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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:
74555b7a 194
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195 LF eq \025 eq \x15 eq \cU eq chr(21) eq CP-1047 21
196 LF eq \045 eq \x25 eq chr(37) eq CP-0037 37
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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
PG
483
484To convert $Config{perlpath} to a file pathname, say:
a10d74f3 485 use Config;
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486 $thisperl = $Config{perlpath};
487 if ($^O ne 'VMS')
488 {$thisperl .= $Config{_exe} unless $thisperl =~ m/$Config{_exe}$/i;}
a10d74f3 489
7137b697
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490=head2 Networking
491
492Don't assume that you can reach the public Internet.
493
494Don't assume that there is only one way to get through firewalls
495to the public Internet.
496
932f293e
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497Don't assume that you can reach outside world through any other port
498than 80, or some web proxy. ftp is blocked by many firewalls.
499
dbc6a9ce
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500Don't assume that you can send email by connecting to the local SMTP port.
501
7137b697 502Don't assume that you can reach yourself or any node by the name
dbc6a9ce 503'localhost'. The same goes for '127.0.0.1'. You will have to try both.
932f293e 504
86feb2c5
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505Don't assume that the host has only one network card, or that it
506can't bind to many virtual IP addresses.
932f293e
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507
508Don't assume a particular network device name.
7137b697 509
dbc6a9ce 510Don't assume a particular set of ioctl()s will work.
7137b697
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511
512Don't assume that you can ping hosts and get replies.
513
dbc6a9ce
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514Don't assume that any particular port (service) will respond.
515
516Don't assume that Sys::Hostname() (or any other API or command)
517returns either a fully qualified hostname or a non-qualified hostname:
518it all depends on how the system had been configured. Also remember
519things like DHCP and NAT-- the hostname you get back might not be very
520useful.
521
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522All the above "don't":s may look daunting, and they are -- but the key
523is to degrade gracefully if one cannot reach the particular network
524service one wants. Croaking or hanging do not look very professional.
525
e41182b5
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526=head2 Interprocess Communication (IPC)
527
b7df3edc
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528In general, don't directly access the system in code meant to be
529portable. That means, no C<system>, C<exec>, C<fork>, C<pipe>,
530C<``>, C<qx//>, C<open> with a C<|>, nor any of the other things
531that makes being a perl hacker worth being.
e41182b5
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532
533Commands that launch external processes are generally supported on
b7df3edc
GS
534most platforms (though many of them do not support any type of
535forking). The problem with using them arises from what you invoke
536them on. External tools are often named differently on different
4375e838 537platforms, may not be available in the same location, might accept
b7df3edc
GS
538different arguments, can behave differently, and often present their
539results in a platform-dependent way. Thus, you should seldom depend
540on them to produce consistent results. (Then again, if you're calling
541I<netstat -a>, you probably don't expect it to run on both Unix and CP/M.)
e41182b5 542
b7df3edc 543One especially common bit of Perl code is opening a pipe to B<sendmail>:
e41182b5 544
b7df3edc
GS
545 open(MAIL, '|/usr/lib/sendmail -t')
546 or die "cannot fork sendmail: $!";
e41182b5
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547
548This is fine for systems programming when sendmail is known to be
549available. But it is not fine for many non-Unix systems, and even
550some Unix systems that may not have sendmail installed. If a portable
b7df3edc
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551solution is needed, see the various distributions on CPAN that deal
552with it. Mail::Mailer and Mail::Send in the MailTools distribution are
553commonly used, and provide several mailing methods, including mail,
554sendmail, and direct SMTP (via Net::SMTP) if a mail transfer agent is
555not available. Mail::Sendmail is a standalone module that provides
556simple, platform-independent mailing.
557
558The Unix System V IPC (C<msg*(), sem*(), shm*()>) is not available
559even on all Unix platforms.
e41182b5 560
a81e5e2e
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561Do not use either the bare result of C<pack("N", 10, 20, 30, 40)> or
562bare v-strings (such as C<v10.20.30.40>) to represent IPv4 addresses:
563both forms just pack the four bytes into network order. That this
564would be equal to the C language C<in_addr> struct (which is what the
565socket code internally uses) is not guaranteed. To be portable use
566the routines of the Socket extension, such as C<inet_aton()>,
567C<inet_ntoa()>, and C<sockaddr_in()>.
6b2463a0 568
e41182b5 569The rule of thumb for portable code is: Do it all in portable Perl, or
0a47030a
GS
570use a module (that may internally implement it with platform-specific
571code, but expose a common interface).
e41182b5 572
e41182b5
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573=head2 External Subroutines (XS)
574
b7df3edc 575XS code can usually be made to work with any platform, but dependent
e41182b5
GS
576libraries, header files, etc., might not be readily available or
577portable, or the XS code itself might be platform-specific, just as Perl
578code might be. If the libraries and headers are portable, then it is
579normally reasonable to make sure the XS code is portable, too.
580
b7df3edc
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581A different type of portability issue arises when writing XS code:
582availability of a C compiler on the end-user's system. C brings
583with it its own portability issues, and writing XS code will expose
584you to some of those. Writing purely in Perl is an easier way to
e41182b5
GS
585achieve portability.
586
e41182b5
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587=head2 Standard Modules
588
589In general, the standard modules work across platforms. Notable
6ab3f9cb 590exceptions are the CPAN module (which currently makes connections to external
e41182b5 591programs that may not be available), platform-specific modules (like
6ab3f9cb 592ExtUtils::MM_VMS), and DBM modules.
e41182b5 593
b7df3edc 594There is no one DBM module available on all platforms.
6ab3f9cb
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595SDBM_File and the others are generally available on all Unix and DOSish
596ports, but not in MacPerl, where only NBDM_File and DB_File are
0a47030a 597available.
e41182b5
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598
599The good news is that at least some DBM module should be available, and
6ab3f9cb 600AnyDBM_File will use whichever module it can find. Of course, then
b7df3edc
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601the code needs to be fairly strict, dropping to the greatest common
602factor (e.g., not exceeding 1K for each record), so that it will
6ab3f9cb 603work with any DBM module. See L<AnyDBM_File> for more details.
e41182b5 604
e41182b5
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605=head2 Time and Date
606
0a47030a 607The system's notion of time of day and calendar date is controlled in
b7df3edc 608widely different ways. Don't assume the timezone is stored in C<$ENV{TZ}>,
0a47030a 609and even if it is, don't assume that you can control the timezone through
c87488a3
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610that variable. Don't assume anything about the three-letter timezone
611abbreviations (for example that MST would be the Mountain Standard Time,
612it's been known to stand for Moscow Standard Time). If you need to
613use timezones, express them in some unambiguous format like the
614exact number of minutes offset from UTC, or the POSIX timezone
615format.
e41182b5 616
322422de 617Don't assume that the epoch starts at 00:00:00, January 1, 1970,
c87488a3
HS
618because that is OS- and implementation-specific. It is better to
619store a date in an unambiguous representation. The ISO 8601 standard
620defines YYYY-MM-DD as the date format, or YYYY-MM-DDTHH-MM-SS
621(that's a literal "T" separating the date from the time).
622Please do use the ISO 8601 instead of making us to guess what
623date 02/03/04 might be. ISO 8601 even sorts nicely as-is.
624A text representation (like "1987-12-18") can be easily converted
625into an OS-specific value using a module like Date::Parse.
626An array of values, such as those returned by C<localtime>, can be
627converted to an OS-specific representation using Time::Local.
322422de 628
19799a22
GS
629When calculating specific times, such as for tests in time or date modules,
630it may be appropriate to calculate an offset for the epoch.
b7df3edc 631
19799a22
GS
632 require Time::Local;
633 $offset = Time::Local::timegm(0, 0, 0, 1, 0, 70);
b7df3edc 634
19799a22
GS
635The value for C<$offset> in Unix will be C<0>, but in Mac OS will be
636some large number. C<$offset> can then be added to a Unix time value
637to get what should be the proper value on any system.
322422de 638
bbac04ed
RGS
639On Windows (at least), you shouldn't pass a negative value to C<gmtime> or
640C<localtime>.
641
322422de
GS
642=head2 Character sets and character encoding
643
ec481373
JH
644Assume very little about character sets.
645
646Assume nothing about numerical values (C<ord>, C<chr>) of characters.
647Do not use explicit code point ranges (like \xHH-\xHH); use for
648example symbolic character classes like C<[:print:]>.
649
650Do not assume that the alphabetic characters are encoded contiguously
651(in the numeric sense). There may be gaps.
652
653Do not assume anything about the ordering of the characters.
654The lowercase letters may come before or after the uppercase letters;
655the lowercase and uppercase may be interlaced so that both `a' and `A'
656come before `b'; the accented and other international characters may
657be interlaced so that E<auml> comes before `b'.
322422de
GS
658
659=head2 Internationalisation
660
b7df3edc
GS
661If you may assume POSIX (a rather large assumption), you may read
662more about the POSIX locale system from L<perllocale>. The locale
663system at least attempts to make things a little bit more portable,
664or at least more convenient and native-friendly for non-English
665users. The system affects character sets and encoding, and date
666and time formatting--amongst other things.
e41182b5 667
c87488a3
HS
668If you really want to be international, you should consider Unicode.
669See L<perluniintro> and L<perlunicode> for more information.
670
11264fdb
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671If you want to use non-ASCII bytes (outside the bytes 0x00..0x7f) in
672the "source code" of your code, to be portable you have to be explicit
673about what bytes they are. Someone might for example be using your
674code under a UTF-8 locale, in which case random native bytes might be
675illegal ("Malformed UTF-8 ...") This means that for example embedding
676ISO 8859-1 bytes beyond 0x7f into your strings might cause trouble
677later. If the bytes are native 8-bit bytes, you can use the C<bytes>
678pragma. If the bytes are in a string (regular expression being a
679curious string), you can often also use the C<\xHH> notation instead
680of embedding the bytes as-is. If they are in some particular legacy
681encoding (ether single-byte or something more complicated), you can
682use the C<encoding> pragma. (If you want to write your code in UTF-8,
683you can use either the C<utf8> pragma, or the C<encoding> pragma.)
684The C<bytes> and C<utf8> pragmata are available since Perl 5.6.0, and
685the C<encoding> pragma since Perl 5.8.0.
686
e41182b5
GS
687=head2 System Resources
688
0a47030a
GS
689If your code is destined for systems with severely constrained (or
690missing!) virtual memory systems then you want to be I<especially> mindful
691of avoiding wasteful constructs such as:
e41182b5
GS
692
693 # NOTE: this is no longer "bad" in perl5.005
694 for (0..10000000) {} # bad
695 for (my $x = 0; $x <= 10000000; ++$x) {} # good
696
697 @lines = <VERY_LARGE_FILE>; # bad
698
699 while (<FILE>) {$file .= $_} # sometimes bad
0a47030a 700 $file = join('', <FILE>); # better
e41182b5 701
b7df3edc
GS
702The last two constructs may appear unintuitive to most people. The
703first repeatedly grows a string, whereas the second allocates a
704large chunk of memory in one go. On some systems, the second is
705more efficient that the first.
0a47030a 706
e41182b5
GS
707=head2 Security
708
b7df3edc
GS
709Most multi-user platforms provide basic levels of security, usually
710implemented at the filesystem level. Some, however, do
a1667ba3 711not-- unfortunately. Thus the notion of user id, or "home" directory,
b7df3edc
GS
712or even the state of being logged-in, may be unrecognizable on many
713platforms. If you write programs that are security-conscious, it
714is usually best to know what type of system you will be running
715under so that you can write code explicitly for that platform (or
716class of platforms).
0a47030a 717
a1667ba3
JH
718Don't assume the UNIX filesystem access semantics: the operating
719system or the filesystem may be using some ACL systems, which are
720richer languages than the usual rwx. Even if the rwx exist,
721their semantics might be different.
722
723(From security viewpoint testing for permissions before attempting to
724do something is silly anyway: if one tries this, there is potential
725for race conditions-- someone or something might change the
726permissions between the permissions check and the actual operation.
727Just try the operation.)
728
729Don't assume the UNIX user and group semantics: especially, don't
2edcc0d9 730expect the C<< $< >> and C<< $> >> (or the C<$(> and C<$)>) to work
a1667ba3
JH
731for switching identities (or memberships).
732
733Don't assume set-uid and set-gid semantics. (And even if you do,
734think twice: set-uid and set-gid are a known can of security worms.)
735
e41182b5
GS
736=head2 Style
737
738For those times when it is necessary to have platform-specific code,
739consider keeping the platform-specific code in one place, making porting
6ab3f9cb 740to other platforms easier. Use the Config module and the special
0a47030a
GS
741variable C<$^O> to differentiate platforms, as described in
742L<"PLATFORMS">.
e41182b5 743
b7df3edc
GS
744Be careful in the tests you supply with your module or programs.
745Module code may be fully portable, but its tests might not be. This
746often happens when tests spawn off other processes or call external
747programs to aid in the testing, or when (as noted above) the tests
c87488a3
HS
748assume certain things about the filesystem and paths. Be careful not
749to depend on a specific output style for errors, such as when checking
750C<$!> after a failed system call. Using C<$!> for anything else than
751displaying it as output is doubtful (though see the Errno module for
752testing reasonably portably for error value). Some platforms expect
753a certain output format, and Perl on those platforms may have been
754adjusted accordingly. Most specifically, don't anchor a regex when
755testing an error value.
e41182b5 756
0a47030a 757=head1 CPAN Testers
e41182b5 758
0a47030a
GS
759Modules uploaded to CPAN are tested by a variety of volunteers on
760different platforms. These CPAN testers are notified by mail of each
e41182b5 761new upload, and reply to the list with PASS, FAIL, NA (not applicable to
0a47030a 762this platform), or UNKNOWN (unknown), along with any relevant notations.
e41182b5
GS
763
764The purpose of the testing is twofold: one, to help developers fix any
0a47030a 765problems in their code that crop up because of lack of testing on other
b7df3edc 766platforms; two, to provide users with information about whether
0a47030a 767a given module works on a given platform.
e41182b5
GS
768
769=over 4
770
771=item Mailing list: cpan-testers@perl.org
772
c997b287 773=item Testing results: http://testers.cpan.org/
e41182b5
GS
774
775=back
776
e41182b5
GS
777=head1 PLATFORMS
778
779As of version 5.002, Perl is built with a C<$^O> variable that
780indicates the operating system it was built on. This was implemented
b7df3edc
GS
781to help speed up code that would otherwise have to C<use Config>
782and use the value of C<$Config{osname}>. Of course, to get more
e41182b5
GS
783detailed information about the system, looking into C<%Config> is
784certainly recommended.
785
b7df3edc
GS
786C<%Config> cannot always be trusted, however, because it was built
787at compile time. If perl was built in one place, then transferred
788elsewhere, some values may be wrong. The values may even have been
789edited after the fact.
6ab3f9cb 790
e41182b5
GS
791=head2 Unix
792
793Perl works on a bewildering variety of Unix and Unix-like platforms (see
794e.g. most of the files in the F<hints/> directory in the source code kit).
795On most of these systems, the value of C<$^O> (hence C<$Config{'osname'}>,
d1e3b762
GS
796too) is determined either by lowercasing and stripping punctuation from the
797first field of the string returned by typing C<uname -a> (or a similar command)
798at the shell prompt or by testing the file system for the presence of
799uniquely named files such as a kernel or header file. Here, for example,
800are a few of the more popular Unix flavors:
e41182b5 801
b7df3edc 802 uname $^O $Config{'archname'}
6ab3f9cb 803 --------------------------------------------
b7df3edc 804 AIX aix aix
6ab3f9cb 805 BSD/OS bsdos i386-bsdos
e1516da7 806 Darwin darwin darwin
6ab3f9cb
GS
807 dgux dgux AViiON-dgux
808 DYNIX/ptx dynixptx i386-dynixptx
b7df3edc 809 FreeBSD freebsd freebsd-i386
d1e3b762 810 Linux linux arm-linux
b7df3edc 811 Linux linux i386-linux
6ab3f9cb
GS
812 Linux linux i586-linux
813 Linux linux ppc-linux
b7df3edc
GS
814 HP-UX hpux PA-RISC1.1
815 IRIX irix irix
b787fad4 816 Mac OS X darwin darwin
d1e3b762
GS
817 MachTen PPC machten powerpc-machten
818 NeXT 3 next next-fat
819 NeXT 4 next OPENSTEP-Mach
6ab3f9cb 820 openbsd openbsd i386-openbsd
b7df3edc 821 OSF1 dec_osf alpha-dec_osf
6ab3f9cb
GS
822 reliantunix-n svr4 RM400-svr4
823 SCO_SV sco_sv i386-sco_sv
824 SINIX-N svr4 RM400-svr4
825 sn4609 unicos CRAY_C90-unicos
826 sn6521 unicosmk t3e-unicosmk
827 sn9617 unicos CRAY_J90-unicos
b7df3edc
GS
828 SunOS solaris sun4-solaris
829 SunOS solaris i86pc-solaris
830 SunOS4 sunos sun4-sunos
e41182b5 831
b7df3edc
GS
832Because the value of C<$Config{archname}> may depend on the
833hardware architecture, it can vary more than the value of C<$^O>.
6ab3f9cb 834
e41182b5
GS
835=head2 DOS and Derivatives
836
b7df3edc 837Perl has long been ported to Intel-style microcomputers running under
e41182b5
GS
838systems like PC-DOS, MS-DOS, OS/2, and most Windows platforms you can
839bring yourself to mention (except for Windows CE, if you count that).
b7df3edc 840Users familiar with I<COMMAND.COM> or I<CMD.EXE> style shells should
e41182b5
GS
841be aware that each of these file specifications may have subtle
842differences:
843
844 $filespec0 = "c:/foo/bar/file.txt";
845 $filespec1 = "c:\\foo\\bar\\file.txt";
846 $filespec2 = 'c:\foo\bar\file.txt';
847 $filespec3 = 'c:\\foo\\bar\\file.txt';
848
b7df3edc
GS
849System calls accept either C</> or C<\> as the path separator.
850However, many command-line utilities of DOS vintage treat C</> as
851the option prefix, so may get confused by filenames containing C</>.
852Aside from calling any external programs, C</> will work just fine,
853and probably better, as it is more consistent with popular usage,
854and avoids the problem of remembering what to backwhack and what
855not to.
e41182b5 856
b7df3edc
GS
857The DOS FAT filesystem can accommodate only "8.3" style filenames. Under
858the "case-insensitive, but case-preserving" HPFS (OS/2) and NTFS (NT)
0a47030a 859filesystems you may have to be careful about case returned with functions
e41182b5
GS
860like C<readdir> or used with functions like C<open> or C<opendir>.
861
b7df3edc
GS
862DOS also treats several filenames as special, such as AUX, PRN,
863NUL, CON, COM1, LPT1, LPT2, etc. Unfortunately, sometimes these
864filenames won't even work if you include an explicit directory
865prefix. It is best to avoid such filenames, if you want your code
866to be portable to DOS and its derivatives. It's hard to know what
867these all are, unfortunately.
e41182b5
GS
868
869Users of these operating systems may also wish to make use of
b7df3edc 870scripts such as I<pl2bat.bat> or I<pl2cmd> to
e41182b5
GS
871put wrappers around your scripts.
872
873Newline (C<\n>) is translated as C<\015\012> by STDIO when reading from
6ab3f9cb
GS
874and writing to files (see L<"Newlines">). C<binmode(FILEHANDLE)>
875will keep C<\n> translated as C<\012> for that filehandle. Since it is a
876no-op on other systems, C<binmode> should be used for cross-platform code
b7df3edc
GS
877that deals with binary data. That's assuming you realize in advance
878that your data is in binary. General-purpose programs should
879often assume nothing about their data.
e41182b5 880
b7df3edc 881The C<$^O> variable and the C<$Config{archname}> values for various
e41182b5
GS
882DOSish perls are as follows:
883
67ac489e
MS
884 OS $^O $Config{archname} ID Version
885 --------------------------------------------------------
886 MS-DOS dos ?
887 PC-DOS dos ?
888 OS/2 os2 ?
889 Windows 3.1 ? ? 0 3 01
890 Windows 95 MSWin32 MSWin32-x86 1 4 00
891 Windows 98 MSWin32 MSWin32-x86 1 4 10
892 Windows ME MSWin32 MSWin32-x86 1 ?
893 Windows NT MSWin32 MSWin32-x86 2 4 xx
894 Windows NT MSWin32 MSWin32-ALPHA 2 4 xx
895 Windows NT MSWin32 MSWin32-ppc 2 4 xx
896 Windows 2000 MSWin32 MSWin32-x86 2 5 xx
897 Windows XP MSWin32 MSWin32-x86 2 ?
898 Windows CE MSWin32 ? 3
899 Cygwin cygwin ?
e41182b5 900
34aaaa84
PP
901The various MSWin32 Perl's can distinguish the OS they are running on
902via the value of the fifth element of the list returned from
903Win32::GetOSVersion(). For example:
904
905 if ($^O eq 'MSWin32') {
906 my @os_version_info = Win32::GetOSVersion();
907 print +('3.1','95','NT')[$os_version_info[4]],"\n";
908 }
909
7939d86b
JH
910There are also Win32::IsWinNT() and Win32::IsWin95(), try C<perldoc Win32>,
911and as of libwin32 0.19 (not part of the core Perl distribution)
912Win32::GetOSName(). The very portable POSIX::uname() will work too:
1d65be3a
JH
913
914 c:\> perl -MPOSIX -we "print join '|', uname"
915 Windows NT|moonru|5.0|Build 2195 (Service Pack 2)|x86
d99f392e 916
e41182b5
GS
917Also see:
918
919=over 4
920
c997b287 921=item *
e41182b5 922
c997b287
GS
923The djgpp environment for DOS, http://www.delorie.com/djgpp/
924and L<perldos>.
e41182b5 925
c997b287 926=item *
e41182b5 927
c997b287
GS
928The EMX environment for DOS, OS/2, etc. emx@iaehv.nl,
929http://www.leo.org/pub/comp/os/os2/leo/gnu/emx+gcc/index.html or
f224927c 930ftp://hobbes.nmsu.edu/pub/os2/dev/emx/ Also L<perlos2>.
e41182b5 931
c997b287 932=item *
d1e3b762 933
c997b287
GS
934Build instructions for Win32 in L<perlwin32>, or under the Cygnus environment
935in L<perlcygwin>.
936
937=item *
938
939The C<Win32::*> modules in L<Win32>.
940
941=item *
942
943The ActiveState Pages, http://www.activestate.com/
944
945=item *
946
947The Cygwin environment for Win32; F<README.cygwin> (installed
47dafe4d 948as L<perlcygwin>), http://www.cygwin.com/
c997b287
GS
949
950=item *
951
952The U/WIN environment for Win32,
cea6626f 953http://www.research.att.com/sw/tools/uwin/
c997b287 954
cea6626f 955=item *
d1e3b762 956
cea6626f 957Build instructions for OS/2, L<perlos2>
d1e3b762 958
e41182b5
GS
959=back
960
dd9f0070 961=head2 S<Mac OS>
e41182b5
GS
962
963Any module requiring XS compilation is right out for most people, because
964MacPerl is built using non-free (and non-cheap!) compilers. Some XS
965modules that can work with MacPerl are built and distributed in binary
6ab3f9cb 966form on CPAN.
e41182b5
GS
967
968Directories are specified as:
969
970 volume:folder:file for absolute pathnames
971 volume:folder: for absolute pathnames
972 :folder:file for relative pathnames
973 :folder: for relative pathnames
974 :file for relative pathnames
975 file for relative pathnames
976
b7df3edc 977Files are stored in the directory in alphabetical order. Filenames are
6ab3f9cb 978limited to 31 characters, and may include any character except for
b7df3edc 979null and C<:>, which is reserved as the path separator.
e41182b5 980
0a47030a 981Instead of C<flock>, see C<FSpSetFLock> and C<FSpRstFLock> in the
6ab3f9cb 982Mac::Files module, or C<chmod(0444, ...)> and C<chmod(0666, ...)>.
e41182b5
GS
983
984In the MacPerl application, you can't run a program from the command line;
985programs that expect C<@ARGV> to be populated can be edited with something
986like the following, which brings up a dialog box asking for the command
987line arguments.
988
989 if (!@ARGV) {
990 @ARGV = split /\s+/, MacPerl::Ask('Arguments?');
991 }
992
b7df3edc 993A MacPerl script saved as a "droplet" will populate C<@ARGV> with the full
e41182b5
GS
994pathnames of the files dropped onto the script.
995
b7df3edc
GS
996Mac users can run programs under a type of command line interface
997under MPW (Macintosh Programmer's Workshop, a free development
998environment from Apple). MacPerl was first introduced as an MPW
999tool, and MPW can be used like a shell:
e41182b5
GS
1000
1001 perl myscript.plx some arguments
1002
1003ToolServer is another app from Apple that provides access to MPW tools
0a47030a 1004from MPW and the MacPerl app, which allows MacPerl programs to use
e41182b5
GS
1005C<system>, backticks, and piped C<open>.
1006
1007"S<Mac OS>" is the proper name for the operating system, but the value
1008in C<$^O> is "MacOS". To determine architecture, version, or whether
1009the application or MPW tool version is running, check:
1010
1011 $is_app = $MacPerl::Version =~ /App/;
1012 $is_tool = $MacPerl::Version =~ /MPW/;
1013 ($version) = $MacPerl::Version =~ /^(\S+)/;
1014 $is_ppc = $MacPerl::Architecture eq 'MacPPC';
1015 $is_68k = $MacPerl::Architecture eq 'Mac68K';
1016
b787fad4
JH
1017S<Mac OS X>, based on NeXT's OpenStep OS, runs MacPerl natively, under the
1018"Classic" environment. There is no "Carbon" version of MacPerl to run
1019under the primary Mac OS X environment. S<Mac OS X> and its Open Source
1020version, Darwin, both run Unix perl natively.
6ab3f9cb 1021
e41182b5
GS
1022Also see:
1023
1024=over 4
1025
c997b287
GS
1026=item *
1027
862b5365 1028MacPerl Development, http://dev.macperl.org/ .
c997b287
GS
1029
1030=item *
1031
862b5365 1032The MacPerl Pages, http://www.macperl.com/ .
e41182b5 1033
c997b287 1034=item *
6ab3f9cb 1035
862b5365 1036The MacPerl mailing lists, http://lists.perl.org/ .
e41182b5
GS
1037
1038=back
1039
e41182b5
GS
1040=head2 VMS
1041
c997b287 1042Perl on VMS is discussed in L<perlvms> in the perl distribution.
b7df3edc 1043Perl on VMS can accept either VMS- or Unix-style file
e41182b5
GS
1044specifications as in either of the following:
1045
1046 $ perl -ne "print if /perl_setup/i" SYS$LOGIN:LOGIN.COM
1047 $ perl -ne "print if /perl_setup/i" /sys$login/login.com
1048
1049but not a mixture of both as in:
1050
1051 $ perl -ne "print if /perl_setup/i" sys$login:/login.com
1052 Can't open sys$login:/login.com: file specification syntax error
1053
1054Interacting with Perl from the Digital Command Language (DCL) shell
1055often requires a different set of quotation marks than Unix shells do.
1056For example:
1057
1058 $ perl -e "print ""Hello, world.\n"""
1059 Hello, world.
1060
b7df3edc 1061There are several ways to wrap your perl scripts in DCL F<.COM> files, if
e41182b5
GS
1062you are so inclined. For example:
1063
1064 $ write sys$output "Hello from DCL!"
1065 $ if p1 .eqs. ""
1066 $ then perl -x 'f$environment("PROCEDURE")
1067 $ else perl -x - 'p1 'p2 'p3 'p4 'p5 'p6 'p7 'p8
1068 $ deck/dollars="__END__"
1069 #!/usr/bin/perl
1070
1071 print "Hello from Perl!\n";
1072
1073 __END__
1074 $ endif
1075
1076Do take care with C<$ ASSIGN/nolog/user SYS$COMMAND: SYS$INPUT> if your
c47ff5f1 1077perl-in-DCL script expects to do things like C<< $read = <STDIN>; >>.
e41182b5
GS
1078
1079Filenames are in the format "name.extension;version". The maximum
1080length for filenames is 39 characters, and the maximum length for
1081extensions is also 39 characters. Version is a number from 1 to
108232767. Valid characters are C</[A-Z0-9$_-]/>.
1083
b7df3edc 1084VMS's RMS filesystem is case-insensitive and does not preserve case.
e41182b5 1085C<readdir> returns lowercased filenames, but specifying a file for
b7df3edc 1086opening remains case-insensitive. Files without extensions have a
e41182b5 1087trailing period on them, so doing a C<readdir> with a file named F<A.;5>
0a47030a
GS
1088will return F<a.> (though that file could be opened with
1089C<open(FH, 'A')>).
e41182b5 1090
f34d0673 1091RMS had an eight level limit on directory depths from any rooted logical
dd9f0070
CN
1092(allowing 16 levels overall) prior to VMS 7.2. Hence
1093C<PERL_ROOT:[LIB.2.3.4.5.6.7.8]> is a valid directory specification but
1094C<PERL_ROOT:[LIB.2.3.4.5.6.7.8.9]> is not. F<Makefile.PL> authors might
1095have to take this into account, but at least they can refer to the former
f34d0673 1096as C</PERL_ROOT/lib/2/3/4/5/6/7/8/>.
e41182b5 1097
6ab3f9cb 1098The VMS::Filespec module, which gets installed as part of the build
0a47030a
GS
1099process on VMS, is a pure Perl module that can easily be installed on
1100non-VMS platforms and can be helpful for conversions to and from RMS
1101native formats.
e41182b5 1102
5e12dbfa
PP
1103What C<\n> represents depends on the type of file opened. It usually
1104represents C<\012> but it could also be C<\015>, C<\012>, C<\015\012>,
1105C<\000>, C<\040>, or nothing depending on the file organiztion and
1106record format. The VMS::Stdio module provides access to the
1107special fopen() requirements of files with unusual attributes on VMS.
e41182b5
GS
1108
1109TCP/IP stacks are optional on VMS, so socket routines might not be
1110implemented. UDP sockets may not be supported.
1111
1112The value of C<$^O> on OpenVMS is "VMS". To determine the architecture
1113that you are running on without resorting to loading all of C<%Config>
1114you can examine the content of the C<@INC> array like so:
1115
1116 if (grep(/VMS_AXP/, @INC)) {
1117 print "I'm on Alpha!\n";
6ab3f9cb 1118
e41182b5
GS
1119 } elsif (grep(/VMS_VAX/, @INC)) {
1120 print "I'm on VAX!\n";
6ab3f9cb 1121
e41182b5
GS
1122 } else {
1123 print "I'm not so sure about where $^O is...\n";
1124 }
1125
b7df3edc
GS
1126On VMS, perl determines the UTC offset from the C<SYS$TIMEZONE_DIFFERENTIAL>
1127logical name. Although the VMS epoch began at 17-NOV-1858 00:00:00.00,
6ab3f9cb 1128calls to C<localtime> are adjusted to count offsets from
b7df3edc 112901-JAN-1970 00:00:00.00, just like Unix.
6ab3f9cb 1130
e41182b5
GS
1131Also see:
1132
1133=over 4
1134
c997b287
GS
1135=item *
1136
1137F<README.vms> (installed as L<README_vms>), L<perlvms>
1138
1139=item *
1140
1141vmsperl list, majordomo@perl.org
e41182b5 1142
c997b287 1143(Put the words C<subscribe vmsperl> in message body.)
e41182b5 1144
c997b287 1145=item *
e41182b5 1146
c997b287 1147vmsperl on the web, http://www.sidhe.org/vmsperl/index.html
e41182b5
GS
1148
1149=back
1150
495c5fdc
GP
1151=head2 VOS
1152
9a997319
JH
1153Perl on VOS is discussed in F<README.vos> in the perl distribution
1154(installed as L<perlvos>). Perl on VOS can accept either VOS- or
1155Unix-style file specifications as in either of the following:
495c5fdc 1156
cc07ed0b
PG
1157 C<< $ perl -ne "print if /perl_setup/i" >system>notices >>
1158 C<< $ perl -ne "print if /perl_setup/i" /system/notices >>
495c5fdc
GP
1159
1160or even a mixture of both as in:
1161
cc07ed0b 1162 C<< $ perl -ne "print if /perl_setup/i" >system/notices >>
495c5fdc 1163
b7df3edc 1164Even though VOS allows the slash character to appear in object
495c5fdc
GP
1165names, because the VOS port of Perl interprets it as a pathname
1166delimiting character, VOS files, directories, or links whose names
1167contain a slash character cannot be processed. Such files must be
a3dfe201
GS
1168renamed before they can be processed by Perl. Note that VOS limits
1169file names to 32 or fewer characters.
495c5fdc 1170
495c5fdc
GP
1171The value of C<$^O> on VOS is "VOS". To determine the architecture that
1172you are running on without resorting to loading all of C<%Config> you
c997b287 1173can examine the content of the @INC array like so:
495c5fdc 1174
24e8e380 1175 if ($^O =~ /VOS/) {
495c5fdc
GP
1176 print "I'm on a Stratus box!\n";
1177 } else {
1178 print "I'm not on a Stratus box!\n";
1179 die;
1180 }
1181
495c5fdc
GP
1182Also see:
1183
1184=over 4
1185
c997b287 1186=item *
495c5fdc 1187
cc07ed0b 1188F<README.vos> (installed as L<perlvos>)
c997b287
GS
1189
1190=item *
1191
1192The VOS mailing list.
495c5fdc
GP
1193
1194There is no specific mailing list for Perl on VOS. You can post
1195comments to the comp.sys.stratus newsgroup, or subscribe to the general
cc07ed0b 1196Stratus mailing list. Send a letter with "subscribe Info-Stratus" in
495c5fdc
GP
1197the message body to majordomo@list.stratagy.com.
1198
c997b287
GS
1199=item *
1200
cc07ed0b 1201VOS Perl on the web at http://ftp.stratus.com/pub/vos/posix/posix.html
495c5fdc
GP
1202
1203=back
1204
e41182b5
GS
1205=head2 EBCDIC Platforms
1206
1207Recent versions of Perl have been ported to platforms such as OS/400 on
d1e3b762
GS
1208AS/400 minicomputers as well as OS/390, VM/ESA, and BS2000 for S/390
1209Mainframes. Such computers use EBCDIC character sets internally (usually
0cc436d0
GS
1210Character Code Set ID 0037 for OS/400 and either 1047 or POSIX-BC for S/390
1211systems). On the mainframe perl currently works under the "Unix system
1212services for OS/390" (formerly known as OpenEdition), VM/ESA OpenEdition, or
1213the BS200 POSIX-BC system (BS2000 is supported in perl 5.6 and greater).
522b859a
JH
1214See L<perlos390> for details. Note that for OS/400 there is also a port of
1215Perl 5.8.1/5.9.0 or later to the PASE which is ASCII-based (as opposed to
1216ILE which is EBCDIC-based), see L<perlos400>.
e41182b5 1217
7c5ffed3
JH
1218As of R2.5 of USS for OS/390 and Version 2.3 of VM/ESA these Unix
1219sub-systems do not support the C<#!> shebang trick for script invocation.
1220Hence, on OS/390 and VM/ESA perl scripts can be executed with a header
1221similar to the following simple script:
e41182b5
GS
1222
1223 : # use perl
1224 eval 'exec /usr/local/bin/perl -S $0 ${1+"$@"}'
1225 if 0;
1226 #!/usr/local/bin/perl # just a comment really
1227
1228 print "Hello from perl!\n";
1229
d1e3b762
GS
1230OS/390 will support the C<#!> shebang trick in release 2.8 and beyond.
1231Calls to C<system> and backticks can use POSIX shell syntax on all
1232S/390 systems.
1233
b7df3edc 1234On the AS/400, if PERL5 is in your library list, you may need
6ab3f9cb
GS
1235to wrap your perl scripts in a CL procedure to invoke them like so:
1236
1237 BEGIN
1238 CALL PGM(PERL5/PERL) PARM('/QOpenSys/hello.pl')
1239 ENDPGM
1240
1241This will invoke the perl script F<hello.pl> in the root of the
1242QOpenSys file system. On the AS/400 calls to C<system> or backticks
1243must use CL syntax.
1244
e41182b5 1245On these platforms, bear in mind that the EBCDIC character set may have
0a47030a
GS
1246an effect on what happens with some perl functions (such as C<chr>,
1247C<pack>, C<print>, C<printf>, C<ord>, C<sort>, C<sprintf>, C<unpack>), as
1248well as bit-fiddling with ASCII constants using operators like C<^>, C<&>
1249and C<|>, not to mention dealing with socket interfaces to ASCII computers
6ab3f9cb 1250(see L<"Newlines">).
e41182b5 1251
b7df3edc
GS
1252Fortunately, most web servers for the mainframe will correctly
1253translate the C<\n> in the following statement to its ASCII equivalent
1254(C<\r> is the same under both Unix and OS/390 & VM/ESA):
e41182b5
GS
1255
1256 print "Content-type: text/html\r\n\r\n";
1257
d1e3b762 1258The values of C<$^O> on some of these platforms includes:
e41182b5 1259
d1e3b762
GS
1260 uname $^O $Config{'archname'}
1261 --------------------------------------------
1262 OS/390 os390 os390
1263 OS400 os400 os400
1264 POSIX-BC posix-bc BS2000-posix-bc
1265 VM/ESA vmesa vmesa
3c075c7d 1266
e41182b5
GS
1267Some simple tricks for determining if you are running on an EBCDIC
1268platform could include any of the following (perhaps all):
1269
1270 if ("\t" eq "\05") { print "EBCDIC may be spoken here!\n"; }
1271
1272 if (ord('A') == 193) { print "EBCDIC may be spoken here!\n"; }
1273
1274 if (chr(169) eq 'z') { print "EBCDIC may be spoken here!\n"; }
1275
b7df3edc 1276One thing you may not want to rely on is the EBCDIC encoding
0a47030a
GS
1277of punctuation characters since these may differ from code page to code
1278page (and once your module or script is rumoured to work with EBCDIC,
1279folks will want it to work with all EBCDIC character sets).
e41182b5
GS
1280
1281Also see:
1282
1283=over 4
1284
c997b287
GS
1285=item *
1286
1287*
d1e3b762 1288
dc5c060f 1289L<perlos390>, F<README.os390>, F<perlbs2000>, F<README.vmesa>,
bb462878 1290L<perlebcdic>.
c997b287
GS
1291
1292=item *
e41182b5
GS
1293
1294The perl-mvs@perl.org list is for discussion of porting issues as well as
1295general usage issues for all EBCDIC Perls. Send a message body of
1296"subscribe perl-mvs" to majordomo@perl.org.
1297
c997b287
GS
1298=item *
1299
1300AS/400 Perl information at
b1866b2d 1301http://as400.rochester.ibm.com/
d1e3b762 1302as well as on CPAN in the F<ports/> directory.
e41182b5
GS
1303
1304=back
1305
b8099c3d
CN
1306=head2 Acorn RISC OS
1307
b7df3edc
GS
1308Because Acorns use ASCII with newlines (C<\n>) in text files as C<\012> like
1309Unix, and because Unix filename emulation is turned on by default,
1310most simple scripts will probably work "out of the box". The native
6ab3f9cb 1311filesystem is modular, and individual filesystems are free to be
0a47030a 1312case-sensitive or insensitive, and are usually case-preserving. Some
b7df3edc 1313native filesystems have name length limits, which file and directory
6ab3f9cb
GS
1314names are silently truncated to fit. Scripts should be aware that the
1315standard filesystem currently has a name length limit of B<10>
1316characters, with up to 77 items in a directory, but other filesystems
0a47030a 1317may not impose such limitations.
b8099c3d
CN
1318
1319Native filenames are of the form
1320
6ab3f9cb 1321 Filesystem#Special_Field::DiskName.$.Directory.Directory.File
dd9f0070 1322
b8099c3d
CN
1323where
1324
1325 Special_Field is not usually present, but may contain . and $ .
1326 Filesystem =~ m|[A-Za-z0-9_]|
1327 DsicName =~ m|[A-Za-z0-9_/]|
1328 $ represents the root directory
1329 . is the path separator
1330 @ is the current directory (per filesystem but machine global)
1331 ^ is the parent directory
1332 Directory and File =~ m|[^\0- "\.\$\%\&:\@\\^\|\177]+|
1333
1334The default filename translation is roughly C<tr|/.|./|;>
1335
6ab3f9cb 1336Note that C<"ADFS::HardDisk.$.File" ne 'ADFS::HardDisk.$.File'> and that
0a47030a
GS
1337the second stage of C<$> interpolation in regular expressions will fall
1338foul of the C<$.> if scripts are not careful.
1339
1340Logical paths specified by system variables containing comma-separated
b7df3edc 1341search lists are also allowed; hence C<System:Modules> is a valid
0a47030a 1342filename, and the filesystem will prefix C<Modules> with each section of
6ab3f9cb 1343C<System$Path> until a name is made that points to an object on disk.
b7df3edc 1344Writing to a new file C<System:Modules> would be allowed only if
0a47030a
GS
1345C<System$Path> contains a single item list. The filesystem will also
1346expand system variables in filenames if enclosed in angle brackets, so
c47ff5f1 1347C<< <System$Dir>.Modules >> would look for the file
0a47030a 1348S<C<$ENV{'System$Dir'} . 'Modules'>>. The obvious implication of this is
c47ff5f1 1349that B<fully qualified filenames can start with C<< <> >>> and should
0a47030a 1350be protected when C<open> is used for input.
b8099c3d
CN
1351
1352Because C<.> was in use as a directory separator and filenames could not
1353be assumed to be unique after 10 characters, Acorn implemented the C
1354compiler to strip the trailing C<.c> C<.h> C<.s> and C<.o> suffix from
1355filenames specified in source code and store the respective files in
b7df3edc 1356subdirectories named after the suffix. Hence files are translated:
b8099c3d
CN
1357
1358 foo.h h.foo
1359 C:foo.h C:h.foo (logical path variable)
1360 sys/os.h sys.h.os (C compiler groks Unix-speak)
1361 10charname.c c.10charname
1362 10charname.o o.10charname
1363 11charname_.c c.11charname (assuming filesystem truncates at 10)
1364
1365The Unix emulation library's translation of filenames to native assumes
b7df3edc
GS
1366that this sort of translation is required, and it allows a user-defined list
1367of known suffixes that it will transpose in this fashion. This may
1368seem transparent, but consider that with these rules C<foo/bar/baz.h>
0a47030a
GS
1369and C<foo/bar/h/baz> both map to C<foo.bar.h.baz>, and that C<readdir> and
1370C<glob> cannot and do not attempt to emulate the reverse mapping. Other
6ab3f9cb 1371C<.>'s in filenames are translated to C</>.
0a47030a 1372
b7df3edc 1373As implied above, the environment accessed through C<%ENV> is global, and
0a47030a 1374the convention is that program specific environment variables are of the
6ab3f9cb
GS
1375form C<Program$Name>. Each filesystem maintains a current directory,
1376and the current filesystem's current directory is the B<global> current
b7df3edc
GS
1377directory. Consequently, sociable programs don't change the current
1378directory but rely on full pathnames, and programs (and Makefiles) cannot
0a47030a
GS
1379assume that they can spawn a child process which can change the current
1380directory without affecting its parent (and everyone else for that
1381matter).
1382
b7df3edc
GS
1383Because native operating system filehandles are global and are currently
1384allocated down from 255, with 0 being a reserved value, the Unix emulation
0a47030a
GS
1385library emulates Unix filehandles. Consequently, you can't rely on
1386passing C<STDIN>, C<STDOUT>, or C<STDERR> to your children.
1387
1388The desire of users to express filenames of the form
c47ff5f1 1389C<< <Foo$Dir>.Bar >> on the command line unquoted causes problems,
0a47030a 1390too: C<``> command output capture has to perform a guessing game. It
c47ff5f1 1391assumes that a string C<< <[^<>]+\$[^<>]> >> is a
0a47030a 1392reference to an environment variable, whereas anything else involving
c47ff5f1 1393C<< < >> or C<< > >> is redirection, and generally manages to be 99%
0a47030a
GS
1394right. Of course, the problem remains that scripts cannot rely on any
1395Unix tools being available, or that any tools found have Unix-like command
1396line arguments.
1397
b7df3edc
GS
1398Extensions and XS are, in theory, buildable by anyone using free
1399tools. In practice, many don't, as users of the Acorn platform are
1400used to binary distributions. MakeMaker does run, but no available
1401make currently copes with MakeMaker's makefiles; even if and when
1402this should be fixed, the lack of a Unix-like shell will cause
1403problems with makefile rules, especially lines of the form C<cd
1404sdbm && make all>, and anything using quoting.
b8099c3d
CN
1405
1406"S<RISC OS>" is the proper name for the operating system, but the value
1407in C<$^O> is "riscos" (because we don't like shouting).
1408
e41182b5
GS
1409=head2 Other perls
1410
b7df3edc
GS
1411Perl has been ported to many platforms that do not fit into any of
1412the categories listed above. Some, such as AmigaOS, Atari MiNT,
1413BeOS, HP MPE/iX, QNX, Plan 9, and VOS, have been well-integrated
1414into the standard Perl source code kit. You may need to see the
1415F<ports/> directory on CPAN for information, and possibly binaries,
1416for the likes of: aos, Atari ST, lynxos, riscos, Novell Netware,
1417Tandem Guardian, I<etc.> (Yes, we know that some of these OSes may
1418fall under the Unix category, but we are not a standards body.)
e41182b5 1419
d1e3b762
GS
1420Some approximate operating system names and their C<$^O> values
1421in the "OTHER" category include:
1422
1423 OS $^O $Config{'archname'}
1424 ------------------------------------------
1425 Amiga DOS amigaos m68k-amigos
cec2c193 1426 BeOS beos
d1e3b762
GS
1427 MPE/iX mpeix PA-RISC1.1
1428
e41182b5
GS
1429See also:
1430
1431=over 4
1432
c997b287
GS
1433=item *
1434
1435Amiga, F<README.amiga> (installed as L<perlamiga>).
1436
1437=item *
d1e3b762 1438
c997b287
GS
1439Atari, F<README.mint> and Guido Flohr's web page
1440http://stud.uni-sb.de/~gufl0000/
e41182b5 1441
c997b287 1442=item *
d1e3b762 1443
c997b287 1444Be OS, F<README.beos>
e41182b5 1445
c997b287
GS
1446=item *
1447
1448HP 300 MPE/iX, F<README.mpeix> and Mark Bixby's web page
34aaaa84 1449http://www.bixby.org/mark/perlix.html
c997b287
GS
1450
1451=item *
e41182b5 1452
6ab3f9cb 1453A free perl5-based PERL.NLM for Novell Netware is available in
c997b287 1454precompiled binary and source code form from http://www.novell.com/
6ab3f9cb 1455as well as from CPAN.
e41182b5 1456
13a2d996 1457=item *
c997b287 1458
e6f03d26 1459S<Plan 9>, F<README.plan9>
d1e3b762 1460
e41182b5
GS
1461=back
1462
e41182b5
GS
1463=head1 FUNCTION IMPLEMENTATIONS
1464
b7df3edc
GS
1465Listed below are functions that are either completely unimplemented
1466or else have been implemented differently on various platforms.
1467Following each description will be, in parentheses, a list of
1468platforms that the description applies to.
e41182b5 1469
b7df3edc
GS
1470The list may well be incomplete, or even wrong in some places. When
1471in doubt, consult the platform-specific README files in the Perl
1472source distribution, and any other documentation resources accompanying
1473a given port.
e41182b5 1474
0a47030a 1475Be aware, moreover, that even among Unix-ish systems there are variations.
e41182b5 1476
b7df3edc
GS
1477For many functions, you can also query C<%Config>, exported by
1478default from the Config module. For example, to check whether the
1479platform has the C<lstat> call, check C<$Config{d_lstat}>. See
1480L<Config> for a full description of available variables.
e41182b5
GS
1481
1482=head2 Alphabetical Listing of Perl Functions
1483
1484=over 8
1485
1486=item -X FILEHANDLE
1487
1488=item -X EXPR
1489
1490=item -X
1491
b7df3edc 1492C<-r>, C<-w>, and C<-x> have a limited meaning only; directories
e41182b5 1493and applications are executable, and there are no uid/gid
b7df3edc 1494considerations. C<-o> is not supported. (S<Mac OS>)
e41182b5 1495
b7df3edc
GS
1496C<-r>, C<-w>, C<-x>, and C<-o> tell whether the file is accessible,
1497which may not reflect UIC-based file protections. (VMS)
e41182b5 1498
b8099c3d
CN
1499C<-s> returns the size of the data fork, not the total size of data fork
1500plus resource fork. (S<Mac OS>).
1501
1502C<-s> by name on an open file will return the space reserved on disk,
1503rather than the current extent. C<-s> on an open filehandle returns the
b7df3edc 1504current size. (S<RISC OS>)
b8099c3d 1505
e41182b5 1506C<-R>, C<-W>, C<-X>, C<-O> are indistinguishable from C<-r>, C<-w>,
b8099c3d 1507C<-x>, C<-o>. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1508
1509C<-b>, C<-c>, C<-k>, C<-g>, C<-p>, C<-u>, C<-A> are not implemented.
1510(S<Mac OS>)
1511
1512C<-g>, C<-k>, C<-l>, C<-p>, C<-u>, C<-A> are not particularly meaningful.
b8099c3d 1513(Win32, VMS, S<RISC OS>)
e41182b5
GS
1514
1515C<-d> is true if passed a device spec without an explicit directory.
1516(VMS)
1517
1518C<-T> and C<-B> are implemented, but might misclassify Mac text files
0a47030a 1519with foreign characters; this is the case will all platforms, but may
b7df3edc 1520affect S<Mac OS> often. (S<Mac OS>)
e41182b5
GS
1521
1522C<-x> (or C<-X>) determine if a file ends in one of the executable
b7df3edc 1523suffixes. C<-S> is meaningless. (Win32)
e41182b5 1524
b8099c3d
CN
1525C<-x> (or C<-X>) determine if a file has an executable file type.
1526(S<RISC OS>)
1527
63f87e49
GS
1528=item alarm SECONDS
1529
1530=item alarm
1531
1532Not implemented. (Win32)
1533
e41182b5
GS
1534=item binmode FILEHANDLE
1535
b7df3edc 1536Meaningless. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1537
1538Reopens file and restores pointer; if function fails, underlying
1539filehandle may be closed, or pointer may be in a different position.
1540(VMS)
1541
1542The value returned by C<tell> may be affected after the call, and
1543the filehandle may be flushed. (Win32)
1544
1545=item chmod LIST
1546
b7df3edc 1547Only limited meaning. Disabling/enabling write permission is mapped to
e41182b5
GS
1548locking/unlocking the file. (S<Mac OS>)
1549
1550Only good for changing "owner" read-write access, "group", and "other"
1551bits are meaningless. (Win32)
1552
b8099c3d
CN
1553Only good for changing "owner" and "other" read-write access. (S<RISC OS>)
1554
495c5fdc
GP
1555Access permissions are mapped onto VOS access-control list changes. (VOS)
1556
4e51f8e4 1557The actual permissions set depend on the value of the C<CYGWIN>
789f0d36 1558in the SYSTEM environment settings. (Cygwin)
4e51f8e4 1559
e41182b5
GS
1560=item chown LIST
1561
3fd80bd6 1562Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1563
1564Does nothing, but won't fail. (Win32)
1565
3fd80bd6
PG
1566A little funky, because VOS's notion of ownership is a little funky (VOS).
1567
e41182b5
GS
1568=item chroot FILENAME
1569
1570=item chroot
1571
e6f03d26 1572Not implemented. (S<Mac OS>, Win32, VMS, S<Plan 9>, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1573
1574=item crypt PLAINTEXT,SALT
1575
1576May not be available if library or source was not provided when building
b8099c3d 1577perl. (Win32)
e41182b5
GS
1578
1579=item dbmclose HASH
1580
e6f03d26 1581Not implemented. (VMS, S<Plan 9>, VOS)
e41182b5
GS
1582
1583=item dbmopen HASH,DBNAME,MODE
1584
e6f03d26 1585Not implemented. (VMS, S<Plan 9>, VOS)
e41182b5
GS
1586
1587=item dump LABEL
1588
b8099c3d 1589Not useful. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1590
1591Not implemented. (Win32)
1592
b8099c3d 1593Invokes VMS debugger. (VMS)
e41182b5
GS
1594
1595=item exec LIST
1596
1597Not implemented. (S<Mac OS>)
1598
7c5ffed3 1599Implemented via Spawn. (VM/ESA)
3c075c7d 1600
0f897271
GS
1601Does not automatically flush output handles on some platforms.
1602(SunOS, Solaris, HP-UX)
1603
fe12c0e8
MS
1604=item exit EXPR
1605
1606=item exit
1607
1608Emulates UNIX exit() (which considers C<exit 1> to indicate an error) by
1609mapping the C<1> to SS$_ABORT (C<44>). This behavior may be overridden
1610with the pragma C<use vmsish 'exit'>. As with the CRTL's exit()
1611function, C<exit 0> is also mapped to an exit status of SS$_NORMAL
1612(C<1>); this mapping cannot be overridden. Any other argument to exit()
1613is used directly as Perl's exit status. (VMS)
1614
e41182b5
GS
1615=item fcntl FILEHANDLE,FUNCTION,SCALAR
1616
1617Not implemented. (Win32, VMS)
1618
1619=item flock FILEHANDLE,OPERATION
1620
495c5fdc 1621Not implemented (S<Mac OS>, VMS, S<RISC OS>, VOS).
e41182b5
GS
1622
1623Available only on Windows NT (not on Windows 95). (Win32)
1624
1625=item fork
1626
3fd80bd6 1627Not implemented. (S<Mac OS>, AmigaOS, S<RISC OS>, VM/ESA, VMS)
0f897271
GS
1628
1629Emulated using multiple interpreters. See L<perlfork>. (Win32)
1630
1631Does not automatically flush output handles on some platforms.
1632(SunOS, Solaris, HP-UX)
e41182b5
GS
1633
1634=item getlogin
1635
b8099c3d 1636Not implemented. (S<Mac OS>, S<RISC OS>)
e41182b5
GS
1637
1638=item getpgrp PID
1639
3fd80bd6 1640Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1641
1642=item getppid
1643
41cbbefa 1644Not implemented. (S<Mac OS>, Win32, S<RISC OS>)
e41182b5
GS
1645
1646=item getpriority WHICH,WHO
1647
7c5ffed3 1648Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1649
1650=item getpwnam NAME
1651
1652Not implemented. (S<Mac OS>, Win32)
1653
b8099c3d
CN
1654Not useful. (S<RISC OS>)
1655
e41182b5
GS
1656=item getgrnam NAME
1657
b8099c3d 1658Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1659
1660=item getnetbyname NAME
1661
e6f03d26 1662Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1663
1664=item getpwuid UID
1665
1666Not implemented. (S<Mac OS>, Win32)
1667
b8099c3d
CN
1668Not useful. (S<RISC OS>)
1669
e41182b5
GS
1670=item getgrgid GID
1671
b8099c3d 1672Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>)
e41182b5
GS
1673
1674=item getnetbyaddr ADDR,ADDRTYPE
1675
e6f03d26 1676Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1677
1678=item getprotobynumber NUMBER
1679
1680Not implemented. (S<Mac OS>)
1681
1682=item getservbyport PORT,PROTO
1683
1684Not implemented. (S<Mac OS>)
1685
1686=item getpwent
1687
7c5ffed3 1688Not implemented. (S<Mac OS>, Win32, VM/ESA)
e41182b5
GS
1689
1690=item getgrent
1691
7c5ffed3 1692Not implemented. (S<Mac OS>, Win32, VMS, VM/ESA)
e41182b5 1693
ef5a6dd7
JH
1694=item gethostbyname
1695
1696C<gethostbyname('localhost')> does not work everywhere: you may have
1697to use C<gethostbyname('127.0.0.1')>. (S<Mac OS>, S<Irix 5>)
1698
e41182b5
GS
1699=item gethostent
1700
1701Not implemented. (S<Mac OS>, Win32)
1702
1703=item getnetent
1704
e6f03d26 1705Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1706
1707=item getprotoent
1708
e6f03d26 1709Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1710
1711=item getservent
1712
e6f03d26 1713Not implemented. (Win32, S<Plan 9>)
e41182b5 1714
e41182b5
GS
1715=item sethostent STAYOPEN
1716
e6f03d26 1717Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1718
1719=item setnetent STAYOPEN
1720
e6f03d26 1721Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1722
1723=item setprotoent STAYOPEN
1724
e6f03d26 1725Not implemented. (S<Mac OS>, Win32, S<Plan 9>, S<RISC OS>)
e41182b5
GS
1726
1727=item setservent STAYOPEN
1728
e6f03d26 1729Not implemented. (S<Plan 9>, Win32, S<RISC OS>)
e41182b5
GS
1730
1731=item endpwent
1732
a3dfe201 1733Not implemented. (S<Mac OS>, MPE/iX, VM/ESA, Win32)
e41182b5
GS
1734
1735=item endgrent
1736
a3dfe201 1737Not implemented. (S<Mac OS>, MPE/iX, S<RISC OS>, VM/ESA, VMS, Win32)
e41182b5
GS
1738
1739=item endhostent
1740
1741Not implemented. (S<Mac OS>, Win32)
1742
1743=item endnetent
1744
e6f03d26 1745Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1746
1747=item endprotoent
1748
e6f03d26 1749Not implemented. (S<Mac OS>, Win32, S<Plan 9>)
e41182b5
GS
1750
1751=item endservent
1752
e6f03d26 1753Not implemented. (S<Plan 9>, Win32)
e41182b5
GS
1754
1755=item getsockopt SOCKET,LEVEL,OPTNAME
1756
e6f03d26 1757Not implemented. (S<Plan 9>)
e41182b5
GS
1758
1759=item glob EXPR
1760
1761=item glob
1762
63f87e49
GS
1763This operator is implemented via the File::Glob extension on most
1764platforms. See L<File::Glob> for portability information.
b8099c3d 1765
e41182b5
GS
1766=item ioctl FILEHANDLE,FUNCTION,SCALAR
1767
1768Not implemented. (VMS)
1769
1770Available only for socket handles, and it does what the ioctlsocket() call
1771in the Winsock API does. (Win32)
1772
b8099c3d
CN
1773Available only for socket handles. (S<RISC OS>)
1774
b350dd2f 1775=item kill SIGNAL, LIST
e41182b5 1776
862b5365
JH
1777C<kill(0, LIST)> is implemented for the sake of taint checking;
1778use with other signals is unimplemented. (S<Mac OS>)
1779
1780Not implemented, hence not useful for taint checking. (S<RISC OS>)
e41182b5 1781
63f87e49
GS
1782C<kill()> doesn't have the semantics of C<raise()>, i.e. it doesn't send
1783a signal to the identified process like it does on Unix platforms.
1784Instead C<kill($sig, $pid)> terminates the process identified by $pid,
1785and makes it exit immediately with exit status $sig. As in Unix, if
1786$sig is 0 and the specified process exists, it returns true without
1787actually terminating it. (Win32)
e41182b5
GS
1788
1789=item link OLDFILE,NEWFILE
1790
a3dfe201 1791Not implemented. (S<Mac OS>, MPE/iX, VMS, S<RISC OS>)
e41182b5 1792
433acd8a
JH
1793Link count not updated because hard links are not quite that hard
1794(They are sort of half-way between hard and soft links). (AmigaOS)
1795
a3dfe201
GS
1796Hard links are implemented on Win32 (Windows NT and Windows 2000)
1797under NTFS only.
1798
e41182b5
GS
1799=item lstat FILEHANDLE
1800
1801=item lstat EXPR
1802
1803=item lstat
1804
b8099c3d 1805Not implemented. (VMS, S<RISC OS>)
e41182b5 1806
63f87e49 1807Return values (especially for device and inode) may be bogus. (Win32)
e41182b5
GS
1808
1809=item msgctl ID,CMD,ARG
1810
1811=item msgget KEY,FLAGS
1812
1813=item msgsnd ID,MSG,FLAGS
1814
1815=item msgrcv ID,VAR,SIZE,TYPE,FLAGS
1816
e6f03d26 1817Not implemented. (S<Mac OS>, Win32, VMS, S<Plan 9>, S<RISC OS>, VOS)
e41182b5
GS
1818
1819=item open FILEHANDLE,EXPR
1820
1821=item open FILEHANDLE
1822
b7df3edc 1823The C<|> variants are supported only if ToolServer is installed.
e41182b5
GS
1824(S<Mac OS>)
1825
c47ff5f1 1826open to C<|-> and C<-|> are unsupported. (S<Mac OS>, Win32, S<RISC OS>)
e41182b5 1827
0f897271
GS
1828Opening a process does not automatically flush output handles on some
1829platforms. (SunOS, Solaris, HP-UX)
1830
e41182b5
GS
1831=item pipe READHANDLE,WRITEHANDLE
1832
433acd8a
JH
1833Very limited functionality. (MiNT)
1834
e41182b5
GS
1835=item readlink EXPR
1836
1837=item readlink
1838
b8099c3d 1839Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5
GS
1840
1841=item select RBITS,WBITS,EBITS,TIMEOUT
1842
689c5c24 1843Only implemented on sockets. (Win32, VMS)
e41182b5 1844
b8099c3d
CN
1845Only reliable on sockets. (S<RISC OS>)
1846
76e05f0b 1847Note that the C<select FILEHANDLE> form is generally portable.
63f87e49 1848
e41182b5
GS
1849=item semctl ID,SEMNUM,CMD,ARG
1850
1851=item semget KEY,NSEMS,FLAGS
1852
1853=item semop KEY,OPSTRING
1854
495c5fdc 1855Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1856
a3dfe201
GS
1857=item setgrent
1858
3fd80bd6 1859Not implemented. (S<Mac OS>, MPE/iX, VMS, Win32, S<RISC OS>, VOS)
a3dfe201 1860
e41182b5
GS
1861=item setpgrp PID,PGRP
1862
495c5fdc 1863Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5
GS
1864
1865=item setpriority WHICH,WHO,PRIORITY
1866
495c5fdc 1867Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1868
a3dfe201
GS
1869=item setpwent
1870
3fd80bd6 1871Not implemented. (S<Mac OS>, MPE/iX, Win32, S<RISC OS>, VOS)
a3dfe201 1872
e41182b5
GS
1873=item setsockopt SOCKET,LEVEL,OPTNAME,OPTVAL
1874
e6f03d26 1875Not implemented. (S<Plan 9>)
e41182b5
GS
1876
1877=item shmctl ID,CMD,ARG
1878
1879=item shmget KEY,SIZE,FLAGS
1880
1881=item shmread ID,VAR,POS,SIZE
1882
1883=item shmwrite ID,STRING,POS,SIZE
1884
495c5fdc 1885Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS)
e41182b5 1886
80cbd5ad
JH
1887=item sockatmark SOCKET
1888
1889A relatively recent addition to socket functions, may not
1890be implemented even in UNIX platforms.
1891
e41182b5
GS
1892=item socketpair SOCKET1,SOCKET2,DOMAIN,TYPE,PROTOCOL
1893
862b5365 1894Not implemented. (Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5
GS
1895
1896=item stat FILEHANDLE
1897
1898=item stat EXPR
1899
1900=item stat
1901
d62e1b7f
JH
1902Platforms that do not have rdev, blksize, or blocks will return these
1903as '', so numeric comparison or manipulation of these fields may cause
1904'not numeric' warnings.
1905
e41182b5 1906mtime and atime are the same thing, and ctime is creation time instead of
3f1f789b
JH
1907inode change time. (S<Mac OS>).
1908
1909ctime not supported on UFS (S<Mac OS X>).
e41182b5 1910
95a3fe12
MS
1911ctime is creation time instead of inode change time (Win32).
1912
e41182b5
GS
1913device and inode are not meaningful. (Win32)
1914
1915device and inode are not necessarily reliable. (VMS)
1916
b8099c3d
CN
1917mtime, atime and ctime all return the last modification time. Device and
1918inode are not necessarily reliable. (S<RISC OS>)
1919
d62e1b7f
JH
1920dev, rdev, blksize, and blocks are not available. inode is not
1921meaningful and will differ between stat calls on the same file. (os2)
1922
73e9292c
JH
1923some versions of cygwin when doing a stat("foo") and if not finding it
1924may then attempt to stat("foo.exe") (Cygwin)
1925
e41182b5
GS
1926=item symlink OLDFILE,NEWFILE
1927
b8099c3d 1928Not implemented. (Win32, VMS, S<RISC OS>)
e41182b5
GS
1929
1930=item syscall LIST
1931
7c5ffed3 1932Not implemented. (S<Mac OS>, Win32, VMS, S<RISC OS>, VOS, VM/ESA)
e41182b5 1933
f34d0673
GS
1934=item sysopen FILEHANDLE,FILENAME,MODE,PERMS
1935
dd9f0070 1936The traditional "0", "1", and "2" MODEs are implemented with different
322422de
GS
1937numeric values on some systems. The flags exported by C<Fcntl>
1938(O_RDONLY, O_WRONLY, O_RDWR) should work everywhere though. (S<Mac
7c5ffed3 1939OS>, OS/390, VM/ESA)
f34d0673 1940
e41182b5
GS
1941=item system LIST
1942
9d6eb86e 1943In general, do not assume the UNIX/POSIX semantics that you can shift
7717d0e7 1944C<$?> right by eight to get the exit value, or that C<$? & 127>
9d6eb86e
JH
1945would give you the number of the signal that terminated the program,
1946or that C<$? & 128> would test true if the program was terminated by a
1947coredump. Instead, use the POSIX W*() interfaces: for example, use
74555b7a
PP
1948WIFEXITED($?) and WEXITVALUE($?) to test for a normal exit and the exit
1949value, WIFSIGNALED($?) and WTERMSIG($?) for a signal exit and the
7717d0e7 1950signal. Core dumping is not a portable concept, so there's no portable
9d6eb86e
JH
1951way to test for that.
1952
e41182b5
GS
1953Only implemented if ToolServer is installed. (S<Mac OS>)
1954
1955As an optimization, may not call the command shell specified in
b7df3edc 1956C<$ENV{PERL5SHELL}>. C<system(1, @args)> spawns an external
e41182b5
GS
1957process and immediately returns its process designator, without
1958waiting for it to terminate. Return value may be used subsequently
63f87e49
GS
1959in C<wait> or C<waitpid>. Failure to spawn() a subprocess is indicated
1960by setting $? to "255 << 8". C<$?> is set in a way compatible with
1961Unix (i.e. the exitstatus of the subprocess is obtained by "$? >> 8",
1962as described in the documentation). (Win32)
e41182b5 1963
b8099c3d
CN
1964There is no shell to process metacharacters, and the native standard is
1965to pass a command line terminated by "\n" "\r" or "\0" to the spawned
c47ff5f1 1966program. Redirection such as C<< > foo >> is performed (if at all) by
b8099c3d
CN
1967the run time library of the spawned program. C<system> I<list> will call
1968the Unix emulation library's C<exec> emulation, which attempts to provide
1969emulation of the stdin, stdout, stderr in force in the parent, providing
1970the child program uses a compatible version of the emulation library.
1971I<scalar> will call the native command line direct and no such emulation
1972of a child Unix program will exists. Mileage B<will> vary. (S<RISC OS>)
1973
433acd8a
JH
1974Far from being POSIX compliant. Because there may be no underlying
1975/bin/sh tries to work around the problem by forking and execing the
9b63e9ec 1976first token in its argument string. Handles basic redirection
c47ff5f1 1977("<" or ">") on its own behalf. (MiNT)
433acd8a 1978
0f897271
GS
1979Does not automatically flush output handles on some platforms.
1980(SunOS, Solaris, HP-UX)
1981
9bc98430
CB
1982The return value is POSIX-like (shifted up by 8 bits), which only allows
1983room for a made-up value derived from the severity bits of the native
198432-bit condition code (unless overridden by C<use vmsish 'status'>).
1985For more details see L<perlvms/$?>. (VMS)
1986
e41182b5
GS
1987=item times
1988
1989Only the first entry returned is nonzero. (S<Mac OS>)
1990
63f87e49
GS
1991"cumulative" times will be bogus. On anything other than Windows NT
1992or Windows 2000, "system" time will be bogus, and "user" time is
1993actually the time returned by the clock() function in the C runtime
1994library. (Win32)
e41182b5 1995
b8099c3d
CN
1996Not useful. (S<RISC OS>)
1997
e41182b5
GS
1998=item truncate FILEHANDLE,LENGTH
1999
2000=item truncate EXPR,LENGTH
2001
6d738113 2002Not implemented. (Older versions of VMS)
e41182b5 2003
3fd80bd6 2004Truncation to same-or-shorter lengths only. (VOS)
495c5fdc 2005
4cfdb94f 2006If a FILEHANDLE is supplied, it must be writable and opened in append
e71a7dc8 2007mode (i.e., use C<<< open(FH, '>>filename') >>>
4cfdb94f
GS
2008or C<sysopen(FH,...,O_APPEND|O_RDWR)>. If a filename is supplied, it
2009should not be held open elsewhere. (Win32)
2010
e41182b5
GS
2011=item umask EXPR
2012
2013=item umask
2014
2015Returns undef where unavailable, as of version 5.005.
2016
b7df3edc
GS
2017C<umask> works but the correct permissions are set only when the file
2018is finally closed. (AmigaOS)
433acd8a 2019
e41182b5
GS
2020=item utime LIST
2021
15c65113 2022Only the modification time is updated. (S<BeOS>, S<Mac OS>, VMS, S<RISC OS>)
e41182b5 2023
322422de
GS
2024May not behave as expected. Behavior depends on the C runtime
2025library's implementation of utime(), and the filesystem being
2026used. The FAT filesystem typically does not support an "access
2027time" field, and it may limit timestamps to a granularity of
2028two seconds. (Win32)
e41182b5
GS
2029
2030=item wait
2031
2032=item waitpid PID,FLAGS
2033
3fd80bd6 2034Not implemented. (S<Mac OS>)
e41182b5
GS
2035
2036Can only be applied to process handles returned for processes spawned
a6f858fb 2037using C<system(1, ...)> or pseudo processes created with C<fork()>. (Win32)
e41182b5 2038
b8099c3d
CN
2039Not useful. (S<RISC OS>)
2040
e41182b5
GS
2041=back
2042
b8099c3d
CN
2043=head1 CHANGES
2044
2045=over 4
2046
3fd80bd6
PG
2047=item v1.49, 12 August 2002
2048
2049Updates for VOS from Paul Green.
2050
fd46a41b
JH
2051=item v1.48, 02 February 2001
2052
2053Various updates from perl5-porters over the past year, supported
2054platforms update from Jarkko Hietaniemi.
2055
c997b287
GS
2056=item v1.47, 22 March 2000
2057
2058Various cleanups from Tom Christiansen, including migration of
2059long platform listings from L<perl>.
2060
56d7751a
GS
2061=item v1.46, 12 February 2000
2062
2063Updates for VOS and MPE/iX. (Peter Prymmer) Other small changes.
2064
0cc436d0
GS
2065=item v1.45, 20 December 1999
2066
2067Small changes from 5.005_63 distribution, more changes to EBCDIC info.
2068
d1e3b762
GS
2069=item v1.44, 19 July 1999
2070
2071A bunch of updates from Peter Prymmer for C<$^O> values,
2072endianness, File::Spec, VMS, BS2000, OS/400.
2073
b7df3edc
GS
2074=item v1.43, 24 May 1999
2075
2076Added a lot of cleaning up from Tom Christiansen.
2077
19799a22 2078=item v1.42, 22 May 1999
b7df3edc 2079
19799a22 2080Added notes about tests, sprintf/printf, and epoch offsets.
b7df3edc 2081
6ab3f9cb
GS
2082=item v1.41, 19 May 1999
2083
2084Lots more little changes to formatting and content.
2085
d1e3b762 2086Added a bunch of C<$^O> and related values
6ab3f9cb
GS
2087for various platforms; fixed mail and web addresses, and added
2088and changed miscellaneous notes. (Peter Prymmer)
2089
2090=item v1.40, 11 April 1999
2091
2092Miscellaneous changes.
2093
2094=item v1.39, 11 February 1999
2ee0eb3c
CN
2095
2096Changes from Jarkko and EMX URL fixes Michael Schwern. Additional
2097note about newlines added.
2098
9b63e9ec
CN
2099=item v1.38, 31 December 1998
2100
2101More changes from Jarkko.
2102
3c075c7d
CN
2103=item v1.37, 19 December 1998
2104
2105More minor changes. Merge two separate version 1.35 documents.
2106
2107=item v1.36, 9 September 1998
2108
2109Updated for Stratus VOS. Also known as version 1.35.
2110
2111=item v1.35, 13 August 1998
495c5fdc 2112
3c075c7d
CN
2113Integrate more minor changes, plus addition of new sections under
2114L<"ISSUES">: L<"Numbers endianness and Width">,
2115L<"Character sets and character encoding">,
2116L<"Internationalisation">.
495c5fdc 2117
3c075c7d 2118=item v1.33, 06 August 1998
0a47030a
GS
2119
2120Integrate more minor changes.
2121
3c075c7d 2122=item v1.32, 05 August 1998
dd9f0070
CN
2123
2124Integrate more minor changes.
2125
3c075c7d 2126=item v1.30, 03 August 1998
b8099c3d
CN
2127
2128Major update for RISC OS, other minor changes.
2129
3c075c7d 2130=item v1.23, 10 July 1998
b8099c3d
CN
2131
2132First public release with perl5.005.
2133
2134=back
e41182b5 2135
ba58ab26
JH
2136=head1 Supported Platforms
2137
522b859a 2138As of July 2002 (the Perl release 5.8.0), the following platforms are
cec2c193
JH
2139able to build Perl from the standard source code distribution
2140available at http://www.cpan.org/src/index.html
2141
2142 AIX
2143 BeOS
6f683aa2 2144 BSD/OS (BSDi)
cec2c193
JH
2145 Cygwin
2146 DG/UX
811b48f2 2147 DOS DJGPP 1)
cec2c193
JH
2148 DYNIX/ptx
2149 EPOC R5
2150 FreeBSD
6f683aa2 2151 HI-UXMPP (Hitachi) (5.8.0 worked but we didn't know it)
cec2c193
JH
2152 HP-UX
2153 IRIX
2154 Linux
8939ba94 2155 Mac OS Classic
6f683aa2 2156 Mac OS X (Darwin)
cec2c193
JH
2157 MPE/iX
2158 NetBSD
2159 NetWare
2160 NonStop-UX
6f683aa2 2161 ReliantUNIX (formerly SINIX)
cec2c193 2162 OpenBSD
6f683aa2 2163 OpenVMS (formerly VMS)
3ebac25b 2164 Open UNIX (Unixware) (since Perl 5.8.1/5.9.0)
cec2c193 2165 OS/2
522b859a 2166 OS/400 (using the PASE) (since Perl 5.8.1/5.9.0)
70de81db 2167 PowerUX
6f683aa2 2168 POSIX-BC (formerly BS2000)
cec2c193
JH
2169 QNX
2170 Solaris
70de81db 2171 SunOS 4
6f683aa2
JH
2172 SUPER-UX (NEC)
2173 Tru64 UNIX (formerly DEC OSF/1, Digital UNIX)
cec2c193
JH
2174 UNICOS
2175 UNICOS/mk
2176 UTS
2177 VOS
811b48f2 2178 Win95/98/ME/2K/XP 2)
c40b5d1d 2179 WinCE
6f683aa2 2180 z/OS (formerly OS/390)
cec2c193 2181 VM/ESA
ba58ab26 2182
811b48f2
JH
2183 1) in DOS mode either the DOS or OS/2 ports can be used
2184 2) compilers: Borland, MinGW (GCC), VC6
cec2c193 2185
c40b5d1d 2186The following platforms worked with the previous releases (5.6 and
cec2c193
JH
21875.7), but we did not manage either to fix or to test these in time
2188for the 5.8.0 release. There is a very good chance that many of these
70de81db 2189will work fine with the 5.8.0.
cec2c193 2190
8da2b1be 2191 BSD/OS
cec2c193
JH
2192 DomainOS
2193 Hurd
2194 LynxOS
2195 MachTen
2196 PowerMAX
2197 SCO SV
cec2c193
JH
2198 SVR4
2199 Unixware
2200 Windows 3.1
ba58ab26 2201
70de81db
JH
2202Known to be broken for 5.8.0 (but 5.6.1 and 5.7.2 can be used):
2203
2204 AmigaOS
2205
ba58ab26 2206The following platforms have been known to build Perl from source in
fd46a41b
JH
2207the past (5.005_03 and earlier), but we haven't been able to verify
2208their status for the current release, either because the
2209hardware/software platforms are rare or because we don't have an
2210active champion on these platforms--or both. They used to work,
2211though, so go ahead and try compiling them, and let perlbug@perl.org
2212of any trouble.
ba58ab26 2213
cec2c193
JH
2214 3b1
2215 A/UX
cec2c193
JH
2216 ConvexOS
2217 CX/UX
2218 DC/OSx
2219 DDE SMES
2220 DOS EMX
2221 Dynix
2222 EP/IX
2223 ESIX
2224 FPS
2225 GENIX
2226 Greenhills
2227 ISC
2228 MachTen 68k
2229 MiNT
2230 MPC
2231 NEWS-OS
2232 NextSTEP
2233 OpenSTEP
2234 Opus
2235 Plan 9
cec2c193 2236 RISC/os
8da2b1be 2237 SCO ODT/OSR
cec2c193
JH
2238 Stellar
2239 SVR2
2240 TI1500
2241 TitanOS
2242 Ultrix
2243 Unisys Dynix
ba58ab26
JH
2244
2245The following platforms have their own source code distributions and
1577cd80 2246binaries available via http://www.cpan.org/ports/
ba58ab26 2247
cec2c193 2248 Perl release
ba58ab26 2249
522b859a 2250 OS/400 (ILE) 5.005_02
cec2c193 2251 Tandem Guardian 5.004
ba58ab26
JH
2252
2253The following platforms have only binaries available via
a93751fa 2254http://www.cpan.org/ports/index.html :
ba58ab26 2255
cec2c193 2256 Perl release
ba58ab26 2257
cec2c193
JH
2258 Acorn RISCOS 5.005_02
2259 AOS 5.002
2260 LynxOS 5.004_02
ba58ab26
JH
2261
2262Although we do suggest that you always build your own Perl from
2263the source code, both for maximal configurability and for security,
2264in case you are in a hurry you can check
a93751fa 2265http://www.cpan.org/ports/index.html for binary distributions.
ba58ab26 2266
c997b287
GS
2267=head1 SEE ALSO
2268
cec2c193 2269L<perlaix>, L<perlamiga>, L<perlapollo>, L<perlbeos>, L<perlbs2000>,
18a271bd 2270L<perlce>, L<perlcygwin>, L<perldgux>, L<perldos>, L<perlepoc>,
469e7be4 2271L<perlebcdic>, L<perlfreebsd>, L<perlhurd>, L<perlhpux>, L<perlirix>,
0d53b15f 2272L<perlmachten>, L<perlmacos>, L<perlmacosx>, L<perlmint>, L<perlmpeix>,
522b859a
JH
2273L<perlnetware>, L<perlos2>, L<perlos390>, L<perlos400>,
2274L<perlplan9>, L<perlqnx>, L<perlsolaris>, L<perltru64>,
2275L<perlunicode>, L<perlvmesa>, L<perlvms>, L<perlvos>,
2276L<perlwin32>, and L<Win32>.
c997b287 2277
e41182b5
GS
2278=head1 AUTHORS / CONTRIBUTORS
2279
06e9666b 2280Abigail <abigail@foad.org>,
c47ff5f1
GS
2281Charles Bailey <bailey@newman.upenn.edu>,
2282Graham Barr <gbarr@pobox.com>,
2283Tom Christiansen <tchrist@perl.com>,
06e9666b 2284Nicholas Clark <nick@ccl4.org>,
c47ff5f1 2285Thomas Dorner <Thomas.Dorner@start.de>,
06e9666b
A
2286Andy Dougherty <doughera@lafayette.edu>,
2287Dominic Dunlop <domo@computer.org>,
2288Neale Ferguson <neale@vma.tabnsw.com.au>,
c47ff5f1 2289David J. Fiander <davidf@mks.com>,
3fd80bd6 2290Paul Green <Paul.Green@stratus.com>,
06e9666b 2291M.J.T. Guy <mjtg@cam.ac.uk>,
61f30a5e 2292Jarkko Hietaniemi <jhi@iki.fi>,
c47ff5f1 2293Luther Huffman <lutherh@stratcom.com>,
06e9666b
A
2294Nick Ing-Simmons <nick@ing-simmons.net>,
2295Andreas J. KE<ouml>nig <a.koenig@mind.de>,
c47ff5f1
GS
2296Markus Laker <mlaker@contax.co.uk>,
2297Andrew M. Langmead <aml@world.std.com>,
2298Larry Moore <ljmoore@freespace.net>,
2299Paul Moore <Paul.Moore@uk.origin-it.com>,
2300Chris Nandor <pudge@pobox.com>,
1afc07ec 2301Matthias Neeracher <neeracher@mac.com>,
e71a7dc8 2302Philip Newton <pne@cpan.org>,
c47ff5f1
GS
2303Gary Ng <71564.1743@CompuServe.COM>,
2304Tom Phoenix <rootbeer@teleport.com>,
2305AndrE<eacute> Pirard <A.Pirard@ulg.ac.be>,
2306Peter Prymmer <pvhp@forte.com>,
2307Hugo van der Sanden <hv@crypt0.demon.co.uk>,
2308Gurusamy Sarathy <gsar@activestate.com>,
2309Paul J. Schinder <schinder@pobox.com>,
2310Michael G Schwern <schwern@pobox.com>,
06e9666b 2311Dan Sugalski <dan@sidhe.org>,
c47ff5f1 2312Nathan Torkington <gnat@frii.com>.
e41182b5 2313