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1=head1 NAME
2
3perlport - Writing portable Perl
4
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5=head1 DESCRIPTION
6
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7Perl runs on numerous operating systems. While most of them share
8much in common, they also have their own unique features.
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9
10This document is meant to help you to find out what constitutes portable
b7df3edc 11Perl code. That way once you make a decision to write portably,
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12you know where the lines are drawn, and you can stay within them.
13
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14There is a tradeoff between taking full advantage of one particular
15type of computer and taking advantage of a full range of them.
16Naturally, as you broaden your range and become more diverse, the
17common factors drop, and you are left with an increasingly smaller
18area of common ground in which you can operate to accomplish a
19particular task. Thus, when you begin attacking a problem, it is
20important to consider under which part of the tradeoff curve you
21want to operate. Specifically, you must decide whether it is
22important that the task that you are coding have the full generality
23of being portable, or whether to just get the job done right now.
24This is the hardest choice to be made. The rest is easy, because
25Perl provides many choices, whichever way you want to approach your
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26problem.
27
28Looking at it another way, writing portable code is usually about
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29willfully limiting your available choices. Naturally, it takes
30discipline and sacrifice to do that. The product of portability
31and convenience may be a constant. You have been warned.
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32
33Be aware of two important points:
34
35=over 4
36
37=item Not all Perl programs have to be portable
38
b7df3edc 39There is no reason you should not use Perl as a language to glue Unix
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40tools together, or to prototype a Macintosh application, or to manage the
41Windows registry. If it makes no sense to aim for portability for one
42reason or another in a given program, then don't bother.
43
b7df3edc 44=item Nearly all of Perl already I<is> portable
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45
46Don't be fooled into thinking that it is hard to create portable Perl
47code. It isn't. Perl tries its level-best to bridge the gaps between
48what's available on different platforms, and all the means available to
49use those features. Thus almost all Perl code runs on any machine
6ab3f9cb 50without modification. But there are some significant issues in
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51writing portable code, and this document is entirely about those issues.
52
53=back
54
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55Here's the general rule: When you approach a task commonly done
56using a whole range of platforms, think about writing portable
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57code. That way, you don't sacrifice much by way of the implementation
58choices you can avail yourself of, and at the same time you can give
59your users lots of platform choices. On the other hand, when you have to
60take advantage of some unique feature of a particular platform, as is
61often the case with systems programming (whether for Unix, Windows,
62S<Mac OS>, VMS, etc.), consider writing platform-specific code.
63
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64When the code will run on only two or three operating systems, you
65may need to consider only the differences of those particular systems.
66The important thing is to decide where the code will run and to be
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67deliberate in your decision.
68
69The material below is separated into three main sections: main issues of
70portability (L<"ISSUES">, platform-specific issues (L<"PLATFORMS">, and
b7df3edc 71built-in perl functions that behave differently on various ports
0a47030a 72(L<"FUNCTION IMPLEMENTATIONS">.
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73
74This information should not be considered complete; it includes possibly
b8099c3d 75transient information about idiosyncrasies of some of the ports, almost
b7df3edc 76all of which are in a state of constant evolution. Thus, this material
e41182b5 77should be considered a perpetual work in progress
cc07ed0b 78(C<< <IMG SRC="yellow_sign.gif" ALT="Under Construction"> >>).
e41182b5 79
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80=head1 ISSUES
81
82=head2 Newlines
83
638bc118 84In most operating systems, lines in files are terminated by newlines.
e41182b5 85Just what is used as a newline may vary from OS to OS. Unix
b7df3edc 86traditionally uses C<\012>, one type of DOSish I/O uses C<\015\012>,
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87and S<Mac OS> uses C<\015>.
88
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89Perl uses C<\n> to represent the "logical" newline, where what is
90logical may depend on the platform in use. In MacPerl, C<\n> always
91means C<\015>. In DOSish perls, C<\n> usually means C<\012>, but
92when accessing a file in "text" mode, STDIO translates it to (or
56d7751a 93from) C<\015\012>, depending on whether you're reading or writing.
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94Unix does the same thing on ttys in canonical mode. C<\015\012>
95is commonly referred to as CRLF.
96
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97A common cause of unportable programs is the misuse of chop() to trim
98newlines:
99
100 # XXX UNPORTABLE!
101 while(<FILE>) {
102 chop;
103 @array = split(/:/);
104 #...
105 }
106
8939ba94 107You can get away with this on Unix and Mac OS (they have a single
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108character end-of-line), but the same program will break under DOSish
109perls because you're only chop()ing half the end-of-line. Instead,
110chomp() should be used to trim newlines. The Dunce::Files module can
111help audit your code for misuses of chop().
112
113When dealing with binary files (or text files in binary mode) be sure
114to explicitly set $/ to the appropriate value for your file format
115before using chomp().
116
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117Because of the "text" mode translation, DOSish perls have limitations
118in using C<seek> and C<tell> on a file accessed in "text" mode.
119Stick to C<seek>-ing to locations you got from C<tell> (and no
120others), and you are usually free to use C<seek> and C<tell> even
121in "text" mode. Using C<seek> or C<tell> or other file operations
122may be non-portable. If you use C<binmode> on a file, however, you
123can usually C<seek> and C<tell> with arbitrary values in safety.
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124
125A common misconception in socket programming is that C<\n> eq C<\012>
0a47030a 126everywhere. When using protocols such as common Internet protocols,
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127C<\012> and C<\015> are called for specifically, and the values of
128the logical C<\n> and C<\r> (carriage return) are not reliable.
129
130 print SOCKET "Hi there, client!\r\n"; # WRONG
131 print SOCKET "Hi there, client!\015\012"; # RIGHT
132
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133However, using C<\015\012> (or C<\cM\cJ>, or C<\x0D\x0A>) can be tedious
134and unsightly, as well as confusing to those maintaining the code. As
6ab3f9cb 135such, the Socket module supplies the Right Thing for those who want it.
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136
137 use Socket qw(:DEFAULT :crlf);
138 print SOCKET "Hi there, client!$CRLF" # RIGHT
139
6ab3f9cb 140When reading from a socket, remember that the default input record
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141separator C<$/> is C<\n>, but robust socket code will recognize as
142either C<\012> or C<\015\012> as end of line:
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143
144 while (<SOCKET>) {
145 # ...
146 }
147
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148Because both CRLF and LF end in LF, the input record separator can
149be set to LF and any CR stripped later. Better to write:
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150
151 use Socket qw(:DEFAULT :crlf);
152 local($/) = LF; # not needed if $/ is already \012
153
154 while (<SOCKET>) {
155 s/$CR?$LF/\n/; # not sure if socket uses LF or CRLF, OK
156 # s/\015?\012/\n/; # same thing
157 }
158
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159This example is preferred over the previous one--even for Unix
160platforms--because now any C<\015>'s (C<\cM>'s) are stripped out
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161(and there was much rejoicing).
162
6ab3f9cb 163Similarly, functions that return text data--such as a function that
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164fetches a web page--should sometimes translate newlines before
165returning the data, if they've not yet been translated to the local
166newline representation. A single line of code will often suffice:
2ee0eb3c 167
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168 $data =~ s/\015?\012/\n/g;
169 return $data;
2ee0eb3c 170
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171Some of this may be confusing. Here's a handy reference to the ASCII CR
172and LF characters. You can print it out and stick it in your wallet.
173
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174 LF eq \012 eq \x0A eq \cJ eq chr(10) eq ASCII 10
175 CR eq \015 eq \x0D eq \cM eq chr(13) eq ASCII 13
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176
177 | Unix | DOS | Mac |
178 ---------------------------
179 \n | LF | LF | CR |
180 \r | CR | CR | LF |
181 \n * | LF | CRLF | CR |
182 \r * | CR | CR | LF |
183 ---------------------------
184 * text-mode STDIO
185
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186The Unix column assumes that you are not accessing a serial line
187(like a tty) in canonical mode. If you are, then CR on input becomes
188"\n", and "\n" on output becomes CRLF.
189
6ab3f9cb 190These are just the most common definitions of C<\n> and C<\r> in Perl.
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191There may well be others. For example, on an EBCDIC implementation
192such as z/OS (OS/390) or OS/400 (using the ILE, the PASE is ASCII-based)
193the above material is similar to "Unix" but the code numbers change:
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194
195 LF eq \025 eq \x15 eq chr(21) eq CP-1047 21
196 LF eq \045 eq \x25 eq \cU eq chr(37) eq CP-0037 37
197 CR eq \015 eq \x0D eq \cM eq chr(13) eq CP-1047 13
198 CR eq \015 eq \x0D eq \cM eq chr(13) eq CP-0037 13
199
200 | z/OS | OS/400 |
201 ----------------------
202 \n | LF | LF |
203 \r | CR | CR |
204 \n * | LF | LF |
205 \r * | CR | CR |
206 ----------------------
207 * text-mode STDIO
6ab3f9cb 208
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209=head2 Numbers endianness and Width
210
211Different CPUs store integers and floating point numbers in different
212orders (called I<endianness>) and widths (32-bit and 64-bit being the
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213most common today). This affects your programs when they attempt to transfer
214numbers in binary format from one CPU architecture to another,
215usually either "live" via network connection, or by storing the
216numbers to secondary storage such as a disk file or tape.
322422de 217
b7df3edc 218Conflicting storage orders make utter mess out of the numbers. If a
d1e3b762 219little-endian host (Intel, VAX) stores 0x12345678 (305419896 in
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220decimal), a big-endian host (Motorola, Sparc, PA) reads it as
2210x78563412 (2018915346 in decimal). Alpha and MIPS can be either:
222Digital/Compaq used/uses them in little-endian mode; SGI/Cray uses
223them in big-endian mode. To avoid this problem in network (socket)
224connections use the C<pack> and C<unpack> formats C<n> and C<N>, the
225"network" orders. These are guaranteed to be portable.
322422de 226
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227You can explore the endianness of your platform by unpacking a
228data structure packed in native format such as:
229
230 print unpack("h*", pack("s2", 1, 2)), "\n";
231 # '10002000' on e.g. Intel x86 or Alpha 21064 in little-endian mode
232 # '00100020' on e.g. Motorola 68040
233
234If you need to distinguish between endian architectures you could use
235either of the variables set like so:
236
237 $is_big_endian = unpack("h*", pack("s", 1)) =~ /01/;
4375e838 238 $is_little_endian = unpack("h*", pack("s", 1)) =~ /^1/;
d1e3b762 239
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240Differing widths can cause truncation even between platforms of equal
241endianness. The platform of shorter width loses the upper parts of the
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242number. There is no good solution for this problem except to avoid
243transferring or storing raw binary numbers.
244
b7df3edc 245One can circumnavigate both these problems in two ways. Either
322422de 246transfer and store numbers always in text format, instead of raw
b7df3edc 247binary, or else consider using modules like Data::Dumper (included in
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248the standard distribution as of Perl 5.005) and Storable (included as
249of perl 5.8). Keeping all data as text significantly simplifies matters.
322422de 250
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251The v-strings are portable only up to v2147483647 (0x7FFFFFFF), that's
252how far EBCDIC, or more precisely UTF-EBCDIC will go.
253
433acd8a 254=head2 Files and Filesystems
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255
256Most platforms these days structure files in a hierarchical fashion.
b7df3edc 257So, it is reasonably safe to assume that all platforms support the
6ab3f9cb 258notion of a "path" to uniquely identify a file on the system. How
b7df3edc 259that path is really written, though, differs considerably.
e41182b5 260
4375e838 261Although similar, file path specifications differ between Unix,
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262Windows, S<Mac OS>, OS/2, VMS, VOS, S<RISC OS>, and probably others.
263Unix, for example, is one of the few OSes that has the elegant idea
264of a single root directory.
322422de 265
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266DOS, OS/2, VMS, VOS, and Windows can work similarly to Unix with C</>
267as path separator, or in their own idiosyncratic ways (such as having
268several root directories and various "unrooted" device files such NIL:
269and LPT:).
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270
271S<Mac OS> uses C<:> as a path separator instead of C</>.
272
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273The filesystem may support neither hard links (C<link>) nor
274symbolic links (C<symlink>, C<readlink>, C<lstat>).
433acd8a 275
6ab3f9cb 276The filesystem may support neither access timestamp nor change
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277timestamp (meaning that about the only portable timestamp is the
278modification timestamp), or one second granularity of any timestamps
279(e.g. the FAT filesystem limits the time granularity to two seconds).
280
74555b7a 281The "inode change timestamp" (the C<-C> filetest) may really be the
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282"creation timestamp" (which it is not in UNIX).
283
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284VOS perl can emulate Unix filenames with C</> as path separator. The
285native pathname characters greater-than, less-than, number-sign, and
286percent-sign are always accepted.
287
6ab3f9cb 288S<RISC OS> perl can emulate Unix filenames with C</> as path
322422de 289separator, or go native and use C<.> for path separator and C<:> to
6ab3f9cb 290signal filesystems and disk names.
e41182b5 291
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292Don't assume UNIX filesystem access semantics: that read, write,
293and execute are all the permissions there are, and even if they exist,
294that their semantics (for example what do r, w, and x mean on
295a directory) are the UNIX ones. The various UNIX/POSIX compatibility
296layers usually try to make interfaces like chmod() work, but sometimes
297there simply is no good mapping.
298
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299If all this is intimidating, have no (well, maybe only a little)
300fear. There are modules that can help. The File::Spec modules
301provide methods to do the Right Thing on whatever platform happens
302to be running the program.
e41182b5 303
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304 use File::Spec::Functions;
305 chdir(updir()); # go up one directory
306 $file = catfile(curdir(), 'temp', 'file.txt');
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307 # on Unix and Win32, './temp/file.txt'
308 # on Mac OS, ':temp:file.txt'
d1e3b762 309 # on VMS, '[.temp]file.txt'
e41182b5 310
b7df3edc 311File::Spec is available in the standard distribution as of version
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3125.004_05. File::Spec::Functions is only in File::Spec 0.7 and later,
313and some versions of perl come with version 0.6. If File::Spec
314is not updated to 0.7 or later, you must use the object-oriented
315interface from File::Spec (or upgrade File::Spec).
e41182b5 316
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317In general, production code should not have file paths hardcoded.
318Making them user-supplied or read from a configuration file is
319better, keeping in mind that file path syntax varies on different
320machines.
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321
322This is especially noticeable in scripts like Makefiles and test suites,
323which often assume C</> as a path separator for subdirectories.
324
b7df3edc 325Also of use is File::Basename from the standard distribution, which
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326splits a pathname into pieces (base filename, full path to directory,
327and file suffix).
328
19799a22 329Even when on a single platform (if you can call Unix a single platform),
b7df3edc 330remember not to count on the existence or the contents of particular
3c075c7d 331system-specific files or directories, like F</etc/passwd>,
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332F</etc/sendmail.conf>, F</etc/resolv.conf>, or even F</tmp/>. For
333example, F</etc/passwd> may exist but not contain the encrypted
334passwords, because the system is using some form of enhanced security.
335Or it may not contain all the accounts, because the system is using NIS.
3c075c7d 336If code does need to rely on such a file, include a description of the
b7df3edc 337file and its format in the code's documentation, then make it easy for
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338the user to override the default location of the file.
339
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340Don't assume a text file will end with a newline. They should,
341but people forget.
e41182b5 342
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343Do not have two files or directories of the same name with different
344case, like F<test.pl> and F<Test.pl>, as many platforms have
345case-insensitive (or at least case-forgiving) filenames. Also, try
346not to have non-word characters (except for C<.>) in the names, and
347keep them to the 8.3 convention, for maximum portability, onerous a
348burden though this may appear.
dd9f0070 349
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350Likewise, when using the AutoSplit module, try to keep your functions to
3518.3 naming and case-insensitive conventions; or, at the least,
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352make it so the resulting files have a unique (case-insensitively)
353first 8 characters.
354
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355Whitespace in filenames is tolerated on most systems, but not all,
356and even on systems where it might be tolerated, some utilities
fe829689 357might become confused by such whitespace.
ec481373 358
b7df3edc 359Many systems (DOS, VMS) cannot have more than one C<.> in their filenames.
433acd8a 360
c47ff5f1 361Don't assume C<< > >> won't be the first character of a filename.
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362Always use C<< < >> explicitly to open a file for reading, or even
363better, use the three-arg version of open, unless you want the user to
364be able to specify a pipe open.
0a47030a 365
fe829689 366 open(FILE, '<', $existing_file) or die $!;
0a47030a 367
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368If filenames might use strange characters, it is safest to open it
369with C<sysopen> instead of C<open>. C<open> is magic and can
c47ff5f1 370translate characters like C<< > >>, C<< < >>, and C<|>, which may
b7df3edc 371be the wrong thing to do. (Sometimes, though, it's the right thing.)
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372Three-arg open can also help protect against this translation in cases
373where it is undesirable.
e41182b5 374
ec481373 375Don't use C<:> as a part of a filename since many systems use that for
8939ba94 376their own semantics (Mac OS Classic for separating pathname components,
ec481373 377many networking schemes and utilities for separating the nodename and
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378the pathname, and so on). For the same reasons, avoid C<@>, C<;> and
379C<|>.
ec481373 380
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381Don't assume that in pathnames you can collapse two leading slashes
382C<//> into one: some networking and clustering filesystems have special
383semantics for that. Let the operating system to sort it out.
384
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385The I<portable filename characters> as defined by ANSI C are
386
387 a b c d e f g h i j k l m n o p q r t u v w x y z
388 A B C D E F G H I J K L M N O P Q R T U V W X Y Z
389 0 1 2 3 4 5 6 7 8 9
390 . _ -
391
08fef530 392and the "-" shouldn't be the first character. If you want to be
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393hypercorrect, stay case-insensitive and within the 8.3 naming
394convention (all the files and directories have to be unique within one
395directory if their names are lowercased and truncated to eight
396characters before the C<.>, if any, and to three characters after the
397C<.>, if any). (And do not use C<.>s in directory names.)
ec481373 398
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399=head2 System Interaction
400
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401Not all platforms provide a command line. These are usually platforms
402that rely primarily on a Graphical User Interface (GUI) for user
403interaction. A program requiring a command line interface might
404not work everywhere. This is probably for the user of the program
405to deal with, so don't stay up late worrying about it.
e41182b5 406
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407Some platforms can't delete or rename files held open by the system,
408this limitation may also apply to changing filesystem metainformation
409like file permissions or owners. Remember to C<close> files when you
410are done with them. Don't C<unlink> or C<rename> an open file. Don't
411C<tie> or C<open> a file already tied or opened; C<untie> or C<close>
412it first.
e41182b5 413
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414Don't open the same file more than once at a time for writing, as some
415operating systems put mandatory locks on such files.
416
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417Don't assume that write/modify permission on a directory gives the
418right to add or delete files/directories in that directory. That is
419filesystem specific: in some filesystems you need write/modify
420permission also (or even just) in the file/directory itself. In some
421filesystems (AFS, DFS) the permission to add/delete directory entries
422is a completely separate permission.
423
424Don't assume that a single C<unlink> completely gets rid of the file:
425some filesystems (most notably the ones in VMS) have versioned
426filesystems, and unlink() removes only the most recent one (it doesn't
427remove all the versions because by default the native tools on those
428platforms remove just the most recent version, too). The portable
429idiom to remove all the versions of a file is
430
94bb614c 431 1 while unlink "file";
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432
433This will terminate if the file is undeleteable for some reason
434(protected, not there, and so on).
435
e41182b5 436Don't count on a specific environment variable existing in C<%ENV>.
0a47030a 437Don't count on C<%ENV> entries being case-sensitive, or even
4a0d0822 438case-preserving. Don't try to clear %ENV by saying C<%ENV = ();>, or,
6be8f7a6 439if you really have to, make it conditional on C<$^O ne 'VMS'> since in
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440VMS the C<%ENV> table is much more than a per-process key-value string
441table.
e41182b5 442
d1e3b762 443Don't count on signals or C<%SIG> for anything.
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444
445Don't count on filename globbing. Use C<opendir>, C<readdir>, and
446C<closedir> instead.
447
b8099c3d 448Don't count on per-program environment variables, or per-program current
dd9f0070 449directories.
b8099c3d 450
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451Don't count on specific values of C<$!>, neither numeric nor
452especially the strings values-- users may switch their locales causing
453error messages to be translated into their languages. If you can
454trust a POSIXish environment, you can portably use the symbols defined
455by the Errno module, like ENOENT. And don't trust on the values of C<$!>
456at all except immediately after a failed system call.
3c075c7d 457
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458=head2 Command names versus file pathnames
459
460Don't assume that the name used to invoke a command or program with
461C<system> or C<exec> can also be used to test for the existence of the
462file that holds the executable code for that command or program.
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463First, many systems have "internal" commands that are built-in to the
464shell or OS and while these commands can be invoked, there is no
465corresponding file. Second, some operating systems (e.g., Cygwin,
466DJGPP, OS/2, and VOS) have required suffixes for executable files;
467these suffixes are generally permitted on the command name but are not
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468required. Thus, a command like "perl" might exist in a file named
469"perl", "perl.exe", or "perl.pm", depending on the operating system.
470The variable "_exe" in the Config module holds the executable suffix,
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471if any. Third, the VMS port carefully sets up $^X and
472$Config{perlpath} so that no further processing is required. This is
473just as well, because the matching regular expression used below would
474then have to deal with a possible trailing version number in the VMS
475file name.
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476
477To convert $^X to a file pathname, taking account of the requirements
478of the various operating system possibilities, say:
479 use Config;
a10d74f3 480 $thisperl = $^X;
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481 if ($^O ne 'VMS')
482 {$thisperl .= $Config{_exe} unless $thisperl =~ m/$Config{_exe}$/i;}
a10d74f3
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483
484To convert $Config{perlpath} to a file pathname, say:
a10d74f3 485 use Config;
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486 $thisperl = $Config{perlpath};
487 if ($^O ne 'VMS')
488 {$thisperl .= $Config{_exe} unless $thisperl =~ m/$Config{_exe}$/i;}
a10d74f3 489
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490=head2 Interprocess Communication (IPC)
491
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492In general, don't directly access the system in code meant to be
493portable. That means, no C<system>, C<exec>, C<fork>, C<pipe>,
494C<``>, C<qx//>, C<open> with a C<|>, nor any of the other things
495that makes being a perl hacker worth being.
e41182b5
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496
497Commands that launch external processes are generally supported on
b7df3edc
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498most platforms (though many of them do not support any type of
499forking). The problem with using them arises from what you invoke
500them on. External tools are often named differently on different
4375e838 501platforms, may not be available in the same location, might accept
b7df3edc
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502different arguments, can behave differently, and often present their
503results in a platform-dependent way. Thus, you should seldom depend
504on them to produce consistent results. (Then again, if you're calling
505I<netstat -a>, you probably don't expect it to run on both Unix and CP/M.)
e41182b5 506
b7df3edc 507One especially common bit of Perl code is opening a pipe to B<sendmail>:
e41182b5 508
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GS
509 open(MAIL, '|/usr/lib/sendmail -t')
510 or die "cannot fork sendmail: $!";
e41182b5
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511
512This is fine for systems programming when sendmail is known to be
513available. But it is not fine for many non-Unix systems, and even
514some Unix systems that may not have sendmail installed. If a portable
b7df3edc
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515solution is needed, see the various distributions on CPAN that deal
516with it. Mail::Mailer and Mail::Send in the MailTools distribution are
517commonly used, and provide several mailing methods, including mail,
518sendmail, and direct SMTP (via Net::SMTP) if a mail transfer agent is
519not available. Mail::Sendmail is a standalone module that provides
520simple, platform-independent mailing.
521
522The Unix System V IPC (C<msg*(), sem*(), shm*()>) is not available
523even on all Unix platforms.
e41182b5 524
a81e5e2e
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525Do not use either the bare result of C<pack("N", 10, 20, 30, 40)> or
526bare v-strings (such as C<v10.20.30.40>) to represent IPv4 addresses:
527both forms just pack the four bytes into network order. That this
528would be equal to the C language C<in_addr> struct (which is what the
529socket code internally uses) is not guaranteed. To be portable use
530the routines of the Socket extension, such as C<inet_aton()>,
531C<inet_ntoa()>, and C<sockaddr_in()>.
6b2463a0 532
e41182b5 533The rule of thumb for portable code is: Do it all in portable Perl, or
0a47030a
GS
534use a module (that may internally implement it with platform-specific
535code, but expose a common interface).
e41182b5 536
e41182b5
GS
537=head2 External Subroutines (XS)
538
b7df3edc 539XS code can usually be made to work with any platform, but dependent
e41182b5
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540libraries, header files, etc., might not be readily available or
541portable, or the XS code itself might be platform-specific, just as Perl
542code might be. If the libraries and headers are portable, then it is
543normally reasonable to make sure the XS code is portable, too.
544
b7df3edc
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545A different type of portability issue arises when writing XS code:
546availability of a C compiler on the end-user's system. C brings
547with it its own portability issues, and writing XS code will expose
548you to some of those. Writing purely in Perl is an easier way to
e41182b5
GS
549achieve portability.
550
e41182b5
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551=head2 Standard Modules
552
553In general, the standard modules work across platforms. Notable
6ab3f9cb 554exceptions are the CPAN module (which currently makes connections to external
e41182b5 555programs that may not be available), platform-specific modules (like
6ab3f9cb 556ExtUtils::MM_VMS), and DBM modules.
e41182b5 557
b7df3edc 558There is no one DBM module available on all platforms.
6ab3f9cb
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559SDBM_File and the others are generally available on all Unix and DOSish
560ports, but not in MacPerl, where only NBDM_File and DB_File are
0a47030a 561available.
e41182b5
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562
563The good news is that at least some DBM module should be available, and
6ab3f9cb 564AnyDBM_File will use whichever module it can find. Of course, then
b7df3edc
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565the code needs to be fairly strict, dropping to the greatest common
566factor (e.g., not exceeding 1K for each record), so that it will
6ab3f9cb 567work with any DBM module. See L<AnyDBM_File> for more details.
e41182b5 568
e41182b5
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569=head2 Time and Date
570
0a47030a 571The system's notion of time of day and calendar date is controlled in
b7df3edc 572widely different ways. Don't assume the timezone is stored in C<$ENV{TZ}>,
0a47030a 573and even if it is, don't assume that you can control the timezone through
c87488a3
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574that variable. Don't assume anything about the three-letter timezone
575abbreviations (for example that MST would be the Mountain Standard Time,
576it's been known to stand for Moscow Standard Time). If you need to
577use timezones, express them in some unambiguous format like the
578exact number of minutes offset from UTC, or the POSIX timezone
579format.
e41182b5 580
322422de 581Don't assume that the epoch starts at 00:00:00, January 1, 1970,
c87488a3
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582because that is OS- and implementation-specific. It is better to
583store a date in an unambiguous representation. The ISO 8601 standard
584defines YYYY-MM-DD as the date format, or YYYY-MM-DDTHH-MM-SS
585(that's a literal "T" separating the date from the time).
586Please do use the ISO 8601 instead of making us to guess what
587date 02/03/04 might be. ISO 8601 even sorts nicely as-is.
588A text representation (like "1987-12-18") can be easily converted
589into an OS-specific value using a module like Date::Parse.
590An array of values, such as those returned by C<localtime>, can be
591converted to an OS-specific representation using Time::Local.
322422de 592
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GS
593When calculating specific times, such as for tests in time or date modules,
594it may be appropriate to calculate an offset for the epoch.
b7df3edc 595
19799a22
GS
596 require Time::Local;
597 $offset = Time::Local::timegm(0, 0, 0, 1, 0, 70);
b7df3edc 598
19799a22
GS
599The value for C<$offset> in Unix will be C<0>, but in Mac OS will be
600some large number. C<$offset> can then be added to a Unix time value
601to get what should be the proper value on any system.
322422de 602
bbac04ed
RGS
603On Windows (at least), you shouldn't pass a negative value to C<gmtime> or
604C<localtime>.
605
322422de
GS
606=head2 Character sets and character encoding
607
ec481373
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608Assume very little about character sets.
609
610Assume nothing about numerical values (C<ord>, C<chr>) of characters.
611Do not use explicit code point ranges (like \xHH-\xHH); use for
612example symbolic character classes like C<[:print:]>.
613
614Do not assume that the alphabetic characters are encoded contiguously
615(in the numeric sense). There may be gaps.
616
617Do not assume anything about the ordering of the characters.
618The lowercase letters may come before or after the uppercase letters;
619the lowercase and uppercase may be interlaced so that both `a' and `A'
620come before `b'; the accented and other international characters may
621be interlaced so that E<auml> comes before `b'.
322422de
GS
622
623=head2 Internationalisation
624
b7df3edc
GS
625If you may assume POSIX (a rather large assumption), you may read
626more about the POSIX locale system from L<perllocale>. The locale
627system at least attempts to make things a little bit more portable,
628or at least more convenient and native-friendly for non-English
629users. The system affects character sets and encoding, and date
630and time formatting--amongst other things.
e41182b5 631
c87488a3
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632If you really want to be international, you should consider Unicode.
633See L<perluniintro> and L<perlunicode> for more information.
634
11264fdb
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635If you want to use non-ASCII bytes (outside the bytes 0x00..0x7f) in
636the "source code" of your code, to be portable you have to be explicit
637about what bytes they are. Someone might for example be using your
638code under a UTF-8 locale, in which case random native bytes might be
639illegal ("Malformed UTF-8 ...") This means that for example embedding
640ISO 8859-1 bytes beyond 0x7f into your strings might cause trouble
641later. If the bytes are native 8-bit bytes, you can use the C<bytes>
642pragma. If the bytes are in a string (regular expression being a
643curious string), you can often also use the C<\xHH> notation instead
644of embedding the bytes as-is. If they are in some particular legacy
645encoding (ether single-byte or something more complicated), you can
646use the C<encoding> pragma. (If you want to write your code in UTF-8,
647you can use either the C<utf8> pragma, or the C<encoding> pragma.)
648The C<bytes> and C<utf8> pragmata are available since Perl 5.6.0, and
649the C<encoding> pragma since Perl 5.8.0.
650
e41182b5
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651=head2 System Resources
652
0a47030a
GS
653If your code is destined for systems with severely constrained (or
654missing!) virtual memory systems then you want to be I<especially> mindful
655of avoiding wasteful constructs such as:
e41182b5
GS
656
657 # NOTE: this is no longer "bad" in perl5.005
658 for (0..10000000) {} # bad
659 for (my $x = 0; $x <= 10000000; ++$x) {} # good
660
661 @lines = <VERY_LARGE_FILE>; # bad
662
663 while (<FILE>) {$file .= $_} # sometimes bad
0a47030a 664 $file = join('', <FILE>); # better
e41182b5 665
b7df3edc
GS
666The last two constructs may appear unintuitive to most people. The
667first repeatedly grows a string, whereas the second allocates a
668large chunk of memory in one go. On some systems, the second is
669more efficient that the first.
0a47030a 670
e41182b5
GS
671=head2 Security
672
b7df3edc
GS
673Most multi-user platforms provide basic levels of security, usually
674implemented at the filesystem level. Some, however, do
a1667ba3 675not-- unfortunately. Thus the notion of user id, or "home" directory,
b7df3edc
GS
676or even the state of being logged-in, may be unrecognizable on many
677platforms. If you write programs that are security-conscious, it
678is usually best to know what type of system you will be running
679under so that you can write code explicitly for that platform (or
680class of platforms).
0a47030a 681
a1667ba3
JH
682Don't assume the UNIX filesystem access semantics: the operating
683system or the filesystem may be using some ACL systems, which are
684richer languages than the usual rwx. Even if the rwx exist,
685their semantics might be different.
686
687(From security viewpoint testing for permissions before attempting to
688do something is silly anyway: if one tries this, there is potential
689for race conditions-- someone or something might change the
690permissions between the permissions check and the actual operation.
691Just try the operation.)
692
693Don't assume the UNIX user and group semantics: especially, don't
2edcc0d9 694expect the C<< $< >> and C<< $> >> (or the C<$(> and C<$)>) to work
a1667ba3
JH
695for switching identities (or memberships).
696
697Don't assume set-uid and set-gid semantics. (And even if you do,
698think twice: set-uid and set-gid are a known can of security worms.)
699
e41182b5
GS
700=head2 Style
701
702For those times when it is necessary to have platform-specific code,
703consider keeping the platform-specific code in one place, making porting
6ab3f9cb 704to other platforms easier. Use the Config module and the special
0a47030a
GS
705variable C<$^O> to differentiate platforms, as described in
706L<"PLATFORMS">.
e41182b5 707
b7df3edc
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708Be careful in the tests you supply with your module or programs.
709Module code may be fully portable, but its tests might not be. This
710often happens when tests spawn off other processes or call external
711programs to aid in the testing, or when (as noted above) the tests
c87488a3
HS
712assume certain things about the filesystem and paths. Be careful not
713to depend on a specific output style for errors, such as when checking
714C<$!> after a failed system call. Using C<$!> for anything else than
715displaying it as output is doubtful (though see the Errno module for
716testing reasonably portably for error value). Some platforms expect
717a certain output format, and Perl on those platforms may have been
718adjusted accordingly. Most specifically, don't anchor a regex when
719testing an error value.
e41182b5 720
0a47030a 721=head1 CPAN Testers
e41182b5 722
0a47030a
GS
723Modules uploaded to CPAN are tested by a variety of volunteers on
724different platforms. These CPAN testers are notified by mail of each
e41182b5 725new upload, and reply to the list with PASS, FAIL, NA (not applicable to
0a47030a 726this platform), or UNKNOWN (unknown), along with any relevant notations.
e41182b5
GS
727
728The purpose of the testing is twofold: one, to help developers fix any
0a47030a 729problems in their code that crop up because of lack of testing on other
b7df3edc 730platforms; two, to provide users with information about whether
0a47030a 731a given module works on a given platform.
e41182b5
GS
732
733=over 4
734
735=item Mailing list: cpan-testers@perl.org
736
c997b287 737=item Testing results: http://testers.cpan.org/
e41182b5
GS
738
739=back
740
e41182b5
GS
741=head1 PLATFORMS
742
743As of version 5.002, Perl is built with a C<$^O> variable that
744indicates the operating system it was built on. This was implemented
b7df3edc
GS
745to help speed up code that would otherwise have to C<use Config>
746and use the value of C<$Config{osname}>. Of course, to get more
e41182b5
GS
747detailed information about the system, looking into C<%Config> is
748certainly recommended.
749
b7df3edc
GS
750C<%Config> cannot always be trusted, however, because it was built
751at compile time. If perl was built in one place, then transferred
752elsewhere, some values may be wrong. The values may even have been
753edited after the fact.
6ab3f9cb 754
e41182b5
GS
755=head2 Unix
756
757Perl works on a bewildering variety of Unix and Unix-like platforms (see
758e.g. most of the files in the F<hints/> directory in the source code kit).
759On most of these systems, the value of C<$^O> (hence C<$Config{'osname'}>,
d1e3b762
GS
760too) is determined either by lowercasing and stripping punctuation from the
761first field of the string returned by typing C<uname -a> (or a similar command)
762at the shell prompt or by testing the file system for the presence of
763uniquely named files such as a kernel or header file. Here, for example,
764are a few of the more popular Unix flavors:
e41182b5 765
b7df3edc 766 uname $^O $Config{'archname'}
6ab3f9cb 767 --------------------------------------------
b7df3edc 768 AIX aix aix
6ab3f9cb 769 BSD/OS bsdos i386-bsdos
e1516da7 770 Darwin darwin darwin
6ab3f9cb
GS
771 dgux dgux AViiON-dgux
772 DYNIX/ptx dynixptx i386-dynixptx
b7df3edc 773 FreeBSD freebsd freebsd-i386
d1e3b762 774 Linux linux arm-linux
b7df3edc 775 Linux linux i386-linux
6ab3f9cb
GS
776 Linux linux i586-linux
777 Linux linux ppc-linux
b7df3edc
GS
778 HP-UX hpux PA-RISC1.1
779 IRIX irix irix
b787fad4 780 Mac OS X darwin darwin
d1e3b762
GS
781 MachTen PPC machten powerpc-machten
782 NeXT 3 next next-fat
783 NeXT 4 next OPENSTEP-Mach
6ab3f9cb 784 openbsd openbsd i386-openbsd
b7df3edc 785 OSF1 dec_osf alpha-dec_osf
6ab3f9cb
GS
786 reliantunix-n svr4 RM400-svr4
787 SCO_SV sco_sv i386-sco_sv
788 SINIX-N svr4 RM400-svr4
789 sn4609 unicos CRAY_C90-unicos
790 sn6521 unicosmk t3e-unicosmk
791 sn9617 unicos CRAY_J90-unicos
b7df3edc
GS
792 SunOS solaris sun4-solaris
793 SunOS solaris i86pc-solaris
794 SunOS4 sunos sun4-sunos
e41182b5 795
b7df3edc
GS
796Because the value of C<$Config{archname}> may depend on the
797hardware architecture, it can vary more than the value of C<$^O>.
6ab3f9cb 798
e41182b5
GS
799=head2 DOS and Derivatives
800
b7df3edc 801Perl has long been ported to Intel-style microcomputers running under
e41182b5
GS
802systems like PC-DOS, MS-DOS, OS/2, and most Windows platforms you can
803bring yourself to mention (except for Windows CE, if you count that).
b7df3edc 804Users familiar with I<COMMAND.COM> or I<CMD.EXE> style shells should
e41182b5
GS
805be aware that each of these file specifications may have subtle
806differences:
807
808 $filespec0 = "c:/foo/bar/file.txt";
809 $filespec1 = "c:\\foo\\bar\\file.txt";
810 $filespec2 = 'c:\foo\bar\file.txt';
811 $filespec3 = 'c:\\foo\\bar\\file.txt';
812
b7df3edc
GS
813System calls accept either C</> or C<\> as the path separator.
814However, many command-line utilities of DOS vintage treat C</> as
815the option prefix, so may get confused by filenames containing C</>.
816Aside from calling any external programs, C</> will work just fine,
817and probably better, as it is more consistent with popular usage,
818and avoids the problem of remembering what to backwhack and what
819not to.
e41182b5 820
b7df3edc
GS
821The DOS FAT filesystem can accommodate only "8.3" style filenames. Under
822the "case-insensitive, but case-preserving" HPFS (OS/2) and NTFS (NT)
0a47030a 823filesystems you may have to be careful about case returned with functions
e41182b5
GS
824like C<readdir> or used with functions like C<open> or C<opendir>.
825
b7df3edc
GS
826DOS also treats several filenames as special, such as AUX, PRN,
827NUL, CON, COM1, LPT1, LPT2, etc. Unfortunately, sometimes these
828filenames won't even work if you include an explicit directory
829prefix. It is best to avoid such filenames, if you want your code
830to be portable to DOS and its derivatives. It's hard to know what
831these all are, unfortunately.
e41182b5
GS
832
833Users of these operating systems may also wish to make use of
b7df3edc 834scripts such as I<pl2bat.bat> or I<pl2cmd> to
e41182b5
GS
835put wrappers around your scripts.
836
837Newline (C<\n>) is translated as C<\015\012> by STDIO when reading from
6ab3f9cb
GS
838and writing to files (see L<"Newlines">). C<binmode(FILEHANDLE)>
839will keep C<\n> translated as C<\012> for that filehandle. Since it is a
840no-op on other systems, C<binmode> should be used for cross-platform code
b7df3edc
GS
841that deals with binary data. That's assuming you realize in advance
842that your data is in binary. General-purpose programs should
843often assume nothing about their data.
e41182b5 844
b7df3edc 845The C<$^O> variable and the C<$Config{archname}> values for various
e41182b5
GS
846DOSish perls are as follows:
847
67ac489e
MS
848 OS $^O $Config{archname} ID Version
849 --------------------------------------------------------
850 MS-DOS dos ?
851 PC-DOS dos ?
852 OS/2 os2 ?
853 Windows 3.1 ? ? 0 3 01
854 Windows 95 MSWin32 MSWin32-x86 1 4 00
855 Windows 98 MSWin32 MSWin32-x86 1 4 10
856 Windows ME MSWin32 MSWin32-x86 1 ?
857 Windows NT MSWin32 MSWin32-x86 2 4 xx
858 Windows NT MSWin32 MSWin32-ALPHA 2 4 xx
859 Windows NT MSWin32 MSWin32-ppc 2 4 xx
860 Windows 2000 MSWin32 MSWin32-x86 2 5 xx
861 Windows XP MSWin32 MSWin32-x86 2 ?
862 Windows CE MSWin32 ? 3
863 Cygwin cygwin ?
e41182b5 864
34aaaa84
PP
865The various MSWin32 Perl's can distinguish the OS they are running on
866via the value of the fifth element of the list returned from
867Win32::GetOSVersion(). For example:
868
869 if ($^O eq 'MSWin32') {
870 my @os_version_info = Win32::GetOSVersion();
871 print +('3.1','95','NT')[$os_version_info[4]],"\n";
872 }
873
7939d86b
JH
874There are also Win32::IsWinNT() and Win32::IsWin95(), try C<perldoc Win32>,
875and as of libwin32 0.19 (not part of the core Perl distribution)
876Win32::GetOSName(). The very portable POSIX::uname() will work too:
1d65be3a
JH
877
878 c:\> perl -MPOSIX -we "print join '|', uname"
879 Windows NT|moonru|5.0|Build 2195 (Service Pack 2)|x86
d99f392e 880
e41182b5
GS
881Also see:
882
883=over 4
884
c997b287 885=item *
e41182b5 886
c997b287
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887The djgpp environment for DOS, http://www.delorie.com/djgpp/
888and L<perldos>.
e41182b5 889
c997b287 890=item *
e41182b5 891
c997b287
GS
892The EMX environment for DOS, OS/2, etc. emx@iaehv.nl,
893http://www.leo.org/pub/comp/os/os2/leo/gnu/emx+gcc/index.html or
f224927c 894ftp://hobbes.nmsu.edu/pub/os2/dev/emx/ Also L<perlos2>.
e41182b5 895
c997b287 896=item *
d1e3b762 897
c997b287
GS
898Build instructions for Win32 in L<perlwin32>, or under the Cygnus environment
899in L<perlcygwin>.
900
901=item *
902
903The C<Win32::*> modules in L<Win32>.
904
905=item *
906
907The ActiveState Pages, http://www.activestate.com/
908
909=item *
910
911The Cygwin environment for Win32; F<README.cygwin> (installed
47dafe4d 912as L<perlcygwin>), http://www.cygwin.com/
c997b287
GS
913
914=item *
915
916The U/WIN environment for Win32,
cea6626f 917http://www.research.att.com/sw/tools/uwin/
c997b287 918
cea6626f 919=item *
d1e3b762 920
cea6626f 921Build instructions for OS/2, L<perlos2>
d1e3b762 922
e41182b5
GS
923=back
924
dd9f0070 925=head2 S<Mac OS>
e41182b5
GS
926
927Any module requiring XS compilation is right out for most people, because
928MacPerl is built using non-free (and non-cheap!) compilers. Some XS
929modules that can work with MacPerl are built and distributed in binary
6ab3f9cb 930form on CPAN.
e41182b5
GS
931
932Directories are specified as:
933
934 volume:folder:file for absolute pathnames
935 volume:folder: for absolute pathnames
936 :folder:file for relative pathnames
937 :folder: for relative pathnames
938 :file for relative pathnames
939 file for relative pathnames
940
b7df3edc 941Files are stored in the directory in alphabetical order. Filenames are
6ab3f9cb 942limited to 31 characters, and may include any character except for
b7df3edc 943null and C<:>, which is reserved as the path separator.
e41182b5 944
0a47030a 945Instead of C<flock>, see C<FSpSetFLock> and C<FSpRstFLock> in the
6ab3f9cb 946Mac::Files module, or C<chmod(0444, ...)> and C<chmod(0666, ...)>.
e41182b5
GS
947
948In the MacPerl application, you can't run a program from the command line;
949programs that expect C<@ARGV> to be populated can be edited with something
950like the following, which brings up a dialog box asking for the command
951line arguments.
952
953 if (!@ARGV) {
954 @ARGV = split /\s+/, MacPerl::Ask('Arguments?');
955 }
956
b7df3edc 957A MacPerl script saved as a "droplet" will populate C<@ARGV> with the full
e41182b5
GS
958pathnames of the files dropped onto the script.
959
b7df3edc
GS
960Mac users can run programs under a type of command line interface
961under MPW (Macintosh Programmer's Workshop, a free development
962environment from Apple). MacPerl was first introduced as an MPW
963tool, and MPW can be used like a shell:
e41182b5
GS
964
965 perl myscript.plx some arguments
966
967ToolServer is another app from Apple that provides access to MPW tools
0a47030a 968from MPW and the MacPerl app, which allows MacPerl programs to use
e41182b5
GS
969C<system>, backticks, and piped C<open>.
970
971"S<Mac OS>" is the proper name for the operating system, but the value
972in C<$^O> is "MacOS". To determine architecture, version, or whether
973the application or MPW tool version is running, check:
974
975 $is_app = $MacPerl::Version =~ /App/;
976 $is_tool = $MacPerl::Version =~ /MPW/;
977 ($version) = $MacPerl::Version =~ /^(\S+)/;
978 $is_ppc = $MacPerl::Architecture eq 'MacPPC';
979 $is_68k = $MacPerl::Architecture eq 'Mac68K';
980
b787fad4
JH
981S<Mac OS X>, based on NeXT's OpenStep OS, runs MacPerl natively, under the
982"Classic" environment. There is no "Carbon" version of MacPerl to run
983under the primary Mac OS X environment. S<Mac OS X> and its Open Source
984version, Darwin, both run Unix perl natively.
6ab3f9cb 985
e41182b5
GS
986Also see:
987
988=over 4
989
c997b287
GS
990=item *
991
862b5365 992MacPerl Development, http://dev.macperl.org/ .
c997b287
GS
993
994=item *
995
862b5365 996The MacPerl Pages, http://www.macperl.com/ .
e41182b5 997
c997b287 998=item *
6ab3f9cb 999
862b5365 1000The MacPerl mailing lists, http://lists.perl.org/ .
e41182b5
GS
1001
1002=back
1003
e41182b5
GS
1004=head2 VMS
1005
c997b287 1006Perl on VMS is discussed in L<perlvms> in the perl distribution.
b7df3edc 1007Perl on VMS can accept either VMS- or Unix-style file
e41182b5
GS
1008specifications as in either of the following:
1009
1010 $ perl -ne "print if /perl_setup/i" SYS$LOGIN:LOGIN.COM
1011 $ perl -ne "print if /perl_setup/i" /sys$login/login.com
1012
1013but not a mixture of both as in:
1014
1015 $ perl -ne "print if /perl_setup/i" sys$login:/login.com
1016 Can't open sys$login:/login.com: file specification syntax error
1017
1018Interacting with Perl from the Digital Command Language (DCL) shell
1019often requires a different set of quotation marks than Unix shells do.
1020For example:
1021
1022 $ perl -e "print ""Hello, world.\n"""
1023 Hello, world.
1024
b7df3edc 1025There are several ways to wrap your perl scripts in DCL F<.COM> files, if
e41182b5
GS
1026you are so inclined. For example:
1027
1028 $ write sys$output "Hello from DCL!"
1029 $ if p1 .eqs. ""
1030 $ then perl -x 'f$environment("PROCEDURE")
1031 $ else perl -x - 'p1 'p2 'p3 'p4 'p5 'p6 'p7 'p8
1032 $ deck/dollars="__END__"
1033 #!/usr/bin/perl
1034
1035 print "Hello from Perl!\n";
1036
1037 __END__
1038 $ endif
1039
1040Do take care with C<$ ASSIGN/nolog/user SYS$COMMAND: SYS$INPUT> if your
c47ff5f1 1041perl-in-DCL script expects to do things like C<< $read = <STDIN>; >>.
e41182b5
GS
1042
1043Filenames are in the format "name.extension;version". The maximum
1044length for filenames is 39 characters, and the maximum length for
1045extensions is also 39 characters. Version is a number from 1 to
104632767. Valid characters are C</[A-Z0-9$_-]/>.
1047
b7df3edc 1048VMS's RMS filesystem is case-insensitive and does not preserve case.
e41182b5 1049C<readdir> returns lowercased filenames, but specifying a file for
b7df3edc 1050opening remains case-insensitive. Files without extensions have a
e41182b5 1051trailing period on them, so doing a C<readdir> with a file named F<A.;5>
0a47030a
GS
1052will return F<a.> (though that file could be opened with
1053C<open(FH, 'A')>).
e41182b5 1054
f34d0673 1055RMS had an eight level limit on directory depths from any rooted logical
dd9f0070
CN
1056(allowing 16 levels overall) prior to VMS 7.2. Hence
1057C<PERL_ROOT:[LIB.2.3.4.5.6.7.8]> is a valid directory specification but
1058C<PERL_ROOT:[LIB.2.3.4.5.6.7.8.9]> is not. F<Makefile.PL> authors might
1059have to take this into account, but at least they can refer to the former
f34d0673 1060as C</PERL_ROOT/lib/2/3/4/5/6/7/8/>.
e41182b5 1061
6ab3f9cb 1062The VMS::Filespec module, which gets installed as part of the build
0a47030a
GS
1063process on VMS, is a pure Perl module that can easily be installed on
1064non-VMS platforms and can be helpful for conversions to and from RMS
1065native formats.
e41182b5 1066
5e12dbfa
PP
1067What C<\n> represents depends on the type of file opened. It usually
1068represents C<\012> but it could also be C<\015>, C<\012>, C<\015\012>,
1069C<\000>, C<\040>, or nothing depending on the file organiztion and
1070record format. The VMS::Stdio module provides access to the
1071special fopen() requirements of files with unusual attributes on VMS.
e41182b5
GS
1072
1073TCP/IP stacks are optional on VMS, so socket routines might not be
1074implemented. UDP sockets may not be supported.
1075
1076The value of C<$^O> on OpenVMS is "VMS". To determine the architecture
1077that you are running on without resorting to loading all of C<%Config>
1078you can examine the content of the C<@INC> array like so:
1079
1080 if (grep(/VMS_AXP/, @INC)) {
1081 print "I'm on Alpha!\n";
6ab3f9cb 1082
e41182b5
GS
1083 } elsif (grep(/VMS_VAX/, @INC)) {
1084 print "I'm on VAX!\n";
6ab3f9cb 1085
e41182b5
GS
1086 } else {
1087 print "I'm not so sure about where $^O is...\n";
1088 }
1089
b7df3edc
GS
1090On VMS, perl determines the UTC offset from the C<SYS$TIMEZONE_DIFFERENTIAL>
1091logical name. Although the VMS epoch began at 17-NOV-1858 00:00:00.00,
6ab3f9cb 1092calls to C<localtime> are adjusted to count offsets from
b7df3edc 109301-JAN-1970 00:00:00.00, just like Unix.
6ab3f9cb 1094
e41182b5
GS
1095Also see:
1096
1097=over 4
1098
c997b287
GS
1099=item *
1100
1101F<README.vms> (installed as L<README_vms>), L<perlvms>
1102
1103=item *
1104
1105vmsperl list, majordomo@perl.org
e41182b5 1106
c997b287 1107(Put the words C<subscribe vmsperl> in message body.)
e41182b5 1108
c997b287 1109=item *
e41182b5 1110
c997b287 1111vmsperl on the web, http://www.sidhe.org/vmsperl/index.html
e41182b5
GS
1112
1113=back
1114
495c5fdc
GP
1115=head2 VOS
1116
9a997319
JH
1117Perl on VOS is discussed in F<README.vos> in the perl distribution
1118(installed as L<perlvos>). Perl on VOS can accept either VOS- or
1119Unix-style file specifications as in either of the following:
495c5fdc 1120
cc07ed0b
PG
1121 C<< $ perl -ne "print if /perl_setup/i" >system>notices >>
1122 C<< $ perl -ne "print if /perl_setup/i" /system/notices >>
495c5fdc
GP
1123
1124or even a mixture of both as in:
1125
cc07ed0b 1126 C<< $ perl -ne "print if /perl_setup/i" >system/notices >>
495c5fdc 1127
b7df3edc 1128Even though VOS allows the slash character to appear in object
495c5fdc
GP
1129names, because the VOS port of Perl interprets it as a pathname
1130delimiting character, VOS files, directories, or links whose names
1131contain a slash character cannot be processed. Such files must be
a3dfe201
GS
1132renamed before they can be processed by Perl. Note that VOS limits
1133file names to 32 or fewer characters.
495c5fdc 1134
495c5fdc
GP
1135The value of C<$^O> on VOS is "VOS". To determine the architecture that
1136you are running on without resorting to loading all of C<%Config> you
c997b287 1137can examine the content of the @INC array like so:
495c5fdc 1138
24e8e380 1139 if ($^O =~ /VOS/) {
495c5fdc
GP
1140 print "I'm on a Stratus box!\n";
1141 } else {
1142 print "I'm not on a Stratus box!\n";
1143 die;
1144 }
1145
495c5fdc
GP
1146Also see:
1147
1148=over 4
1149
c997b287 1150=item *
495c5fdc 1151
cc07ed0b 1152F<README.vos> (installed as L<perlvos>)
c997b287
GS
1153
1154=item *
1155
1156The VOS mailing list.
495c5fdc
GP
1157
1158There is no specific mailing list for Perl on VOS. You can post
1159comments to the comp.sys.stratus newsgroup, or subscribe to the general
cc07ed0b 1160Stratus mailing list. Send a letter with "subscribe Info-Stratus" in
495c5fdc
GP
1161the message body to majordomo@list.stratagy.com.
1162
c997b287
GS
1163=item *
1164
cc07ed0b 1165VOS Perl on the web at http://ftp.stratus.com/pub/vos/posix/posix.html
495c5fdc
GP
1166
1167=back
1168
e41182b5
GS
1169=head2 EBCDIC Platforms
1170
1171Recent versions of Perl have been ported to platforms such as OS/400 on
d1e3b762
GS
1172AS/400 minicomputers as well as OS/390, VM/ESA, and BS2000 for S/390
1173Mainframes. Such computers use EBCDIC character sets internally (usually
0cc436d0
GS
1174Character Code Set ID 0037 for OS/400 and either 1047 or POSIX-BC for S/390
1175systems). On the mainframe perl currently works under the "Unix system
1176services for OS/390" (formerly known as OpenEdition), VM/ESA OpenEdition, or
1177the BS200 POSIX-BC system (BS2000 is supported in perl 5.6 and greater).
522b859a
JH
1178See L<perlos390> for details. Note that for OS/400 there is also a port of
1179Perl 5.8.1/5.9.0 or later to the PASE which is ASCII-based (as opposed to
1180ILE which is EBCDIC-based), see L<perlos400>.
e41182b5 1181
7c5ffed3
JH
1182As of R2.5 of USS for OS/390 and Version 2.3 of VM/ESA these Unix
1183sub-systems do not support the C<#!> shebang trick for script invocation.
1184Hence, on OS/390 and VM/ESA perl scripts can be executed with a header
1185similar to the following simple script:
e41182b5
GS
1186
1187 : # use perl
1188 eval 'exec /usr/local/bin/perl -S $0 ${1+"$@"}'
1189 if 0;
1190 #!/usr/local/bin/perl # just a comment really
1191
1192 print "Hello from perl!\n";
1193
d1e3b762
GS
1194OS/390 will support the C<#!> shebang trick in release 2.8 and beyond.
1195Calls to C<system> and backticks can use POSIX shell syntax on all
1196S/390 systems.
1197
b7df3edc 1198On the AS/400, if PERL5 is in your library list, you may need
6ab3f9cb
GS
1199to wrap your perl scripts in a CL procedure to invoke them like so:
1200
1201 BEGIN
1202 CALL PGM(PERL5/PERL) PARM('/QOpenSys/hello.pl')
1203 ENDPGM
1204
1205This will invoke the perl script F<hello.pl> in the root of the
1206QOpenSys file system. On the AS/400 calls to C<system> or backticks
1207must use CL syntax.
1208
e41182b5 1209On these platforms, bear in mind that the EBCDIC character set may have
0a47030a
GS
1210an effect on what happens with some perl functions (such as C<chr>,
1211C<pack>, C<print>, C<printf>, C<ord>, C<sort>, C<sprintf>, C<unpack>), as
1212well as bit-fiddling with ASCII constants using operators like C<^>, C<&>
1213and C<|>, not to mention dealing with socket interfaces to ASCII computers
6ab3f9cb 1214(see L<"Newlines">).
e41182b5 1215
b7df3edc
GS
1216Fortunately, most web servers for the mainframe will correctly
1217translate the C<\n> in the following statement to its ASCII equivalent
1218(C<\r> is the same under both Unix and OS/390 & VM/ESA):
e41182b5
GS
1219
1220 print "Content-type: text/html\r\n\r\n";
1221
d1e3b762 1222The values of C<$^O> on some of these platforms includes:
e41182b5 1223
d1e3b762
GS
1224 uname $^O $Config{'archname'}
1225 --------------------------------------------
1226 OS/390 os390 os390
1227 OS400 os400 os400
1228 POSIX-BC posix-bc BS2000-posix-bc
1229 VM/ESA vmesa vmesa
3c075c7d 1230
e41182b5
GS
1231Some simple tricks for determining if you are running on an EBCDIC
1232platform could include any of the following (perhaps all):
1233
1234 if ("\t" eq "\05") { print "EBCDIC may be spoken here!\n"; }
1235
1236 if (ord('A') == 193) { print "EBCDIC may be spoken here!\n"; }
1237
1238 if (chr(169) eq 'z') { print "EBCDIC may be spoken here!\n"; }
1239
b7df3edc 1240One thing you may not want to rely on is the EBCDIC encoding
0a47030a
GS
1241of punctuation characters since these may differ from code page to code
1242page (and once your module or script is rumoured to work with EBCDIC,
1243folks will want it to work with all EBCDIC character sets).
e41182b5
GS
1244
1245Also see:
1246
1247=over 4
1248
c997b287
GS
1249=item *
1250
1251*
d1e3b762 1252
dc5c060f 1253L<perlos390>, F<README.os390>, F<perlbs2000>, F<README.vmesa>,
bb462878 1254L<perlebcdic>.
c997b287
GS
1255
1256=item *
e41182b5
GS
1257
1258The perl-mvs@perl.org list is for discussion of porting issues as well as
1259general usage issues for all EBCDIC Perls. Send a message body of
1260"subscribe perl-mvs" to majordomo@perl.org.
1261
c997b287
GS
1262=item *
1263
1264AS/400 Perl information at
b1866b2d 1265http://as400.rochester.ibm.com/
d1e3b762 1266as well as on CPAN in the F<ports/> directory.
e41182b5
GS
1267
1268=back
1269
b8099c3d
CN
1270=head2 Acorn RISC OS
1271
b7df3edc
GS
1272Because Acorns use ASCII with newlines (C<\n>) in text files as C<\012> like
1273Unix, and because Unix filename emulation is turned on by default,
1274most simple scripts will probably work "out of the box". The native
6ab3f9cb 1275filesystem is modular, and individual filesystems are free to be
0a47030a 1276case-sensitive or insensitive, and are usually case-preserving. Some
b7df3edc 1277native filesystems have name length limits, which file and directory
6ab3f9cb
GS
1278names are silently truncated to fit. Scripts should be aware that the
1279standard filesystem currently has a name length limit of B<10>
1280characters, with up to 77 items in a directory, but other filesystems
0a47030a 1281may not impose such limitations.
b8099c3d
CN
1282
1283Native filenames are of the form
1284
6ab3f9cb 1285 Filesystem#Special_Field::DiskName.$.Directory.Directory.File
dd9f0070 1286
b8099c3d
CN
1287where
1288
1289 Special_Field is not usually present, but may contain . and $ .
1290 Filesystem =~ m|[A-Za-z0-9_]|
1291 DsicName =~ m|[A-Za-z0-9_/]|
1292 $ represents the root directory
1293 . is the path separator
1294 @ is the current directory (per filesystem but machine global)
1295 ^ is the parent directory
1296 Directory and File =~ m|[^\0- "\.\$\%\&:\@\\^\|\177]+|
1297
1298The default filename translation is roughly C<tr|/.|./|;>
1299
6ab3f9cb 1300Note that C<"ADFS::HardDisk.$.File" ne 'ADFS::HardDisk.$.File'> and that
0a47030a
GS
1301the second stage of C<$> interpolation in regular expressions will fall
1302foul of the C<$.> if scripts are not careful.
1303
1304Logical paths specified by system variables containing comma-separated
b7df3edc 1305search lists are also allowed; hence C<System:Modules> is a valid
0a47030a 1306filename, and the filesystem will prefix C<Modules> with each section of
6ab3f9cb 1307C<System$Path> until a name is made that points to an object on disk.
b7df3edc 1308Writing to a new file C<System:Modules> would be allowed only if
0a47030a
GS
1309C<System$Path> contains a single item list. The filesystem will also
1310expand system variables in filenames if enclosed in angle brackets, so
c47ff5f1 1311C<< <System$Dir>.Modules >> would look for the file
0a47030a 1312S<C<$ENV{'System$Dir'} . 'Modules'>>. The obvious implication of this is
c47ff5f1 1313that B<fully qualified filenames can start with C<< <> >>> and should
0a47030a 1314be protected when C<open> is used for input.
b8099c3d
CN
1315
1316Because C<.> was in use as a directory separator and filenames could not
1317be assumed to be unique after 10 characters, Acorn implemented the C
1318compiler to strip the trailing C<.c> C<.h> C<.s> and C<.o> suffix from
1319filenames specified in source code and store the respective files in
b7df3edc 1320subdirectories named after the suffix. Hence files are translated:
b8099c3d
CN
1321
1322 foo.h h.foo
1323 C:foo.h C:h.foo (logical path variable)
1324 sys/os.h sys.h.os (C compiler groks Unix-speak)
1325 10charname.c c.10charname
1326 10charname.o o.10charname
1327 11charname_.c c.11charname (assuming filesystem truncates at 10)
1328
1329The Unix emulation library's translation of filenames to native assumes
b7df3edc
GS
1330that this sort of translation is required, and it allows a user-defined list
1331of known suffixes that it will transpose in this fashion. This may
1332seem transparent, but consider that with these rules C<foo/bar/baz.h>
0a47030a
GS
1333and C<foo/bar/h/baz> both map to C<foo.bar.h.baz>, and that C<readdir> and
1334C<glob> cannot and do not attempt to emulate the reverse mapping. Other
6ab3f9cb 1335C<.>'s in filenames are translated to C</>.
0a47030a 1336
b7df3edc 1337As implied above, the environment accessed through C<%ENV> is global, and
0a47030a 1338the convention is that program specific environment variables are of the
6ab3f9cb
GS
1339form C<Program$Name>. Each filesystem maintains a current directory,
1340and the current filesystem's current directory is the B<global> current
b7df3edc
GS
1341directory. Consequently, sociable programs don't change the current
1342directory but rely on full pathnames, and programs (and Makefiles) cannot
0a47030a
GS
1343assume that they can spawn a child process which can change the current
1344directory without affecting its parent (and everyone else for that
1345matter).
1346
b7df3edc
GS
1347Because native operating system filehandles are global and are currently
1348allocated down from 255, with 0 being a reserved value, the Unix emulation
0a47030a
GS
1349library emulates Unix filehandles. Consequently, you can't rely on
1350passing C<STDIN>, C<STDOUT>, or C<STDERR> to your children.
1351
1352The desire of users to express filenames of the form
c47ff5f1 1353C<< <Foo$Dir>.Bar >> on the command line unquoted causes problems,
0a47030a 1354too: C<``> command output capture has to perform a guessing game. It
c47ff5f1 1355assumes that a string C<< <[^<>]+\$[^<>]> >> is a
0a47030a 1356reference to an environment variable, whereas anything else involving
c47ff5f1 1357C<< < >> or C<< > >> is redirection, and generally manages to be 99%
0a47030a
GS
1358right. Of course, the problem remains that scripts cannot rely on any
1359Unix tools being available, or that any tools found have Unix-like command
1360line arguments.
1361
b7df3edc
GS
1362Extensions and XS are, in theory, buildable by anyone using free
1363tools. In practice, many don't, as users of the Acorn platform are
1364used to binary distributions. MakeMaker does run, but no available
1365make currently copes with MakeMaker's makefiles; even if and when
1366this should be fixed, the lack of a Unix-like shell will cause
1367problems with makefile rules, especially lines of the form C<cd
1368sdbm && make all>, and anything using quoting.
b8099c3d
CN
1369
1370"S<RISC OS>" is the proper name for the operating system, but the value
1371in C<$^O> is "riscos" (because we don't like shouting).
1372
e41182b5
GS
1373=head2 Other perls
1374
b7df3edc
GS
1375Perl has been ported to many platforms that do not fit into any of
1376the categories listed above. Some, such as AmigaOS, Atari MiNT,
1377BeOS, HP MPE/iX, QNX, Plan 9, and VOS, have been well-integrated
1378into the standard Perl source code kit. You may need to see the
1379F<ports/> directory on CPAN for information, and possibly binaries,
1380for the likes of: aos, Atari ST, lynxos, riscos, Novell Netware,
1381Tandem Guardian, I<etc.> (Yes, we know that some of these OSes may
1382fall under the Unix category, but we are not a standards body.)
e41182b5 1383
d1e3b762
GS
1384Some approximate operating system names and their C<$^O> values
1385in the "OTHER" category include:
1386
1387 OS $^O $Config{'archname'}
1388 ------------------------------------------
1389 Amiga DOS amigaos m68k-amigos
cec2c193 1390 BeOS beos
d1e3b762
GS
1391 MPE/iX mpeix PA-RISC1.1
1392
e41182b5
GS
1393See also:
1394
1395=over 4
1396
c997b287
GS
1397=item *
1398
1399Amiga, F<README.amiga> (installed as L<perlamiga>).
1400
1401=item *
d1e3b762 1402
c997b287
GS
1403Atari, F<README.mint> and Guido Flohr's web page
1404http://stud.uni-sb.de/~gufl0000/
e41182b5 1405
c997b287 1406=item *
d1e3b762 1407
c997b287 1408Be OS, F<README.beos>
e41182b5 1409
c997b287
GS
1410=item *
1411
1412HP 300 MPE/iX, F<README.mpeix> and Mark Bixby's web page
34aaaa84 1413http://www.bixby.org/mark/perlix.html
c997b287
GS
1414
1415=item *
e41182b5 1416
6ab3f9cb 1417A free perl5-based PERL.NLM for Novell Netware is available in
c997b287 1418precompiled binary and source code form from http://www.novell.com/
6ab3f9cb 1419as well as from CPAN.
e41182b5 1420
13a2d996 1421=item *
c997b287 1422
e6f03d26 1423S<Plan 9>, F<README.plan9>
d1e3b762 1424
e41182b5
GS
1425=back
1426
e41182b5
GS
1427=head1 FUNCTION IMPLEMENTATIONS
1428
b7df3edc
GS
1429Listed below are functions that are either completely unimplemented
1430or else have been implemented differently on various platforms.
1431Following each description will be, in parentheses, a list of
1432platforms that the description applies to.
e41182b5 1433
b7df3edc
GS
1434The list may well be incomplete, or even wrong in some places. When
1435in doubt, consult the platform-specific README files in the Perl
1436source distribution, and any other documentation resources accompanying
1437a given port.
e41182b5 1438
0a47030a 1439Be aware, moreover, that even among Unix-ish systems there are variations.
e41182b5 1440
b7df3edc
GS
1441For many functions, you can also query C<%Config>, exported by
1442default from the Config module. For example, to check whether the
1443platform has the C<lstat> call, check C<$Config{d_lstat}>. See
1444L<Config> for a full description of available variables.
e41182b5
GS
1445
1446=head2 Alphabetical Listing of Perl Functions
1447
1448=over 8
1449
1450=item -X FILEHANDLE
1451
1452=item -X EXPR
1453
1454=item -X
1455
b7df3edc 1456C<-r>, C<-w>, and C<-x> have a limited meaning only; directories
e41182b5 1457and applications are executable, and there are no uid/gid
b7df3edc 1458considerations. C<-o> is not supported. (S<Mac OS>)
e41182b5 1459
b7df3edc
GS
1460C<-r>, C<-w>, C<-x>, and C<-o> tell whether the file is accessible,
1461which may not reflect UIC-based file protections. (VMS)
e41182b5 1462
b8099c3d
CN
1463C<-s> returns the size of the data fork, not the total size of data fork
1464plus resource fork. (S<Mac OS>).
1465
1466C<-s> by name on an open file will return the space reserved on disk,
1467rather than the current extent. C<-s> on an open filehandle returns the
b7df3edc 1468current size. (S<RISC OS>)
b8099c3d 1469
e41182b5 1470C<-R>, C<-W>, C<-X>, C<-O> are indistinguishable from C<-r>, C<-w>,
b8099c3d 1471C<-x>, C<-o>. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1472
1473C<-b>, C<-c>, C<-k>, C<-g>, C<-p>, C<-u>, C<-A> are not implemented.
1474(S<Mac OS>)
1475
1476C<-g>, C<-k>, C<-l>, C<-p>, C<-u>, C<-A> are not particularly meaningful.
b8099c3d 1477(Win32, VMS, S<RISC OS>)
e41182b5
GS
1478
1479C<-d> is true if passed a device spec without an explicit directory.
1480(VMS)
1481
1482C<-T> and C<-B> are implemented, but might misclassify Mac text files
0a47030a 1483with foreign characters; this is the case will all platforms, but may
b7df3edc 1484affect S<Mac OS> often. (S<Mac OS>)
e41182b5
GS
1485
1486C<-x> (or C<-X>) determine if a file ends in one of the executable
b7df3edc 1487suffixes. C<-S> is meaningless. (Win32)
e41182b5 1488
b8099c3d
CN
1489C<-x> (or C<-X>) determine if a file has an executable file type.
1490(S<RISC OS>)
1491
63f87e49
GS
1492=item alarm SECONDS
1493
1494=item alarm
1495
1496Not implemented. (Win32)
1497
e41182b5
GS
1498=item binmode FILEHANDLE
1499
b7df3edc 1500Meaningless. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1501
1502Reopens file and restores pointer; if function fails, underlying
1503filehandle may be closed, or pointer may be in a different position.
1504(VMS)
1505
1506The value returned by C<tell> may be affected after the call, and
1507the filehandle may be flushed. (Win32)
1508
1509=item chmod LIST
1510
b7df3edc 1511Only limited meaning. Disabling/enabling write permission is mapped to
e41182b5
GS
1512locking/unlocking the file. (S<Mac OS>)
1513
1514Only good for changing "owner" read-write access, "group", and "other"
1515bits are meaningless. (Win32)
1516
b8099c3d
CN
1517Only good for changing "owner" and "other" read-write access. (S<RISC OS>)
1518
495c5fdc
GP
1519Access permissions are mapped onto VOS access-control list changes. (VOS)
1520
4e51f8e4 1521The actual permissions set depend on the value of the C<CYGWIN>
789f0d36 1522in the SYSTEM environment settings. (Cygwin)
4e51f8e4 1523
e41182b5
GS
1524=item chown LIST
1525
3fd80bd6 1526Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1527
1528Does nothing, but won't fail. (Win32)
1529
3fd80bd6
PG
1530A little funky, because VOS's notion of ownership is a little funky (VOS).
1531
e41182b5
GS
1532=item chroot FILENAME
1533
1534=item chroot
1535
e6f03d26 1536Not implemented. (S<Mac OS>, Win32, VMS, S<Plan 9>, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1537
1538=item crypt PLAINTEXT,SALT
1539
1540May not be available if library or source was not provided when building
b8099c3d 1541perl. (Win32)
e41182b5
GS
1542
1543=item dbmclose HASH
1544
e6f03d26 1545Not implemented. (VMS, S<Plan 9>, VOS)
e41182b5
GS
1546
1547=item dbmopen HASH,DBNAME,MODE
1548
e6f03d26 1549Not implemented. (VMS, S<Plan 9>, VOS)
e41182b5
GS
1550
1551=item dump LABEL
1552
b8099c3d 1553Not useful. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1554
1555Not implemented. (Win32)
1556
b8099c3d 1557Invokes VMS debugger. (VMS)
e41182b5
GS
1558
1559=item exec LIST
1560
1561Not implemented. (S<Mac OS>)
1562
7c5ffed3 1563Implemented via Spawn. (VM/ESA)
3c075c7d 1564
0f897271
GS
1565Does not automatically flush output handles on some platforms.
1566(SunOS, Solaris, HP-UX)
1567
fe12c0e8
MS
1568=item exit EXPR
1569
1570=item exit
1571
1572Emulates UNIX exit() (which considers C<exit 1> to indicate an error) by
1573mapping the C<1> to SS$_ABORT (C<44>). This behavior may be overridden
1574with the pragma C<use vmsish 'exit'>. As with the CRTL's exit()
1575function, C<exit 0> is also mapped to an exit status of SS$_NORMAL
1576(C<1>); this mapping cannot be overridden. Any other argument to exit()
1577is used directly as Perl's exit status. (VMS)
1578
e41182b5
GS
1579=item fcntl FILEHANDLE,FUNCTION,SCALAR
1580
1581Not implemented. (Win32, VMS)
1582
1583=item flock FILEHANDLE,OPERATION
1584
495c5fdc 1585Not implemented (S<Mac OS>, VMS, S<RISC OS>, VOS).
e41182b5
GS
1586
1587Available only on Windows NT (not on Windows 95). (Win32)
1588
1589=item fork
1590
3fd80bd6 1591Not implemented. (S<Mac OS>, AmigaOS, S<RISC OS>, VM/ESA, VMS)
0f897271
GS
1592
1593Emulated using multiple interpreters. See L<perlfork>. (Win32)
1594
1595Does not automatically flush output handles on some platforms.
1596(SunOS, Solaris, HP-UX)
e41182b5
GS
1597
1598=item getlogin
1599
b8099c3d 1600Not implemented. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1601
1602=item getpgrp PID
1603
3fd80bd6 1604Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1605
1606=item getppid
1607
41cbbefa 1608Not implemented. (S<Mac OS>, Win32, S<RISC OS>)
e41182b5
GS
1609
1610=item getpriority WHICH,WHO
1611
7c5ffed3 1612Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1613
1614=item getpwnam NAME
1615
1616Not implemented. (S<Mac OS>, Win32)
1617
b8099c3d
CN
1618Not useful. (S<RISC OS>)
1619
e41182b5
GS
1620=item getgrnam NAME
1621
b8099c3d 1622Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1623
1624=item getnetbyname NAME
1625
e6f03d26 1626Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1627
1628=item getpwuid UID
1629
1630Not implemented. (S<Mac OS>, Win32)
1631
b8099c3d
CN
1632Not useful. (S<RISC OS>)
1633
e41182b5
GS
1634=item getgrgid GID
1635
b8099c3d 1636Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1637
1638=item getnetbyaddr ADDR,ADDRTYPE
1639
e6f03d26 1640Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1641
1642=item getprotobynumber NUMBER
1643
1644Not implemented. (S<Mac OS>)
1645
1646=item getservbyport PORT,PROTO
1647
1648Not implemented. (S<Mac OS>)
1649
1650=item getpwent
1651
7c5ffed3 1652Not implemented. (S<Mac OS>, Win32, VM/ESA)
e41182b5
GS
1653
1654=item getgrent
1655
7c5ffed3 1656Not implemented. (S<Mac OS>, Win32, VMS, VM/ESA)
e41182b5 1657
ef5a6dd7
JH
1658=item gethostbyname
1659
1660C<gethostbyname('localhost')> does not work everywhere: you may have
1661to use C<gethostbyname('127.0.0.1')>. (S<Mac OS>, S<Irix 5>)
1662
e41182b5
GS
1663=item gethostent
1664
1665Not implemented. (S<Mac OS>, Win32)
1666
1667=item getnetent
1668
e6f03d26 1669Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1670
1671=item getprotoent
1672
e6f03d26 1673Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1674
1675=item getservent
1676
e6f03d26 1677Not implemented. (Win32, S<Plan 9>)
e41182b5 1678
e41182b5
GS
1679=item sethostent STAYOPEN
1680
e6f03d26 1681Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1682
1683=item setnetent STAYOPEN
1684
e6f03d26 1685Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1686
1687=item setprotoent STAYOPEN
1688
e6f03d26 1689Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1690
1691=item setservent STAYOPEN
1692
e6f03d26 1693Not implemented. (S<Plan 9>, Win32, S<RISC OS>)
e41182b5
GS
1694
1695=item endpwent
1696
a3dfe201 1697Not implemented. (S<Mac OS>, MPE/iX, VM/ESA, Win32)
e41182b5
GS
1698
1699=item endgrent
1700
a3dfe201 1701Not implemented. (S<Mac OS>, MPE/iX, S<RISC OS>, VM/ESA, VMS, Win32)
e41182b5
GS
1702
1703=item endhostent
1704
1705Not implemented. (S<Mac OS>, Win32)
1706
1707=item endnetent
1708
e6f03d26 1709Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1710
1711=item endprotoent
1712
e6f03d26 1713Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1714
1715=item endservent
1716
e6f03d26 1717Not implemented. (S<Plan 9>, Win32)
e41182b5
GS
1718
1719=item getsockopt SOCKET,LEVEL,OPTNAME
1720
e6f03d26 1721Not implemented. (S<Plan 9>)
e41182b5
GS
1722
1723=item glob EXPR
1724
1725=item glob
1726
63f87e49
GS
1727This operator is implemented via the File::Glob extension on most
1728platforms. See L<File::Glob> for portability information.
b8099c3d 1729
e41182b5
GS
1730=item ioctl FILEHANDLE,FUNCTION,SCALAR
1731
1732Not implemented. (VMS)
1733
1734Available only for socket handles, and it does what the ioctlsocket() call
1735in the Winsock API does. (Win32)
1736
b8099c3d
CN
1737Available only for socket handles. (S<RISC OS>)
1738
b350dd2f 1739=item kill SIGNAL, LIST
e41182b5 1740
862b5365
JH
1741C<kill(0, LIST)> is implemented for the sake of taint checking;
1742use with other signals is unimplemented. (S<Mac OS>)
1743
1744Not implemented, hence not useful for taint checking. (S<RISC OS>)
e41182b5 1745
63f87e49
GS
1746C<kill()> doesn't have the semantics of C<raise()>, i.e. it doesn't send
1747a signal to the identified process like it does on Unix platforms.
1748Instead C<kill($sig, $pid)> terminates the process identified by $pid,
1749and makes it exit immediately with exit status $sig. As in Unix, if
1750$sig is 0 and the specified process exists, it returns true without
1751actually terminating it. (Win32)
e41182b5
GS
1752
1753=item link OLDFILE,NEWFILE
1754
a3dfe201 1755Not implemented. (S<Mac OS>, MPE/iX, VMS, S<RISC OS>)
e41182b5 1756
433acd8a
JH
1757Link count not updated because hard links are not quite that hard
1758(They are sort of half-way between hard and soft links). (AmigaOS)
1759
a3dfe201
GS
1760Hard links are implemented on Win32 (Windows NT and Windows 2000)
1761under NTFS only.
1762
e41182b5
GS
1763=item lstat FILEHANDLE
1764
1765=item lstat EXPR
1766
1767=item lstat
1768
b8099c3d 1769Not implemented. (VMS, S<RISC OS>)
e41182b5 1770
63f87e49 1771Return values (especially for device and inode) may be bogus. (Win32)
e41182b5
GS
1772
1773=item msgctl ID,CMD,ARG
1774
1775=item msgget KEY,FLAGS
1776
1777=item msgsnd ID,MSG,FLAGS
1778
1779=item msgrcv ID,VAR,SIZE,TYPE,FLAGS
1780
e6f03d26 1781Not implemented. (S<Mac OS>, Win32, VMS, S<Plan 9>, S<RISC OS>, VOS)
e41182b5
GS
1782
1783=item open FILEHANDLE,EXPR
1784
1785=item open FILEHANDLE
1786
b7df3edc 1787The C<|> variants are supported only if ToolServer is installed.
e41182b5
GS
1788(S<Mac OS>)
1789
c47ff5f1 1790open to C<|-> and C<-|> are unsupported. (S<Mac OS>, Win32, S<RISC OS>)
e41182b5 1791
0f897271
GS
1792Opening a process does not automatically flush output handles on some
1793platforms. (SunOS, Solaris, HP-UX)
1794
e41182b5
GS
1795=item pipe READHANDLE,WRITEHANDLE
1796
433acd8a
JH
1797Very limited functionality. (MiNT)
1798
e41182b5
GS
1799=item readlink EXPR
1800
1801=item readlink
1802
b8099c3d 1803Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5
GS
1804
1805=item select RBITS,WBITS,EBITS,TIMEOUT
1806
689c5c24 1807Only implemented on sockets. (Win32, VMS)
e41182b5 1808
b8099c3d
CN
1809Only reliable on sockets. (S<RISC OS>)
1810
76e05f0b 1811Note that the C<select FILEHANDLE> form is generally portable.
63f87e49 1812
e41182b5
GS
1813=item semctl ID,SEMNUM,CMD,ARG
1814
1815=item semget KEY,NSEMS,FLAGS
1816
1817=item semop KEY,OPSTRING
1818
495c5fdc 1819Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1820
a3dfe201
GS
1821=item setgrent
1822
3fd80bd6 1823Not implemented. (S<Mac OS>, MPE/iX, VMS, Win32, S<RISC OS>, VOS)
a3dfe201 1824
e41182b5
GS
1825=item setpgrp PID,PGRP
1826
495c5fdc 1827Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5
GS
1828
1829=item setpriority WHICH,WHO,PRIORITY
1830
495c5fdc 1831Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1832
a3dfe201
GS
1833=item setpwent
1834
3fd80bd6 1835Not implemented. (S<Mac OS>, MPE/iX, Win32, S<RISC OS>, VOS)
a3dfe201 1836
e41182b5
GS
1837=item setsockopt SOCKET,LEVEL,OPTNAME,OPTVAL
1838
e6f03d26 1839Not implemented. (S<Plan 9>)
e41182b5
GS
1840
1841=item shmctl ID,CMD,ARG
1842
1843=item shmget KEY,SIZE,FLAGS
1844
1845=item shmread ID,VAR,POS,SIZE
1846
1847=item shmwrite ID,STRING,POS,SIZE
1848
495c5fdc 1849Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1850
80cbd5ad
JH
1851=item sockatmark SOCKET
1852
1853A relatively recent addition to socket functions, may not
1854be implemented even in UNIX platforms.
1855
e41182b5
GS
1856=item socketpair SOCKET1,SOCKET2,DOMAIN,TYPE,PROTOCOL
1857
862b5365 1858Not implemented. (Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1859
1860=item stat FILEHANDLE
1861
1862=item stat EXPR
1863
1864=item stat
1865
d62e1b7f
JH
1866Platforms that do not have rdev, blksize, or blocks will return these
1867as '', so numeric comparison or manipulation of these fields may cause
1868'not numeric' warnings.
1869
e41182b5 1870mtime and atime are the same thing, and ctime is creation time instead of
3f1f789b
JH
1871inode change time. (S<Mac OS>).
1872
1873ctime not supported on UFS (S<Mac OS X>).
e41182b5 1874
95a3fe12
MS
1875ctime is creation time instead of inode change time (Win32).
1876
e41182b5
GS
1877device and inode are not meaningful. (Win32)
1878
1879device and inode are not necessarily reliable. (VMS)
1880
b8099c3d
CN
1881mtime, atime and ctime all return the last modification time. Device and
1882inode are not necessarily reliable. (S<RISC OS>)
1883
d62e1b7f
JH
1884dev, rdev, blksize, and blocks are not available. inode is not
1885meaningful and will differ between stat calls on the same file. (os2)
1886
73e9292c
JH
1887some versions of cygwin when doing a stat("foo") and if not finding it
1888may then attempt to stat("foo.exe") (Cygwin)
1889
e41182b5
GS
1890=item symlink OLDFILE,NEWFILE
1891
b8099c3d 1892Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5
GS
1893
1894=item syscall LIST
1895
7c5ffed3 1896Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5 1897
f34d0673
GS
1898=item sysopen FILEHANDLE,FILENAME,MODE,PERMS
1899
dd9f0070 1900The traditional "0", "1", and "2" MODEs are implemented with different
322422de
GS
1901numeric values on some systems. The flags exported by C<Fcntl>
1902(O_RDONLY, O_WRONLY, O_RDWR) should work everywhere though. (S<Mac
7c5ffed3 1903OS>, OS/390, VM/ESA)
f34d0673 1904
e41182b5
GS
1905=item system LIST
1906
9d6eb86e 1907In general, do not assume the UNIX/POSIX semantics that you can shift
7717d0e7 1908C<$?> right by eight to get the exit value, or that C<$? & 127>
9d6eb86e
JH
1909would give you the number of the signal that terminated the program,
1910or that C<$? & 128> would test true if the program was terminated by a
1911coredump. Instead, use the POSIX W*() interfaces: for example, use
74555b7a
PP
1912WIFEXITED($?) and WEXITVALUE($?) to test for a normal exit and the exit
1913value, WIFSIGNALED($?) and WTERMSIG($?) for a signal exit and the
7717d0e7 1914signal. Core dumping is not a portable concept, so there's no portable
9d6eb86e
JH
1915way to test for that.
1916
e41182b5
GS
1917Only implemented if ToolServer is installed. (S<Mac OS>)
1918
1919As an optimization, may not call the command shell specified in
b7df3edc 1920C<$ENV{PERL5SHELL}>. C<system(1, @args)> spawns an external
e41182b5
GS
1921process and immediately returns its process designator, without
1922waiting for it to terminate. Return value may be used subsequently
63f87e49
GS
1923in C<wait> or C<waitpid>. Failure to spawn() a subprocess is indicated
1924by setting $? to "255 << 8". C<$?> is set in a way compatible with
1925Unix (i.e. the exitstatus of the subprocess is obtained by "$? >> 8",
1926as described in the documentation). (Win32)
e41182b5 1927
b8099c3d
CN
1928There is no shell to process metacharacters, and the native standard is
1929to pass a command line terminated by "\n" "\r" or "\0" to the spawned
c47ff5f1 1930program. Redirection such as C<< > foo >> is performed (if at all) by
b8099c3d
CN
1931the run time library of the spawned program. C<system> I<list> will call
1932the Unix emulation library's C<exec> emulation, which attempts to provide
1933emulation of the stdin, stdout, stderr in force in the parent, providing
1934the child program uses a compatible version of the emulation library.
1935I<scalar> will call the native command line direct and no such emulation
1936of a child Unix program will exists. Mileage B<will> vary. (S<RISC OS>)
1937
433acd8a
JH
1938Far from being POSIX compliant. Because there may be no underlying
1939/bin/sh tries to work around the problem by forking and execing the
9b63e9ec 1940first token in its argument string. Handles basic redirection
c47ff5f1 1941("<" or ">") on its own behalf. (MiNT)
433acd8a 1942
0f897271
GS
1943Does not automatically flush output handles on some platforms.
1944(SunOS, Solaris, HP-UX)
1945
9bc98430
CB
1946The return value is POSIX-like (shifted up by 8 bits), which only allows
1947room for a made-up value derived from the severity bits of the native
194832-bit condition code (unless overridden by C<use vmsish 'status'>).
1949For more details see L<perlvms/$?>. (VMS)
1950
e41182b5
GS
1951=item times
1952
1953Only the first entry returned is nonzero. (S<Mac OS>)
1954
63f87e49
GS
1955"cumulative" times will be bogus. On anything other than Windows NT
1956or Windows 2000, "system" time will be bogus, and "user" time is
1957actually the time returned by the clock() function in the C runtime
1958library. (Win32)
e41182b5 1959
b8099c3d
CN
1960Not useful. (S<RISC OS>)
1961
e41182b5
GS
1962=item truncate FILEHANDLE,LENGTH
1963
1964=item truncate EXPR,LENGTH
1965
6d738113 1966Not implemented. (Older versions of VMS)
e41182b5 1967
3fd80bd6 1968Truncation to same-or-shorter lengths only. (VOS)
495c5fdc 1969
4cfdb94f 1970If a FILEHANDLE is supplied, it must be writable and opened in append
e71a7dc8 1971mode (i.e., use C<<< open(FH, '>>filename') >>>
4cfdb94f
GS
1972or C<sysopen(FH,...,O_APPEND|O_RDWR)>. If a filename is supplied, it
1973should not be held open elsewhere. (Win32)
1974
e41182b5
GS
1975=item umask EXPR
1976
1977=item umask
1978
1979Returns undef where unavailable, as of version 5.005.
1980
b7df3edc
GS
1981C<umask> works but the correct permissions are set only when the file
1982is finally closed. (AmigaOS)
433acd8a 1983
e41182b5
GS
1984=item utime LIST
1985
15c65113 1986Only the modification time is updated. (S<BeOS>, S<Mac OS>, VMS, S<RISC OS>)
e41182b5 1987
322422de
GS
1988May not behave as expected. Behavior depends on the C runtime
1989library's implementation of utime(), and the filesystem being
1990used. The FAT filesystem typically does not support an "access
1991time" field, and it may limit timestamps to a granularity of
1992two seconds. (Win32)
e41182b5
GS
1993
1994=item wait
1995
1996=item waitpid PID,FLAGS
1997
3fd80bd6 1998Not implemented. (S<Mac OS>)
e41182b5
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1999
2000Can only be applied to process handles returned for processes spawned
a6f858fb 2001using C<system(1, ...)> or pseudo processes created with C<fork()>. (Win32)
e41182b5 2002
b8099c3d
CN
2003Not useful. (S<RISC OS>)
2004
e41182b5
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2005=back
2006
b8099c3d
CN
2007=head1 CHANGES
2008
2009=over 4
2010
3fd80bd6
PG
2011=item v1.49, 12 August 2002
2012
2013Updates for VOS from Paul Green.
2014
fd46a41b
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2015=item v1.48, 02 February 2001
2016
2017Various updates from perl5-porters over the past year, supported
2018platforms update from Jarkko Hietaniemi.
2019
c997b287
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2020=item v1.47, 22 March 2000
2021
2022Various cleanups from Tom Christiansen, including migration of
2023long platform listings from L<perl>.
2024
56d7751a
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2025=item v1.46, 12 February 2000
2026
2027Updates for VOS and MPE/iX. (Peter Prymmer) Other small changes.
2028
0cc436d0
GS
2029=item v1.45, 20 December 1999
2030
2031Small changes from 5.005_63 distribution, more changes to EBCDIC info.
2032
d1e3b762
GS
2033=item v1.44, 19 July 1999
2034
2035A bunch of updates from Peter Prymmer for C<$^O> values,
2036endianness, File::Spec, VMS, BS2000, OS/400.
2037
b7df3edc
GS
2038=item v1.43, 24 May 1999
2039
2040Added a lot of cleaning up from Tom Christiansen.
2041
19799a22 2042=item v1.42, 22 May 1999
b7df3edc 2043
19799a22 2044Added notes about tests, sprintf/printf, and epoch offsets.
b7df3edc 2045
6ab3f9cb
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2046=item v1.41, 19 May 1999
2047
2048Lots more little changes to formatting and content.
2049
d1e3b762 2050Added a bunch of C<$^O> and related values
6ab3f9cb
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2051for various platforms; fixed mail and web addresses, and added
2052and changed miscellaneous notes. (Peter Prymmer)
2053
2054=item v1.40, 11 April 1999
2055
2056Miscellaneous changes.
2057
2058=item v1.39, 11 February 1999
2ee0eb3c
CN
2059
2060Changes from Jarkko and EMX URL fixes Michael Schwern. Additional
2061note about newlines added.
2062
9b63e9ec
CN
2063=item v1.38, 31 December 1998
2064
2065More changes from Jarkko.
2066
3c075c7d
CN
2067=item v1.37, 19 December 1998
2068
2069More minor changes. Merge two separate version 1.35 documents.
2070
2071=item v1.36, 9 September 1998
2072
2073Updated for Stratus VOS. Also known as version 1.35.
2074
2075=item v1.35, 13 August 1998
495c5fdc 2076
3c075c7d
CN
2077Integrate more minor changes, plus addition of new sections under
2078L<"ISSUES">: L<"Numbers endianness and Width">,
2079L<"Character sets and character encoding">,
2080L<"Internationalisation">.
495c5fdc 2081
3c075c7d 2082=item v1.33, 06 August 1998
0a47030a
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2083
2084Integrate more minor changes.
2085
3c075c7d 2086=item v1.32, 05 August 1998
dd9f0070
CN
2087
2088Integrate more minor changes.
2089
3c075c7d 2090=item v1.30, 03 August 1998
b8099c3d
CN
2091
2092Major update for RISC OS, other minor changes.
2093
3c075c7d 2094=item v1.23, 10 July 1998
b8099c3d
CN
2095
2096First public release with perl5.005.
2097
2098=back
e41182b5 2099
ba58ab26
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2100=head1 Supported Platforms
2101
522b859a 2102As of July 2002 (the Perl release 5.8.0), the following platforms are
cec2c193
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2103able to build Perl from the standard source code distribution
2104available at http://www.cpan.org/src/index.html
2105
2106 AIX
2107 BeOS
6f683aa2 2108 BSD/OS (BSDi)
cec2c193
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2109 Cygwin
2110 DG/UX
811b48f2 2111 DOS DJGPP 1)
cec2c193
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2112 DYNIX/ptx
2113 EPOC R5
2114 FreeBSD
6f683aa2 2115 HI-UXMPP (Hitachi) (5.8.0 worked but we didn't know it)
cec2c193
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2116 HP-UX
2117 IRIX
2118 Linux
8939ba94 2119 Mac OS Classic
6f683aa2 2120 Mac OS X (Darwin)
cec2c193
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2121 MPE/iX
2122 NetBSD
2123 NetWare
2124 NonStop-UX
6f683aa2 2125 ReliantUNIX (formerly SINIX)
cec2c193 2126 OpenBSD
6f683aa2 2127 OpenVMS (formerly VMS)
3ebac25b 2128 Open UNIX (Unixware) (since Perl 5.8.1/5.9.0)
cec2c193 2129 OS/2
522b859a 2130 OS/400 (using the PASE) (since Perl 5.8.1/5.9.0)
70de81db 2131 PowerUX
6f683aa2 2132 POSIX-BC (formerly BS2000)
cec2c193
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2133 QNX
2134 Solaris
70de81db 2135 SunOS 4
6f683aa2
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2136 SUPER-UX (NEC)
2137 Tru64 UNIX (formerly DEC OSF/1, Digital UNIX)
cec2c193
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2138 UNICOS
2139 UNICOS/mk
2140 UTS
2141 VOS
811b48f2 2142 Win95/98/ME/2K/XP 2)
c40b5d1d 2143 WinCE
6f683aa2 2144 z/OS (formerly OS/390)
cec2c193 2145 VM/ESA
ba58ab26 2146
811b48f2
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2147 1) in DOS mode either the DOS or OS/2 ports can be used
2148 2) compilers: Borland, MinGW (GCC), VC6
cec2c193 2149
c40b5d1d 2150The following platforms worked with the previous releases (5.6 and
cec2c193
JH
21515.7), but we did not manage either to fix or to test these in time
2152for the 5.8.0 release. There is a very good chance that many of these
70de81db 2153will work fine with the 5.8.0.
cec2c193 2154
8da2b1be 2155 BSD/OS
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2156 DomainOS
2157 Hurd
2158 LynxOS
2159 MachTen
2160 PowerMAX
2161 SCO SV
cec2c193
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2162 SVR4
2163 Unixware
2164 Windows 3.1
ba58ab26 2165
70de81db
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2166Known to be broken for 5.8.0 (but 5.6.1 and 5.7.2 can be used):
2167
2168 AmigaOS
2169
ba58ab26 2170The following platforms have been known to build Perl from source in
fd46a41b
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2171the past (5.005_03 and earlier), but we haven't been able to verify
2172their status for the current release, either because the
2173hardware/software platforms are rare or because we don't have an
2174active champion on these platforms--or both. They used to work,
2175though, so go ahead and try compiling them, and let perlbug@perl.org
2176of any trouble.
ba58ab26 2177
cec2c193
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2178 3b1
2179 A/UX
cec2c193
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2180 ConvexOS
2181 CX/UX
2182 DC/OSx
2183 DDE SMES
2184 DOS EMX
2185 Dynix
2186 EP/IX
2187 ESIX
2188 FPS
2189 GENIX
2190 Greenhills
2191 ISC
2192 MachTen 68k
2193 MiNT
2194 MPC
2195 NEWS-OS
2196 NextSTEP
2197 OpenSTEP
2198 Opus
2199 Plan 9
cec2c193 2200 RISC/os
8da2b1be 2201 SCO ODT/OSR
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2202 Stellar
2203 SVR2
2204 TI1500
2205 TitanOS
2206 Ultrix
2207 Unisys Dynix
ba58ab26
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2208
2209The following platforms have their own source code distributions and
1577cd80 2210binaries available via http://www.cpan.org/ports/
ba58ab26 2211
cec2c193 2212 Perl release
ba58ab26 2213
522b859a 2214 OS/400 (ILE) 5.005_02
cec2c193 2215 Tandem Guardian 5.004
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2216
2217The following platforms have only binaries available via
a93751fa 2218http://www.cpan.org/ports/index.html :
ba58ab26 2219
cec2c193 2220 Perl release
ba58ab26 2221
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2222 Acorn RISCOS 5.005_02
2223 AOS 5.002
2224 LynxOS 5.004_02
ba58ab26
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2225
2226Although we do suggest that you always build your own Perl from
2227the source code, both for maximal configurability and for security,
2228in case you are in a hurry you can check
a93751fa 2229http://www.cpan.org/ports/index.html for binary distributions.
ba58ab26 2230
c997b287
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2231=head1 SEE ALSO
2232
cec2c193 2233L<perlaix>, L<perlamiga>, L<perlapollo>, L<perlbeos>, L<perlbs2000>,
18a271bd 2234L<perlce>, L<perlcygwin>, L<perldgux>, L<perldos>, L<perlepoc>,
469e7be4 2235L<perlebcdic>, L<perlfreebsd>, L<perlhurd>, L<perlhpux>, L<perlirix>,
18a271bd 2236L<perlmachten>, L<perlmacos>, L<perlmint>, L<perlmpeix>,
522b859a
JH
2237L<perlnetware>, L<perlos2>, L<perlos390>, L<perlos400>,
2238L<perlplan9>, L<perlqnx>, L<perlsolaris>, L<perltru64>,
2239L<perlunicode>, L<perlvmesa>, L<perlvms>, L<perlvos>,
2240L<perlwin32>, and L<Win32>.
c997b287 2241
e41182b5
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2242=head1 AUTHORS / CONTRIBUTORS
2243
06e9666b 2244Abigail <abigail@foad.org>,
c47ff5f1
GS
2245Charles Bailey <bailey@newman.upenn.edu>,
2246Graham Barr <gbarr@pobox.com>,
2247Tom Christiansen <tchrist@perl.com>,
06e9666b 2248Nicholas Clark <nick@ccl4.org>,
c47ff5f1 2249Thomas Dorner <Thomas.Dorner@start.de>,
06e9666b
A
2250Andy Dougherty <doughera@lafayette.edu>,
2251Dominic Dunlop <domo@computer.org>,
2252Neale Ferguson <neale@vma.tabnsw.com.au>,
c47ff5f1 2253David J. Fiander <davidf@mks.com>,
3fd80bd6 2254Paul Green <Paul.Green@stratus.com>,
06e9666b 2255M.J.T. Guy <mjtg@cam.ac.uk>,
61f30a5e 2256Jarkko Hietaniemi <jhi@iki.fi>,
c47ff5f1 2257Luther Huffman <lutherh@stratcom.com>,
06e9666b
A
2258Nick Ing-Simmons <nick@ing-simmons.net>,
2259Andreas J. KE<ouml>nig <a.koenig@mind.de>,
c47ff5f1
GS
2260Markus Laker <mlaker@contax.co.uk>,
2261Andrew M. Langmead <aml@world.std.com>,
2262Larry Moore <ljmoore@freespace.net>,
2263Paul Moore <Paul.Moore@uk.origin-it.com>,
2264Chris Nandor <pudge@pobox.com>,
1afc07ec 2265Matthias Neeracher <neeracher@mac.com>,
e71a7dc8 2266Philip Newton <pne@cpan.org>,
c47ff5f1
GS
2267Gary Ng <71564.1743@CompuServe.COM>,
2268Tom Phoenix <rootbeer@teleport.com>,
2269AndrE<eacute> Pirard <A.Pirard@ulg.ac.be>,
2270Peter Prymmer <pvhp@forte.com>,
2271Hugo van der Sanden <hv@crypt0.demon.co.uk>,
2272Gurusamy Sarathy <gsar@activestate.com>,
2273Paul J. Schinder <schinder@pobox.com>,
2274Michael G Schwern <schwern@pobox.com>,
06e9666b 2275Dan Sugalski <dan@sidhe.org>,
c47ff5f1 2276Nathan Torkington <gnat@frii.com>.
e41182b5 2277