Z
389 0 1 2 3 4 5 6 7 8 9
390 . _ -
391
08fef530 392and the "-" shouldn't be the first character. If you want to be
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393hypercorrect, stay case-insensitive and within the 8.3 naming
394convention (all the files and directories have to be unique within one
395directory if their names are lowercased and truncated to eight
396characters before the C<.>, if any, and to three characters after the
397C<.>, if any). (And do not use C<.>s in directory names.)
ec481373 398
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399=head2 System Interaction
400
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401Not all platforms provide a command line. These are usually platforms
402that rely primarily on a Graphical User Interface (GUI) for user
403interaction. A program requiring a command line interface might
404not work everywhere. This is probably for the user of the program
405to deal with, so don't stay up late worrying about it.
e41182b5 406
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407Some platforms can't delete or rename files held open by the system.
408Remember to C<close> files when you are done with them. Don't
409C<unlink> or C<rename> an open file. Don't C<tie> or C<open> a
410file already tied or opened; C<untie> or C<close> it first.
e41182b5 411
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412Don't open the same file more than once at a time for writing, as some
413operating systems put mandatory locks on such files.
414
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415Don't assume that write/modify permission on a directory gives the
416right to add or delete files/directories in that directory. That is
417filesystem specific: in some filesystems you need write/modify
418permission also (or even just) in the file/directory itself. In some
419filesystems (AFS, DFS) the permission to add/delete directory entries
420is a completely separate permission.
421
422Don't assume that a single C<unlink> completely gets rid of the file:
423some filesystems (most notably the ones in VMS) have versioned
424filesystems, and unlink() removes only the most recent one (it doesn't
425remove all the versions because by default the native tools on those
426platforms remove just the most recent version, too). The portable
427idiom to remove all the versions of a file is
428
94bb614c 429 1 while unlink "file";
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430
431This will terminate if the file is undeleteable for some reason
432(protected, not there, and so on).
433
e41182b5 434Don't count on a specific environment variable existing in C<%ENV>.
0a47030a 435Don't count on C<%ENV> entries being case-sensitive, or even
4a0d0822 436case-preserving. Don't try to clear %ENV by saying C<%ENV = ();>, or,
6be8f7a6 437if you really have to, make it conditional on C<$^O ne 'VMS'> since in
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438VMS the C<%ENV> table is much more than a per-process key-value string
439table.
e41182b5 440
d1e3b762 441Don't count on signals or C<%SIG> for anything.
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442
443Don't count on filename globbing. Use C<opendir>, C<readdir>, and
444C<closedir> instead.
445
b8099c3d 446Don't count on per-program environment variables, or per-program current
dd9f0070 447directories.
b8099c3d 448
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449Don't count on specific values of C<$!>.
450
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451=head2 Command names versus file pathnames
452
453Don't assume that the name used to invoke a command or program with
454C<system> or C<exec> can also be used to test for the existence of the
455file that holds the executable code for that command or program.
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456First, many systems have "internal" commands that are built-in to the
457shell or OS and while these commands can be invoked, there is no
458corresponding file. Second, some operating systems (e.g., Cygwin,
459DJGPP, OS/2, and VOS) have required suffixes for executable files;
460these suffixes are generally permitted on the command name but are not
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461required. Thus, a command like "perl" might exist in a file named
462"perl", "perl.exe", or "perl.pm", depending on the operating system.
463The variable "_exe" in the Config module holds the executable suffix,
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464if any. Third, the VMS port carefully sets up $^X and
465$Config{perlpath} so that no further processing is required. This is
466just as well, because the matching regular expression used below would
467then have to deal with a possible trailing version number in the VMS
468file name.
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469
470To convert $^X to a file pathname, taking account of the requirements
471of the various operating system possibilities, say:
472 use Config;
a10d74f3 473 $thisperl = $^X;
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474 if ($^O ne 'VMS')
475 {$thisperl .= $Config{_exe} unless $thisperl =~ m/$Config{_exe}$/i;}
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476
477To convert $Config{perlpath} to a file pathname, say:
a10d74f3 478 use Config;
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479 $thisperl = $Config{perlpath};
480 if ($^O ne 'VMS')
481 {$thisperl .= $Config{_exe} unless $thisperl =~ m/$Config{_exe}$/i;}
a10d74f3 482
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483=head2 Interprocess Communication (IPC)
484
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485In general, don't directly access the system in code meant to be
486portable. That means, no C<system>, C<exec>, C<fork>, C<pipe>,
487C<``>, C<qx//>, C<open> with a C<|>, nor any of the other things
488that makes being a perl hacker worth being.
e41182b5
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489
490Commands that launch external processes are generally supported on
b7df3edc
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491most platforms (though many of them do not support any type of
492forking). The problem with using them arises from what you invoke
493them on. External tools are often named differently on different
4375e838 494platforms, may not be available in the same location, might accept
b7df3edc
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495different arguments, can behave differently, and often present their
496results in a platform-dependent way. Thus, you should seldom depend
497on them to produce consistent results. (Then again, if you're calling
498I<netstat -a>, you probably don't expect it to run on both Unix and CP/M.)
e41182b5 499
b7df3edc 500One especially common bit of Perl code is opening a pipe to B<sendmail>:
e41182b5 501
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502 open(MAIL, '|/usr/lib/sendmail -t')
503 or die "cannot fork sendmail: $!";
e41182b5
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504
505This is fine for systems programming when sendmail is known to be
506available. But it is not fine for many non-Unix systems, and even
507some Unix systems that may not have sendmail installed. If a portable
b7df3edc
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508solution is needed, see the various distributions on CPAN that deal
509with it. Mail::Mailer and Mail::Send in the MailTools distribution are
510commonly used, and provide several mailing methods, including mail,
511sendmail, and direct SMTP (via Net::SMTP) if a mail transfer agent is
512not available. Mail::Sendmail is a standalone module that provides
513simple, platform-independent mailing.
514
515The Unix System V IPC (C<msg*(), sem*(), shm*()>) is not available
516even on all Unix platforms.
e41182b5 517
a81e5e2e
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518Do not use either the bare result of C<pack("N", 10, 20, 30, 40)> or
519bare v-strings (such as C<v10.20.30.40>) to represent IPv4 addresses:
520both forms just pack the four bytes into network order. That this
521would be equal to the C language C<in_addr> struct (which is what the
522socket code internally uses) is not guaranteed. To be portable use
523the routines of the Socket extension, such as C<inet_aton()>,
524C<inet_ntoa()>, and C<sockaddr_in()>.
6b2463a0 525
e41182b5 526The rule of thumb for portable code is: Do it all in portable Perl, or
0a47030a
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527use a module (that may internally implement it with platform-specific
528code, but expose a common interface).
e41182b5 529
e41182b5
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530=head2 External Subroutines (XS)
531
b7df3edc 532XS code can usually be made to work with any platform, but dependent
e41182b5
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533libraries, header files, etc., might not be readily available or
534portable, or the XS code itself might be platform-specific, just as Perl
535code might be. If the libraries and headers are portable, then it is
536normally reasonable to make sure the XS code is portable, too.
537
b7df3edc
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
cc07ed0b
PG
1096Perl on VOS can be built using two different compilers and two different
1097versions of the POSIX runtime. The recommended method for building full
1098Perl is with the GNU C compiler and the generally-available version of
1099VOS POSIX support. See F<README.vos> (installed as L<perlvos>) for
1100restrictions that apply when Perl is built using the VOS Standard C
1101compiler or the alpha version of VOS POSIX support.
495c5fdc
GP
1102
1103The value of C<$^O> on VOS is "VOS". To determine the architecture that
1104you are running on without resorting to loading all of C<%Config> you
c997b287 1105can examine the content of the @INC array like so:
495c5fdc 1106
24e8e380 1107 if ($^O =~ /VOS/) {
495c5fdc
GP
1108 print "I'm on a Stratus box!\n";
1109 } else {
1110 print "I'm not on a Stratus box!\n";
1111 die;
1112 }
1113
1114 if (grep(/860/, @INC)) {
1115 print "This box is a Stratus XA/R!\n";
6ab3f9cb 1116
495c5fdc 1117 } elsif (grep(/7100/, @INC)) {
24e8e380 1118 print "This box is a Stratus HP 7100 or 8xxx!\n";
6ab3f9cb 1119
495c5fdc 1120 } elsif (grep(/8000/, @INC)) {
24e8e380 1121 print "This box is a Stratus HP 8xxx!\n";
6ab3f9cb 1122
495c5fdc 1123 } else {
24e8e380 1124 print "This box is a Stratus 68K!\n";
495c5fdc
GP
1125 }
1126
1127Also see:
1128
1129=over 4
1130
c997b287 1131=item *
495c5fdc 1132
cc07ed0b 1133F<README.vos> (installed as L<perlvos>)
c997b287
GS
1134
1135=item *
1136
1137The VOS mailing list.
495c5fdc
GP
1138
1139There is no specific mailing list for Perl on VOS. You can post
1140comments to the comp.sys.stratus newsgroup, or subscribe to the general
cc07ed0b 1141Stratus mailing list. Send a letter with "subscribe Info-Stratus" in
495c5fdc
GP
1142the message body to majordomo@list.stratagy.com.
1143
c997b287
GS
1144=item *
1145
cc07ed0b 1146VOS Perl on the web at http://ftp.stratus.com/pub/vos/posix/posix.html
495c5fdc
GP
1147
1148=back
1149
e41182b5
GS
1150=head2 EBCDIC Platforms
1151
1152Recent versions of Perl have been ported to platforms such as OS/400 on
d1e3b762
GS
1153AS/400 minicomputers as well as OS/390, VM/ESA, and BS2000 for S/390
1154Mainframes. Such computers use EBCDIC character sets internally (usually
0cc436d0
GS
1155Character Code Set ID 0037 for OS/400 and either 1047 or POSIX-BC for S/390
1156systems). On the mainframe perl currently works under the "Unix system
1157services for OS/390" (formerly known as OpenEdition), VM/ESA OpenEdition, or
1158the BS200 POSIX-BC system (BS2000 is supported in perl 5.6 and greater).
c997b287 1159See L<perlos390> for details.
e41182b5 1160
7c5ffed3
JH
1161As of R2.5 of USS for OS/390 and Version 2.3 of VM/ESA these Unix
1162sub-systems do not support the C<#!> shebang trick for script invocation.
1163Hence, on OS/390 and VM/ESA perl scripts can be executed with a header
1164similar to the following simple script:
e41182b5
GS
1165
1166 : # use perl
1167 eval 'exec /usr/local/bin/perl -S $0 ${1+"$@"}'
1168 if 0;
1169 #!/usr/local/bin/perl # just a comment really
1170
1171 print "Hello from perl!\n";
1172
d1e3b762
GS
1173OS/390 will support the C<#!> shebang trick in release 2.8 and beyond.
1174Calls to C<system> and backticks can use POSIX shell syntax on all
1175S/390 systems.
1176
b7df3edc 1177On the AS/400, if PERL5 is in your library list, you may need
6ab3f9cb
GS
1178to wrap your perl scripts in a CL procedure to invoke them like so:
1179
1180 BEGIN
1181 CALL PGM(PERL5/PERL) PARM('/QOpenSys/hello.pl')
1182 ENDPGM
1183
1184This will invoke the perl script F<hello.pl> in the root of the
1185QOpenSys file system. On the AS/400 calls to C<system> or backticks
1186must use CL syntax.
1187
e41182b5 1188On these platforms, bear in mind that the EBCDIC character set may have
0a47030a
GS
1189an effect on what happens with some perl functions (such as C<chr>,
1190C<pack>, C<print>, C<printf>, C<ord>, C<sort>, C<sprintf>, C<unpack>), as
1191well as bit-fiddling with ASCII constants using operators like C<^>, C<&>
1192and C<|>, not to mention dealing with socket interfaces to ASCII computers
6ab3f9cb 1193(see L<"Newlines">).
e41182b5 1194
b7df3edc
GS
1195Fortunately, most web servers for the mainframe will correctly
1196translate the C<\n> in the following statement to its ASCII equivalent
1197(C<\r> is the same under both Unix and OS/390 & VM/ESA):
e41182b5
GS
1198
1199 print "Content-type: text/html\r\n\r\n";
1200
d1e3b762 1201The values of C<$^O> on some of these platforms includes:
e41182b5 1202
d1e3b762
GS
1203 uname $^O $Config{'archname'}
1204 --------------------------------------------
1205 OS/390 os390 os390
1206 OS400 os400 os400
1207 POSIX-BC posix-bc BS2000-posix-bc
1208 VM/ESA vmesa vmesa
3c075c7d 1209
e41182b5
GS
1210Some simple tricks for determining if you are running on an EBCDIC
1211platform could include any of the following (perhaps all):
1212
1213 if ("\t" eq "\05") { print "EBCDIC may be spoken here!\n"; }
1214
1215 if (ord('A') == 193) { print "EBCDIC may be spoken here!\n"; }
1216
1217 if (chr(169) eq 'z') { print "EBCDIC may be spoken here!\n"; }
1218
b7df3edc 1219One thing you may not want to rely on is the EBCDIC encoding
0a47030a
GS
1220of punctuation characters since these may differ from code page to code
1221page (and once your module or script is rumoured to work with EBCDIC,
1222folks will want it to work with all EBCDIC character sets).
e41182b5
GS
1223
1224Also see:
1225
1226=over 4
1227
c997b287
GS
1228=item *
1229
1230*
d1e3b762 1231
dc5c060f 1232L<perlos390>, F<README.os390>, F<perlbs2000>, F<README.vmesa>,
bb462878 1233L<perlebcdic>.
c997b287
GS
1234
1235=item *
e41182b5
GS
1236
1237The perl-mvs@perl.org list is for discussion of porting issues as well as
1238general usage issues for all EBCDIC Perls. Send a message body of
1239"subscribe perl-mvs" to majordomo@perl.org.
1240
c997b287
GS
1241=item *
1242
1243AS/400 Perl information at
b1866b2d 1244http://as400.rochester.ibm.com/
d1e3b762 1245as well as on CPAN in the F<ports/> directory.
e41182b5
GS
1246
1247=back
1248
b8099c3d
CN
1249=head2 Acorn RISC OS
1250
b7df3edc
GS
1251Because Acorns use ASCII with newlines (C<\n>) in text files as C<\012> like
1252Unix, and because Unix filename emulation is turned on by default,
1253most simple scripts will probably work "out of the box". The native
6ab3f9cb 1254filesystem is modular, and individual filesystems are free to be
0a47030a 1255case-sensitive or insensitive, and are usually case-preserving. Some
b7df3edc 1256native filesystems have name length limits, which file and directory
6ab3f9cb
GS
1257names are silently truncated to fit. Scripts should be aware that the
1258standard filesystem currently has a name length limit of B<10>
1259characters, with up to 77 items in a directory, but other filesystems
0a47030a 1260may not impose such limitations.
b8099c3d
CN
1261
1262Native filenames are of the form
1263
6ab3f9cb 1264 Filesystem#Special_Field::DiskName.$.Directory.Directory.File
dd9f0070 1265
b8099c3d
CN
1266where
1267
1268 Special_Field is not usually present, but may contain . and $ .
1269 Filesystem =~ m|[A-Za-z0-9_]|
1270 DsicName =~ m|[A-Za-z0-9_/]|
1271 $ represents the root directory
1272 . is the path separator
1273 @ is the current directory (per filesystem but machine global)
1274 ^ is the parent directory
1275 Directory and File =~ m|[^\0- "\.\$\%\&:\@\\^\|\177]+|
1276
1277The default filename translation is roughly C<tr|/.|./|;>
1278
6ab3f9cb 1279Note that C<"ADFS::HardDisk.$.File" ne 'ADFS::HardDisk.$.File'> and that
0a47030a
GS
1280the second stage of C<$> interpolation in regular expressions will fall
1281foul of the C<$.> if scripts are not careful.
1282
1283Logical paths specified by system variables containing comma-separated
b7df3edc 1284search lists are also allowed; hence C<System:Modules> is a valid
0a47030a 1285filename, and the filesystem will prefix C<Modules> with each section of
6ab3f9cb 1286C<System$Path> until a name is made that points to an object on disk.
b7df3edc 1287Writing to a new file C<System:Modules> would be allowed only if
0a47030a
GS
1288C<System$Path> contains a single item list. The filesystem will also
1289expand system variables in filenames if enclosed in angle brackets, so
c47ff5f1 1290C<< <System$Dir>.Modules >> would look for the file
0a47030a 1291S<C<$ENV{'System$Dir'} . 'Modules'>>. The obvious implication of this is
c47ff5f1 1292that B<fully qualified filenames can start with C<< <> >>> and should
0a47030a 1293be protected when C<open> is used for input.
b8099c3d
CN
1294
1295Because C<.> was in use as a directory separator and filenames could not
1296be assumed to be unique after 10 characters, Acorn implemented the C
1297compiler to strip the trailing C<.c> C<.h> C<.s> and C<.o> suffix from
1298filenames specified in source code and store the respective files in
b7df3edc 1299subdirectories named after the suffix. Hence files are translated:
b8099c3d
CN
1300
1301 foo.h h.foo
1302 C:foo.h C:h.foo (logical path variable)
1303 sys/os.h sys.h.os (C compiler groks Unix-speak)
1304 10charname.c c.10charname
1305 10charname.o o.10charname
1306 11charname_.c c.11charname (assuming filesystem truncates at 10)
1307
1308The Unix emulation library's translation of filenames to native assumes
b7df3edc
GS
1309that this sort of translation is required, and it allows a user-defined list
1310of known suffixes that it will transpose in this fashion. This may
1311seem transparent, but consider that with these rules C<foo/bar/baz.h>
0a47030a
GS
1312and C<foo/bar/h/baz> both map to C<foo.bar.h.baz>, and that C<readdir> and
1313C<glob> cannot and do not attempt to emulate the reverse mapping. Other
6ab3f9cb 1314C<.>'s in filenames are translated to C</>.
0a47030a 1315
b7df3edc 1316As implied above, the environment accessed through C<%ENV> is global, and
0a47030a 1317the convention is that program specific environment variables are of the
6ab3f9cb
GS
1318form C<Program$Name>. Each filesystem maintains a current directory,
1319and the current filesystem's current directory is the B<global> current
b7df3edc
GS
1320directory. Consequently, sociable programs don't change the current
1321directory but rely on full pathnames, and programs (and Makefiles) cannot
0a47030a
GS
1322assume that they can spawn a child process which can change the current
1323directory without affecting its parent (and everyone else for that
1324matter).
1325
b7df3edc
GS
1326Because native operating system filehandles are global and are currently
1327allocated down from 255, with 0 being a reserved value, the Unix emulation
0a47030a
GS
1328library emulates Unix filehandles. Consequently, you can't rely on
1329passing C<STDIN>, C<STDOUT>, or C<STDERR> to your children.
1330
1331The desire of users to express filenames of the form
c47ff5f1 1332C<< <Foo$Dir>.Bar >> on the command line unquoted causes problems,
0a47030a 1333too: C<``> command output capture has to perform a guessing game. It
c47ff5f1 1334assumes that a string C<< <[^<>]+\$[^<>]> >> is a
0a47030a 1335reference to an environment variable, whereas anything else involving
c47ff5f1 1336C<< < >> or C<< > >> is redirection, and generally manages to be 99%
0a47030a
GS
1337right. Of course, the problem remains that scripts cannot rely on any
1338Unix tools being available, or that any tools found have Unix-like command
1339line arguments.
1340
b7df3edc
GS
1341Extensions and XS are, in theory, buildable by anyone using free
1342tools. In practice, many don't, as users of the Acorn platform are
1343used to binary distributions. MakeMaker does run, but no available
1344make currently copes with MakeMaker's makefiles; even if and when
1345this should be fixed, the lack of a Unix-like shell will cause
1346problems with makefile rules, especially lines of the form C<cd
1347sdbm && make all>, and anything using quoting.
b8099c3d
CN
1348
1349"S<RISC OS>" is the proper name for the operating system, but the value
1350in C<$^O> is "riscos" (because we don't like shouting).
1351
e41182b5
GS
1352=head2 Other perls
1353
b7df3edc
GS
1354Perl has been ported to many platforms that do not fit into any of
1355the categories listed above. Some, such as AmigaOS, Atari MiNT,
1356BeOS, HP MPE/iX, QNX, Plan 9, and VOS, have been well-integrated
1357into the standard Perl source code kit. You may need to see the
1358F<ports/> directory on CPAN for information, and possibly binaries,
1359for the likes of: aos, Atari ST, lynxos, riscos, Novell Netware,
1360Tandem Guardian, I<etc.> (Yes, we know that some of these OSes may
1361fall under the Unix category, but we are not a standards body.)
e41182b5 1362
d1e3b762
GS
1363Some approximate operating system names and their C<$^O> values
1364in the "OTHER" category include:
1365
1366 OS $^O $Config{'archname'}
1367 ------------------------------------------
1368 Amiga DOS amigaos m68k-amigos
cec2c193 1369 BeOS beos
d1e3b762
GS
1370 MPE/iX mpeix PA-RISC1.1
1371
e41182b5
GS
1372See also:
1373
1374=over 4
1375
c997b287
GS
1376=item *
1377
1378Amiga, F<README.amiga> (installed as L<perlamiga>).
1379
1380=item *
d1e3b762 1381
c997b287
GS
1382Atari, F<README.mint> and Guido Flohr's web page
1383http://stud.uni-sb.de/~gufl0000/
e41182b5 1384
c997b287 1385=item *
d1e3b762 1386
c997b287 1387Be OS, F<README.beos>
e41182b5 1388
c997b287
GS
1389=item *
1390
1391HP 300 MPE/iX, F<README.mpeix> and Mark Bixby's web page
34aaaa84 1392http://www.bixby.org/mark/perlix.html
c997b287
GS
1393
1394=item *
e41182b5 1395
6ab3f9cb 1396A free perl5-based PERL.NLM for Novell Netware is available in
c997b287 1397precompiled binary and source code form from http://www.novell.com/
6ab3f9cb 1398as well as from CPAN.
e41182b5 1399
13a2d996 1400=item *
c997b287
GS
1401
1402Plan 9, F<README.plan9>
d1e3b762 1403
e41182b5
GS
1404=back
1405
e41182b5
GS
1406=head1 FUNCTION IMPLEMENTATIONS
1407
b7df3edc
GS
1408Listed below are functions that are either completely unimplemented
1409or else have been implemented differently on various platforms.
1410Following each description will be, in parentheses, a list of
1411platforms that the description applies to.
e41182b5 1412
b7df3edc
GS
1413The list may well be incomplete, or even wrong in some places. When
1414in doubt, consult the platform-specific README files in the Perl
1415source distribution, and any other documentation resources accompanying
1416a given port.
e41182b5 1417
0a47030a 1418Be aware, moreover, that even among Unix-ish systems there are variations.
e41182b5 1419
b7df3edc
GS
1420For many functions, you can also query C<%Config>, exported by
1421default from the Config module. For example, to check whether the
1422platform has the C<lstat> call, check C<$Config{d_lstat}>. See
1423L<Config> for a full description of available variables.
e41182b5
GS
1424
1425=head2 Alphabetical Listing of Perl Functions
1426
1427=over 8
1428
1429=item -X FILEHANDLE
1430
1431=item -X EXPR
1432
1433=item -X
1434
b7df3edc 1435C<-r>, C<-w>, and C<-x> have a limited meaning only; directories
e41182b5 1436and applications are executable, and there are no uid/gid
b7df3edc 1437considerations. C<-o> is not supported. (S<Mac OS>)
e41182b5 1438
b7df3edc
GS
1439C<-r>, C<-w>, C<-x>, and C<-o> tell whether the file is accessible,
1440which may not reflect UIC-based file protections. (VMS)
e41182b5 1441
b8099c3d
CN
1442C<-s> returns the size of the data fork, not the total size of data fork
1443plus resource fork. (S<Mac OS>).
1444
1445C<-s> by name on an open file will return the space reserved on disk,
1446rather than the current extent. C<-s> on an open filehandle returns the
b7df3edc 1447current size. (S<RISC OS>)
b8099c3d 1448
e41182b5 1449C<-R>, C<-W>, C<-X>, C<-O> are indistinguishable from C<-r>, C<-w>,
b8099c3d 1450C<-x>, C<-o>. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1451
1452C<-b>, C<-c>, C<-k>, C<-g>, C<-p>, C<-u>, C<-A> are not implemented.
1453(S<Mac OS>)
1454
1455C<-g>, C<-k>, C<-l>, C<-p>, C<-u>, C<-A> are not particularly meaningful.
b8099c3d 1456(Win32, VMS, S<RISC OS>)
e41182b5
GS
1457
1458C<-d> is true if passed a device spec without an explicit directory.
1459(VMS)
1460
1461C<-T> and C<-B> are implemented, but might misclassify Mac text files
0a47030a 1462with foreign characters; this is the case will all platforms, but may
b7df3edc 1463affect S<Mac OS> often. (S<Mac OS>)
e41182b5
GS
1464
1465C<-x> (or C<-X>) determine if a file ends in one of the executable
b7df3edc 1466suffixes. C<-S> is meaningless. (Win32)
e41182b5 1467
b8099c3d
CN
1468C<-x> (or C<-X>) determine if a file has an executable file type.
1469(S<RISC OS>)
1470
63f87e49
GS
1471=item alarm SECONDS
1472
1473=item alarm
1474
1475Not implemented. (Win32)
1476
e41182b5
GS
1477=item binmode FILEHANDLE
1478
b7df3edc 1479Meaningless. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1480
1481Reopens file and restores pointer; if function fails, underlying
1482filehandle may be closed, or pointer may be in a different position.
1483(VMS)
1484
1485The value returned by C<tell> may be affected after the call, and
1486the filehandle may be flushed. (Win32)
1487
1488=item chmod LIST
1489
b7df3edc 1490Only limited meaning. Disabling/enabling write permission is mapped to
e41182b5
GS
1491locking/unlocking the file. (S<Mac OS>)
1492
1493Only good for changing "owner" read-write access, "group", and "other"
1494bits are meaningless. (Win32)
1495
b8099c3d
CN
1496Only good for changing "owner" and "other" read-write access. (S<RISC OS>)
1497
495c5fdc
GP
1498Access permissions are mapped onto VOS access-control list changes. (VOS)
1499
4e51f8e4 1500The actual permissions set depend on the value of the C<CYGWIN>
789f0d36 1501in the SYSTEM environment settings. (Cygwin)
4e51f8e4 1502
e41182b5
GS
1503=item chown LIST
1504
495c5fdc 1505Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>, VOS)
e41182b5
GS
1506
1507Does nothing, but won't fail. (Win32)
1508
1509=item chroot FILENAME
1510
1511=item chroot
1512
7c5ffed3 1513Not implemented. (S<Mac OS>, Win32, VMS, Plan9, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1514
1515=item crypt PLAINTEXT,SALT
1516
1517May not be available if library or source was not provided when building
b8099c3d 1518perl. (Win32)
e41182b5 1519
495c5fdc
GP
1520Not implemented. (VOS)
1521
e41182b5
GS
1522=item dbmclose HASH
1523
495c5fdc 1524Not implemented. (VMS, Plan9, VOS)
e41182b5
GS
1525
1526=item dbmopen HASH,DBNAME,MODE
1527
495c5fdc 1528Not implemented. (VMS, Plan9, VOS)
e41182b5
GS
1529
1530=item dump LABEL
1531
b8099c3d 1532Not useful. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1533
1534Not implemented. (Win32)
1535
b8099c3d 1536Invokes VMS debugger. (VMS)
e41182b5
GS
1537
1538=item exec LIST
1539
1540Not implemented. (S<Mac OS>)
1541
7c5ffed3 1542Implemented via Spawn. (VM/ESA)
3c075c7d 1543
0f897271
GS
1544Does not automatically flush output handles on some platforms.
1545(SunOS, Solaris, HP-UX)
1546
fe12c0e8
MS
1547=item exit EXPR
1548
1549=item exit
1550
1551Emulates UNIX exit() (which considers C<exit 1> to indicate an error) by
1552mapping the C<1> to SS$_ABORT (C<44>). This behavior may be overridden
1553with the pragma C<use vmsish 'exit'>. As with the CRTL's exit()
1554function, C<exit 0> is also mapped to an exit status of SS$_NORMAL
1555(C<1>); this mapping cannot be overridden. Any other argument to exit()
1556is used directly as Perl's exit status. (VMS)
1557
e41182b5
GS
1558=item fcntl FILEHANDLE,FUNCTION,SCALAR
1559
1560Not implemented. (Win32, VMS)
1561
1562=item flock FILEHANDLE,OPERATION
1563
495c5fdc 1564Not implemented (S<Mac OS>, VMS, S<RISC OS>, VOS).
e41182b5
GS
1565
1566Available only on Windows NT (not on Windows 95). (Win32)
1567
1568=item fork
1569
0f897271
GS
1570Not implemented. (S<Mac OS>, AmigaOS, S<RISC OS>, VOS, VM/ESA)
1571
1572Emulated using multiple interpreters. See L<perlfork>. (Win32)
1573
1574Does not automatically flush output handles on some platforms.
1575(SunOS, Solaris, HP-UX)
e41182b5
GS
1576
1577=item getlogin
1578
b8099c3d 1579Not implemented. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1580
1581=item getpgrp PID
1582
495c5fdc 1583Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5
GS
1584
1585=item getppid
1586
b8099c3d 1587Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1588
1589=item getpriority WHICH,WHO
1590
7c5ffed3 1591Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1592
1593=item getpwnam NAME
1594
1595Not implemented. (S<Mac OS>, Win32)
1596
b8099c3d
CN
1597Not useful. (S<RISC OS>)
1598
e41182b5
GS
1599=item getgrnam NAME
1600
b8099c3d 1601Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1602
1603=item getnetbyname NAME
1604
1605Not implemented. (S<Mac OS>, Win32, Plan9)
1606
1607=item getpwuid UID
1608
1609Not implemented. (S<Mac OS>, Win32)
1610
b8099c3d
CN
1611Not useful. (S<RISC OS>)
1612
e41182b5
GS
1613=item getgrgid GID
1614
b8099c3d 1615Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1616
1617=item getnetbyaddr ADDR,ADDRTYPE
1618
1619Not implemented. (S<Mac OS>, Win32, Plan9)
1620
1621=item getprotobynumber NUMBER
1622
1623Not implemented. (S<Mac OS>)
1624
1625=item getservbyport PORT,PROTO
1626
1627Not implemented. (S<Mac OS>)
1628
1629=item getpwent
1630
7c5ffed3 1631Not implemented. (S<Mac OS>, Win32, VM/ESA)
e41182b5
GS
1632
1633=item getgrent
1634
7c5ffed3 1635Not implemented. (S<Mac OS>, Win32, VMS, VM/ESA)
e41182b5
GS
1636
1637=item gethostent
1638
1639Not implemented. (S<Mac OS>, Win32)
1640
1641=item getnetent
1642
1643Not implemented. (S<Mac OS>, Win32, Plan9)
1644
1645=item getprotoent
1646
1647Not implemented. (S<Mac OS>, Win32, Plan9)
1648
1649=item getservent
1650
1651Not implemented. (Win32, Plan9)
1652
e41182b5
GS
1653=item sethostent STAYOPEN
1654
b8099c3d 1655Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>)
e41182b5
GS
1656
1657=item setnetent STAYOPEN
1658
b8099c3d 1659Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>)
e41182b5
GS
1660
1661=item setprotoent STAYOPEN
1662
b8099c3d 1663Not implemented. (S<Mac OS>, Win32, Plan9, S<RISC OS>)
e41182b5
GS
1664
1665=item setservent STAYOPEN
1666
b8099c3d 1667Not implemented. (Plan9, Win32, S<RISC OS>)
e41182b5
GS
1668
1669=item endpwent
1670
a3dfe201 1671Not implemented. (S<Mac OS>, MPE/iX, VM/ESA, Win32)
e41182b5
GS
1672
1673=item endgrent
1674
a3dfe201 1675Not implemented. (S<Mac OS>, MPE/iX, S<RISC OS>, VM/ESA, VMS, Win32)
e41182b5
GS
1676
1677=item endhostent
1678
1679Not implemented. (S<Mac OS>, Win32)
1680
1681=item endnetent
1682
1683Not implemented. (S<Mac OS>, Win32, Plan9)
1684
1685=item endprotoent
1686
1687Not implemented. (S<Mac OS>, Win32, Plan9)
1688
1689=item endservent
1690
1691Not implemented. (Plan9, Win32)
1692
1693=item getsockopt SOCKET,LEVEL,OPTNAME
1694
97c10e77 1695Not implemented. (Plan9)
e41182b5
GS
1696
1697=item glob EXPR
1698
1699=item glob
1700
63f87e49
GS
1701This operator is implemented via the File::Glob extension on most
1702platforms. See L<File::Glob> for portability information.
b8099c3d 1703
e41182b5
GS
1704=item ioctl FILEHANDLE,FUNCTION,SCALAR
1705
1706Not implemented. (VMS)
1707
1708Available only for socket handles, and it does what the ioctlsocket() call
1709in the Winsock API does. (Win32)
1710
b8099c3d
CN
1711Available only for socket handles. (S<RISC OS>)
1712
b350dd2f 1713=item kill SIGNAL, LIST
e41182b5 1714
862b5365
JH
1715C<kill(0, LIST)> is implemented for the sake of taint checking;
1716use with other signals is unimplemented. (S<Mac OS>)
1717
1718Not implemented, hence not useful for taint checking. (S<RISC OS>)
e41182b5 1719
63f87e49
GS
1720C<kill()> doesn't have the semantics of C<raise()>, i.e. it doesn't send
1721a signal to the identified process like it does on Unix platforms.
1722Instead C<kill($sig, $pid)> terminates the process identified by $pid,
1723and makes it exit immediately with exit status $sig. As in Unix, if
1724$sig is 0 and the specified process exists, it returns true without
1725actually terminating it. (Win32)
e41182b5
GS
1726
1727=item link OLDFILE,NEWFILE
1728
a3dfe201 1729Not implemented. (S<Mac OS>, MPE/iX, VMS, S<RISC OS>)
e41182b5 1730
433acd8a
JH
1731Link count not updated because hard links are not quite that hard
1732(They are sort of half-way between hard and soft links). (AmigaOS)
1733
a3dfe201
GS
1734Hard links are implemented on Win32 (Windows NT and Windows 2000)
1735under NTFS only.
1736
e41182b5
GS
1737=item lstat FILEHANDLE
1738
1739=item lstat EXPR
1740
1741=item lstat
1742
b8099c3d 1743Not implemented. (VMS, S<RISC OS>)
e41182b5 1744
63f87e49 1745Return values (especially for device and inode) may be bogus. (Win32)
e41182b5
GS
1746
1747=item msgctl ID,CMD,ARG
1748
1749=item msgget KEY,FLAGS
1750
1751=item msgsnd ID,MSG,FLAGS
1752
1753=item msgrcv ID,VAR,SIZE,TYPE,FLAGS
1754
495c5fdc 1755Not implemented. (S<Mac OS>, Win32, VMS, Plan9, S<RISC OS>, VOS)
e41182b5
GS
1756
1757=item open FILEHANDLE,EXPR
1758
1759=item open FILEHANDLE
1760
b7df3edc 1761The C<|> variants are supported only if ToolServer is installed.
e41182b5
GS
1762(S<Mac OS>)
1763
c47ff5f1 1764open to C<|-> and C<-|> are unsupported. (S<Mac OS>, Win32, S<RISC OS>)
e41182b5 1765
0f897271
GS
1766Opening a process does not automatically flush output handles on some
1767platforms. (SunOS, Solaris, HP-UX)
1768
e41182b5
GS
1769=item pipe READHANDLE,WRITEHANDLE
1770
433acd8a
JH
1771Very limited functionality. (MiNT)
1772
e41182b5
GS
1773=item readlink EXPR
1774
1775=item readlink
1776
b8099c3d 1777Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5
GS
1778
1779=item select RBITS,WBITS,EBITS,TIMEOUT
1780
689c5c24 1781Only implemented on sockets. (Win32, VMS)
e41182b5 1782
b8099c3d
CN
1783Only reliable on sockets. (S<RISC OS>)
1784
76e05f0b 1785Note that the C<select FILEHANDLE> form is generally portable.
63f87e49 1786
e41182b5
GS
1787=item semctl ID,SEMNUM,CMD,ARG
1788
1789=item semget KEY,NSEMS,FLAGS
1790
1791=item semop KEY,OPSTRING
1792
495c5fdc 1793Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1794
a3dfe201
GS
1795=item setgrent
1796
74555b7a 1797Not implemented. (S<Mac OS>, MPE/iX, VMS, Win32, VMS, S<RISC OS>)
a3dfe201 1798
e41182b5
GS
1799=item setpgrp PID,PGRP
1800
495c5fdc 1801Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5
GS
1802
1803=item setpriority WHICH,WHO,PRIORITY
1804
495c5fdc 1805Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1806
a3dfe201
GS
1807=item setpwent
1808
74555b7a 1809Not implemented. (S<Mac OS>, MPE/iX, Win32, S<RISC OS>)
a3dfe201 1810
e41182b5
GS
1811=item setsockopt SOCKET,LEVEL,OPTNAME,OPTVAL
1812
97c10e77 1813Not implemented. (Plan9)
e41182b5
GS
1814
1815=item shmctl ID,CMD,ARG
1816
1817=item shmget KEY,SIZE,FLAGS
1818
1819=item shmread ID,VAR,POS,SIZE
1820
1821=item shmwrite ID,STRING,POS,SIZE
1822
495c5fdc 1823Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1824
80cbd5ad
JH
1825=item sockatmark SOCKET
1826
1827A relatively recent addition to socket functions, may not
1828be implemented even in UNIX platforms.
1829
e41182b5
GS
1830=item socketpair SOCKET1,SOCKET2,DOMAIN,TYPE,PROTOCOL
1831
862b5365 1832Not implemented. (Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1833
1834=item stat FILEHANDLE
1835
1836=item stat EXPR
1837
1838=item stat
1839
d62e1b7f
JH
1840Platforms that do not have rdev, blksize, or blocks will return these
1841as '', so numeric comparison or manipulation of these fields may cause
1842'not numeric' warnings.
1843
e41182b5 1844mtime and atime are the same thing, and ctime is creation time instead of
3f1f789b
JH
1845inode change time. (S<Mac OS>).
1846
1847ctime not supported on UFS (S<Mac OS X>).
e41182b5 1848
95a3fe12
MS
1849ctime is creation time instead of inode change time (Win32).
1850
e41182b5
GS
1851device and inode are not meaningful. (Win32)
1852
1853device and inode are not necessarily reliable. (VMS)
1854
b8099c3d
CN
1855mtime, atime and ctime all return the last modification time. Device and
1856inode are not necessarily reliable. (S<RISC OS>)
1857
d62e1b7f
JH
1858dev, rdev, blksize, and blocks are not available. inode is not
1859meaningful and will differ between stat calls on the same file. (os2)
1860
73e9292c
JH
1861some versions of cygwin when doing a stat("foo") and if not finding it
1862may then attempt to stat("foo.exe") (Cygwin)
1863
e41182b5
GS
1864=item symlink OLDFILE,NEWFILE
1865
b8099c3d 1866Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5
GS
1867
1868=item syscall LIST
1869
7c5ffed3 1870Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5 1871
f34d0673
GS
1872=item sysopen FILEHANDLE,FILENAME,MODE,PERMS
1873
dd9f0070 1874The traditional "0", "1", and "2" MODEs are implemented with different
322422de
GS
1875numeric values on some systems. The flags exported by C<Fcntl>
1876(O_RDONLY, O_WRONLY, O_RDWR) should work everywhere though. (S<Mac
7c5ffed3 1877OS>, OS/390, VM/ESA)
f34d0673 1878
e41182b5
GS
1879=item system LIST
1880
9d6eb86e 1881In general, do not assume the UNIX/POSIX semantics that you can shift
7717d0e7 1882C<$?> right by eight to get the exit value, or that C<$? & 127>
9d6eb86e
JH
1883would give you the number of the signal that terminated the program,
1884or that C<$? & 128> would test true if the program was terminated by a
1885coredump. Instead, use the POSIX W*() interfaces: for example, use
74555b7a
PP
1886WIFEXITED($?) and WEXITVALUE($?) to test for a normal exit and the exit
1887value, WIFSIGNALED($?) and WTERMSIG($?) for a signal exit and the
7717d0e7 1888signal. Core dumping is not a portable concept, so there's no portable
9d6eb86e
JH
1889way to test for that.
1890
e41182b5
GS
1891Only implemented if ToolServer is installed. (S<Mac OS>)
1892
1893As an optimization, may not call the command shell specified in
b7df3edc 1894C<$ENV{PERL5SHELL}>. C<system(1, @args)> spawns an external
e41182b5
GS
1895process and immediately returns its process designator, without
1896waiting for it to terminate. Return value may be used subsequently
63f87e49
GS
1897in C<wait> or C<waitpid>. Failure to spawn() a subprocess is indicated
1898by setting $? to "255 << 8". C<$?> is set in a way compatible with
1899Unix (i.e. the exitstatus of the subprocess is obtained by "$? >> 8",
1900as described in the documentation). (Win32)
e41182b5 1901
b8099c3d
CN
1902There is no shell to process metacharacters, and the native standard is
1903to pass a command line terminated by "\n" "\r" or "\0" to the spawned
c47ff5f1 1904program. Redirection such as C<< > foo >> is performed (if at all) by
b8099c3d
CN
1905the run time library of the spawned program. C<system> I<list> will call
1906the Unix emulation library's C<exec> emulation, which attempts to provide
1907emulation of the stdin, stdout, stderr in force in the parent, providing
1908the child program uses a compatible version of the emulation library.
1909I<scalar> will call the native command line direct and no such emulation
1910of a child Unix program will exists. Mileage B<will> vary. (S<RISC OS>)
1911
433acd8a
JH
1912Far from being POSIX compliant. Because there may be no underlying
1913/bin/sh tries to work around the problem by forking and execing the
9b63e9ec 1914first token in its argument string. Handles basic redirection
c47ff5f1 1915("<" or ">") on its own behalf. (MiNT)
433acd8a 1916
0f897271
GS
1917Does not automatically flush output handles on some platforms.
1918(SunOS, Solaris, HP-UX)
1919
9bc98430
CB
1920The return value is POSIX-like (shifted up by 8 bits), which only allows
1921room for a made-up value derived from the severity bits of the native
192232-bit condition code (unless overridden by C<use vmsish 'status'>).
1923For more details see L<perlvms/$?>. (VMS)
1924
e41182b5
GS
1925=item times
1926
1927Only the first entry returned is nonzero. (S<Mac OS>)
1928
63f87e49
GS
1929"cumulative" times will be bogus. On anything other than Windows NT
1930or Windows 2000, "system" time will be bogus, and "user" time is
1931actually the time returned by the clock() function in the C runtime
1932library. (Win32)
e41182b5 1933
b8099c3d
CN
1934Not useful. (S<RISC OS>)
1935
e41182b5
GS
1936=item truncate FILEHANDLE,LENGTH
1937
1938=item truncate EXPR,LENGTH
1939
6d738113 1940Not implemented. (Older versions of VMS)
e41182b5 1941
495c5fdc
GP
1942Truncation to zero-length only. (VOS)
1943
4cfdb94f 1944If a FILEHANDLE is supplied, it must be writable and opened in append
e71a7dc8 1945mode (i.e., use C<<< open(FH, '>>filename') >>>
4cfdb94f
GS
1946or C<sysopen(FH,...,O_APPEND|O_RDWR)>. If a filename is supplied, it
1947should not be held open elsewhere. (Win32)
1948
e41182b5
GS
1949=item umask EXPR
1950
1951=item umask
1952
1953Returns undef where unavailable, as of version 5.005.
1954
b7df3edc
GS
1955C<umask> works but the correct permissions are set only when the file
1956is finally closed. (AmigaOS)
433acd8a 1957
e41182b5
GS
1958=item utime LIST
1959
15c65113 1960Only the modification time is updated. (S<BeOS>, S<Mac OS>, VMS, S<RISC OS>)
e41182b5 1961
322422de
GS
1962May not behave as expected. Behavior depends on the C runtime
1963library's implementation of utime(), and the filesystem being
1964used. The FAT filesystem typically does not support an "access
1965time" field, and it may limit timestamps to a granularity of
1966two seconds. (Win32)
e41182b5
GS
1967
1968=item wait
1969
1970=item waitpid PID,FLAGS
1971
495c5fdc 1972Not implemented. (S<Mac OS>, VOS)
e41182b5
GS
1973
1974Can only be applied to process handles returned for processes spawned
a6f858fb 1975using C<system(1, ...)> or pseudo processes created with C<fork()>. (Win32)
e41182b5 1976
b8099c3d
CN
1977Not useful. (S<RISC OS>)
1978
e41182b5
GS
1979=back
1980
b8099c3d
CN
1981=head1 CHANGES
1982
1983=over 4
1984
fd46a41b
JH
1985=item v1.48, 02 February 2001
1986
1987Various updates from perl5-porters over the past year, supported
1988platforms update from Jarkko Hietaniemi.
1989
c997b287
GS
1990=item v1.47, 22 March 2000
1991
1992Various cleanups from Tom Christiansen, including migration of
1993long platform listings from L<perl>.
1994
56d7751a
GS
1995=item v1.46, 12 February 2000
1996
1997Updates for VOS and MPE/iX. (Peter Prymmer) Other small changes.
1998
0cc436d0
GS
1999=item v1.45, 20 December 1999
2000
2001Small changes from 5.005_63 distribution, more changes to EBCDIC info.
2002
d1e3b762
GS
2003=item v1.44, 19 July 1999
2004
2005A bunch of updates from Peter Prymmer for C<$^O> values,
2006endianness, File::Spec, VMS, BS2000, OS/400.
2007
b7df3edc
GS
2008=item v1.43, 24 May 1999
2009
2010Added a lot of cleaning up from Tom Christiansen.
2011
19799a22 2012=item v1.42, 22 May 1999
b7df3edc 2013
19799a22 2014Added notes about tests, sprintf/printf, and epoch offsets.
b7df3edc 2015
6ab3f9cb
GS
2016=item v1.41, 19 May 1999
2017
2018Lots more little changes to formatting and content.
2019
d1e3b762 2020Added a bunch of C<$^O> and related values
6ab3f9cb
GS
2021for various platforms; fixed mail and web addresses, and added
2022and changed miscellaneous notes. (Peter Prymmer)
2023
2024=item v1.40, 11 April 1999
2025
2026Miscellaneous changes.
2027
2028=item v1.39, 11 February 1999
2ee0eb3c
CN
2029
2030Changes from Jarkko and EMX URL fixes Michael Schwern. Additional
2031note about newlines added.
2032
9b63e9ec
CN
2033=item v1.38, 31 December 1998
2034
2035More changes from Jarkko.
2036
3c075c7d
CN
2037=item v1.37, 19 December 1998
2038
2039More minor changes. Merge two separate version 1.35 documents.
2040
2041=item v1.36, 9 September 1998
2042
2043Updated for Stratus VOS. Also known as version 1.35.
2044
2045=item v1.35, 13 August 1998
495c5fdc 2046
3c075c7d
CN
2047Integrate more minor changes, plus addition of new sections under
2048L<"ISSUES">: L<"Numbers endianness and Width">,
2049L<"Character sets and character encoding">,
2050L<"Internationalisation">.
495c5fdc 2051
3c075c7d 2052=item v1.33, 06 August 1998
0a47030a
GS
2053
2054Integrate more minor changes.
2055
3c075c7d 2056=item v1.32, 05 August 1998
dd9f0070
CN
2057
2058Integrate more minor changes.
2059
3c075c7d 2060=item v1.30, 03 August 1998
b8099c3d
CN
2061
2062Major update for RISC OS, other minor changes.
2063
3c075c7d 2064=item v1.23, 10 July 1998
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CN
2065
2066First public release with perl5.005.
2067
2068=back
e41182b5 2069
ba58ab26
JH
2070=head1 Supported Platforms
2071
cec2c193
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2072As of June 2002 (the Perl release 5.8.0), the following platforms are
2073able to build Perl from the standard source code distribution
2074available at http://www.cpan.org/src/index.html
2075
2076 AIX
2077 BeOS
2078 Cygwin
2079 DG/UX
2080 DOS DJGPP 1)
2081 DYNIX/ptx
2082 EPOC R5
2083 FreeBSD
2084 HP-UX
2085 IRIX
2086 Linux
8939ba94
JH
2087 Mac OS Classic
2088 Mac OS X (Darwin)
cec2c193
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2089 MPE/iX
2090 NetBSD
2091 NetWare
2092 NonStop-UX
2093 ReliantUNIX (SINIX)
2094 OpenBSD
2095 OpenVMS (VMS)
2096 OS/2
2097 POSIX-BC (BS2000)
2098 QNX
2099 Solaris
bb5ad0af 2100 SUPER-UX
cec2c193
JH
2101 Tru64 UNIX (DEC OSF/1, Digital UNIX)
2102 UNICOS
2103 UNICOS/mk
2104 UTS
2105 VOS
bb5ad0af 2106 Win95/98/ME/2K/XP 2)
c40b5d1d 2107 WinCE
cec2c193
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2108 z/OS (OS/390)
2109 VM/ESA
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2110
2111 1) in DOS mode either the DOS or OS/2 ports can be used
c40b5d1d 2112 2) compilers: Borland, Cygwin (GCC), MinGW (GCC), VC6
cec2c193 2113
c40b5d1d 2114The following platforms worked with the previous releases (5.6 and
cec2c193
JH
21155.7), but we did not manage either to fix or to test these in time
2116for the 5.8.0 release. There is a very good chance that many of these
2117will work fine with the 5.8.0. The only one known for certain to be
2118broken for 5.8.0 is the AmigaOS.
2119
2120 AmigaOS
2121 DomainOS
2122 Hurd
2123 LynxOS
2124 MachTen
2125 PowerMAX
2126 SCO SV
2127 SunOS 4
2128 SVR4
2129 Unixware
2130 Windows 3.1
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2131
2132The following platforms have been known to build Perl from source in
fd46a41b
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2133the past (5.005_03 and earlier), but we haven't been able to verify
2134their status for the current release, either because the
2135hardware/software platforms are rare or because we don't have an
2136active champion on these platforms--or both. They used to work,
2137though, so go ahead and try compiling them, and let perlbug@perl.org
2138of any trouble.
ba58ab26 2139
cec2c193
JH
2140 3b1
2141 A/UX
2142 BSD/OS
2143 ConvexOS
2144 CX/UX
2145 DC/OSx
2146 DDE SMES
2147 DOS EMX
2148 Dynix
2149 EP/IX
2150 ESIX
2151 FPS
2152 GENIX
2153 Greenhills
2154 ISC
2155 MachTen 68k
2156 MiNT
2157 MPC
2158 NEWS-OS
2159 NextSTEP
2160 OpenSTEP
2161 Opus
2162 Plan 9
2163 PowerUX
2164 RISC/os
2165 SCO ODT/OSR
2166 Stellar
2167 SVR2
2168 TI1500
2169 TitanOS
2170 Ultrix
2171 Unisys Dynix
2172 Unixware
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2173
2174The following platforms have their own source code distributions and
1577cd80 2175binaries available via http://www.cpan.org/ports/
ba58ab26 2176
cec2c193 2177 Perl release
ba58ab26 2178
cec2c193
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2179 OS/400 5.005_02
2180 Tandem Guardian 5.004
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2181
2182The following platforms have only binaries available via
a93751fa 2183http://www.cpan.org/ports/index.html :
ba58ab26 2184
cec2c193 2185 Perl release
ba58ab26 2186
cec2c193
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2187 Acorn RISCOS 5.005_02
2188 AOS 5.002
2189 LynxOS 5.004_02
ba58ab26
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2190
2191Although we do suggest that you always build your own Perl from
2192the source code, both for maximal configurability and for security,
2193in case you are in a hurry you can check
a93751fa 2194http://www.cpan.org/ports/index.html for binary distributions.
ba58ab26 2195
c997b287
GS
2196=head1 SEE ALSO
2197
cec2c193 2198L<perlaix>, L<perlamiga>, L<perlapollo>, L<perlbeos>, L<perlbs2000>,
18a271bd 2199L<perlce>, L<perlcygwin>, L<perldgux>, L<perldos>, L<perlepoc>,
469e7be4 2200L<perlebcdic>, L<perlfreebsd>, L<perlhurd>, L<perlhpux>, L<perlirix>,
18a271bd
JH
2201L<perlmachten>, L<perlmacos>, L<perlmint>, L<perlmpeix>,
2202L<perlnetware>, L<perlos2>, L<perlos390>, L<perlplan9>, L<perlqnx>,
2203L<perlsolaris>, L<perltru64>, L<perlunicode>, L<perlvmesa>,
2204L<perlvms>, L<perlvos>, L<perlwin32>, and L<Win32>.
c997b287 2205
e41182b5
GS
2206=head1 AUTHORS / CONTRIBUTORS
2207
06e9666b 2208Abigail <abigail@foad.org>,
c47ff5f1
GS
2209Charles Bailey <bailey@newman.upenn.edu>,
2210Graham Barr <gbarr@pobox.com>,
2211Tom Christiansen <tchrist@perl.com>,
06e9666b 2212Nicholas Clark <nick@ccl4.org>,
c47ff5f1 2213Thomas Dorner <Thomas.Dorner@start.de>,
06e9666b
A
2214Andy Dougherty <doughera@lafayette.edu>,
2215Dominic Dunlop <domo@computer.org>,
2216Neale Ferguson <neale@vma.tabnsw.com.au>,
c47ff5f1
GS
2217David J. Fiander <davidf@mks.com>,
2218Paul Green <Paul_Green@stratus.com>,
06e9666b 2219M.J.T. Guy <mjtg@cam.ac.uk>,
61f30a5e 2220Jarkko Hietaniemi <jhi@iki.fi>,
c47ff5f1 2221Luther Huffman <lutherh@stratcom.com>,
06e9666b
A
2222Nick Ing-Simmons <nick@ing-simmons.net>,
2223Andreas J. KE<ouml>nig <a.koenig@mind.de>,
c47ff5f1
GS
2224Markus Laker <mlaker@contax.co.uk>,
2225Andrew M. Langmead <aml@world.std.com>,
2226Larry Moore <ljmoore@freespace.net>,
2227Paul Moore <Paul.Moore@uk.origin-it.com>,
2228Chris Nandor <pudge@pobox.com>,
1afc07ec 2229Matthias Neeracher <neeracher@mac.com>,
e71a7dc8 2230Philip Newton <pne@cpan.org>,
c47ff5f1
GS
2231Gary Ng <71564.1743@CompuServe.COM>,
2232Tom Phoenix <rootbeer@teleport.com>,
2233AndrE<eacute> Pirard <A.Pirard@ulg.ac.be>,
2234Peter Prymmer <pvhp@forte.com>,
2235Hugo van der Sanden <hv@crypt0.demon.co.uk>,
2236Gurusamy Sarathy <gsar@activestate.com>,
2237Paul J. Schinder <schinder@pobox.com>,
2238Michael G Schwern <schwern@pobox.com>,
06e9666b 2239Dan Sugalski <dan@sidhe.org>,
c47ff5f1 2240Nathan Torkington <gnat@frii.com>.
e41182b5 2241