Commit | Line | Data |
---|---|---|
e41182b5 GS |
1 | =head1 NAME |
2 | ||
3 | perlport - Writing portable Perl | |
4 | ||
5 | ||
6 | =head1 DESCRIPTION | |
7 | ||
8 | Perl runs on a variety of operating systems. While most of them share | |
9 | a lot in common, they also have their own very particular and unique | |
10 | features. | |
11 | ||
12 | This document is meant to help you to find out what constitutes portable | |
13 | perl code, so that once you have made your decision to write portably, | |
14 | you know where the lines are drawn, and you can stay within them. | |
15 | ||
16 | There is a tradeoff between taking full advantage of B<a> particular type | |
17 | of computer, and taking advantage of a full B<range> of them. Naturally, | |
18 | as you make your range bigger (and thus more diverse), the common denominators | |
19 | drop, and you are left with fewer areas of common ground in which | |
20 | you can operate to accomplish a particular task. Thus, when you begin | |
21 | attacking a problem, it is important to consider which part of the tradeoff | |
22 | curve you want to operate under. Specifically, whether it is important to | |
23 | you that the task that you are coding needs the full generality of being | |
24 | portable, or if it is sufficient to just get the job done. This is the | |
25 | hardest choice to be made. The rest is easy, because Perl provides lots | |
26 | of choices, whichever way you want to approach your problem. | |
27 | ||
28 | Looking at it another way, writing portable code is usually about willfully | |
29 | limiting your available choices. Naturally, it takes discipline to do that. | |
30 | ||
31 | Be aware of two important points: | |
32 | ||
33 | =over 4 | |
34 | ||
35 | =item Not all Perl programs have to be portable | |
36 | ||
37 | There is no reason why you should not use Perl as a language to glue Unix | |
38 | tools together, or to prototype a Macintosh application, or to manage the | |
39 | Windows registry. If it makes no sense to aim for portability for one | |
40 | reason or another in a given program, then don't bother. | |
41 | ||
42 | =item The vast majority of Perl B<is> portable | |
43 | ||
44 | Don't be fooled into thinking that it is hard to create portable Perl | |
45 | code. It isn't. Perl tries its level-best to bridge the gaps between | |
46 | what's available on different platforms, and all the means available to | |
47 | use those features. Thus almost all Perl code runs on any machine | |
48 | without modification. But there I<are> some significant issues in | |
49 | writing portable code, and this document is entirely about those issues. | |
50 | ||
51 | =back | |
52 | ||
53 | Here's the general rule: When you approach a task that is commonly done | |
54 | using a whole range of platforms, think in terms of writing portable | |
55 | code. That way, you don't sacrifice much by way of the implementation | |
56 | choices you can avail yourself of, and at the same time you can give | |
57 | your users lots of platform choices. On the other hand, when you have to | |
58 | take advantage of some unique feature of a particular platform, as is | |
59 | often the case with systems programming (whether for Unix, Windows, | |
60 | S<Mac OS>, VMS, etc.), consider writing platform-specific code. | |
61 | ||
62 | When the code will run on only two or three operating systems, then you may | |
63 | only need to consider the differences of those particular systems. The | |
64 | important thing is to decide where the code will run, and to be deliberate | |
65 | in your decision. | |
66 | ||
67 | This information should not be considered complete; it includes possibly | |
68 | transient information about idiosyncracies of some of the ports, almost | |
69 | all of which are in a state of constant evolution. Thus this material | |
70 | should be considered a perpetual work in progress | |
71 | (E<lt>IMG SRC="yellow_sign.gif" ALT="Under Construction"E<gt>). | |
72 | ||
73 | ||
74 | =head1 ISSUES | |
75 | ||
76 | =head2 Newlines | |
77 | ||
78 | In most operating systems, lines in files are separated with newlines. | |
79 | Just what is used as a newline may vary from OS to OS. Unix | |
80 | traditionally uses C<\012>, one kind of Windows I/O uses C<\015\012>, | |
81 | and S<Mac OS> uses C<\015>. | |
82 | ||
83 | Perl uses C<\n> to represent the "logical" newline, where what | |
84 | is logical may depend on the platform in use. In MacPerl, C<\n> | |
85 | always means C<\015>. In DOSish perls, C<\n> usually means C<\012>, but | |
86 | when accessing a file in "text" mode, STDIO translates it to (or from) | |
87 | C<\015\012>. | |
88 | ||
89 | Due to the "text" mode translation, DOSish perls have limitations | |
90 | of using C<seek> and C<tell> when a file is being accessed in "text" | |
91 | mode. Specifically, if you stick to C<seek>-ing to locations you got | |
92 | from C<tell> (and no others), you are usually free to use C<seek> and | |
93 | C<tell> even in "text" mode. In general, using C<seek> or C<tell> or | |
94 | other file operations that count bytes instead of characters, without | |
95 | considering the length of C<\n>, may be non-portable. If you use | |
96 | C<binmode> on a file, however, you can usually use C<seek> and C<tell> | |
97 | with arbitrary values quite safely. | |
98 | ||
99 | A common misconception in socket programming is that C<\n> eq C<\012> | |
100 | everywhere. When using protocols, such as common Internet protocols, | |
101 | C<\012> and C<\015> are called for specifically, and the values of | |
102 | the logical C<\n> and C<\r> (carriage return) are not reliable. | |
103 | ||
104 | print SOCKET "Hi there, client!\r\n"; # WRONG | |
105 | print SOCKET "Hi there, client!\015\012"; # RIGHT | |
106 | ||
107 | [NOTE: this does not necessarily apply to communications that are | |
108 | filtered by another program or module before sending to the socket; the | |
109 | the most popular EBCDIC webserver, for instance, accepts C<\r\n>, | |
110 | which translates those characters, along with all other | |
111 | characters in text streams, from EBCDIC to ASCII.] | |
112 | ||
113 | However, C<\015\012> (or C<\cM\cJ>, or C<\x0D\x0A>) can be tedious and | |
114 | unsightly, as well as confusing to those maintaining the code. As such, | |
115 | the C<Socket> module supplies the Right Thing for those who want it. | |
116 | ||
117 | use Socket qw(:DEFAULT :crlf); | |
118 | print SOCKET "Hi there, client!$CRLF" # RIGHT | |
119 | ||
120 | When reading I<from> a socket, remember that the default input record | |
121 | separator (C<$/>) is C<\n>, but code like this should recognize C<$/> as | |
122 | C<\012> or C<\015\012>: | |
123 | ||
124 | while (<SOCKET>) { | |
125 | # ... | |
126 | } | |
127 | ||
128 | Better: | |
129 | ||
130 | use Socket qw(:DEFAULT :crlf); | |
131 | local($/) = LF; # not needed if $/ is already \012 | |
132 | ||
133 | while (<SOCKET>) { | |
134 | s/$CR?$LF/\n/; # not sure if socket uses LF or CRLF, OK | |
135 | # s/\015?\012/\n/; # same thing | |
136 | } | |
137 | ||
138 | And this example is actually better than the previous one even for Unix | |
139 | platforms, because now any C<\015>'s (C<\cM>'s) are stripped out | |
140 | (and there was much rejoicing). | |
141 | ||
142 | ||
143 | =head2 File Paths | |
144 | ||
145 | Most platforms these days structure files in a hierarchical fashion. | |
146 | So, it is reasonably safe to assume that any platform supports the | |
147 | notion of a "path" to uniquely identify a file on the system. Just | |
148 | how that path is actually written, differs. | |
149 | ||
150 | While they are similar, file path specifications differ between Unix, | |
151 | Windows, S<Mac OS>, OS/2, VMS and probably others. Unix, for example, is | |
152 | one of the few OSes that has the idea of a root directory. S<Mac OS> | |
153 | uses C<:> as a path separator instead of C</>. VMS, Windows, and OS/2 | |
154 | can work similarly to Unix with C</> as path separator, or in their own | |
155 | idiosyncratic ways. | |
156 | ||
157 | As with the newline problem above, there are modules that can help. The | |
158 | C<File::Spec> modules provide methods to do the Right Thing on whatever | |
159 | platform happens to be running the program. | |
160 | ||
161 | use File::Spec; | |
162 | chdir(File::Spec->updir()); # go up one directory | |
163 | $file = File::Spec->catfile( | |
164 | File::Spec->curdir(), 'temp', 'file.txt' | |
165 | ); | |
166 | # on Unix and Win32, './temp/file.txt' | |
167 | # on Mac OS, ':temp:file.txt' | |
168 | ||
169 | File::Spec is available in the standard distribution, as of version | |
170 | 5.004_05. | |
171 | ||
172 | In general, production code should not have file paths hardcoded; making | |
173 | them user supplied or from a configuration file is better, keeping in mind | |
174 | that file path syntax varies on different machines. | |
175 | ||
176 | This is especially noticeable in scripts like Makefiles and test suites, | |
177 | which often assume C</> as a path separator for subdirectories. | |
178 | ||
179 | Also of use is C<File::Basename>, from the standard distribution, which | |
180 | splits a pathname into pieces (base filename, full path to directory, | |
181 | and file suffix). | |
182 | ||
183 | Remember not to count on the existence of system-specific files, like | |
184 | F</etc/resolv.conf>. If code does need to rely on such a file, include a | |
185 | description of the file and its format in the code's documentation, and | |
186 | make it easy for the user to override the default location of the file. | |
187 | ||
188 | ||
189 | =head2 System Interaction | |
190 | ||
191 | Not all platforms provide for the notion of a command line, necessarily. | |
192 | These are usually platforms that rely on a Graphical User Interface (GUI) | |
193 | for user interaction. So a program requiring command lines might not work | |
194 | everywhere. But this is probably for the user of the program to deal | |
195 | with. | |
196 | ||
197 | Some platforms can't delete or rename files that are being held open by | |
198 | the system. Remember to C<close> files when you are done with them. | |
199 | Don't C<unlink> or C<rename> an open file. Don't C<tie> to or C<open> a | |
200 | file that is already tied to or opened; C<untie> or C<close> first. | |
201 | ||
202 | Don't count on a specific environment variable existing in C<%ENV>. | |
203 | Don't even count on C<%ENV> entries being case-sensitive, or even | |
204 | case-preserving. | |
205 | ||
206 | Don't count on signals in portable programs. | |
207 | ||
208 | Don't count on filename globbing. Use C<opendir>, C<readdir>, and | |
209 | C<closedir> instead. | |
210 | ||
211 | ||
212 | =head2 Interprocess Communication (IPC) | |
213 | ||
214 | In general, don't directly access the system in code that is meant to be | |
215 | portable. That means, no: C<system>, C<exec>, C<fork>, C<pipe>, C<``>, | |
216 | C<qx//>, C<open> with a C<|>, or any of the other things that makes being | |
217 | a Unix perl hacker worth being. | |
218 | ||
219 | Commands that launch external processes are generally supported on | |
220 | most platforms (though many of them do not support any type of forking), | |
221 | but the problem with using them arises from what you invoke with them. | |
222 | External tools are often named differently on different platforms, often | |
223 | not available in the same location, often accept different arguments, | |
224 | often behave differently, and often represent their results in a | |
225 | platform-dependent way. Thus you should seldom depend on them to produce | |
226 | consistent results. | |
227 | ||
228 | One especially common bit of Perl code is opening a pipe to sendmail: | |
229 | ||
230 | open(MAIL, '|/usr/lib/sendmail -t') or die $!; | |
231 | ||
232 | This is fine for systems programming when sendmail is known to be | |
233 | available. But it is not fine for many non-Unix systems, and even | |
234 | some Unix systems that may not have sendmail installed. If a portable | |
235 | solution is needed, see the C<Mail::Send> and C<Mail::Mailer> modules | |
236 | in the C<MailTools> distribution. C<Mail::Mailer> provides several | |
237 | mailing methods, including mail, sendmail, and direct SMTP | |
238 | (via C<Net::SMTP>) if a mail transfer agent is not available. | |
239 | ||
240 | The rule of thumb for portable code is: Do it all in portable Perl, or | |
241 | use a module that may internally implement it with platform-specific code, | |
242 | but expose a common interface. By portable Perl, we mean code that | |
243 | avoids the constructs described in this document as being non-portable. | |
244 | ||
245 | ||
246 | =head2 External Subroutines (XS) | |
247 | ||
248 | XS code, in general, can be made to work with any platform; but dependent | |
249 | libraries, header files, etc., might not be readily available or | |
250 | portable, or the XS code itself might be platform-specific, just as Perl | |
251 | code might be. If the libraries and headers are portable, then it is | |
252 | normally reasonable to make sure the XS code is portable, too. | |
253 | ||
254 | There is a different kind of portability issue with writing XS | |
255 | code: availability of a C compiler on the end-user's system. C brings with | |
256 | it its own portability issues, and writing XS code will expose you to | |
257 | some of those. Writing purely in perl is a comparatively easier way to | |
258 | achieve portability. | |
259 | ||
260 | ||
261 | =head2 Standard Modules | |
262 | ||
263 | In general, the standard modules work across platforms. Notable | |
264 | exceptions are C<CPAN.pm> (which currently makes connections to external | |
265 | programs that may not be available), platform-specific modules (like | |
266 | C<ExtUtils::MM_VMS>), and DBM modules. | |
267 | ||
268 | There is no one DBM module that is available on all platforms. | |
269 | C<SDBM_File> and the others are generally available on all Unix and DOSish | |
270 | ports, but not in MacPerl, where C<NBDM_File> and C<DB_File> are available. | |
271 | ||
272 | The good news is that at least some DBM module should be available, and | |
273 | C<AnyDBM_File> will use whichever module it can find. Of course, then | |
274 | the code needs to be fairly strict, dropping to the lowest common | |
275 | denominator (e.g., not exceeding 1K for each record). | |
276 | ||
277 | ||
278 | =head2 Time and Date | |
279 | ||
280 | The system's notion of time of day and calendar date is controlled in widely | |
281 | different ways. Don't assume the timezone is stored in C<$ENV{TZ}>, and even | |
282 | if it is, don't assume that you can control the timezone through that | |
283 | variable. | |
284 | ||
285 | Don't assume that the epoch starts at January 1, 1970, because that is | |
286 | OS-specific. Better to store a date in an unambiguous representation. | |
287 | A text representation (like C<1 Jan 1970>) can be easily converted into an | |
288 | OS-specific value using a module like C<Date::Parse>. An array of values, | |
289 | such as those returned by C<localtime>, can be converted to an OS-specific | |
290 | representation using C<Time::Local>. | |
291 | ||
292 | ||
293 | =head2 System Resources | |
294 | ||
295 | If your code is destined for systems with severely constrained (or missing!) | |
296 | virtual memory systems then you want to be especially mindful of avoiding | |
297 | wasteful constructs such as: | |
298 | ||
299 | # NOTE: this is no longer "bad" in perl5.005 | |
300 | for (0..10000000) {} # bad | |
301 | for (my $x = 0; $x <= 10000000; ++$x) {} # good | |
302 | ||
303 | @lines = <VERY_LARGE_FILE>; # bad | |
304 | ||
305 | while (<FILE>) {$file .= $_} # sometimes bad | |
306 | $file = join '', <FILE>; # better | |
307 | ||
308 | The last two may appear unintuitive to most people. The first of those | |
309 | two constructs repeatedly grows a string, while the second allocates a | |
310 | large chunk of memory in one go. On some systems, the latter is more | |
311 | efficient that the former. | |
312 | ||
313 | =head2 Security | |
314 | ||
315 | Most Unix platforms provide basic levels of security that is usually felt | |
316 | at the file-system level. Other platforms usually don't (unfortunately). | |
317 | Thus the notion of User-ID, or "home" directory, or even the state of | |
318 | being logged-in may be unrecognizable on may platforms. If you write | |
319 | programs that are security conscious, it is usually best to know what | |
320 | type of system you will be operating under, and write code explicitly | |
321 | for that platform (or class of platforms). | |
322 | ||
323 | =head2 Style | |
324 | ||
325 | For those times when it is necessary to have platform-specific code, | |
326 | consider keeping the platform-specific code in one place, making porting | |
327 | to other platforms easier. Use the C<Config> module and the special | |
328 | variable C<$^O> to differentiate platforms, as described in L<"PLATFORMS">. | |
329 | ||
330 | ||
331 | =head1 CPAN TESTERS | |
332 | ||
333 | Module uploaded to CPAN are tested by a variety of volunteers on | |
334 | different platforms. These CPAN testers are notified by e-mail of each | |
335 | new upload, and reply to the list with PASS, FAIL, NA (not applicable to | |
336 | this platform), or ???? (unknown), along with any relevant notations. | |
337 | ||
338 | The purpose of the testing is twofold: one, to help developers fix any | |
339 | problems in their code; two, to provide users with information about | |
340 | whether or not a given module works on a given platform. | |
341 | ||
342 | =over 4 | |
343 | ||
344 | =item Mailing list: cpan-testers@perl.org | |
345 | ||
346 | =item Testing results: C<http://www.connect.net/gbarr/cpan-test/> | |
347 | ||
348 | =back | |
349 | ||
350 | ||
351 | =head1 PLATFORMS | |
352 | ||
353 | As of version 5.002, Perl is built with a C<$^O> variable that | |
354 | indicates the operating system it was built on. This was implemented | |
355 | to help speed up code that would otherwise have to C<use Config;> and | |
356 | use the value of C<$Config{'osname'}>. Of course, to get | |
357 | detailed information about the system, looking into C<%Config> is | |
358 | certainly recommended. | |
359 | ||
360 | =head2 Unix | |
361 | ||
362 | Perl works on a bewildering variety of Unix and Unix-like platforms (see | |
363 | e.g. most of the files in the F<hints/> directory in the source code kit). | |
364 | On most of these systems, the value of C<$^O> (hence C<$Config{'osname'}>, | |
365 | too) is determined by lowercasing and stripping punctuation from the first | |
366 | field of the string returned by typing | |
367 | ||
368 | % uname -a | |
369 | ||
370 | (or a similar command) at the shell prompt. Here, for example, are a few | |
371 | of the more popular Unix flavors: | |
372 | ||
373 | uname $^O | |
374 | -------------------- | |
375 | AIX aix | |
376 | FreeBSD freebsd | |
377 | Linux linux | |
378 | HP-UX hpux | |
379 | OSF1 dec_osf | |
380 | SunOS solaris | |
381 | SunOS4 sunos | |
382 | ||
383 | ||
384 | =head2 DOS and Derivatives | |
385 | ||
386 | Perl has long been ported to PC style microcomputers running under | |
387 | systems like PC-DOS, MS-DOS, OS/2, and most Windows platforms you can | |
388 | bring yourself to mention (except for Windows CE, if you count that). | |
389 | Users familiar with I<COMMAND.COM> and/or I<CMD.EXE> style shells should | |
390 | be aware that each of these file specifications may have subtle | |
391 | differences: | |
392 | ||
393 | $filespec0 = "c:/foo/bar/file.txt"; | |
394 | $filespec1 = "c:\\foo\\bar\\file.txt"; | |
395 | $filespec2 = 'c:\foo\bar\file.txt'; | |
396 | $filespec3 = 'c:\\foo\\bar\\file.txt'; | |
397 | ||
398 | System calls accept either C</> or C<\> as the path separator. However, | |
399 | many command-line utilities of DOS vintage treat C</> as the option | |
400 | prefix, so they may get confused by filenames containing C</>. Aside | |
401 | from calling any external programs, C</> will work just fine, and | |
402 | probably better, as it is more consistent with popular usage, and avoids | |
403 | the problem of remembering what to backwhack and what not to. | |
404 | ||
405 | The DOS FAT file system can only accomodate "8.3" style filenames. Under | |
406 | the "case insensitive, but case preserving" HPFS (OS/2) and NTFS (NT) | |
407 | file systems you may have to be careful about case returned with functions | |
408 | like C<readdir> or used with functions like C<open> or C<opendir>. | |
409 | ||
410 | DOS also treats several filenames as special, such as AUX, PRN, NUL, CON, | |
411 | COM1, LPT1, LPT2 etc. Unfortunately these filenames won't even work | |
412 | if you include an explicit directory prefix, in some cases. It is best | |
413 | to avoid such filenames, if you want your code to be portable to DOS | |
414 | and its derivatives. | |
415 | ||
416 | Users of these operating systems may also wish to make use of | |
417 | scripts such as I<pl2bat.bat> or I<pl2cmd> as appropriate to | |
418 | put wrappers around your scripts. | |
419 | ||
420 | Newline (C<\n>) is translated as C<\015\012> by STDIO when reading from | |
421 | and writing to files. C<binmode(FILEHANDLE)> will keep C<\n> translated | |
422 | as C<\012> for that filehandle. Since it is a noop on other systems, | |
423 | C<binmode> should be used for cross-platform code that deals with binary | |
424 | data. | |
425 | ||
426 | The C<$^O> variable and the C<$Config{'archname'}> values for various | |
427 | DOSish perls are as follows: | |
428 | ||
429 | OS $^O $Config{'archname'} | |
430 | -------------------------------------------- | |
431 | MS-DOS dos | |
432 | PC-DOS dos | |
433 | OS/2 os2 | |
434 | Windows 95 MSWin32 MSWin32-x86 | |
435 | Windows NT MSWin32 MSWin32-x86 | |
436 | Windows NT MSWin32 MSWin32-alpha | |
437 | Windows NT MSWin32 MSWin32-ppc | |
438 | ||
439 | Also see: | |
440 | ||
441 | =over 4 | |
442 | ||
443 | =item The djgpp environment for DOS, C<http://www.delorie.com/djgpp/> | |
444 | ||
445 | =item The EMX environment for DOS, OS/2, etc. C<emx@iaehv.nl>, | |
446 | C<http://www.juge.com/bbs/Hobb.19.html> | |
447 | ||
448 | =item Build instructions for Win32, L<perlwin32>. | |
449 | ||
450 | =item The ActiveState Pages, C<http://www.activestate.com/> | |
451 | ||
452 | =back | |
453 | ||
454 | ||
455 | =head2 MacPerl | |
456 | ||
457 | Any module requiring XS compilation is right out for most people, because | |
458 | MacPerl is built using non-free (and non-cheap!) compilers. Some XS | |
459 | modules that can work with MacPerl are built and distributed in binary | |
460 | form on CPAN. See I<MacPerl: Power and Ease> for more details. | |
461 | ||
462 | Directories are specified as: | |
463 | ||
464 | volume:folder:file for absolute pathnames | |
465 | volume:folder: for absolute pathnames | |
466 | :folder:file for relative pathnames | |
467 | :folder: for relative pathnames | |
468 | :file for relative pathnames | |
469 | file for relative pathnames | |
470 | ||
471 | Files in a directory are stored in alphabetical order. Filenames are | |
472 | limited to 31 characters, and may include any character except C<:>, | |
473 | which is reserved as a path separator. | |
474 | ||
475 | Instead of C<flock>, see C<FSpSetFLock> and C<FSpRstFLock> in | |
476 | C<Mac::Files>. | |
477 | ||
478 | In the MacPerl application, you can't run a program from the command line; | |
479 | programs that expect C<@ARGV> to be populated can be edited with something | |
480 | like the following, which brings up a dialog box asking for the command | |
481 | line arguments. | |
482 | ||
483 | if (!@ARGV) { | |
484 | @ARGV = split /\s+/, MacPerl::Ask('Arguments?'); | |
485 | } | |
486 | ||
487 | A MacPerl script saved as a droplet will populate C<@ARGV> with the full | |
488 | pathnames of the files dropped onto the script. | |
489 | ||
490 | Mac users can use programs on a kind of command line under MPW (Macintosh | |
491 | Programmer's Workshop, a free development environment from Apple). | |
492 | MacPerl was first introduced as an MPW tool, and MPW can be used like a | |
493 | shell: | |
494 | ||
495 | perl myscript.plx some arguments | |
496 | ||
497 | ToolServer is another app from Apple that provides access to MPW tools | |
498 | from MPW and the MacPerl app, which allows MacPerl program to use | |
499 | C<system>, backticks, and piped C<open>. | |
500 | ||
501 | "S<Mac OS>" is the proper name for the operating system, but the value | |
502 | in C<$^O> is "MacOS". To determine architecture, version, or whether | |
503 | the application or MPW tool version is running, check: | |
504 | ||
505 | $is_app = $MacPerl::Version =~ /App/; | |
506 | $is_tool = $MacPerl::Version =~ /MPW/; | |
507 | ($version) = $MacPerl::Version =~ /^(\S+)/; | |
508 | $is_ppc = $MacPerl::Architecture eq 'MacPPC'; | |
509 | $is_68k = $MacPerl::Architecture eq 'Mac68K'; | |
510 | ||
511 | ||
512 | Also see: | |
513 | ||
514 | =over 4 | |
515 | ||
516 | =item The MacPerl Pages, C<http://www.ptf.com/macperl/>. | |
517 | ||
518 | =item The MacPerl mailing list, C<mac-perl-request@iis.ee.ethz.ch>. | |
519 | ||
520 | =back | |
521 | ||
522 | ||
523 | =head2 VMS | |
524 | ||
525 | Perl on VMS is discussed in F<vms/perlvms.pod> in the perl distribution. | |
526 | Note that perl on VMS can accept either VMS or Unix style file | |
527 | specifications as in either of the following: | |
528 | ||
529 | $ perl -ne "print if /perl_setup/i" SYS$LOGIN:LOGIN.COM | |
530 | $ perl -ne "print if /perl_setup/i" /sys$login/login.com | |
531 | ||
532 | but not a mixture of both as in: | |
533 | ||
534 | $ perl -ne "print if /perl_setup/i" sys$login:/login.com | |
535 | Can't open sys$login:/login.com: file specification syntax error | |
536 | ||
537 | Interacting with Perl from the Digital Command Language (DCL) shell | |
538 | often requires a different set of quotation marks than Unix shells do. | |
539 | For example: | |
540 | ||
541 | $ perl -e "print ""Hello, world.\n""" | |
542 | Hello, world. | |
543 | ||
544 | There are a number of ways to wrap your perl scripts in DCL .COM files if | |
545 | you are so inclined. For example: | |
546 | ||
547 | $ write sys$output "Hello from DCL!" | |
548 | $ if p1 .eqs. "" | |
549 | $ then perl -x 'f$environment("PROCEDURE") | |
550 | $ else perl -x - 'p1 'p2 'p3 'p4 'p5 'p6 'p7 'p8 | |
551 | $ deck/dollars="__END__" | |
552 | #!/usr/bin/perl | |
553 | ||
554 | print "Hello from Perl!\n"; | |
555 | ||
556 | __END__ | |
557 | $ endif | |
558 | ||
559 | Do take care with C<$ ASSIGN/nolog/user SYS$COMMAND: SYS$INPUT> if your | |
560 | perl-in-DCL script expects to do things like C<$read = E<lt>STDINE<gt>;>. | |
561 | ||
562 | Filenames are in the format "name.extension;version". The maximum | |
563 | length for filenames is 39 characters, and the maximum length for | |
564 | extensions is also 39 characters. Version is a number from 1 to | |
565 | 32767. Valid characters are C</[A-Z0-9$_-]/>. | |
566 | ||
567 | VMS' RMS filesystem is case insensitive and does not preserve case. | |
568 | C<readdir> returns lowercased filenames, but specifying a file for | |
569 | opening remains case insensitive. Files without extensions have a | |
570 | trailing period on them, so doing a C<readdir> with a file named F<A.;5> | |
571 | will return F<a.> (though that file could be opened with C<open(FH, 'A')>. | |
572 | ||
573 | RMS has an eight level limit on directory depths from any rooted logical | |
574 | (allowing 16 levels overall). Hence C<PERL_ROOT:[LIB.2.3.4.5.6.7.8]> | |
575 | is a valid directory specification but C<PERL_ROOT:[LIB.2.3.4.5.6.7.8.9]> | |
576 | is not. F<Makefile.PL> authors might have to take this into account, but | |
577 | at least they can refer to the former as C</PERL_ROOT/lib/2/3/4/5/6/7/8/>. | |
578 | ||
579 | The C<VMS::Filespec> module, which gets installed as part | |
580 | of the build process on VMS, is a pure Perl module that can easily be | |
581 | installed on non-VMS platforms and can be helpful for conversions to | |
582 | and from RMS native formats. | |
583 | ||
584 | What C<\n> represents depends on the type of file that is open. It could | |
585 | be C<\015>, C<\012>, C<\015\012>, or nothing. Reading from a file | |
586 | translates newlines to C<\012>, unless C<binmode> was executed on that | |
587 | handle, just like DOSish perls. | |
588 | ||
589 | TCP/IP stacks are optional on VMS, so socket routines might not be | |
590 | implemented. UDP sockets may not be supported. | |
591 | ||
592 | The value of C<$^O> on OpenVMS is "VMS". To determine the architecture | |
593 | that you are running on without resorting to loading all of C<%Config> | |
594 | you can examine the content of the C<@INC> array like so: | |
595 | ||
596 | if (grep(/VMS_AXP/, @INC)) { | |
597 | print "I'm on Alpha!\n"; | |
598 | } elsif (grep(/VMS_VAX/, @INC)) { | |
599 | print "I'm on VAX!\n"; | |
600 | } else { | |
601 | print "I'm not so sure about where $^O is...\n"; | |
602 | } | |
603 | ||
604 | Also see: | |
605 | ||
606 | =over 4 | |
607 | ||
608 | =item L<perlvms.pod> | |
609 | ||
610 | =item vmsperl list, C<vmsperl-request@newman.upenn.edu> | |
611 | ||
612 | Put words C<SUBSCRIBE VMSPERL> in message body. | |
613 | ||
614 | =item vmsperl on the web, C<http://www.sidhe.org/vmsperl/index.html> | |
615 | ||
616 | =back | |
617 | ||
618 | ||
619 | =head2 EBCDIC Platforms | |
620 | ||
621 | Recent versions of Perl have been ported to platforms such as OS/400 on | |
622 | AS/400 minicomputers as well as OS/390 for IBM Mainframes. Such computers | |
623 | use EBCDIC character sets internally (usually Character Code Set ID 00819 | |
624 | for OS/400 and IBM-1047 for OS/390). Note that on the mainframe perl | |
625 | currently works under the "Unix system services for OS/390" (formerly | |
626 | known as OpenEdition). | |
627 | ||
628 | As of R2.5 of USS for OS/390 that Unix sub-system did not support the | |
629 | C<#!> shebang trick for script invocation. Hence, on OS/390 perl scripts | |
630 | can executed with a header similar to the following simple script: | |
631 | ||
632 | : # use perl | |
633 | eval 'exec /usr/local/bin/perl -S $0 ${1+"$@"}' | |
634 | if 0; | |
635 | #!/usr/local/bin/perl # just a comment really | |
636 | ||
637 | print "Hello from perl!\n"; | |
638 | ||
639 | On these platforms, bear in mind that the EBCDIC character set may have | |
640 | an effect on what happens with perl functions such as C<chr>, C<pack>, | |
641 | C<print>, C<printf>, C<ord>, C<sort>, C<sprintf>, C<unpack>; as well as | |
642 | bit-fiddling with ASCII constants using operators like C<^>, C<&> and | |
643 | C<|>; not to mention dealing with socket interfaces to ASCII computers | |
644 | (see L<"NEWLINES">). | |
645 | ||
646 | Fortunately, most web servers for the mainframe will correctly translate | |
647 | the C<\n> in the following statement to its ASCII equivalent (note that | |
648 | C<\r> is the same under both ASCII and EBCDIC): | |
649 | ||
650 | print "Content-type: text/html\r\n\r\n"; | |
651 | ||
652 | The value of C<$^O> on OS/390 is "os390". | |
653 | ||
654 | Some simple tricks for determining if you are running on an EBCDIC | |
655 | platform could include any of the following (perhaps all): | |
656 | ||
657 | if ("\t" eq "\05") { print "EBCDIC may be spoken here!\n"; } | |
658 | ||
659 | if (ord('A') == 193) { print "EBCDIC may be spoken here!\n"; } | |
660 | ||
661 | if (chr(169) eq 'z') { print "EBCDIC may be spoken here!\n"; } | |
662 | ||
663 | Note that one thing you may not want to rely on is the EBCDIC encoding | |
664 | of punctuation characters since these may differ from code page to code page | |
665 | (and once your module or script is rumoured to work with EBCDIC, folks will | |
666 | want it to work with all EBCDIC character sets). | |
667 | ||
668 | Also see: | |
669 | ||
670 | =over 4 | |
671 | ||
672 | =item perl-mvs list | |
673 | ||
674 | The perl-mvs@perl.org list is for discussion of porting issues as well as | |
675 | general usage issues for all EBCDIC Perls. Send a message body of | |
676 | "subscribe perl-mvs" to majordomo@perl.org. | |
677 | ||
678 | =item AS/400 Perl information at C<http://as400.rochester.ibm.com> | |
679 | ||
680 | =back | |
681 | ||
682 | =head2 Other perls | |
683 | ||
9d116dd7 JH |
684 | Perl has been ported to a variety of platforms that do not fit into |
685 | any of the above categories. Some, such as AmigaOS, BeOS, MPE/iX, | |
686 | OS/390 (MVS), QNX, and Plan 9, have been well integrated into the | |
687 | standard Perl source code kit. You may need to see the F<ports/> | |
688 | directory on CPAN for information, and possibly binaries, for the | |
689 | likes of: acorn, aos, atari, lynxos, riscos, Tandem Guardian, vos, | |
690 | I<etc.> (yes we know that some of these OSes may fall under the Unix | |
691 | category but we are not a standards body.) | |
e41182b5 GS |
692 | |
693 | See also: | |
694 | ||
695 | =over 4 | |
696 | ||
697 | =item Atari, Guido Flohr's page C<http://stud.uni-sb.de/~gufl0000/> | |
698 | ||
699 | =item HP 300 MPE/iX C<http://www.cccd.edu/~markb/perlix.html> | |
700 | ||
701 | =item Novell Netware | |
702 | ||
703 | A free Perl 5 based PERL.NLM for Novell Netware is available from | |
704 | C<http://www.novell.com/> | |
705 | ||
706 | =back | |
707 | ||
708 | ||
709 | =head1 FUNCTION IMPLEMENTATIONS | |
710 | ||
711 | Listed below are functions unimplemented or implemented differently on | |
712 | various platforms. Following each description will be, in parentheses, a | |
713 | list of platforms that the description applies to. | |
714 | ||
715 | The list may very well be incomplete, or wrong in some places. When in | |
716 | doubt, consult the platform-specific README files in the Perl source | |
717 | distribution, and other documentation resources for a given port. | |
718 | ||
719 | Be aware, moreover, that even among Unix-ish systems there are variations, | |
720 | and not all functions listed here are necessarily available, though | |
721 | most usually are. | |
722 | ||
723 | For many functions, you can also query C<%Config>, exported by default | |
724 | from C<Config.pm>. For example, to check if the platform has the C<lstat> | |
725 | call, check C<$Config{'d_lstat'}>. See L<Config> for a full description | |
726 | of available variables. | |
727 | ||
728 | ||
729 | =head2 Alphabetical Listing of Perl Functions | |
730 | ||
731 | =over 8 | |
732 | ||
733 | =item -X FILEHANDLE | |
734 | ||
735 | =item -X EXPR | |
736 | ||
737 | =item -X | |
738 | ||
739 | C<-r>, C<-w>, and C<-x> have only a very limited meaning; directories | |
740 | and applications are executable, and there are no uid/gid | |
741 | considerations. C<-o> is not supported. (S<Mac OS>) | |
742 | ||
743 | C<-r>, C<-w>, C<-x>, and C<-o> tell whether or not file is accessible, | |
744 | which may not reflect UIC-based file protections. (VMS) | |
745 | ||
746 | C<-R>, C<-W>, C<-X>, C<-O> are indistinguishable from C<-r>, C<-w>, | |
747 | C<-x>, C<-o>. (S<Mac OS>, Win32, VMS) | |
748 | ||
749 | C<-b>, C<-c>, C<-k>, C<-g>, C<-p>, C<-u>, C<-A> are not implemented. | |
750 | (S<Mac OS>) | |
751 | ||
752 | C<-g>, C<-k>, C<-l>, C<-p>, C<-u>, C<-A> are not particularly meaningful. | |
753 | (Win32, VMS) | |
754 | ||
755 | C<-d> is true if passed a device spec without an explicit directory. | |
756 | (VMS) | |
757 | ||
758 | C<-T> and C<-B> are implemented, but might misclassify Mac text files | |
759 | with foreign characters; this is the case will all platforms, but | |
760 | affects S<Mac OS> a lot. (S<Mac OS>) | |
761 | ||
762 | C<-x> (or C<-X>) determine if a file ends in one of the executable | |
763 | suffixes. C<-S> is meaningless. (Win32) | |
764 | ||
765 | =item binmode FILEHANDLE | |
766 | ||
767 | Meaningless. (S<Mac OS>) | |
768 | ||
769 | Reopens file and restores pointer; if function fails, underlying | |
770 | filehandle may be closed, or pointer may be in a different position. | |
771 | (VMS) | |
772 | ||
773 | The value returned by C<tell> may be affected after the call, and | |
774 | the filehandle may be flushed. (Win32) | |
775 | ||
776 | =item chmod LIST | |
777 | ||
778 | Only limited meaning. Disabling/enabling write permission is mapped to | |
779 | locking/unlocking the file. (S<Mac OS>) | |
780 | ||
781 | Only good for changing "owner" read-write access, "group", and "other" | |
782 | bits are meaningless. (Win32) | |
783 | ||
784 | =item chown LIST | |
785 | ||
786 | Not implemented. (S<Mac OS>, Win32, Plan9) | |
787 | ||
788 | Does nothing, but won't fail. (Win32) | |
789 | ||
790 | =item chroot FILENAME | |
791 | ||
792 | =item chroot | |
793 | ||
794 | Not implemented. (S<Mac OS>, Win32, VMS, Plan9) | |
795 | ||
796 | =item crypt PLAINTEXT,SALT | |
797 | ||
798 | May not be available if library or source was not provided when building | |
799 | perl. (Win32) | |
800 | ||
801 | =item dbmclose HASH | |
802 | ||
803 | Not implemented. (VMS, Plan9) | |
804 | ||
805 | =item dbmopen HASH,DBNAME,MODE | |
806 | ||
807 | Not implemented. (VMS, Plan9) | |
808 | ||
809 | =item dump LABEL | |
810 | ||
811 | Not useful. (S<Mac OS>) | |
812 | ||
813 | Not implemented. (Win32) | |
814 | ||
815 | Invokes VMS debugger. (VMS) | |
816 | ||
817 | =item exec LIST | |
818 | ||
819 | Not implemented. (S<Mac OS>) | |
820 | ||
821 | =item fcntl FILEHANDLE,FUNCTION,SCALAR | |
822 | ||
823 | Not implemented. (Win32, VMS) | |
824 | ||
825 | =item flock FILEHANDLE,OPERATION | |
826 | ||
827 | Not implemented (S<Mac OS>, VMS). | |
828 | ||
829 | Available only on Windows NT (not on Windows 95). (Win32) | |
830 | ||
831 | =item fork | |
832 | ||
833 | Not implemented. (S<Mac OS>, Win32, AmigaOS) | |
834 | ||
835 | =item getlogin | |
836 | ||
837 | Not implemented. (S<Mac OS>) | |
838 | ||
839 | =item getpgrp PID | |
840 | ||
841 | Not implemented. (S<Mac OS>, Win32, VMS) | |
842 | ||
843 | =item getppid | |
844 | ||
845 | Not implemented. (S<Mac OS>, Win32, VMS) | |
846 | ||
847 | =item getpriority WHICH,WHO | |
848 | ||
849 | Not implemented. (S<Mac OS>, Win32, VMS) | |
850 | ||
851 | =item getpwnam NAME | |
852 | ||
853 | Not implemented. (S<Mac OS>, Win32) | |
854 | ||
855 | =item getgrnam NAME | |
856 | ||
857 | Not implemented. (S<Mac OS>, Win32, VMS) | |
858 | ||
859 | =item getnetbyname NAME | |
860 | ||
861 | Not implemented. (S<Mac OS>, Win32, Plan9) | |
862 | ||
863 | =item getpwuid UID | |
864 | ||
865 | Not implemented. (S<Mac OS>, Win32) | |
866 | ||
867 | =item getgrgid GID | |
868 | ||
869 | Not implemented. (S<Mac OS>, Win32, VMS) | |
870 | ||
871 | =item getnetbyaddr ADDR,ADDRTYPE | |
872 | ||
873 | Not implemented. (S<Mac OS>, Win32, Plan9) | |
874 | ||
875 | =item getprotobynumber NUMBER | |
876 | ||
877 | Not implemented. (S<Mac OS>) | |
878 | ||
879 | =item getservbyport PORT,PROTO | |
880 | ||
881 | Not implemented. (S<Mac OS>) | |
882 | ||
883 | =item getpwent | |
884 | ||
885 | Not implemented. (S<Mac OS>, Win32) | |
886 | ||
887 | =item getgrent | |
888 | ||
889 | Not implemented. (S<Mac OS>, Win32, VMS) | |
890 | ||
891 | =item gethostent | |
892 | ||
893 | Not implemented. (S<Mac OS>, Win32) | |
894 | ||
895 | =item getnetent | |
896 | ||
897 | Not implemented. (S<Mac OS>, Win32, Plan9) | |
898 | ||
899 | =item getprotoent | |
900 | ||
901 | Not implemented. (S<Mac OS>, Win32, Plan9) | |
902 | ||
903 | =item getservent | |
904 | ||
905 | Not implemented. (Win32, Plan9) | |
906 | ||
907 | =item setpwent | |
908 | ||
909 | Not implemented. (S<Mac OS>, Win32) | |
910 | ||
911 | =item setgrent | |
912 | ||
913 | Not implemented. (S<Mac OS>, Win32, VMS) | |
914 | ||
915 | =item sethostent STAYOPEN | |
916 | ||
917 | Not implemented. (S<Mac OS>, Win32, Plan9) | |
918 | ||
919 | =item setnetent STAYOPEN | |
920 | ||
921 | Not implemented. (S<Mac OS>, Win32, Plan9) | |
922 | ||
923 | =item setprotoent STAYOPEN | |
924 | ||
925 | Not implemented. (S<Mac OS>, Win32, Plan9) | |
926 | ||
927 | =item setservent STAYOPEN | |
928 | ||
929 | Not implemented. (Plan9, Win32) | |
930 | ||
931 | =item endpwent | |
932 | ||
933 | Not implemented. (S<Mac OS>, Win32) | |
934 | ||
935 | =item endgrent | |
936 | ||
937 | Not implemented. (S<Mac OS>, Win32, VMS) | |
938 | ||
939 | =item endhostent | |
940 | ||
941 | Not implemented. (S<Mac OS>, Win32) | |
942 | ||
943 | =item endnetent | |
944 | ||
945 | Not implemented. (S<Mac OS>, Win32, Plan9) | |
946 | ||
947 | =item endprotoent | |
948 | ||
949 | Not implemented. (S<Mac OS>, Win32, Plan9) | |
950 | ||
951 | =item endservent | |
952 | ||
953 | Not implemented. (Plan9, Win32) | |
954 | ||
955 | =item getsockopt SOCKET,LEVEL,OPTNAME | |
956 | ||
957 | Not implemented. (S<Mac OS>, Plan9) | |
958 | ||
959 | =item glob EXPR | |
960 | ||
961 | =item glob | |
962 | ||
963 | Globbing built-in, but only C<*> and C<?> metacharacters are supported. | |
964 | (S<Mac OS>) | |
965 | ||
966 | Features depend on external perlglob.exe or perlglob.bat. May be overridden | |
967 | with something like File::DosGlob, which is recommended. (Win32) | |
968 | ||
969 | =item ioctl FILEHANDLE,FUNCTION,SCALAR | |
970 | ||
971 | Not implemented. (VMS) | |
972 | ||
973 | Available only for socket handles, and it does what the ioctlsocket() call | |
974 | in the Winsock API does. (Win32) | |
975 | ||
976 | =item kill LIST | |
977 | ||
978 | Not implemented. (S<Mac OS>) | |
979 | ||
980 | Available only for process handles returned by the C<system(1, ...)> method of | |
981 | spawning a process. (Win32) | |
982 | ||
983 | =item link OLDFILE,NEWFILE | |
984 | ||
985 | Not implemented. (S<Mac OS>, Win32, VMS) | |
986 | ||
987 | =item lstat FILEHANDLE | |
988 | ||
989 | =item lstat EXPR | |
990 | ||
991 | =item lstat | |
992 | ||
993 | Not implemented. (VMS) | |
994 | ||
995 | Return values may be bogus. (Win32) | |
996 | ||
997 | =item msgctl ID,CMD,ARG | |
998 | ||
999 | =item msgget KEY,FLAGS | |
1000 | ||
1001 | =item msgsnd ID,MSG,FLAGS | |
1002 | ||
1003 | =item msgrcv ID,VAR,SIZE,TYPE,FLAGS | |
1004 | ||
1005 | Not implemented. (S<Mac OS>, Win32, VMS, Plan9) | |
1006 | ||
1007 | =item open FILEHANDLE,EXPR | |
1008 | ||
1009 | =item open FILEHANDLE | |
1010 | ||
1011 | The C<|> variants are only supported if ToolServer is installed. | |
1012 | (S<Mac OS>) | |
1013 | ||
1014 | open to C<|-> and C<-|> are unsupported. (S<Mac OS>, Win32) | |
1015 | ||
1016 | =item pipe READHANDLE,WRITEHANDLE | |
1017 | ||
1018 | Not implemented. (S<Mac OS>) | |
1019 | ||
1020 | =item readlink EXPR | |
1021 | ||
1022 | =item readlink | |
1023 | ||
1024 | Not implemented. (Win32, VMS) | |
1025 | ||
1026 | =item select RBITS,WBITS,EBITS,TIMEOUT | |
1027 | ||
1028 | Only implemented on sockets. (Win32) | |
1029 | ||
1030 | =item semctl ID,SEMNUM,CMD,ARG | |
1031 | ||
1032 | =item semget KEY,NSEMS,FLAGS | |
1033 | ||
1034 | =item semop KEY,OPSTRING | |
1035 | ||
1036 | Not implemented. (S<Mac OS>, Win32, VMS) | |
1037 | ||
1038 | =item setpgrp PID,PGRP | |
1039 | ||
1040 | Not implemented. (S<Mac OS>, Win32, VMS) | |
1041 | ||
1042 | =item setpriority WHICH,WHO,PRIORITY | |
1043 | ||
1044 | Not implemented. (S<Mac OS>, Win32, VMS) | |
1045 | ||
1046 | =item setsockopt SOCKET,LEVEL,OPTNAME,OPTVAL | |
1047 | ||
1048 | Not implemented. (S<Mac OS>, Plan9) | |
1049 | ||
1050 | =item shmctl ID,CMD,ARG | |
1051 | ||
1052 | =item shmget KEY,SIZE,FLAGS | |
1053 | ||
1054 | =item shmread ID,VAR,POS,SIZE | |
1055 | ||
1056 | =item shmwrite ID,STRING,POS,SIZE | |
1057 | ||
1058 | Not implemented. (S<Mac OS>, Win32, VMS) | |
1059 | ||
1060 | =item socketpair SOCKET1,SOCKET2,DOMAIN,TYPE,PROTOCOL | |
1061 | ||
1062 | Not implemented. (S<Mac OS>, Win32, VMS) | |
1063 | ||
1064 | =item stat FILEHANDLE | |
1065 | ||
1066 | =item stat EXPR | |
1067 | ||
1068 | =item stat | |
1069 | ||
1070 | mtime and atime are the same thing, and ctime is creation time instead of | |
1071 | inode change time. (S<Mac OS>) | |
1072 | ||
1073 | device and inode are not meaningful. (Win32) | |
1074 | ||
1075 | device and inode are not necessarily reliable. (VMS) | |
1076 | ||
1077 | =item symlink OLDFILE,NEWFILE | |
1078 | ||
1079 | Not implemented. (Win32, VMS) | |
1080 | ||
1081 | =item syscall LIST | |
1082 | ||
1083 | Not implemented. (S<Mac OS>, Win32, VMS) | |
1084 | ||
1085 | =item system LIST | |
1086 | ||
1087 | Only implemented if ToolServer is installed. (S<Mac OS>) | |
1088 | ||
1089 | As an optimization, may not call the command shell specified in | |
1090 | C<$ENV{PERL5SHELL}>. C<system(1, @args)> spawns an external | |
1091 | process and immediately returns its process designator, without | |
1092 | waiting for it to terminate. Return value may be used subsequently | |
1093 | in C<wait> or C<waitpid>. (Win32) | |
1094 | ||
1095 | =item times | |
1096 | ||
1097 | Only the first entry returned is nonzero. (S<Mac OS>) | |
1098 | ||
1099 | "cumulative" times will be bogus. On anything other than Windows NT, | |
1100 | "system" time will be bogus, and "user" time is actually the time | |
1101 | returned by the clock() function in the C runtime library. (Win32) | |
1102 | ||
1103 | =item truncate FILEHANDLE,LENGTH | |
1104 | ||
1105 | =item truncate EXPR,LENGTH | |
1106 | ||
1107 | Not implemented. (VMS) | |
1108 | ||
1109 | =item umask EXPR | |
1110 | ||
1111 | =item umask | |
1112 | ||
1113 | Returns undef where unavailable, as of version 5.005. | |
1114 | ||
1115 | =item utime LIST | |
1116 | ||
1117 | Only the modification time is updated. (S<Mac OS>, VMS) | |
1118 | ||
1119 | May not behave as expected. (Win32) | |
1120 | ||
1121 | =item wait | |
1122 | ||
1123 | =item waitpid PID,FLAGS | |
1124 | ||
1125 | Not implemented. (S<Mac OS>) | |
1126 | ||
1127 | Can only be applied to process handles returned for processes spawned | |
1128 | using C<system(1, ...)>. (Win32) | |
1129 | ||
1130 | =back | |
1131 | ||
1132 | ||
1133 | =head1 AUTHORS / CONTRIBUTORS | |
1134 | ||
1135 | Chris Nandor E<lt>pudge@pobox.comE<gt>, | |
1136 | Gurusamy Sarathy E<lt>gsar@umich.eduE<gt>, | |
1137 | Peter Prymmer E<lt>pvhp@forte.comE<gt>, | |
1138 | Tom Christiansen E<lt>tchrist@perl.comE<gt>, | |
1139 | Nathan Torkington E<lt>gnat@frii.comE<gt>, | |
1140 | Paul Moore E<lt>Paul.Moore@uk.origin-it.comE<gt>, | |
1141 | Matthias Neercher E<lt>neeri@iis.ee.ethz.chE<gt>, | |
1142 | Charles Bailey E<lt>bailey@genetics.upenn.eduE<gt>, | |
1143 | Luther Huffman E<lt>lutherh@stratcom.comE<gt>, | |
1144 | Gary Ng E<lt>71564.1743@CompuServe.COME<gt>, | |
1145 | Nick Ing-Simmons E<lt>nick@ni-s.u-net.comE<gt>, | |
1146 | Paul J. Schinder E<lt>schinder@pobox.comE<gt>, | |
1147 | Tom Phoenix E<lt>rootbeer@teleport.comE<gt>, | |
1148 | Hugo van der Sanden E<lt>h.sanden@elsevier.nlE<gt>, | |
1149 | Dominic Dunlop E<lt>domo@vo.luE<gt>, | |
1150 | Dan Sugalski E<lt>sugalskd@ous.eduE<gt>, | |
1151 | Andreas J. Koenig E<lt>koenig@kulturbox.deE<gt>, | |
1152 | Andrew M. Langmead E<lt>aml@world.std.comE<gt>, | |
1153 | Andy Dougherty E<lt>doughera@lafcol.lafayette.eduE<gt>, | |
1154 | Abigail E<lt>abigail@fnx.comE<gt>. | |
1155 | ||
1156 | This document is maintained by Chris Nandor. | |
1157 | ||
1158 | =head1 VERSION | |
1159 | ||
1160 | Version 1.23, last modified 10 July 1998. | |
1161 |