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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;
68fb0eb7
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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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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
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534use a module (that may internally implement it with platform-specific
535code, but expose a common interface).
e41182b5 536
e41182b5
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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.
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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
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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 $offset = Time::Local::timegm(0, 0, 0, 1, 0, 70);
b7df3edc 598
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599The value for C<$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.
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602
603=head2 Character sets and character encoding
604
ec481373
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605Assume very little about character sets.
606
607Assume nothing about numerical values (C<ord>, C<chr>) of characters.
608Do not use explicit code point ranges (like \xHH-\xHH); use for
609example symbolic character classes like C<[:print:]>.
610
611Do not assume that the alphabetic characters are encoded contiguously
612(in the numeric sense). There may be gaps.
613
614Do not assume anything about the ordering of the characters.
615The lowercase letters may come before or after the uppercase letters;
616the lowercase and uppercase may be interlaced so that both `a' and `A'
617come before `b'; the accented and other international characters may
618be interlaced so that E<auml> comes before `b'.
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619
620=head2 Internationalisation
621
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622If you may assume POSIX (a rather large assumption), you may read
623more about the POSIX locale system from L<perllocale>. The locale
624system at least attempts to make things a little bit more portable,
625or at least more convenient and native-friendly for non-English
626users. The system affects character sets and encoding, and date
627and time formatting--amongst other things.
e41182b5 628
c87488a3
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629If you really want to be international, you should consider Unicode.
630See L<perluniintro> and L<perlunicode> for more information.
631
e41182b5
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632=head2 System Resources
633
0a47030a
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634If your code is destined for systems with severely constrained (or
635missing!) virtual memory systems then you want to be I<especially> mindful
636of avoiding wasteful constructs such as:
e41182b5
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637
638 # NOTE: this is no longer "bad" in perl5.005
639 for (0..10000000) {} # bad
640 for (my $x = 0; $x <= 10000000; ++$x) {} # good
641
642 @lines = <VERY_LARGE_FILE>; # bad
643
644 while (<FILE>) {$file .= $_} # sometimes bad
0a47030a 645 $file = join('', <FILE>); # better
e41182b5 646
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647The last two constructs may appear unintuitive to most people. The
648first repeatedly grows a string, whereas the second allocates a
649large chunk of memory in one go. On some systems, the second is
650more efficient that the first.
0a47030a 651
e41182b5
GS
652=head2 Security
653
b7df3edc
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654Most multi-user platforms provide basic levels of security, usually
655implemented at the filesystem level. Some, however, do
a1667ba3 656not-- unfortunately. Thus the notion of user id, or "home" directory,
b7df3edc
GS
657or even the state of being logged-in, may be unrecognizable on many
658platforms. If you write programs that are security-conscious, it
659is usually best to know what type of system you will be running
660under so that you can write code explicitly for that platform (or
661class of platforms).
0a47030a 662
a1667ba3
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663Don't assume the UNIX filesystem access semantics: the operating
664system or the filesystem may be using some ACL systems, which are
665richer languages than the usual rwx. Even if the rwx exist,
666their semantics might be different.
667
668(From security viewpoint testing for permissions before attempting to
669do something is silly anyway: if one tries this, there is potential
670for race conditions-- someone or something might change the
671permissions between the permissions check and the actual operation.
672Just try the operation.)
673
674Don't assume the UNIX user and group semantics: especially, don't
2edcc0d9 675expect the C<< $< >> and C<< $> >> (or the C<$(> and C<$)>) to work
a1667ba3
JH
676for switching identities (or memberships).
677
678Don't assume set-uid and set-gid semantics. (And even if you do,
679think twice: set-uid and set-gid are a known can of security worms.)
680
e41182b5
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681=head2 Style
682
683For those times when it is necessary to have platform-specific code,
684consider keeping the platform-specific code in one place, making porting
6ab3f9cb 685to other platforms easier. Use the Config module and the special
0a47030a
GS
686variable C<$^O> to differentiate platforms, as described in
687L<"PLATFORMS">.
e41182b5 688
b7df3edc
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689Be careful in the tests you supply with your module or programs.
690Module code may be fully portable, but its tests might not be. This
691often happens when tests spawn off other processes or call external
692programs to aid in the testing, or when (as noted above) the tests
c87488a3
HS
693assume certain things about the filesystem and paths. Be careful not
694to depend on a specific output style for errors, such as when checking
695C<$!> after a failed system call. Using C<$!> for anything else than
696displaying it as output is doubtful (though see the Errno module for
697testing reasonably portably for error value). Some platforms expect
698a certain output format, and Perl on those platforms may have been
699adjusted accordingly. Most specifically, don't anchor a regex when
700testing an error value.
e41182b5 701
0a47030a 702=head1 CPAN Testers
e41182b5 703
0a47030a
GS
704Modules uploaded to CPAN are tested by a variety of volunteers on
705different platforms. These CPAN testers are notified by mail of each
e41182b5 706new upload, and reply to the list with PASS, FAIL, NA (not applicable to
0a47030a 707this platform), or UNKNOWN (unknown), along with any relevant notations.
e41182b5
GS
708
709The purpose of the testing is twofold: one, to help developers fix any
0a47030a 710problems in their code that crop up because of lack of testing on other
b7df3edc 711platforms; two, to provide users with information about whether
0a47030a 712a given module works on a given platform.
e41182b5
GS
713
714=over 4
715
716=item Mailing list: cpan-testers@perl.org
717
c997b287 718=item Testing results: http://testers.cpan.org/
e41182b5
GS
719
720=back
721
e41182b5
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722=head1 PLATFORMS
723
724As of version 5.002, Perl is built with a C<$^O> variable that
725indicates the operating system it was built on. This was implemented
b7df3edc
GS
726to help speed up code that would otherwise have to C<use Config>
727and use the value of C<$Config{osname}>. Of course, to get more
e41182b5
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728detailed information about the system, looking into C<%Config> is
729certainly recommended.
730
b7df3edc
GS
731C<%Config> cannot always be trusted, however, because it was built
732at compile time. If perl was built in one place, then transferred
733elsewhere, some values may be wrong. The values may even have been
734edited after the fact.
6ab3f9cb 735
e41182b5
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736=head2 Unix
737
738Perl works on a bewildering variety of Unix and Unix-like platforms (see
739e.g. most of the files in the F<hints/> directory in the source code kit).
740On most of these systems, the value of C<$^O> (hence C<$Config{'osname'}>,
d1e3b762
GS
741too) is determined either by lowercasing and stripping punctuation from the
742first field of the string returned by typing C<uname -a> (or a similar command)
743at the shell prompt or by testing the file system for the presence of
744uniquely named files such as a kernel or header file. Here, for example,
745are a few of the more popular Unix flavors:
e41182b5 746
b7df3edc 747 uname $^O $Config{'archname'}
6ab3f9cb 748 --------------------------------------------
b7df3edc 749 AIX aix aix
6ab3f9cb 750 BSD/OS bsdos i386-bsdos
e1516da7 751 Darwin darwin darwin
6ab3f9cb
GS
752 dgux dgux AViiON-dgux
753 DYNIX/ptx dynixptx i386-dynixptx
b7df3edc 754 FreeBSD freebsd freebsd-i386
d1e3b762 755 Linux linux arm-linux
b7df3edc 756 Linux linux i386-linux
6ab3f9cb
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757 Linux linux i586-linux
758 Linux linux ppc-linux
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759 HP-UX hpux PA-RISC1.1
760 IRIX irix irix
b787fad4 761 Mac OS X darwin darwin
d1e3b762
GS
762 MachTen PPC machten powerpc-machten
763 NeXT 3 next next-fat
764 NeXT 4 next OPENSTEP-Mach
6ab3f9cb 765 openbsd openbsd i386-openbsd
b7df3edc 766 OSF1 dec_osf alpha-dec_osf
6ab3f9cb
GS
767 reliantunix-n svr4 RM400-svr4
768 SCO_SV sco_sv i386-sco_sv
769 SINIX-N svr4 RM400-svr4
770 sn4609 unicos CRAY_C90-unicos
771 sn6521 unicosmk t3e-unicosmk
772 sn9617 unicos CRAY_J90-unicos
b7df3edc
GS
773 SunOS solaris sun4-solaris
774 SunOS solaris i86pc-solaris
775 SunOS4 sunos sun4-sunos
e41182b5 776
b7df3edc
GS
777Because the value of C<$Config{archname}> may depend on the
778hardware architecture, it can vary more than the value of C<$^O>.
6ab3f9cb 779
e41182b5
GS
780=head2 DOS and Derivatives
781
b7df3edc 782Perl has long been ported to Intel-style microcomputers running under
e41182b5
GS
783systems like PC-DOS, MS-DOS, OS/2, and most Windows platforms you can
784bring yourself to mention (except for Windows CE, if you count that).
b7df3edc 785Users familiar with I<COMMAND.COM> or I<CMD.EXE> style shells should
e41182b5
GS
786be aware that each of these file specifications may have subtle
787differences:
788
789 $filespec0 = "c:/foo/bar/file.txt";
790 $filespec1 = "c:\\foo\\bar\\file.txt";
791 $filespec2 = 'c:\foo\bar\file.txt';
792 $filespec3 = 'c:\\foo\\bar\\file.txt';
793
b7df3edc
GS
794System calls accept either C</> or C<\> as the path separator.
795However, many command-line utilities of DOS vintage treat C</> as
796the option prefix, so may get confused by filenames containing C</>.
797Aside from calling any external programs, C</> will work just fine,
798and probably better, as it is more consistent with popular usage,
799and avoids the problem of remembering what to backwhack and what
800not to.
e41182b5 801
b7df3edc
GS
802The DOS FAT filesystem can accommodate only "8.3" style filenames. Under
803the "case-insensitive, but case-preserving" HPFS (OS/2) and NTFS (NT)
0a47030a 804filesystems you may have to be careful about case returned with functions
e41182b5
GS
805like C<readdir> or used with functions like C<open> or C<opendir>.
806
b7df3edc
GS
807DOS also treats several filenames as special, such as AUX, PRN,
808NUL, CON, COM1, LPT1, LPT2, etc. Unfortunately, sometimes these
809filenames won't even work if you include an explicit directory
810prefix. It is best to avoid such filenames, if you want your code
811to be portable to DOS and its derivatives. It's hard to know what
812these all are, unfortunately.
e41182b5
GS
813
814Users of these operating systems may also wish to make use of
b7df3edc 815scripts such as I<pl2bat.bat> or I<pl2cmd> to
e41182b5
GS
816put wrappers around your scripts.
817
818Newline (C<\n>) is translated as C<\015\012> by STDIO when reading from
6ab3f9cb
GS
819and writing to files (see L<"Newlines">). C<binmode(FILEHANDLE)>
820will keep C<\n> translated as C<\012> for that filehandle. Since it is a
821no-op on other systems, C<binmode> should be used for cross-platform code
b7df3edc
GS
822that deals with binary data. That's assuming you realize in advance
823that your data is in binary. General-purpose programs should
824often assume nothing about their data.
e41182b5 825
b7df3edc 826The C<$^O> variable and the C<$Config{archname}> values for various
e41182b5
GS
827DOSish perls are as follows:
828
67ac489e
MS
829 OS $^O $Config{archname} ID Version
830 --------------------------------------------------------
831 MS-DOS dos ?
832 PC-DOS dos ?
833 OS/2 os2 ?
834 Windows 3.1 ? ? 0 3 01
835 Windows 95 MSWin32 MSWin32-x86 1 4 00
836 Windows 98 MSWin32 MSWin32-x86 1 4 10
837 Windows ME MSWin32 MSWin32-x86 1 ?
838 Windows NT MSWin32 MSWin32-x86 2 4 xx
839 Windows NT MSWin32 MSWin32-ALPHA 2 4 xx
840 Windows NT MSWin32 MSWin32-ppc 2 4 xx
841 Windows 2000 MSWin32 MSWin32-x86 2 5 xx
842 Windows XP MSWin32 MSWin32-x86 2 ?
843 Windows CE MSWin32 ? 3
844 Cygwin cygwin ?
e41182b5 845
34aaaa84
PP
846The various MSWin32 Perl's can distinguish the OS they are running on
847via the value of the fifth element of the list returned from
848Win32::GetOSVersion(). For example:
849
850 if ($^O eq 'MSWin32') {
851 my @os_version_info = Win32::GetOSVersion();
852 print +('3.1','95','NT')[$os_version_info[4]],"\n";
853 }
854
7939d86b
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855There are also Win32::IsWinNT() and Win32::IsWin95(), try C<perldoc Win32>,
856and as of libwin32 0.19 (not part of the core Perl distribution)
857Win32::GetOSName(). The very portable POSIX::uname() will work too:
1d65be3a
JH
858
859 c:\> perl -MPOSIX -we "print join '|', uname"
860 Windows NT|moonru|5.0|Build 2195 (Service Pack 2)|x86
d99f392e 861
e41182b5
GS
862Also see:
863
864=over 4
865
c997b287 866=item *
e41182b5 867
c997b287
GS
868The djgpp environment for DOS, http://www.delorie.com/djgpp/
869and L<perldos>.
e41182b5 870
c997b287 871=item *
e41182b5 872
c997b287
GS
873The EMX environment for DOS, OS/2, etc. emx@iaehv.nl,
874http://www.leo.org/pub/comp/os/os2/leo/gnu/emx+gcc/index.html or
f224927c 875ftp://hobbes.nmsu.edu/pub/os2/dev/emx/ Also L<perlos2>.
e41182b5 876
c997b287 877=item *
d1e3b762 878
c997b287
GS
879Build instructions for Win32 in L<perlwin32>, or under the Cygnus environment
880in L<perlcygwin>.
881
882=item *
883
884The C<Win32::*> modules in L<Win32>.
885
886=item *
887
888The ActiveState Pages, http://www.activestate.com/
889
890=item *
891
892The Cygwin environment for Win32; F<README.cygwin> (installed
47dafe4d 893as L<perlcygwin>), http://www.cygwin.com/
c997b287
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894
895=item *
896
897The U/WIN environment for Win32,
cea6626f 898http://www.research.att.com/sw/tools/uwin/
c997b287 899
cea6626f 900=item *
d1e3b762 901
cea6626f 902Build instructions for OS/2, L<perlos2>
d1e3b762 903
e41182b5
GS
904=back
905
dd9f0070 906=head2 S<Mac OS>
e41182b5
GS
907
908Any module requiring XS compilation is right out for most people, because
909MacPerl is built using non-free (and non-cheap!) compilers. Some XS
910modules that can work with MacPerl are built and distributed in binary
6ab3f9cb 911form on CPAN.
e41182b5
GS
912
913Directories are specified as:
914
915 volume:folder:file for absolute pathnames
916 volume:folder: for absolute pathnames
917 :folder:file for relative pathnames
918 :folder: for relative pathnames
919 :file for relative pathnames
920 file for relative pathnames
921
b7df3edc 922Files are stored in the directory in alphabetical order. Filenames are
6ab3f9cb 923limited to 31 characters, and may include any character except for
b7df3edc 924null and C<:>, which is reserved as the path separator.
e41182b5 925
0a47030a 926Instead of C<flock>, see C<FSpSetFLock> and C<FSpRstFLock> in the
6ab3f9cb 927Mac::Files module, or C<chmod(0444, ...)> and C<chmod(0666, ...)>.
e41182b5
GS
928
929In the MacPerl application, you can't run a program from the command line;
930programs that expect C<@ARGV> to be populated can be edited with something
931like the following, which brings up a dialog box asking for the command
932line arguments.
933
934 if (!@ARGV) {
935 @ARGV = split /\s+/, MacPerl::Ask('Arguments?');
936 }
937
b7df3edc 938A MacPerl script saved as a "droplet" will populate C<@ARGV> with the full
e41182b5
GS
939pathnames of the files dropped onto the script.
940
b7df3edc
GS
941Mac users can run programs under a type of command line interface
942under MPW (Macintosh Programmer's Workshop, a free development
943environment from Apple). MacPerl was first introduced as an MPW
944tool, and MPW can be used like a shell:
e41182b5
GS
945
946 perl myscript.plx some arguments
947
948ToolServer is another app from Apple that provides access to MPW tools
0a47030a 949from MPW and the MacPerl app, which allows MacPerl programs to use
e41182b5
GS
950C<system>, backticks, and piped C<open>.
951
952"S<Mac OS>" is the proper name for the operating system, but the value
953in C<$^O> is "MacOS". To determine architecture, version, or whether
954the application or MPW tool version is running, check:
955
956 $is_app = $MacPerl::Version =~ /App/;
957 $is_tool = $MacPerl::Version =~ /MPW/;
958 ($version) = $MacPerl::Version =~ /^(\S+)/;
959 $is_ppc = $MacPerl::Architecture eq 'MacPPC';
960 $is_68k = $MacPerl::Architecture eq 'Mac68K';
961
b787fad4
JH
962S<Mac OS X>, based on NeXT's OpenStep OS, runs MacPerl natively, under the
963"Classic" environment. There is no "Carbon" version of MacPerl to run
964under the primary Mac OS X environment. S<Mac OS X> and its Open Source
965version, Darwin, both run Unix perl natively.
6ab3f9cb 966
e41182b5
GS
967Also see:
968
969=over 4
970
c997b287
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971=item *
972
862b5365 973MacPerl Development, http://dev.macperl.org/ .
c997b287
GS
974
975=item *
976
862b5365 977The MacPerl Pages, http://www.macperl.com/ .
e41182b5 978
c997b287 979=item *
6ab3f9cb 980
862b5365 981The MacPerl mailing lists, http://lists.perl.org/ .
e41182b5
GS
982
983=back
984
e41182b5
GS
985=head2 VMS
986
c997b287 987Perl on VMS is discussed in L<perlvms> in the perl distribution.
b7df3edc 988Perl on VMS can accept either VMS- or Unix-style file
e41182b5
GS
989specifications as in either of the following:
990
991 $ perl -ne "print if /perl_setup/i" SYS$LOGIN:LOGIN.COM
992 $ perl -ne "print if /perl_setup/i" /sys$login/login.com
993
994but not a mixture of both as in:
995
996 $ perl -ne "print if /perl_setup/i" sys$login:/login.com
997 Can't open sys$login:/login.com: file specification syntax error
998
999Interacting with Perl from the Digital Command Language (DCL) shell
1000often requires a different set of quotation marks than Unix shells do.
1001For example:
1002
1003 $ perl -e "print ""Hello, world.\n"""
1004 Hello, world.
1005
b7df3edc 1006There are several ways to wrap your perl scripts in DCL F<.COM> files, if
e41182b5
GS
1007you are so inclined. For example:
1008
1009 $ write sys$output "Hello from DCL!"
1010 $ if p1 .eqs. ""
1011 $ then perl -x 'f$environment("PROCEDURE")
1012 $ else perl -x - 'p1 'p2 'p3 'p4 'p5 'p6 'p7 'p8
1013 $ deck/dollars="__END__"
1014 #!/usr/bin/perl
1015
1016 print "Hello from Perl!\n";
1017
1018 __END__
1019 $ endif
1020
1021Do take care with C<$ ASSIGN/nolog/user SYS$COMMAND: SYS$INPUT> if your
c47ff5f1 1022perl-in-DCL script expects to do things like C<< $read = <STDIN>; >>.
e41182b5
GS
1023
1024Filenames are in the format "name.extension;version". The maximum
1025length for filenames is 39 characters, and the maximum length for
1026extensions is also 39 characters. Version is a number from 1 to
102732767. Valid characters are C</[A-Z0-9$_-]/>.
1028
b7df3edc 1029VMS's RMS filesystem is case-insensitive and does not preserve case.
e41182b5 1030C<readdir> returns lowercased filenames, but specifying a file for
b7df3edc 1031opening remains case-insensitive. Files without extensions have a
e41182b5 1032trailing period on them, so doing a C<readdir> with a file named F<A.;5>
0a47030a
GS
1033will return F<a.> (though that file could be opened with
1034C<open(FH, 'A')>).
e41182b5 1035
f34d0673 1036RMS had an eight level limit on directory depths from any rooted logical
dd9f0070
CN
1037(allowing 16 levels overall) prior to VMS 7.2. Hence
1038C<PERL_ROOT:[LIB.2.3.4.5.6.7.8]> is a valid directory specification but
1039C<PERL_ROOT:[LIB.2.3.4.5.6.7.8.9]> is not. F<Makefile.PL> authors might
1040have to take this into account, but at least they can refer to the former
f34d0673 1041as C</PERL_ROOT/lib/2/3/4/5/6/7/8/>.
e41182b5 1042
6ab3f9cb 1043The VMS::Filespec module, which gets installed as part of the build
0a47030a
GS
1044process on VMS, is a pure Perl module that can easily be installed on
1045non-VMS platforms and can be helpful for conversions to and from RMS
1046native formats.
e41182b5 1047
5e12dbfa
PP
1048What C<\n> represents depends on the type of file opened. It usually
1049represents C<\012> but it could also be C<\015>, C<\012>, C<\015\012>,
1050C<\000>, C<\040>, or nothing depending on the file organiztion and
1051record format. The VMS::Stdio module provides access to the
1052special fopen() requirements of files with unusual attributes on VMS.
e41182b5
GS
1053
1054TCP/IP stacks are optional on VMS, so socket routines might not be
1055implemented. UDP sockets may not be supported.
1056
1057The value of C<$^O> on OpenVMS is "VMS". To determine the architecture
1058that you are running on without resorting to loading all of C<%Config>
1059you can examine the content of the C<@INC> array like so:
1060
1061 if (grep(/VMS_AXP/, @INC)) {
1062 print "I'm on Alpha!\n";
6ab3f9cb 1063
e41182b5
GS
1064 } elsif (grep(/VMS_VAX/, @INC)) {
1065 print "I'm on VAX!\n";
6ab3f9cb 1066
e41182b5
GS
1067 } else {
1068 print "I'm not so sure about where $^O is...\n";
1069 }
1070
b7df3edc
GS
1071On VMS, perl determines the UTC offset from the C<SYS$TIMEZONE_DIFFERENTIAL>
1072logical name. Although the VMS epoch began at 17-NOV-1858 00:00:00.00,
6ab3f9cb 1073calls to C<localtime> are adjusted to count offsets from
b7df3edc 107401-JAN-1970 00:00:00.00, just like Unix.
6ab3f9cb 1075
e41182b5
GS
1076Also see:
1077
1078=over 4
1079
c997b287
GS
1080=item *
1081
1082F<README.vms> (installed as L<README_vms>), L<perlvms>
1083
1084=item *
1085
1086vmsperl list, majordomo@perl.org
e41182b5 1087
c997b287 1088(Put the words C<subscribe vmsperl> in message body.)
e41182b5 1089
c997b287 1090=item *
e41182b5 1091
c997b287 1092vmsperl on the web, http://www.sidhe.org/vmsperl/index.html
e41182b5
GS
1093
1094=back
1095
495c5fdc
GP
1096=head2 VOS
1097
9a997319
JH
1098Perl on VOS is discussed in F<README.vos> in the perl distribution
1099(installed as L<perlvos>). Perl on VOS can accept either VOS- or
1100Unix-style file specifications as in either of the following:
495c5fdc 1101
cc07ed0b
PG
1102 C<< $ perl -ne "print if /perl_setup/i" >system>notices >>
1103 C<< $ perl -ne "print if /perl_setup/i" /system/notices >>
495c5fdc
GP
1104
1105or even a mixture of both as in:
1106
cc07ed0b 1107 C<< $ perl -ne "print if /perl_setup/i" >system/notices >>
495c5fdc 1108
b7df3edc 1109Even though VOS allows the slash character to appear in object
495c5fdc
GP
1110names, because the VOS port of Perl interprets it as a pathname
1111delimiting character, VOS files, directories, or links whose names
1112contain a slash character cannot be processed. Such files must be
a3dfe201
GS
1113renamed before they can be processed by Perl. Note that VOS limits
1114file names to 32 or fewer characters.
495c5fdc 1115
495c5fdc
GP
1116The value of C<$^O> on VOS is "VOS". To determine the architecture that
1117you are running on without resorting to loading all of C<%Config> you
c997b287 1118can examine the content of the @INC array like so:
495c5fdc 1119
24e8e380 1120 if ($^O =~ /VOS/) {
495c5fdc
GP
1121 print "I'm on a Stratus box!\n";
1122 } else {
1123 print "I'm not on a Stratus box!\n";
1124 die;
1125 }
1126
495c5fdc
GP
1127Also see:
1128
1129=over 4
1130
c997b287 1131=item *
495c5fdc 1132
cc07ed0b 1133F<README.vos> (installed as L<perlvos>)
c997b287
GS
1134
1135=item *
1136
1137The VOS mailing list.
495c5fdc
GP
1138
1139There is no specific mailing list for Perl on VOS. You can post
1140comments to the comp.sys.stratus newsgroup, or subscribe to the general
cc07ed0b 1141Stratus mailing list. Send a letter with "subscribe Info-Stratus" in
495c5fdc
GP
1142the message body to majordomo@list.stratagy.com.
1143
c997b287
GS
1144=item *
1145
cc07ed0b 1146VOS Perl on the web at http://ftp.stratus.com/pub/vos/posix/posix.html
495c5fdc
GP
1147
1148=back
1149
e41182b5
GS
1150=head2 EBCDIC Platforms
1151
1152Recent versions of Perl have been ported to platforms such as OS/400 on
d1e3b762
GS
1153AS/400 minicomputers as well as OS/390, VM/ESA, and BS2000 for S/390
1154Mainframes. Such computers use EBCDIC character sets internally (usually
0cc436d0
GS
1155Character Code Set ID 0037 for OS/400 and either 1047 or POSIX-BC for S/390
1156systems). On the mainframe perl currently works under the "Unix system
1157services for OS/390" (formerly known as OpenEdition), VM/ESA OpenEdition, or
1158the BS200 POSIX-BC system (BS2000 is supported in perl 5.6 and greater).
522b859a
JH
1159See L<perlos390> for details. Note that for OS/400 there is also a port of
1160Perl 5.8.1/5.9.0 or later to the PASE which is ASCII-based (as opposed to
1161ILE which is EBCDIC-based), see L<perlos400>.
e41182b5 1162
7c5ffed3
JH
1163As of R2.5 of USS for OS/390 and Version 2.3 of VM/ESA these Unix
1164sub-systems do not support the C<#!> shebang trick for script invocation.
1165Hence, on OS/390 and VM/ESA perl scripts can be executed with a header
1166similar to the following simple script:
e41182b5
GS
1167
1168 : # use perl
1169 eval 'exec /usr/local/bin/perl -S $0 ${1+"$@"}'
1170 if 0;
1171 #!/usr/local/bin/perl # just a comment really
1172
1173 print "Hello from perl!\n";
1174
d1e3b762
GS
1175OS/390 will support the C<#!> shebang trick in release 2.8 and beyond.
1176Calls to C<system> and backticks can use POSIX shell syntax on all
1177S/390 systems.
1178
b7df3edc 1179On the AS/400, if PERL5 is in your library list, you may need
6ab3f9cb
GS
1180to wrap your perl scripts in a CL procedure to invoke them like so:
1181
1182 BEGIN
1183 CALL PGM(PERL5/PERL) PARM('/QOpenSys/hello.pl')
1184 ENDPGM
1185
1186This will invoke the perl script F<hello.pl> in the root of the
1187QOpenSys file system. On the AS/400 calls to C<system> or backticks
1188must use CL syntax.
1189
e41182b5 1190On these platforms, bear in mind that the EBCDIC character set may have
0a47030a
GS
1191an effect on what happens with some perl functions (such as C<chr>,
1192C<pack>, C<print>, C<printf>, C<ord>, C<sort>, C<sprintf>, C<unpack>), as
1193well as bit-fiddling with ASCII constants using operators like C<^>, C<&>
1194and C<|>, not to mention dealing with socket interfaces to ASCII computers
6ab3f9cb 1195(see L<"Newlines">).
e41182b5 1196
b7df3edc
GS
1197Fortunately, most web servers for the mainframe will correctly
1198translate the C<\n> in the following statement to its ASCII equivalent
1199(C<\r> is the same under both Unix and OS/390 & VM/ESA):
e41182b5
GS
1200
1201 print "Content-type: text/html\r\n\r\n";
1202
d1e3b762 1203The values of C<$^O> on some of these platforms includes:
e41182b5 1204
d1e3b762
GS
1205 uname $^O $Config{'archname'}
1206 --------------------------------------------
1207 OS/390 os390 os390
1208 OS400 os400 os400
1209 POSIX-BC posix-bc BS2000-posix-bc
1210 VM/ESA vmesa vmesa
3c075c7d 1211
e41182b5
GS
1212Some simple tricks for determining if you are running on an EBCDIC
1213platform could include any of the following (perhaps all):
1214
1215 if ("\t" eq "\05") { print "EBCDIC may be spoken here!\n"; }
1216
1217 if (ord('A') == 193) { print "EBCDIC may be spoken here!\n"; }
1218
1219 if (chr(169) eq 'z') { print "EBCDIC may be spoken here!\n"; }
1220
b7df3edc 1221One thing you may not want to rely on is the EBCDIC encoding
0a47030a
GS
1222of punctuation characters since these may differ from code page to code
1223page (and once your module or script is rumoured to work with EBCDIC,
1224folks will want it to work with all EBCDIC character sets).
e41182b5
GS
1225
1226Also see:
1227
1228=over 4
1229
c997b287
GS
1230=item *
1231
1232*
d1e3b762 1233
dc5c060f 1234L<perlos390>, F<README.os390>, F<perlbs2000>, F<README.vmesa>,
bb462878 1235L<perlebcdic>.
c997b287
GS
1236
1237=item *
e41182b5
GS
1238
1239The perl-mvs@perl.org list is for discussion of porting issues as well as
1240general usage issues for all EBCDIC Perls. Send a message body of
1241"subscribe perl-mvs" to majordomo@perl.org.
1242
c997b287
GS
1243=item *
1244
1245AS/400 Perl information at
b1866b2d 1246http://as400.rochester.ibm.com/
d1e3b762 1247as well as on CPAN in the F<ports/> directory.
e41182b5
GS
1248
1249=back
1250
b8099c3d
CN
1251=head2 Acorn RISC OS
1252
b7df3edc
GS
1253Because Acorns use ASCII with newlines (C<\n>) in text files as C<\012> like
1254Unix, and because Unix filename emulation is turned on by default,
1255most simple scripts will probably work "out of the box". The native
6ab3f9cb 1256filesystem is modular, and individual filesystems are free to be
0a47030a 1257case-sensitive or insensitive, and are usually case-preserving. Some
b7df3edc 1258native filesystems have name length limits, which file and directory
6ab3f9cb
GS
1259names are silently truncated to fit. Scripts should be aware that the
1260standard filesystem currently has a name length limit of B<10>
1261characters, with up to 77 items in a directory, but other filesystems
0a47030a 1262may not impose such limitations.
b8099c3d
CN
1263
1264Native filenames are of the form
1265
6ab3f9cb 1266 Filesystem#Special_Field::DiskName.$.Directory.Directory.File
dd9f0070 1267
b8099c3d
CN
1268where
1269
1270 Special_Field is not usually present, but may contain . and $ .
1271 Filesystem =~ m|[A-Za-z0-9_]|
1272 DsicName =~ m|[A-Za-z0-9_/]|
1273 $ represents the root directory
1274 . is the path separator
1275 @ is the current directory (per filesystem but machine global)
1276 ^ is the parent directory
1277 Directory and File =~ m|[^\0- "\.\$\%\&:\@\\^\|\177]+|
1278
1279The default filename translation is roughly C<tr|/.|./|;>
1280
6ab3f9cb 1281Note that C<"ADFS::HardDisk.$.File" ne 'ADFS::HardDisk.$.File'> and that
0a47030a
GS
1282the second stage of C<$> interpolation in regular expressions will fall
1283foul of the C<$.> if scripts are not careful.
1284
1285Logical paths specified by system variables containing comma-separated
b7df3edc 1286search lists are also allowed; hence C<System:Modules> is a valid
0a47030a 1287filename, and the filesystem will prefix C<Modules> with each section of
6ab3f9cb 1288C<System$Path> until a name is made that points to an object on disk.
b7df3edc 1289Writing to a new file C<System:Modules> would be allowed only if
0a47030a
GS
1290C<System$Path> contains a single item list. The filesystem will also
1291expand system variables in filenames if enclosed in angle brackets, so
c47ff5f1 1292C<< <System$Dir>.Modules >> would look for the file
0a47030a 1293S<C<$ENV{'System$Dir'} . 'Modules'>>. The obvious implication of this is
c47ff5f1 1294that B<fully qualified filenames can start with C<< <> >>> and should
0a47030a 1295be protected when C<open> is used for input.
b8099c3d
CN
1296
1297Because C<.> was in use as a directory separator and filenames could not
1298be assumed to be unique after 10 characters, Acorn implemented the C
1299compiler to strip the trailing C<.c> C<.h> C<.s> and C<.o> suffix from
1300filenames specified in source code and store the respective files in
b7df3edc 1301subdirectories named after the suffix. Hence files are translated:
b8099c3d
CN
1302
1303 foo.h h.foo
1304 C:foo.h C:h.foo (logical path variable)
1305 sys/os.h sys.h.os (C compiler groks Unix-speak)
1306 10charname.c c.10charname
1307 10charname.o o.10charname
1308 11charname_.c c.11charname (assuming filesystem truncates at 10)
1309
1310The Unix emulation library's translation of filenames to native assumes
b7df3edc
GS
1311that this sort of translation is required, and it allows a user-defined list
1312of known suffixes that it will transpose in this fashion. This may
1313seem transparent, but consider that with these rules C<foo/bar/baz.h>
0a47030a
GS
1314and C<foo/bar/h/baz> both map to C<foo.bar.h.baz>, and that C<readdir> and
1315C<glob> cannot and do not attempt to emulate the reverse mapping. Other
6ab3f9cb 1316C<.>'s in filenames are translated to C</>.
0a47030a 1317
b7df3edc 1318As implied above, the environment accessed through C<%ENV> is global, and
0a47030a 1319the convention is that program specific environment variables are of the
6ab3f9cb
GS
1320form C<Program$Name>. Each filesystem maintains a current directory,
1321and the current filesystem's current directory is the B<global> current
b7df3edc
GS
1322directory. Consequently, sociable programs don't change the current
1323directory but rely on full pathnames, and programs (and Makefiles) cannot
0a47030a
GS
1324assume that they can spawn a child process which can change the current
1325directory without affecting its parent (and everyone else for that
1326matter).
1327
b7df3edc
GS
1328Because native operating system filehandles are global and are currently
1329allocated down from 255, with 0 being a reserved value, the Unix emulation
0a47030a
GS
1330library emulates Unix filehandles. Consequently, you can't rely on
1331passing C<STDIN>, C<STDOUT>, or C<STDERR> to your children.
1332
1333The desire of users to express filenames of the form
c47ff5f1 1334C<< <Foo$Dir>.Bar >> on the command line unquoted causes problems,
0a47030a 1335too: C<``> command output capture has to perform a guessing game. It
c47ff5f1 1336assumes that a string C<< <[^<>]+\$[^<>]> >> is a
0a47030a 1337reference to an environment variable, whereas anything else involving
c47ff5f1 1338C<< < >> or C<< > >> is redirection, and generally manages to be 99%
0a47030a
GS
1339right. Of course, the problem remains that scripts cannot rely on any
1340Unix tools being available, or that any tools found have Unix-like command
1341line arguments.
1342
b7df3edc
GS
1343Extensions and XS are, in theory, buildable by anyone using free
1344tools. In practice, many don't, as users of the Acorn platform are
1345used to binary distributions. MakeMaker does run, but no available
1346make currently copes with MakeMaker's makefiles; even if and when
1347this should be fixed, the lack of a Unix-like shell will cause
1348problems with makefile rules, especially lines of the form C<cd
1349sdbm && make all>, and anything using quoting.
b8099c3d
CN
1350
1351"S<RISC OS>" is the proper name for the operating system, but the value
1352in C<$^O> is "riscos" (because we don't like shouting).
1353
e41182b5
GS
1354=head2 Other perls
1355
b7df3edc
GS
1356Perl has been ported to many platforms that do not fit into any of
1357the categories listed above. Some, such as AmigaOS, Atari MiNT,
1358BeOS, HP MPE/iX, QNX, Plan 9, and VOS, have been well-integrated
1359into the standard Perl source code kit. You may need to see the
1360F<ports/> directory on CPAN for information, and possibly binaries,
1361for the likes of: aos, Atari ST, lynxos, riscos, Novell Netware,
1362Tandem Guardian, I<etc.> (Yes, we know that some of these OSes may
1363fall under the Unix category, but we are not a standards body.)
e41182b5 1364
d1e3b762
GS
1365Some approximate operating system names and their C<$^O> values
1366in the "OTHER" category include:
1367
1368 OS $^O $Config{'archname'}
1369 ------------------------------------------
1370 Amiga DOS amigaos m68k-amigos
cec2c193 1371 BeOS beos
d1e3b762
GS
1372 MPE/iX mpeix PA-RISC1.1
1373
e41182b5
GS
1374See also:
1375
1376=over 4
1377
c997b287
GS
1378=item *
1379
1380Amiga, F<README.amiga> (installed as L<perlamiga>).
1381
1382=item *
d1e3b762 1383
c997b287
GS
1384Atari, F<README.mint> and Guido Flohr's web page
1385http://stud.uni-sb.de/~gufl0000/
e41182b5 1386
c997b287 1387=item *
d1e3b762 1388
c997b287 1389Be OS, F<README.beos>
e41182b5 1390
c997b287
GS
1391=item *
1392
1393HP 300 MPE/iX, F<README.mpeix> and Mark Bixby's web page
34aaaa84 1394http://www.bixby.org/mark/perlix.html
c997b287
GS
1395
1396=item *
e41182b5 1397
6ab3f9cb 1398A free perl5-based PERL.NLM for Novell Netware is available in
c997b287 1399precompiled binary and source code form from http://www.novell.com/
6ab3f9cb 1400as well as from CPAN.
e41182b5 1401
13a2d996 1402=item *
c997b287 1403
e6f03d26 1404S<Plan 9>, F<README.plan9>
d1e3b762 1405
e41182b5
GS
1406=back
1407
e41182b5
GS
1408=head1 FUNCTION IMPLEMENTATIONS
1409
b7df3edc
GS
1410Listed below are functions that are either completely unimplemented
1411or else have been implemented differently on various platforms.
1412Following each description will be, in parentheses, a list of
1413platforms that the description applies to.
e41182b5 1414
b7df3edc
GS
1415The list may well be incomplete, or even wrong in some places. When
1416in doubt, consult the platform-specific README files in the Perl
1417source distribution, and any other documentation resources accompanying
1418a given port.
e41182b5 1419
0a47030a 1420Be aware, moreover, that even among Unix-ish systems there are variations.
e41182b5 1421
b7df3edc
GS
1422For many functions, you can also query C<%Config>, exported by
1423default from the Config module. For example, to check whether the
1424platform has the C<lstat> call, check C<$Config{d_lstat}>. See
1425L<Config> for a full description of available variables.
e41182b5
GS
1426
1427=head2 Alphabetical Listing of Perl Functions
1428
1429=over 8
1430
1431=item -X FILEHANDLE
1432
1433=item -X EXPR
1434
1435=item -X
1436
b7df3edc 1437C<-r>, C<-w>, and C<-x> have a limited meaning only; directories
e41182b5 1438and applications are executable, and there are no uid/gid
b7df3edc 1439considerations. C<-o> is not supported. (S<Mac OS>)
e41182b5 1440
b7df3edc
GS
1441C<-r>, C<-w>, C<-x>, and C<-o> tell whether the file is accessible,
1442which may not reflect UIC-based file protections. (VMS)
e41182b5 1443
b8099c3d
CN
1444C<-s> returns the size of the data fork, not the total size of data fork
1445plus resource fork. (S<Mac OS>).
1446
1447C<-s> by name on an open file will return the space reserved on disk,
1448rather than the current extent. C<-s> on an open filehandle returns the
b7df3edc 1449current size. (S<RISC OS>)
b8099c3d 1450
e41182b5 1451C<-R>, C<-W>, C<-X>, C<-O> are indistinguishable from C<-r>, C<-w>,
b8099c3d 1452C<-x>, C<-o>. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1453
1454C<-b>, C<-c>, C<-k>, C<-g>, C<-p>, C<-u>, C<-A> are not implemented.
1455(S<Mac OS>)
1456
1457C<-g>, C<-k>, C<-l>, C<-p>, C<-u>, C<-A> are not particularly meaningful.
b8099c3d 1458(Win32, VMS, S<RISC OS>)
e41182b5
GS
1459
1460C<-d> is true if passed a device spec without an explicit directory.
1461(VMS)
1462
1463C<-T> and C<-B> are implemented, but might misclassify Mac text files
0a47030a 1464with foreign characters; this is the case will all platforms, but may
b7df3edc 1465affect S<Mac OS> often. (S<Mac OS>)
e41182b5
GS
1466
1467C<-x> (or C<-X>) determine if a file ends in one of the executable
b7df3edc 1468suffixes. C<-S> is meaningless. (Win32)
e41182b5 1469
b8099c3d
CN
1470C<-x> (or C<-X>) determine if a file has an executable file type.
1471(S<RISC OS>)
1472
63f87e49
GS
1473=item alarm SECONDS
1474
1475=item alarm
1476
1477Not implemented. (Win32)
1478
e41182b5
GS
1479=item binmode FILEHANDLE
1480
b7df3edc 1481Meaningless. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1482
1483Reopens file and restores pointer; if function fails, underlying
1484filehandle may be closed, or pointer may be in a different position.
1485(VMS)
1486
1487The value returned by C<tell> may be affected after the call, and
1488the filehandle may be flushed. (Win32)
1489
1490=item chmod LIST
1491
b7df3edc 1492Only limited meaning. Disabling/enabling write permission is mapped to
e41182b5
GS
1493locking/unlocking the file. (S<Mac OS>)
1494
1495Only good for changing "owner" read-write access, "group", and "other"
1496bits are meaningless. (Win32)
1497
b8099c3d
CN
1498Only good for changing "owner" and "other" read-write access. (S<RISC OS>)
1499
495c5fdc
GP
1500Access permissions are mapped onto VOS access-control list changes. (VOS)
1501
4e51f8e4 1502The actual permissions set depend on the value of the C<CYGWIN>
789f0d36 1503in the SYSTEM environment settings. (Cygwin)
4e51f8e4 1504
e41182b5
GS
1505=item chown LIST
1506
3fd80bd6 1507Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1508
1509Does nothing, but won't fail. (Win32)
1510
3fd80bd6
PG
1511A little funky, because VOS's notion of ownership is a little funky (VOS).
1512
e41182b5
GS
1513=item chroot FILENAME
1514
1515=item chroot
1516
e6f03d26 1517Not implemented. (S<Mac OS>, Win32, VMS, S<Plan 9>, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1518
1519=item crypt PLAINTEXT,SALT
1520
1521May not be available if library or source was not provided when building
b8099c3d 1522perl. (Win32)
e41182b5
GS
1523
1524=item dbmclose HASH
1525
e6f03d26 1526Not implemented. (VMS, S<Plan 9>, VOS)
e41182b5
GS
1527
1528=item dbmopen HASH,DBNAME,MODE
1529
e6f03d26 1530Not implemented. (VMS, S<Plan 9>, VOS)
e41182b5
GS
1531
1532=item dump LABEL
1533
b8099c3d 1534Not useful. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1535
1536Not implemented. (Win32)
1537
b8099c3d 1538Invokes VMS debugger. (VMS)
e41182b5
GS
1539
1540=item exec LIST
1541
1542Not implemented. (S<Mac OS>)
1543
7c5ffed3 1544Implemented via Spawn. (VM/ESA)
3c075c7d 1545
0f897271
GS
1546Does not automatically flush output handles on some platforms.
1547(SunOS, Solaris, HP-UX)
1548
fe12c0e8
MS
1549=item exit EXPR
1550
1551=item exit
1552
1553Emulates UNIX exit() (which considers C<exit 1> to indicate an error) by
1554mapping the C<1> to SS$_ABORT (C<44>). This behavior may be overridden
1555with the pragma C<use vmsish 'exit'>. As with the CRTL's exit()
1556function, C<exit 0> is also mapped to an exit status of SS$_NORMAL
1557(C<1>); this mapping cannot be overridden. Any other argument to exit()
1558is used directly as Perl's exit status. (VMS)
1559
e41182b5
GS
1560=item fcntl FILEHANDLE,FUNCTION,SCALAR
1561
1562Not implemented. (Win32, VMS)
1563
1564=item flock FILEHANDLE,OPERATION
1565
495c5fdc 1566Not implemented (S<Mac OS>, VMS, S<RISC OS>, VOS).
e41182b5
GS
1567
1568Available only on Windows NT (not on Windows 95). (Win32)
1569
1570=item fork
1571
3fd80bd6 1572Not implemented. (S<Mac OS>, AmigaOS, S<RISC OS>, VM/ESA, VMS)
0f897271
GS
1573
1574Emulated using multiple interpreters. See L<perlfork>. (Win32)
1575
1576Does not automatically flush output handles on some platforms.
1577(SunOS, Solaris, HP-UX)
e41182b5
GS
1578
1579=item getlogin
1580
b8099c3d 1581Not implemented. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1582
1583=item getpgrp PID
1584
3fd80bd6 1585Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1586
1587=item getppid
1588
41cbbefa 1589Not implemented. (S<Mac OS>, Win32, S<RISC OS>)
e41182b5
GS
1590
1591=item getpriority WHICH,WHO
1592
7c5ffed3 1593Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1594
1595=item getpwnam NAME
1596
1597Not implemented. (S<Mac OS>, Win32)
1598
b8099c3d
CN
1599Not useful. (S<RISC OS>)
1600
e41182b5
GS
1601=item getgrnam NAME
1602
b8099c3d 1603Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1604
1605=item getnetbyname NAME
1606
e6f03d26 1607Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1608
1609=item getpwuid UID
1610
1611Not implemented. (S<Mac OS>, Win32)
1612
b8099c3d
CN
1613Not useful. (S<RISC OS>)
1614
e41182b5
GS
1615=item getgrgid GID
1616
b8099c3d 1617Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1618
1619=item getnetbyaddr ADDR,ADDRTYPE
1620
e6f03d26 1621Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1622
1623=item getprotobynumber NUMBER
1624
1625Not implemented. (S<Mac OS>)
1626
1627=item getservbyport PORT,PROTO
1628
1629Not implemented. (S<Mac OS>)
1630
1631=item getpwent
1632
7c5ffed3 1633Not implemented. (S<Mac OS>, Win32, VM/ESA)
e41182b5
GS
1634
1635=item getgrent
1636
7c5ffed3 1637Not implemented. (S<Mac OS>, Win32, VMS, VM/ESA)
e41182b5 1638
ef5a6dd7
JH
1639=item gethostbyname
1640
1641C<gethostbyname('localhost')> does not work everywhere: you may have
1642to use C<gethostbyname('127.0.0.1')>. (S<Mac OS>, S<Irix 5>)
1643
e41182b5
GS
1644=item gethostent
1645
1646Not implemented. (S<Mac OS>, Win32)
1647
1648=item getnetent
1649
e6f03d26 1650Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1651
1652=item getprotoent
1653
e6f03d26 1654Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1655
1656=item getservent
1657
e6f03d26 1658Not implemented. (Win32, S<Plan 9>)
e41182b5 1659
e41182b5
GS
1660=item sethostent STAYOPEN
1661
e6f03d26 1662Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1663
1664=item setnetent STAYOPEN
1665
e6f03d26 1666Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1667
1668=item setprotoent STAYOPEN
1669
e6f03d26 1670Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1671
1672=item setservent STAYOPEN
1673
e6f03d26 1674Not implemented. (S<Plan 9>, Win32, S<RISC OS>)
e41182b5
GS
1675
1676=item endpwent
1677
a3dfe201 1678Not implemented. (S<Mac OS>, MPE/iX, VM/ESA, Win32)
e41182b5
GS
1679
1680=item endgrent
1681
a3dfe201 1682Not implemented. (S<Mac OS>, MPE/iX, S<RISC OS>, VM/ESA, VMS, Win32)
e41182b5
GS
1683
1684=item endhostent
1685
1686Not implemented. (S<Mac OS>, Win32)
1687
1688=item endnetent
1689
e6f03d26 1690Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1691
1692=item endprotoent
1693
e6f03d26 1694Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1695
1696=item endservent
1697
e6f03d26 1698Not implemented. (S<Plan 9>, Win32)
e41182b5
GS
1699
1700=item getsockopt SOCKET,LEVEL,OPTNAME
1701
e6f03d26 1702Not implemented. (S<Plan 9>)
e41182b5
GS
1703
1704=item glob EXPR
1705
1706=item glob
1707
63f87e49
GS
1708This operator is implemented via the File::Glob extension on most
1709platforms. See L<File::Glob> for portability information.
b8099c3d 1710
e41182b5
GS
1711=item ioctl FILEHANDLE,FUNCTION,SCALAR
1712
1713Not implemented. (VMS)
1714
1715Available only for socket handles, and it does what the ioctlsocket() call
1716in the Winsock API does. (Win32)
1717
b8099c3d
CN
1718Available only for socket handles. (S<RISC OS>)
1719
b350dd2f 1720=item kill SIGNAL, LIST
e41182b5 1721
862b5365
JH
1722C<kill(0, LIST)> is implemented for the sake of taint checking;
1723use with other signals is unimplemented. (S<Mac OS>)
1724
1725Not implemented, hence not useful for taint checking. (S<RISC OS>)
e41182b5 1726
63f87e49
GS
1727C<kill()> doesn't have the semantics of C<raise()>, i.e. it doesn't send
1728a signal to the identified process like it does on Unix platforms.
1729Instead C<kill($sig, $pid)> terminates the process identified by $pid,
1730and makes it exit immediately with exit status $sig. As in Unix, if
1731$sig is 0 and the specified process exists, it returns true without
1732actually terminating it. (Win32)
e41182b5
GS
1733
1734=item link OLDFILE,NEWFILE
1735
a3dfe201 1736Not implemented. (S<Mac OS>, MPE/iX, VMS, S<RISC OS>)
e41182b5 1737
433acd8a
JH
1738Link count not updated because hard links are not quite that hard
1739(They are sort of half-way between hard and soft links). (AmigaOS)
1740
a3dfe201
GS
1741Hard links are implemented on Win32 (Windows NT and Windows 2000)
1742under NTFS only.
1743
e41182b5
GS
1744=item lstat FILEHANDLE
1745
1746=item lstat EXPR
1747
1748=item lstat
1749
b8099c3d 1750Not implemented. (VMS, S<RISC OS>)
e41182b5 1751
63f87e49 1752Return values (especially for device and inode) may be bogus. (Win32)
e41182b5
GS
1753
1754=item msgctl ID,CMD,ARG
1755
1756=item msgget KEY,FLAGS
1757
1758=item msgsnd ID,MSG,FLAGS
1759
1760=item msgrcv ID,VAR,SIZE,TYPE,FLAGS
1761
e6f03d26 1762Not implemented. (S<Mac OS>, Win32, VMS, S<Plan 9>, S<RISC OS>, VOS)
e41182b5
GS
1763
1764=item open FILEHANDLE,EXPR
1765
1766=item open FILEHANDLE
1767
b7df3edc 1768The C<|> variants are supported only if ToolServer is installed.
e41182b5
GS
1769(S<Mac OS>)
1770
c47ff5f1 1771open to C<|-> and C<-|> are unsupported. (S<Mac OS>, Win32, S<RISC OS>)
e41182b5 1772
0f897271
GS
1773Opening a process does not automatically flush output handles on some
1774platforms. (SunOS, Solaris, HP-UX)
1775
e41182b5
GS
1776=item pipe READHANDLE,WRITEHANDLE
1777
433acd8a
JH
1778Very limited functionality. (MiNT)
1779
e41182b5
GS
1780=item readlink EXPR
1781
1782=item readlink
1783
b8099c3d 1784Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5
GS
1785
1786=item select RBITS,WBITS,EBITS,TIMEOUT
1787
689c5c24 1788Only implemented on sockets. (Win32, VMS)
e41182b5 1789
b8099c3d
CN
1790Only reliable on sockets. (S<RISC OS>)
1791
76e05f0b 1792Note that the C<select FILEHANDLE> form is generally portable.
63f87e49 1793
e41182b5
GS
1794=item semctl ID,SEMNUM,CMD,ARG
1795
1796=item semget KEY,NSEMS,FLAGS
1797
1798=item semop KEY,OPSTRING
1799
495c5fdc 1800Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1801
a3dfe201
GS
1802=item setgrent
1803
3fd80bd6 1804Not implemented. (S<Mac OS>, MPE/iX, VMS, Win32, S<RISC OS>, VOS)
a3dfe201 1805
e41182b5
GS
1806=item setpgrp PID,PGRP
1807
495c5fdc 1808Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5
GS
1809
1810=item setpriority WHICH,WHO,PRIORITY
1811
495c5fdc 1812Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1813
a3dfe201
GS
1814=item setpwent
1815
3fd80bd6 1816Not implemented. (S<Mac OS>, MPE/iX, Win32, S<RISC OS>, VOS)
a3dfe201 1817
e41182b5
GS
1818=item setsockopt SOCKET,LEVEL,OPTNAME,OPTVAL
1819
e6f03d26 1820Not implemented. (S<Plan 9>)
e41182b5
GS
1821
1822=item shmctl ID,CMD,ARG
1823
1824=item shmget KEY,SIZE,FLAGS
1825
1826=item shmread ID,VAR,POS,SIZE
1827
1828=item shmwrite ID,STRING,POS,SIZE
1829
495c5fdc 1830Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1831
80cbd5ad
JH
1832=item sockatmark SOCKET
1833
1834A relatively recent addition to socket functions, may not
1835be implemented even in UNIX platforms.
1836
e41182b5
GS
1837=item socketpair SOCKET1,SOCKET2,DOMAIN,TYPE,PROTOCOL
1838
862b5365 1839Not implemented. (Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1840
1841=item stat FILEHANDLE
1842
1843=item stat EXPR
1844
1845=item stat
1846
d62e1b7f
JH
1847Platforms that do not have rdev, blksize, or blocks will return these
1848as '', so numeric comparison or manipulation of these fields may cause
1849'not numeric' warnings.
1850
e41182b5 1851mtime and atime are the same thing, and ctime is creation time instead of
3f1f789b
JH
1852inode change time. (S<Mac OS>).
1853
1854ctime not supported on UFS (S<Mac OS X>).
e41182b5 1855
95a3fe12
MS
1856ctime is creation time instead of inode change time (Win32).
1857
e41182b5
GS
1858device and inode are not meaningful. (Win32)
1859
1860device and inode are not necessarily reliable. (VMS)
1861
b8099c3d
CN
1862mtime, atime and ctime all return the last modification time. Device and
1863inode are not necessarily reliable. (S<RISC OS>)
1864
d62e1b7f
JH
1865dev, rdev, blksize, and blocks are not available. inode is not
1866meaningful and will differ between stat calls on the same file. (os2)
1867
73e9292c
JH
1868some versions of cygwin when doing a stat("foo") and if not finding it
1869may then attempt to stat("foo.exe") (Cygwin)
1870
e41182b5
GS
1871=item symlink OLDFILE,NEWFILE
1872
b8099c3d 1873Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5
GS
1874
1875=item syscall LIST
1876
7c5ffed3 1877Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5 1878
f34d0673
GS
1879=item sysopen FILEHANDLE,FILENAME,MODE,PERMS
1880
dd9f0070 1881The traditional "0", "1", and "2" MODEs are implemented with different
322422de
GS
1882numeric values on some systems. The flags exported by C<Fcntl>
1883(O_RDONLY, O_WRONLY, O_RDWR) should work everywhere though. (S<Mac
7c5ffed3 1884OS>, OS/390, VM/ESA)
f34d0673 1885
e41182b5
GS
1886=item system LIST
1887
9d6eb86e 1888In general, do not assume the UNIX/POSIX semantics that you can shift
7717d0e7 1889C<$?> right by eight to get the exit value, or that C<$? & 127>
9d6eb86e
JH
1890would give you the number of the signal that terminated the program,
1891or that C<$? & 128> would test true if the program was terminated by a
1892coredump. Instead, use the POSIX W*() interfaces: for example, use
74555b7a
PP
1893WIFEXITED($?) and WEXITVALUE($?) to test for a normal exit and the exit
1894value, WIFSIGNALED($?) and WTERMSIG($?) for a signal exit and the
7717d0e7 1895signal. Core dumping is not a portable concept, so there's no portable
9d6eb86e
JH
1896way to test for that.
1897
e41182b5
GS
1898Only implemented if ToolServer is installed. (S<Mac OS>)
1899
1900As an optimization, may not call the command shell specified in
b7df3edc 1901C<$ENV{PERL5SHELL}>. C<system(1, @args)> spawns an external
e41182b5
GS
1902process and immediately returns its process designator, without
1903waiting for it to terminate. Return value may be used subsequently
63f87e49
GS
1904in C<wait> or C<waitpid>. Failure to spawn() a subprocess is indicated
1905by setting $? to "255 << 8". C<$?> is set in a way compatible with
1906Unix (i.e. the exitstatus of the subprocess is obtained by "$? >> 8",
1907as described in the documentation). (Win32)
e41182b5 1908
b8099c3d
CN
1909There is no shell to process metacharacters, and the native standard is
1910to pass a command line terminated by "\n" "\r" or "\0" to the spawned
c47ff5f1 1911program. Redirection such as C<< > foo >> is performed (if at all) by
b8099c3d
CN
1912the run time library of the spawned program. C<system> I<list> will call
1913the Unix emulation library's C<exec> emulation, which attempts to provide
1914emulation of the stdin, stdout, stderr in force in the parent, providing
1915the child program uses a compatible version of the emulation library.
1916I<scalar> will call the native command line direct and no such emulation
1917of a child Unix program will exists. Mileage B<will> vary. (S<RISC OS>)
1918
433acd8a
JH
1919Far from being POSIX compliant. Because there may be no underlying
1920/bin/sh tries to work around the problem by forking and execing the
9b63e9ec 1921first token in its argument string. Handles basic redirection
c47ff5f1 1922("<" or ">") on its own behalf. (MiNT)
433acd8a 1923
0f897271
GS
1924Does not automatically flush output handles on some platforms.
1925(SunOS, Solaris, HP-UX)
1926
9bc98430
CB
1927The return value is POSIX-like (shifted up by 8 bits), which only allows
1928room for a made-up value derived from the severity bits of the native
192932-bit condition code (unless overridden by C<use vmsish 'status'>).
1930For more details see L<perlvms/$?>. (VMS)
1931
e41182b5
GS
1932=item times
1933
1934Only the first entry returned is nonzero. (S<Mac OS>)
1935
63f87e49
GS
1936"cumulative" times will be bogus. On anything other than Windows NT
1937or Windows 2000, "system" time will be bogus, and "user" time is
1938actually the time returned by the clock() function in the C runtime
1939library. (Win32)
e41182b5 1940
b8099c3d
CN
1941Not useful. (S<RISC OS>)
1942
e41182b5
GS
1943=item truncate FILEHANDLE,LENGTH
1944
1945=item truncate EXPR,LENGTH
1946
6d738113 1947Not implemented. (Older versions of VMS)
e41182b5 1948
3fd80bd6 1949Truncation to same-or-shorter lengths only. (VOS)
495c5fdc 1950
4cfdb94f 1951If a FILEHANDLE is supplied, it must be writable and opened in append
e71a7dc8 1952mode (i.e., use C<<< open(FH, '>>filename') >>>
4cfdb94f
GS
1953or C<sysopen(FH,...,O_APPEND|O_RDWR)>. If a filename is supplied, it
1954should not be held open elsewhere. (Win32)
1955
e41182b5
GS
1956=item umask EXPR
1957
1958=item umask
1959
1960Returns undef where unavailable, as of version 5.005.
1961
b7df3edc
GS
1962C<umask> works but the correct permissions are set only when the file
1963is finally closed. (AmigaOS)
433acd8a 1964
e41182b5
GS
1965=item utime LIST
1966
15c65113 1967Only the modification time is updated. (S<BeOS>, S<Mac OS>, VMS, S<RISC OS>)
e41182b5 1968
322422de
GS
1969May not behave as expected. Behavior depends on the C runtime
1970library's implementation of utime(), and the filesystem being
1971used. The FAT filesystem typically does not support an "access
1972time" field, and it may limit timestamps to a granularity of
1973two seconds. (Win32)
e41182b5
GS
1974
1975=item wait
1976
1977=item waitpid PID,FLAGS
1978
3fd80bd6 1979Not implemented. (S<Mac OS>)
e41182b5
GS
1980
1981Can only be applied to process handles returned for processes spawned
a6f858fb 1982using C<system(1, ...)> or pseudo processes created with C<fork()>. (Win32)
e41182b5 1983
b8099c3d
CN
1984Not useful. (S<RISC OS>)
1985
e41182b5
GS
1986=back
1987
b8099c3d
CN
1988=head1 CHANGES
1989
1990=over 4
1991
3fd80bd6
PG
1992=item v1.49, 12 August 2002
1993
1994Updates for VOS from Paul Green.
1995
fd46a41b
JH
1996=item v1.48, 02 February 2001
1997
1998Various updates from perl5-porters over the past year, supported
1999platforms update from Jarkko Hietaniemi.
2000
c997b287
GS
2001=item v1.47, 22 March 2000
2002
2003Various cleanups from Tom Christiansen, including migration of
2004long platform listings from L<perl>.
2005
56d7751a
GS
2006=item v1.46, 12 February 2000
2007
2008Updates for VOS and MPE/iX. (Peter Prymmer) Other small changes.
2009
0cc436d0
GS
2010=item v1.45, 20 December 1999
2011
2012Small changes from 5.005_63 distribution, more changes to EBCDIC info.
2013
d1e3b762
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2014=item v1.44, 19 July 1999
2015
2016A bunch of updates from Peter Prymmer for C<$^O> values,
2017endianness, File::Spec, VMS, BS2000, OS/400.
2018
b7df3edc
GS
2019=item v1.43, 24 May 1999
2020
2021Added a lot of cleaning up from Tom Christiansen.
2022
19799a22 2023=item v1.42, 22 May 1999
b7df3edc 2024
19799a22 2025Added notes about tests, sprintf/printf, and epoch offsets.
b7df3edc 2026
6ab3f9cb
GS
2027=item v1.41, 19 May 1999
2028
2029Lots more little changes to formatting and content.
2030
d1e3b762 2031Added a bunch of C<$^O> and related values
6ab3f9cb
GS
2032for various platforms; fixed mail and web addresses, and added
2033and changed miscellaneous notes. (Peter Prymmer)
2034
2035=item v1.40, 11 April 1999
2036
2037Miscellaneous changes.
2038
2039=item v1.39, 11 February 1999
2ee0eb3c
CN
2040
2041Changes from Jarkko and EMX URL fixes Michael Schwern. Additional
2042note about newlines added.
2043
9b63e9ec
CN
2044=item v1.38, 31 December 1998
2045
2046More changes from Jarkko.
2047
3c075c7d
CN
2048=item v1.37, 19 December 1998
2049
2050More minor changes. Merge two separate version 1.35 documents.
2051
2052=item v1.36, 9 September 1998
2053
2054Updated for Stratus VOS. Also known as version 1.35.
2055
2056=item v1.35, 13 August 1998
495c5fdc 2057
3c075c7d
CN
2058Integrate more minor changes, plus addition of new sections under
2059L<"ISSUES">: L<"Numbers endianness and Width">,
2060L<"Character sets and character encoding">,
2061L<"Internationalisation">.
495c5fdc 2062
3c075c7d 2063=item v1.33, 06 August 1998
0a47030a
GS
2064
2065Integrate more minor changes.
2066
3c075c7d 2067=item v1.32, 05 August 1998
dd9f0070
CN
2068
2069Integrate more minor changes.
2070
3c075c7d 2071=item v1.30, 03 August 1998
b8099c3d
CN
2072
2073Major update for RISC OS, other minor changes.
2074
3c075c7d 2075=item v1.23, 10 July 1998
b8099c3d
CN
2076
2077First public release with perl5.005.
2078
2079=back
e41182b5 2080
ba58ab26
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2081=head1 Supported Platforms
2082
522b859a 2083As of July 2002 (the Perl release 5.8.0), the following platforms are
cec2c193
JH
2084able to build Perl from the standard source code distribution
2085available at http://www.cpan.org/src/index.html
2086
2087 AIX
2088 BeOS
2089 Cygwin
2090 DG/UX
811b48f2 2091 DOS DJGPP 1)
cec2c193
JH
2092 DYNIX/ptx
2093 EPOC R5
2094 FreeBSD
2095 HP-UX
2096 IRIX
2097 Linux
8939ba94
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2098 Mac OS Classic
2099 Mac OS X (Darwin)
cec2c193
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2100 MPE/iX
2101 NetBSD
2102 NetWare
2103 NonStop-UX
2104 ReliantUNIX (SINIX)
2105 OpenBSD
2106 OpenVMS (VMS)
2107 OS/2
522b859a 2108 OS/400 (using the PASE) (since Perl 5.8.1/5.9.0)
70de81db 2109 PowerUX
cec2c193
JH
2110 POSIX-BC (BS2000)
2111 QNX
2112 Solaris
70de81db 2113 SunOS 4
bb5ad0af 2114 SUPER-UX
cec2c193
JH
2115 Tru64 UNIX (DEC OSF/1, Digital UNIX)
2116 UNICOS
2117 UNICOS/mk
2118 UTS
2119 VOS
811b48f2 2120 Win95/98/ME/2K/XP 2)
c40b5d1d 2121 WinCE
cec2c193
JH
2122 z/OS (OS/390)
2123 VM/ESA
ba58ab26 2124
811b48f2
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2125 1) in DOS mode either the DOS or OS/2 ports can be used
2126 2) compilers: Borland, MinGW (GCC), VC6
cec2c193 2127
c40b5d1d 2128The following platforms worked with the previous releases (5.6 and
cec2c193
JH
21295.7), but we did not manage either to fix or to test these in time
2130for the 5.8.0 release. There is a very good chance that many of these
70de81db 2131will work fine with the 5.8.0.
cec2c193 2132
8da2b1be 2133 BSD/OS
cec2c193
JH
2134 DomainOS
2135 Hurd
2136 LynxOS
2137 MachTen
2138 PowerMAX
2139 SCO SV
cec2c193
JH
2140 SVR4
2141 Unixware
2142 Windows 3.1
ba58ab26 2143
70de81db
JH
2144Known to be broken for 5.8.0 (but 5.6.1 and 5.7.2 can be used):
2145
2146 AmigaOS
2147
ba58ab26 2148The following platforms have been known to build Perl from source in
fd46a41b
JH
2149the past (5.005_03 and earlier), but we haven't been able to verify
2150their status for the current release, either because the
2151hardware/software platforms are rare or because we don't have an
2152active champion on these platforms--or both. They used to work,
2153though, so go ahead and try compiling them, and let perlbug@perl.org
2154of any trouble.
ba58ab26 2155
cec2c193
JH
2156 3b1
2157 A/UX
cec2c193
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2158 ConvexOS
2159 CX/UX
2160 DC/OSx
2161 DDE SMES
2162 DOS EMX
2163 Dynix
2164 EP/IX
2165 ESIX
2166 FPS
2167 GENIX
2168 Greenhills
2169 ISC
2170 MachTen 68k
2171 MiNT
2172 MPC
2173 NEWS-OS
2174 NextSTEP
2175 OpenSTEP
2176 Opus
2177 Plan 9
cec2c193 2178 RISC/os
8da2b1be 2179 SCO ODT/OSR
cec2c193
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2180 Stellar
2181 SVR2
2182 TI1500
2183 TitanOS
2184 Ultrix
2185 Unisys Dynix
ba58ab26
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2186
2187The following platforms have their own source code distributions and
1577cd80 2188binaries available via http://www.cpan.org/ports/
ba58ab26 2189
cec2c193 2190 Perl release
ba58ab26 2191
522b859a 2192 OS/400 (ILE) 5.005_02
cec2c193 2193 Tandem Guardian 5.004
ba58ab26
JH
2194
2195The following platforms have only binaries available via
a93751fa 2196http://www.cpan.org/ports/index.html :
ba58ab26 2197
cec2c193 2198 Perl release
ba58ab26 2199
cec2c193
JH
2200 Acorn RISCOS 5.005_02
2201 AOS 5.002
2202 LynxOS 5.004_02
ba58ab26
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2203
2204Although we do suggest that you always build your own Perl from
2205the source code, both for maximal configurability and for security,
2206in case you are in a hurry you can check
a93751fa 2207http://www.cpan.org/ports/index.html for binary distributions.
ba58ab26 2208
c997b287
GS
2209=head1 SEE ALSO
2210
cec2c193 2211L<perlaix>, L<perlamiga>, L<perlapollo>, L<perlbeos>, L<perlbs2000>,
18a271bd 2212L<perlce>, L<perlcygwin>, L<perldgux>, L<perldos>, L<perlepoc>,
469e7be4 2213L<perlebcdic>, L<perlfreebsd>, L<perlhurd>, L<perlhpux>, L<perlirix>,
18a271bd 2214L<perlmachten>, L<perlmacos>, L<perlmint>, L<perlmpeix>,
522b859a
JH
2215L<perlnetware>, L<perlos2>, L<perlos390>, L<perlos400>,
2216L<perlplan9>, L<perlqnx>, L<perlsolaris>, L<perltru64>,
2217L<perlunicode>, L<perlvmesa>, L<perlvms>, L<perlvos>,
2218L<perlwin32>, and L<Win32>.
c997b287 2219
e41182b5
GS
2220=head1 AUTHORS / CONTRIBUTORS
2221
06e9666b 2222Abigail <abigail@foad.org>,
c47ff5f1
GS
2223Charles Bailey <bailey@newman.upenn.edu>,
2224Graham Barr <gbarr@pobox.com>,
2225Tom Christiansen <tchrist@perl.com>,
06e9666b 2226Nicholas Clark <nick@ccl4.org>,
c47ff5f1 2227Thomas Dorner <Thomas.Dorner@start.de>,
06e9666b
A
2228Andy Dougherty <doughera@lafayette.edu>,
2229Dominic Dunlop <domo@computer.org>,
2230Neale Ferguson <neale@vma.tabnsw.com.au>,
c47ff5f1 2231David J. Fiander <davidf@mks.com>,
3fd80bd6 2232Paul Green <Paul.Green@stratus.com>,
06e9666b 2233M.J.T. Guy <mjtg@cam.ac.uk>,
61f30a5e 2234Jarkko Hietaniemi <jhi@iki.fi>,
c47ff5f1 2235Luther Huffman <lutherh@stratcom.com>,
06e9666b
A
2236Nick Ing-Simmons <nick@ing-simmons.net>,
2237Andreas J. KE<ouml>nig <a.koenig@mind.de>,
c47ff5f1
GS
2238Markus Laker <mlaker@contax.co.uk>,
2239Andrew M. Langmead <aml@world.std.com>,
2240Larry Moore <ljmoore@freespace.net>,
2241Paul Moore <Paul.Moore@uk.origin-it.com>,
2242Chris Nandor <pudge@pobox.com>,
1afc07ec 2243Matthias Neeracher <neeracher@mac.com>,
e71a7dc8 2244Philip Newton <pne@cpan.org>,
c47ff5f1
GS
2245Gary Ng <71564.1743@CompuServe.COM>,
2246Tom Phoenix <rootbeer@teleport.com>,
2247AndrE<eacute> Pirard <A.Pirard@ulg.ac.be>,
2248Peter Prymmer <pvhp@forte.com>,
2249Hugo van der Sanden <hv@crypt0.demon.co.uk>,
2250Gurusamy Sarathy <gsar@activestate.com>,
2251Paul J. Schinder <schinder@pobox.com>,
2252Michael G Schwern <schwern@pobox.com>,
06e9666b 2253Dan Sugalski <dan@sidhe.org>,
c47ff5f1 2254Nathan Torkington <gnat@frii.com>.
e41182b5 2255