1 If you read this file _as_is_, just ignore the funny characters you
2 see. It is written in the POD format (see perlpod manpage) which is
3 specially designed to be readable as is.
7 perlos2 - Perl under OS/2, DOS, Win0.3*, Win0.95 and WinNT.
11 One can read this document in the following formats:
18 to list some (not all may be available simultaneously), or it may
19 be read I<as is>: either as F<README.os2>, or F<pod/perlos2.pod>.
21 To read the F<.INF> version of documentation (B<very> recommended)
22 outside of OS/2, one needs an IBM's reader (may be available on IBM
23 ftp sites (?) (URL anyone?)) or shipped with PC DOS 7.0 and IBM's
26 A copy of a Win* viewer is contained in the "Just add OS/2 Warp" package
28 ftp://ftp.software.ibm.com/ps/products/os2/tools/jaow/jaow.zip
30 in F<?:\JUST_ADD\view.exe>. This gives one an access to EMX's
31 F<.INF> docs as well (text form is available in F</emx/doc> in
32 EMX's distribution). There is also a different viewer named xview.
34 Note that if you have F<lynx.exe> or F<netscape.exe> installed, you can follow WWW links
35 from this document in F<.INF> format. If you have EMX docs installed
36 correctly, you can follow library links (you need to have C<view emxbook>
37 working by setting C<EMXBOOK> environment variable as it is described
42 Contents (This may be a little bit obsolete)
44 perlos2 - Perl under OS/2, DOS, Win0.3*, Win0.95 and WinNT.
52 - Starting Perl programs under OS/2 (and DOS and...)
53 - Starting OS/2 (and DOS) programs under Perl
54 Frequently asked questions
56 - I cannot run external programs
57 - I cannot embed perl into my program, or use perl.dll from my
58 - `` and pipe-open do not work under DOS.
59 - Cannot start find.exe "pattern" file
61 - Automatic binary installation
62 - Manual binary installation
64 Accessing documentation
76 - Application of the patches
80 - Installing the built perl
83 - Some / became \ in pdksh.
84 - 'errno' - unresolved external
85 - Problems with tr or sed
86 - Some problem (forget which ;-)
87 - Library ... not found
89 - op/sprintf test failure
90 Specific (mis)features of OS/2 port
91 - setpriority, getpriority
93 - extproc on the first line
100 - Centralized management of resources
107 - Why dynamic linking?
117 - Text-mode filehandles
119 - DLL name mangling: pre 5.6.2
120 - DLL name mangling: 5.6.2 and beyond
121 - DLL forwarder generation
123 - Calls to external programs
134 The target is to make OS/2 one of the best supported platform for
135 using/building/developing Perl and I<Perl applications>, as well as
136 make Perl the best language to use under OS/2. The secondary target is
137 to try to make this work under DOS and Win* as well (but not B<too> hard).
139 The current state is quite close to this target. Known limitations:
145 Some *nix programs use fork() a lot; with the mostly useful flavors of
146 perl for OS/2 (there are several built simultaneously) this is
147 supported; but some flavors do not support this (e.g., when Perl is
148 called from inside REXX). Using fork() after
149 I<use>ing dynamically loading extensions would not work with I<very> old
154 You need a separate perl executable F<perl__.exe> (see L</perl__.exe>)
155 if you want to use PM code in your application (as Perl/Tk or OpenGL
156 Perl modules do) without having a text-mode window present.
158 While using the standard F<perl.exe> from a text-mode window is possible
159 too, I have seen cases when this causes degradation of the system stability.
160 Using F<perl__.exe> avoids such a degradation.
164 There is no simple way to access WPS objects. The only way I know
165 is via C<OS2::REXX> and C<SOM> extensions (see L<OS2::REXX>, L<SOM>).
166 However, we do not have access to
167 convenience methods of Object-REXX. (Is it possible at all? I know
168 of no Object-REXX API.) The C<SOM> extension (currently in alpha-text)
169 may eventually remove this shortcoming; however, due to the fact that
170 DII is not supported by the C<SOM> module, using C<SOM> is not as
171 convenient as one would like it.
175 Please keep this list up-to-date by informing me about other items.
179 Since OS/2 port of perl uses a remarkable EMX environment, it can
180 run (and build extensions, and - possibly - be built itself) under any
181 environment which can run EMX. The current list is DOS,
182 DOS-inside-OS/2, Win0.3*, Win0.95 and WinNT. Out of many perl flavors,
183 only one works, see L<"perl_.exe">.
185 Note that not all features of Perl are available under these
186 environments. This depends on the features the I<extender> - most
187 probably RSX - decided to implement.
189 Cf. L</Prerequisites>.
197 EMX runtime is required (may be substituted by RSX). Note that
198 it is possible to make F<perl_.exe> to run under DOS without any
199 external support by binding F<emx.exe>/F<rsx.exe> to it, see C<emxbind>. Note
200 that under DOS for best results one should use RSX runtime, which
201 has much more functions working (like C<fork>, C<popen> and so on). In
202 fact RSX is required if there is no VCPI present. Note the
203 RSX requires DPMI. Many implementations of DPMI are known to be very
206 Only the latest runtime is supported, currently C<0.9d fix 03>. Perl may run
207 under earlier versions of EMX, but this is not tested.
209 One can get different parts of EMX from, say
211 ftp://crydee.sai.msu.ru/pub/comp/os/os2/leo/gnu/emx+gcc/
212 http://hobbes.nmsu.edu/h-browse.php?dir=/pub/os2/dev/emx/v0.9d/
214 The runtime component should have the name F<emxrt.zip>.
216 B<NOTE>. When using F<emx.exe>/F<rsx.exe>, it is enough to have them on your path. One
217 does not need to specify them explicitly (though this
225 To run Perl on DPMI platforms one needs RSX runtime. This is
226 needed under DOS-inside-OS/2, Win0.3*, Win0.95 and WinNT (see
227 L<"Other OSes">). RSX would not work with VCPI
228 only, as EMX would, it requires DMPI.
230 Having RSX and the latest F<sh.exe> one gets a fully functional
231 B<*nix>-ish environment under DOS, say, C<fork>, C<``> and
232 pipe-C<open> work. In fact, MakeMaker works (for static build), so one
233 can have Perl development environment under DOS.
235 One can get RSX from, say
237 http://cd.textfiles.com/hobbesos29804/disk1/EMX09C/
238 ftp://crydee.sai.msu.ru/pub/comp/os/os2/leo/gnu/emx+gcc/contrib/
240 Contact the author on C<rainer@mathematik.uni-bielefeld.de>.
242 The latest F<sh.exe> with DOS hooks is available in
244 http://www.ilyaz.org/software/os2/
246 as F<sh_dos.zip> or under similar names starting with C<sh>, C<pdksh> etc.
250 Perl does not care about file systems, but the perl library contains
251 many files with long names, so to install it intact one needs a file
252 system which supports long file names.
254 Note that if you do not plan to build the perl itself, it may be
255 possible to fool EMX to truncate file names. This is not supported,
256 read EMX docs to see how to do it.
260 To start external programs with complicated command lines (like with
261 pipes in between, and/or quoting of arguments), Perl uses an external
262 shell. With EMX port such shell should be named F<sh.exe>, and located
263 either in the wired-in-during-compile locations (usually F<F:/bin>),
264 or in configurable location (see L<"PERL_SH_DIR">).
266 For best results use EMX pdksh. The standard binary (5.2.14 or later) runs
267 under DOS (with L</RSX>) as well, see
269 http://www.ilyaz.org/software/os2/
273 =head2 Starting Perl programs under OS/2 (and DOS and...)
275 Start your Perl program F<foo.pl> with arguments C<arg1 arg2 arg3> the
276 same way as on any other platform, by
278 perl foo.pl arg1 arg2 arg3
280 If you want to specify perl options C<-my_opts> to the perl itself (as
281 opposed to your program), use
283 perl -my_opts foo.pl arg1 arg2 arg3
285 Alternately, if you use OS/2-ish shell, like CMD or 4os2, put
286 the following at the start of your perl script:
288 extproc perl -S -my_opts
290 rename your program to F<foo.cmd>, and start it by typing
294 Note that because of stupid OS/2 limitations the full path of the perl
295 script is not available when you use C<extproc>, thus you are forced to
296 use C<-S> perl switch, and your script should be on the C<PATH>. As a plus
297 side, if you know a full path to your script, you may still start it
300 perl ../../blah/foo.cmd arg1 arg2 arg3
302 (note that the argument C<-my_opts> is taken care of by the C<extproc> line
303 in your script, see L<C<extproc> on the first line>).
305 To understand what the above I<magic> does, read perl docs about C<-S>
306 switch - see L<perlrun>, and cmdref about C<extproc>:
313 or whatever method you prefer.
315 There are also endless possibilities to use I<executable extensions> of
316 4os2, I<associations> of WPS and so on... However, if you use
317 *nixish shell (like F<sh.exe> supplied in the binary distribution),
318 you need to follow the syntax specified in L<perlrun/"Command Switches">.
320 Note that B<-S> switch supports scripts with additional extensions
321 F<.cmd>, F<.btm>, F<.bat>, F<.pl> as well.
323 =head2 Starting OS/2 (and DOS) programs under Perl
325 This is what system() (see L<perlfunc/system>), C<``> (see
326 L<perlop/"I/O Operators">), and I<open pipe> (see L<perlfunc/open>)
327 are for. (Avoid exec() (see L<perlfunc/exec>) unless you know what you
330 Note however that to use some of these operators you need to have a
331 sh-syntax shell installed (see L<"Pdksh">,
332 L<"Frequently asked questions">), and perl should be able to find it
333 (see L<"PERL_SH_DIR">).
335 The cases when the shell is used are:
341 One-argument system() (see L<perlfunc/system>), exec() (see L<perlfunc/exec>)
342 with redirection or shell meta-characters;
346 Pipe-open (see L<perlfunc/open>) with the command which contains redirection
347 or shell meta-characters;
351 Backticks C<``> (see L<perlop/"I/O Operators">) with the command which contains
352 redirection or shell meta-characters;
356 If the executable called by system()/exec()/pipe-open()/C<``> is a script
357 with the "magic" C<#!> line or C<extproc> line which specifies shell;
361 If the executable called by system()/exec()/pipe-open()/C<``> is a script
362 without "magic" line, and C<$ENV{EXECSHELL}> is set to shell;
366 If the executable called by system()/exec()/pipe-open()/C<``> is not
367 found (is not this remark obsolete?);
371 For globbing (see L<perlfunc/glob>, L<perlop/"I/O Operators">)
372 (obsolete? Perl uses builtin globbing nowadays...).
376 For the sake of speed for a common case, in the above algorithms
377 backslashes in the command name are not considered as shell metacharacters.
379 Perl starts scripts which begin with cookies
380 C<extproc> or C<#!> directly, without an intervention of shell. Perl uses the
381 same algorithm to find the executable as F<pdksh>: if the path
382 on C<#!> line does not work, and contains C</>, then the directory
383 part of the executable is ignored, and the executable
384 is searched in F<.> and on C<PATH>. To find arguments for these scripts
385 Perl uses a different algorithm than F<pdksh>: up to 3 arguments are
386 recognized, and trailing whitespace is stripped.
389 does not contain such a cooky, then to avoid calling F<sh.exe>, Perl uses
390 the same algorithm as F<pdksh>: if C<$ENV{EXECSHELL}> is set, the
391 script is given as the first argument to this command, if not set, then
392 C<$ENV{COMSPEC} /c> is used (or a hardwired guess if C<$ENV{COMSPEC}> is
395 When starting scripts directly, Perl uses exactly the same algorithm as for
396 the search of script given by B<-S> command-line option: it will look in
397 the current directory, then on components of C<$ENV{PATH}> using the
398 following order of appended extensions: no extension, F<.cmd>, F<.btm>,
401 Note that Perl will start to look for scripts only if OS/2 cannot start the
402 specified application, thus C<system 'blah'> will not look for a script if
403 there is an executable file F<blah.exe> I<anywhere> on C<PATH>. In
404 other words, C<PATH> is essentially searched twice: once by the OS for
405 an executable, then by Perl for scripts.
407 Note also that executable files on OS/2 can have an arbitrary extension, but
408 F<.exe> will be automatically appended if no dot is present in the name. The
409 workaround is as simple as that: since F<blah.> and F<blah> denote the same
410 file (at list on FAT and HPFS file systems), to start an executable residing in
411 file F<n:/bin/blah> (no extension) give an argument C<n:/bin/blah.> (dot
412 appended) to system().
414 Perl will start PM programs from VIO (=text-mode) Perl process in a
416 the opposite is not true: when you start a non-PM program from a PM
417 Perl process, Perl would not run it in a separate session. If a separate
418 session is desired, either ensure
419 that shell will be used, as in C<system 'cmd /c myprog'>, or start it using
420 optional arguments to system() documented in C<OS2::Process> module. This
421 is considered to be a feature.
423 =head1 Frequently asked questions
425 =head2 "It does not work"
427 Perl binary distributions come with a F<testperl.cmd> script which tries
428 to detect common problems with misconfigured installations. There is a
429 pretty large chance it will discover which step of the installation you
430 managed to goof. C<;-)>
432 =head2 I cannot run external programs
438 Did you run your programs with C<-w> switch? See
439 L<Starting OSE<sol>2 (and DOS) programs under Perl>.
443 Do you try to run I<internal> shell commands, like C<`copy a b`>
444 (internal for F<cmd.exe>), or C<`glob a*b`> (internal for ksh)? You
445 need to specify your shell explicitly, like C<`cmd /c copy a b`>,
446 since Perl cannot deduce which commands are internal to your shell.
450 =head2 I cannot embed perl into my program, or use F<perl.dll> from my
455 =item Is your program EMX-compiled with C<-Zmt -Zcrtdll>?
457 Well, nowadays Perl DLL should be usable from a differently compiled
458 program too... If you can run Perl code from REXX scripts (see
459 L<OS2::REXX>), then there are some other aspect of interaction which
460 are overlooked by the current hackish code to support
461 differently-compiled principal programs.
463 If everything else fails, you need to build a stand-alone DLL for
464 perl. Contact me, I did it once. Sockets would not work, as a lot of
467 =item Did you use L<ExtUtils::Embed>?
469 Some time ago I had reports it does not work. Nowadays it is checked
470 in the Perl test suite, so grep F<./t> subdirectory of the build tree
471 (as well as F<*.t> files in the F<./lib> subdirectory) to find how it
472 should be done "correctly".
476 =head2 C<``> and pipe-C<open> do not work under DOS.
478 This may a variant of just L<"I cannot run external programs">, or a
479 deeper problem. Basically: you I<need> RSX (see L</Prerequisites>)
480 for these commands to work, and you may need a port of F<sh.exe> which
481 understands command arguments. One of such ports is listed in
482 L</Prerequisites> under RSX. Do not forget to set variable
483 C<L<"PERL_SH_DIR">> as well.
485 DPMI is required for RSX.
487 =head2 Cannot start C<find.exe "pattern" file>
489 The whole idea of the "standard C API to start applications" is that
490 the forms C<foo> and C<"foo"> of program arguments are completely
491 interchangeable. F<find> breaks this paradigm;
496 are not equivalent; F<find> cannot be started directly using the above
497 API. One needs a way to surround the doublequotes in some other
498 quoting construction, necessarily having an extra non-Unixish shell in
503 system 'cmd', '/c', 'find "pattern" file';
504 `cmd /c 'find "pattern" file'`
506 This would start F<find.exe> via F<cmd.exe> via C<sh.exe> via
507 C<perl.exe>, but this is a price to pay if you want to use
508 non-conforming program.
512 =head2 Automatic binary installation
514 The most convenient way of installing a binary distribution of perl is via perl installer
515 F<install.exe>. Just follow the instructions, and 99% of the
516 installation blues would go away.
518 Note however, that you need to have F<unzip.exe> on your path, and
519 EMX environment I<running>. The latter means that if you just
520 installed EMX, and made all the needed changes to F<Config.sys>,
521 you may need to reboot in between. Check EMX runtime by running
525 Binary installer also creates a folder on your desktop with some useful
526 objects. If you need to change some aspects of the work of the binary
527 installer, feel free to edit the file F<Perl.pkg>. This may be useful
528 e.g., if you need to run the installer many times and do not want to
529 make many interactive changes in the GUI.
531 B<Things not taken care of by automatic binary installation:>
535 =item C<PERL_BADLANG>
537 may be needed if you change your codepage I<after> perl installation,
538 and the new value is not supported by EMX. See L<"PERL_BADLANG">.
540 =item C<PERL_BADFREE>
542 see L<"PERL_BADFREE">.
546 This file resides somewhere deep in the location you installed your
547 perl library, find it out by
549 perl -MConfig -le "print $INC{'Config.pm'}"
551 While most important values in this file I<are> updated by the binary
552 installer, some of them may need to be hand-edited. I know no such
553 data, please keep me informed if you find one. Moreover, manual
554 changes to the installed version may need to be accompanied by an edit
559 B<NOTE>. Because of a typo the binary installer of 5.00305
560 would install a variable C<PERL_SHPATH> into F<Config.sys>. Please
561 remove this variable and put C<L</PERL_SH_DIR>> instead.
563 =head2 Manual binary installation
565 As of version 5.00305, OS/2 perl binary distribution comes split
566 into 11 components. Unfortunately, to enable configurable binary
567 installation, the file paths in the zip files are not absolute, but
568 relative to some directory.
570 Note that the extraction with the stored paths is still necessary
571 (default with unzip, specify C<-d> to pkunzip). However, you
572 need to know where to extract the files. You need also to manually
573 change entries in F<Config.sys> to reflect where did you put the
574 files. Note that if you have some primitive unzipper (like
575 C<pkunzip>), you may get a lot of warnings/errors during
576 unzipping. Upgrade to C<(w)unzip>.
578 Below is the sample of what to do to reproduce the configuration on my
579 machine. In F<VIEW.EXE> you can press C<Ctrl-Insert> now, and
580 cut-and-paste from the resulting file - created in the directory you
581 started F<VIEW.EXE> from.
583 For each component, we mention environment variables related to each
584 installation directory. Either choose directories to match your
585 values of the variables, or create/append-to variables to take into
586 account the directories.
590 =item Perl VIO and PM executables (dynamically linked)
592 unzip perl_exc.zip *.exe *.ico -d f:/emx.add/bin
593 unzip perl_exc.zip *.dll -d f:/emx.add/dll
595 (have the directories with C<*.exe> on PATH, and C<*.dll> on
598 =item Perl_ VIO executable (statically linked)
600 unzip perl_aou.zip -d f:/emx.add/bin
602 (have the directory on PATH);
604 =item Executables for Perl utilities
606 unzip perl_utl.zip -d f:/emx.add/bin
608 (have the directory on PATH);
610 =item Main Perl library
612 unzip perl_mlb.zip -d f:/perllib/lib
614 If this directory is exactly the same as the prefix which was compiled
615 into F<perl.exe>, you do not need to change
616 anything. However, for perl to find the library if you use a different
618 C<set PERLLIB_PREFIX> in F<Config.sys>, see L<"PERLLIB_PREFIX">.
620 =item Additional Perl modules
622 unzip perl_ste.zip -d f:/perllib/lib/site_perl/5.19.3/
624 Same remark as above applies. Additionally, if this directory is not
625 one of directories on @INC (and @INC is influenced by C<PERLLIB_PREFIX>), you
627 directory and subdirectory F<./os2> in C<PERLLIB> or C<PERL5LIB>
628 variable. Do not use C<PERL5LIB> unless you have it set already. See
629 L<perl/"ENVIRONMENT">.
631 B<[Check whether this extraction directory is still applicable with
632 the new directory structure layout!]>
634 =item Tools to compile Perl modules
636 unzip perl_blb.zip -d f:/perllib/lib
638 Same remark as for F<perl_ste.zip>.
640 =item Manpages for Perl and utilities
642 unzip perl_man.zip -d f:/perllib/man
644 This directory should better be on C<MANPATH>. You need to have a
645 working F<man> to access these files.
647 =item Manpages for Perl modules
649 unzip perl_mam.zip -d f:/perllib/man
651 This directory should better be on C<MANPATH>. You need to have a
652 working man to access these files.
654 =item Source for Perl documentation
656 unzip perl_pod.zip -d f:/perllib/lib
658 This is used by the C<perldoc> program (see L<perldoc>), and may be used to
659 generate HTML documentation usable by WWW browsers, and
660 documentation in zillions of other formats: C<info>, C<LaTeX>,
661 C<Acrobat>, C<FrameMaker> and so on. [Use programs such as
664 =item Perl manual in F<.INF> format
666 unzip perl_inf.zip -d d:/os2/book
668 This directory should better be on C<BOOKSHELF>.
672 unzip perl_sh.zip -d f:/bin
674 This is used by perl to run external commands which explicitly
675 require shell, like the commands using I<redirection> and I<shell
676 metacharacters>. It is also used instead of explicit F</bin/sh>.
678 Set C<PERL_SH_DIR> (see L<"PERL_SH_DIR">) if you move F<sh.exe> from
681 B<Note.> It may be possible to use some other sh-compatible shell (untested).
685 After you installed the components you needed and updated the
686 F<Config.sys> correspondingly, you need to hand-edit
687 F<Config.pm>. This file resides somewhere deep in the location you
688 installed your perl library, find it out by
690 perl -MConfig -le "print $INC{'Config.pm'}"
692 You need to correct all the entries which look like file paths (they
693 currently start with C<f:/>).
697 The automatic and manual perl installation leave precompiled paths
698 inside perl executables. While these paths are overwriteable (see
699 L<"PERLLIB_PREFIX">, L<"PERL_SH_DIR">), some people may prefer
700 binary editing of paths inside the executables/DLLs.
702 =head1 Accessing documentation
704 Depending on how you built/installed perl you may have (otherwise
705 identical) Perl documentation in the following formats:
707 =head2 OS/2 F<.INF> file
709 Most probably the most convenient form. Under OS/2 view it as
714 view perl ExtUtils::MakeMaker
716 (currently the last two may hit a wrong location, but this may improve
717 soon). Under Win* see L<"SYNOPSIS">.
719 If you want to build the docs yourself, and have I<OS/2 toolkit>, run
723 in F</perllib/lib/pod> directory, then
727 (Expect a lot of errors during the both steps.) Now move it on your
732 If you have perl documentation in the source form, perl utilities
733 installed, and GNU groff installed, you may use
737 perldoc ExtUtils::MakeMaker
739 to access the perl documentation in the text form (note that you may get
740 better results using perl manpages).
742 Alternately, try running pod2text on F<.pod> files.
746 If you have F<man> installed on your system, and you installed perl
747 manpages, use something like this:
751 man ExtUtils.MakeMaker
753 to access documentation for different components of Perl. Start with
757 Note that dot (F<.>) is used as a package separator for documentation
758 for packages, and as usual, sometimes you need to give the section - C<3>
759 above - to avoid shadowing by the I<less(1) manpage>.
761 Make sure that the directory B<above> the directory with manpages is
762 on our C<MANPATH>, like this
764 set MANPATH=c:/man;f:/perllib/man
766 for Perl manpages in C<f:/perllib/man/man1/> etc.
770 If you have some WWW browser available, installed the Perl
771 documentation in the source form, and Perl utilities, you can build
772 HTML docs. Cd to directory with F<.pod> files, and do like this
774 cd f:/perllib/lib/pod
777 After this you can direct your browser the file F<perl.html> in this
778 directory, and go ahead with reading docs, like this:
780 explore file:///f:/perllib/lib/pod/perl.html
782 Alternatively you may be able to get these docs prebuilt from CPAN.
784 =head2 GNU C<info> files
786 Users of Emacs would appreciate it very much, especially with
787 C<CPerl> mode loaded. You need to get latest C<pod2texi> from C<CPAN>,
788 or, alternately, the prebuilt info pages.
792 for C<Acrobat> are available on CPAN (may be for slightly older version of
797 can be constructed using C<pod2latex>.
801 Here we discuss how to build Perl under OS/2.
803 =head2 The short story
805 Assume that you are a seasoned porter, so are sure that all the necessary
806 tools are already present on your system, and you know how to get the Perl
807 source distribution. Untar it, change to the extract directory, and
809 gnupatch -p0 < os2\diff.configure
810 sh Configure -des -D prefix=f:/perllib
817 This puts the executables in f:/perllib/bin. Manually move them to the
818 C<PATH>, manually move the built F<perl*.dll> to C<LIBPATH> (here for
819 Perl DLL F<*> is a not-very-meaningful hex checksum), and run
821 make installcmd INSTALLCMDDIR=d:/ir/on/path
823 Assuming that the C<man>-files were put on an appropriate location,
824 this completes the installation of minimal Perl system. (The binary
825 distribution contains also a lot of additional modules, and the
826 documentation in INF format.)
828 What follows is a detailed guide through these steps.
832 You need to have the latest EMX development environment, the full
833 GNU tool suite (gawk renamed to awk, and GNU F<find.exe>
834 earlier on path than the OS/2 F<find.exe>, same with F<sort.exe>, to
840 ). You need the latest version of F<pdksh> installed as F<sh.exe>.
842 Check that you have B<BSD> libraries and headers installed, and -
843 optionally - Berkeley DB headers and libraries, and crypt.
845 Possible locations to get the files:
848 ftp://ftp.uni-heidelberg.de/pub/os2/unix/
849 http://hobbes.nmsu.edu/h-browse.php?dir=/pub/os2
850 http://cd.textfiles.com/hobbesos29804/disk1/DEV32/
851 http://cd.textfiles.com/hobbesos29804/disk1/EMX09C/
853 It is reported that the following archives contain enough utils to
854 build perl: F<gnufutil.zip>, F<gnusutil.zip>, F<gnututil.zip>, F<gnused.zip>,
855 F<gnupatch.zip>, F<gnuawk.zip>, F<gnumake.zip>, F<gnugrep.zip>, F<bsddev.zip> and
856 F<ksh527rt.zip> (or a later version). Note that all these utilities are
857 known to be available from LEO:
859 ftp://crydee.sai.msu.ru/pub/comp/os/os2/leo/gnu/
861 Note also that the F<db.lib> and F<db.a> from the EMX distribution
862 are not suitable for multi-threaded compile (even single-threaded
863 flavor of Perl uses multi-threaded C RTL, for
864 compatibility with XFree86-OS/2). Get a corrected one from
866 http://www.ilyaz.org/software/os2/db_mt.zip
868 If you have I<exactly the same version of Perl> installed already,
869 make sure that no copies or perl are currently running. Later steps
870 of the build may fail since an older version of F<perl.dll> loaded into
871 memory may be found. Running C<make test> becomes meaningless, since
872 the test are checking a previous build of perl (this situation is detected
873 and reported by F<lib/os2_base.t> test). Do not forget to unset
874 C<PERL_EMXLOAD_SEC> in environment.
876 Also make sure that you have F</tmp> directory on the current drive,
877 and F<.> directory in your C<LIBPATH>. One may try to correct the
882 if you use something like F<CMD.EXE> or latest versions of
883 F<4os2.exe>. (Setting BEGINLIBPATH to just C<.> is ignored by the
886 Make sure your gcc is good for C<-Zomf> linking: run C<omflibs>
887 script in F</emx/lib> directory.
889 Check that you have link386 installed. It comes standard with OS/2,
890 but may be not installed due to customization. If typing
894 shows you do not have it, do I<Selective install>, and choose C<Link
895 object modules> in I<Optional system utilities/More>. If you get into
896 link386 prompts, press C<Ctrl-C> to exit.
898 =head2 Getting perl source
900 You need to fetch the latest perl source (including developers
901 releases). With some probability it is located in
903 http://www.cpan.org/src/
904 http://www.cpan.org/src/unsupported
906 If not, you may need to dig in the indices to find it in the directory
907 of the current maintainer.
909 Quick cycle of developers release may break the OS/2 build time to
912 http://www.cpan.org/ports/os2/
914 may indicate the latest release which was publicly released by the
915 maintainer. Note that the release may include some additional patches
916 to apply to the current source of perl.
920 tar vzxf perl5.00409.tar.gz
922 You may see a message about errors while extracting F<Configure>. This is
923 because there is a conflict with a similarly-named file F<configure>.
925 Change to the directory of extraction.
927 =head2 Application of the patches
929 You need to apply the patches in F<./os2/diff.*> like this:
931 gnupatch -p0 < os2\diff.configure
933 You may also need to apply the patches supplied with the binary
934 distribution of perl. It also makes sense to look on the
935 perl5-porters mailing list for the latest OS/2-related patches (see
936 L<http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/>). Such
937 patches usually contain strings C</os2/> and C<patch>, so it makes
938 sense looking for these strings.
942 You may look into the file F<./hints/os2.sh> and correct anything
943 wrong you find there. I do not expect it is needed anywhere.
947 sh Configure -des -D prefix=f:/perllib
949 C<prefix> means: where to install the resulting perl library. Giving
950 correct prefix you may avoid the need to specify C<PERLLIB_PREFIX>,
951 see L<"PERLLIB_PREFIX">.
953 I<Ignore the message about missing C<ln>, and about C<-c> option to
954 tr>. The latter is most probably already fixed, if you see it and can trace
955 where the latter spurious warning comes from, please inform me.
961 At some moment the built may die, reporting a I<version mismatch> or
962 I<unable to run F<perl>>. This means that you do not have F<.> in
963 your LIBPATH, so F<perl.exe> cannot find the needed F<perl67B2.dll> (treat
964 these hex digits as line noise). After this is fixed the build
965 should finish without a lot of fuss.
973 All tests should succeed (with some of them skipped). If you have the
974 same version of Perl installed, it is crucial that you have C<.> early
975 in your LIBPATH (or in BEGINLIBPATH), otherwise your tests will most
976 probably test the wrong version of Perl.
978 Some tests may generate extra messages similar to
982 =item A lot of C<bad free>
984 in database tests related to Berkeley DB. I<This should be fixed already.>
985 If it persists, you may disable this warnings, see L<"PERL_BADFREE">.
987 =item Process terminated by SIGTERM/SIGINT
989 This is a standard message issued by OS/2 applications. *nix
990 applications die in silence. It is considered to be a feature. One can
991 easily disable this by appropriate sighandlers.
993 However the test engine bleeds these message to screen in unexpected
994 moments. Two messages of this kind I<should> be present during
999 To get finer test reports, call
1003 The report with F<io/pipe.t> failing may look like this:
1005 Failed Test Status Wstat Total Fail Failed List of failed
1006 ------------------------------------------------------------
1007 io/pipe.t 12 1 8.33% 9
1008 7 tests skipped, plus 56 subtests skipped.
1009 Failed 1/195 test scripts, 99.49% okay. 1/6542 subtests failed, 99.98% okay.
1011 The reasons for most important skipped tests are:
1021 Checks C<atime> and C<mtime> of C<stat()> - unfortunately, HPFS
1022 provides only 2sec time granularity (for compatibility with FAT?).
1026 Checks C<truncate()> on a filehandle just opened for write - I do not
1027 know why this should or should not work.
1033 Checks C<stat()>. Tests:
1039 Checks C<atime> and C<mtime> of C<stat()> - unfortunately, HPFS
1040 provides only 2sec time granularity (for compatibility with FAT?).
1046 =head2 Installing the built perl
1048 If you haven't yet moved C<perl*.dll> onto LIBPATH, do it now.
1054 It would put the generated files into needed locations. Manually put
1055 F<perl.exe>, F<perl__.exe> and F<perl___.exe> to a location on your
1056 PATH, F<perl.dll> to a location on your LIBPATH.
1060 make installcmd INSTALLCMDDIR=d:/ir/on/path
1062 to convert perl utilities to F<.cmd> files and put them on
1063 PATH. You need to put F<.EXE>-utilities on path manually. They are
1064 installed in C<$prefix/bin>, here C<$prefix> is what you gave to
1065 F<Configure>, see L</Making>.
1067 If you use C<man>, either move the installed F<*/man/> directories to
1068 your C<MANPATH>, or modify C<MANPATH> to match the location. (One
1069 could have avoided this by providing a correct C<manpath> option to
1070 F<./Configure>, or editing F<./config.sh> between configuring and
1073 =head2 C<a.out>-style build
1075 Proceed as above, but make F<perl_.exe> (see L<"perl_.exe">) by
1084 Manually put F<perl_.exe> to a location on your PATH.
1086 B<Note.> The build process for C<perl_> I<does not know> about all the
1087 dependencies, so you should make sure that anything is up-to-date,
1094 =head1 Building a binary distribution
1096 [This section provides a short overview only...]
1098 Building should proceed differently depending on whether the version of perl
1099 you install is already present and used on your system, or is a new version
1100 not yet used. The description below assumes that the version is new, so
1101 installing its DLLs and F<.pm> files will not disrupt the operation of your
1102 system even if some intermediate steps are not yet fully working.
1104 The other cases require a little bit more convoluted procedures. Below I
1105 suppose that the current version of Perl is C<5.8.2>, so the executables are
1112 Fully build and test the Perl distribution. Make sure that no tests are
1113 failing with C<test> and C<aout_test> targets; fix the bugs in Perl and
1114 the Perl test suite detected by these tests. Make sure that C<all_test>
1115 make target runs as clean as possible. Check that F<os2/perlrexx.cmd>
1120 Fully install Perl, including C<installcmd> target. Copy the generated DLLs
1121 to C<LIBPATH>; copy the numbered Perl executables (as in F<perl5.8.2.exe>)
1122 to C<PATH>; copy C<perl_.exe> to C<PATH> as C<perl_5.8.2.exe>. Think whether
1123 you need backward-compatibility DLLs. In most cases you do not need to install
1124 them yet; but sometime this may simplify the following steps.
1128 Make sure that C<CPAN.pm> can download files from CPAN. If not, you may need
1129 to manually install C<Net::FTP>.
1133 Install the bundle C<Bundle::OS2_default>
1135 perl5.8.2 -MCPAN -e "install Bundle::OS2_default" < nul |& tee 00cpan_i_1
1137 This may take a couple of hours on 1GHz processor (when run the first time).
1138 And this should not be necessarily a smooth procedure. Some modules may not
1139 specify required dependencies, so one may need to repeat this procedure several
1140 times until the results stabilize.
1142 perl5.8.2 -MCPAN -e "install Bundle::OS2_default" < nul |& tee 00cpan_i_2
1143 perl5.8.2 -MCPAN -e "install Bundle::OS2_default" < nul |& tee 00cpan_i_3
1145 Even after they stabilize, some tests may fail.
1147 Fix as many discovered bugs as possible. Document all the bugs which are not
1148 fixed, and all the failures with unknown reasons. Inspect the produced logs
1149 F<00cpan_i_1> to find suspiciously skipped tests, and other fishy events.
1151 Keep in mind that I<installation> of some modules may fail too: for example,
1152 the DLLs to update may be already loaded by F<CPAN.pm>. Inspect the C<install>
1153 logs (in the example above F<00cpan_i_1> etc) for errors, and install things
1156 cd $CPANHOME/.cpan/build/Digest-MD5-2.31
1159 Some distributions may fail some tests, but you may want to install them
1160 anyway (as above, or via C<force install> command of C<CPAN.pm> shell-mode).
1162 Since this procedure may take quite a long time to complete, it makes sense
1163 to "freeze" your CPAN configuration by disabling periodic updates of the
1164 local copy of CPAN index: set C<index_expire> to some big value (I use 365),
1165 then save the settings
1167 CPAN> o conf index_expire 365
1170 Reset back to the default value C<1> when you are finished.
1174 When satisfied with the results, rerun the C<installcmd> target. Now you
1175 can copy C<perl5.8.2.exe> to C<perl.exe>, and install the other OMF-build
1176 executables: C<perl__.exe> etc. They are ready to be used.
1180 Change to the C<./pod> directory of the build tree, download the Perl logo
1181 F<CamelGrayBig.BMP>, and run
1183 ( perl2ipf > perl.ipf ) |& tee 00ipf
1184 ipfc /INF perl.ipf |& tee 00inf
1186 This produces the Perl docs online book C<perl.INF>. Install in on
1191 Now is the time to build statically linked executable F<perl_.exe> which
1192 includes newly-installed via C<Bundle::OS2_default> modules. Doing testing
1193 via C<CPAN.pm> is going to be painfully slow, since it statically links
1194 a new executable per XS extension.
1196 Here is a possible workaround: create a toplevel F<Makefile.PL> in
1197 F<$CPANHOME/.cpan/build/> with contents being (compare with L<Making
1198 executables with a custom collection of statically loaded extensions>)
1200 use ExtUtils::MakeMaker;
1201 WriteMakefile NAME => 'dummy';
1205 perl_5.8.2.exe Makefile.PL <nul |& tee 00aout_c1
1206 make -k all test <nul |& 00aout_t1
1208 Again, this procedure should not be absolutely smooth. Some C<Makefile.PL>'s
1209 in subdirectories may be buggy, and would not run as "child" scripts. The
1210 interdependency of modules can strike you; however, since non-XS modules
1211 are already installed, the prerequisites of most modules have a very good
1212 chance to be present.
1214 If you discover some glitches, move directories of problematic modules to a
1215 different location; if these modules are non-XS modules, you may just ignore
1216 them - they are already installed; the remaining, XS, modules you need to
1217 install manually one by one.
1219 After each such removal you need to rerun the C<Makefile.PL>/C<make> process;
1220 usually this procedure converges soon. (But be sure to convert all the
1221 necessary external C libraries from F<.lib> format to F<.a> format: run one of
1224 emximp -o foo.a foo.lib
1226 whichever is appropriate.) Also, make sure that the DLLs for external
1227 libraries are usable with with executables compiled without C<-Zmtd> options.
1229 When you are sure that only a few subdirectories
1230 lead to failures, you may want to add C<-j4> option to C<make> to speed up
1231 skipping subdirectories with already finished build.
1233 When you are satisfied with the results of tests, install the build C libraries
1236 make install |& tee 00aout_i
1238 Now you can rename the file F<./perl.exe> generated during the last phase
1239 to F<perl_5.8.2.exe>; place it on C<PATH>; if there is an inter-dependency
1240 between some XS modules, you may need to repeat the C<test>/C<install> loop
1241 with this new executable and some excluded modules - until the procedure
1244 Now you have all the necessary F<.a> libraries for these Perl modules in the
1245 places where Perl builder can find it. Use the perl builder: change to an
1246 empty directory, create a "dummy" F<Makefile.PL> again, and run
1248 perl_5.8.2.exe Makefile.PL |& tee 00c
1249 make perl |& tee 00p
1251 This should create an executable F<./perl.exe> with all the statically loaded
1252 extensions built in. Compare the generated F<perlmain.c> files to make sure
1253 that during the iterations the number of loaded extensions only increases.
1254 Rename F<./perl.exe> to F<perl_5.8.2.exe> on C<PATH>.
1256 When it converges, you got a functional variant of F<perl_5.8.2.exe>; copy it
1257 to C<perl_.exe>. You are done with generation of the local Perl installation.
1261 Make sure that the installed modules are actually installed in the location
1262 of the new Perl, and are not inherited from entries of @INC given for
1263 inheritance from the older versions of Perl: set C<PERLLIB_582_PREFIX> to
1264 redirect the new version of Perl to a new location, and copy the installed
1265 files to this new location. Redo the tests to make sure that the versions of
1266 modules inherited from older versions of Perl are not needed.
1268 Actually, the log output of L<pod2ipf(1)> during the step 6 gives a very detailed
1269 info about which modules are loaded from which place; so you may use it as
1270 an additional verification tool.
1272 Check that some temporary files did not make into the perl install tree.
1273 Run something like this
1275 pfind . -f "!(/\.(pm|pl|ix|al|h|a|lib|txt|pod|imp|bs|dll|ld|bs|inc|xbm|yml|cgi|uu|e2x|skip|packlist|eg|cfg|html|pub|enc|all|ini|po|pot)$/i or /^\w+$/") | less
1277 in the install tree (both top one and F<sitelib> one).
1279 Compress all the DLLs with F<lxlite>. The tiny F<.exe> can be compressed with
1280 C</c:max> (the bug only appears when there is a fixup in the last 6 bytes of a
1281 page (?); since the tiny executables are much smaller than a page, the bug
1282 will not hit). Do not compress C<perl_.exe> - it would not work under DOS.
1286 Now you can generate the binary distribution. This is done by running the
1287 test of the CPAN distribution C<OS2::SoftInstaller>. Tune up the file
1288 F<test.pl> to suit the layout of current version of Perl first. Do not
1289 forget to pack the necessary external DLLs accordingly. Include the
1290 description of the bugs and test suite failures you could not fix. Include
1291 the small-stack versions of Perl executables from Perl build directory.
1293 Include F<perl5.def> so that people can relink the perl DLL preserving
1294 the binary compatibility, or can create compatibility DLLs. Include the diff
1295 files (C<diff -pu old new>) of fixes you did so that people can rebuild your
1296 version. Include F<perl5.map> so that one can use remote debugging.
1300 Share what you did with the other people. Relax. Enjoy fruits of your work.
1304 Brace yourself for thanks, bug reports, hate mail and spam coming as result
1305 of the previous step. No good deed should remain unpunished!
1309 =head1 Building custom F<.EXE> files
1311 The Perl executables can be easily rebuilt at any moment. Moreover, one can
1312 use the I<embedding> interface (see L<perlembed>) to make very customized
1315 =head2 Making executables with a custom collection of statically loaded extensions
1317 It is a little bit easier to do so while I<decreasing> the list of statically
1318 loaded extensions. We discuss this case only here.
1324 Change to an empty directory, and create a placeholder <Makefile.PL>:
1326 use ExtUtils::MakeMaker;
1327 WriteMakefile NAME => 'dummy';
1331 Run it with the flavor of Perl (F<perl.exe> or F<perl_.exe>) you want to
1338 Ask it to create new Perl executable:
1342 (you may need to manually add C<PERLTYPE=-DPERL_CORE> to this commandline on
1343 some versions of Perl; the symptom is that the command-line globbing does not
1344 work from OS/2 shells with the newly-compiled executable; check with
1346 .\perl.exe -wle "print for @ARGV" *
1352 The previous step created F<perlmain.c> which contains a list of newXS() calls
1353 near the end. Removing unnecessary calls, and rerunning
1357 will produce a customized executable.
1361 =head2 Making executables with a custom search-paths
1363 The default perl executable is flexible enough to support most usages.
1364 However, one may want something yet more flexible; for example, one may want
1365 to find Perl DLL relatively to the location of the EXE file; or one may want
1366 to ignore the environment when setting the Perl-library search patch, etc.
1368 If you fill comfortable with I<embedding> interface (see L<perlembed>), such
1369 things are easy to do repeating the steps outlined in L<Making
1370 executables with a custom collection of statically loaded extensions>, and
1371 doing more comprehensive edits to main() of F<perlmain.c>. The people with
1372 little desire to understand Perl can just rename main(), and do necessary
1373 modification in a custom main() which calls the renamed function in appropriate
1376 However, there is a third way: perl DLL exports the main() function and several
1377 callbacks to customize the search path. Below is a complete example of a
1384 Looks for Perl DLL in the directory C<$exedir/../dll>;
1388 Prepends the above directory to C<BEGINLIBPATH>;
1392 Fails if the Perl DLL found via C<BEGINLIBPATH> is different from what was
1393 loaded on step 1; e.g., another process could have loaded it from C<LIBPATH>
1394 or from a different value of C<BEGINLIBPATH>. In these cases one needs to
1395 modify the setting of the system so that this other process either does not
1396 run, or loads the DLL from C<BEGINLIBPATH> with C<LIBPATHSTRICT=T> (available
1397 with kernels after September 2000).
1401 Loads Perl library from C<$exedir/../dll/lib/>.
1405 Uses Bourne shell from C<$exedir/../dll/sh/ksh.exe>.
1409 For best results compile the C file below with the same options as the Perl
1410 DLL. However, a lot of functionality will work even if the executable is not
1411 an EMX applications, e.g., if compiled with
1413 gcc -Wall -DDOSISH -DOS2=1 -O2 -s -Zomf -Zsys perl-starter.c \
1414 -DPERL_DLL_BASENAME=\"perl312F\" -Zstack 8192 -Zlinker /PM:VIO
1416 Here is the sample C file:
1420 /* These are needed for compile if os2.h includes os2tk.h, not os2emx.h */
1421 #define INCL_DOSPROCESS
1425 #define PERL_IN_MINIPERLMAIN_C
1432 die_with(char *msg1, char *msg2, char *msg3, char *msg4)
1435 char *s = " error: ";
1437 DosWrite(2, me, strlen(me), &c);
1438 DosWrite(2, s, strlen(s), &c);
1439 DosWrite(2, msg1, strlen(msg1), &c);
1440 DosWrite(2, msg2, strlen(msg2), &c);
1441 DosWrite(2, msg3, strlen(msg3), &c);
1442 DosWrite(2, msg4, strlen(msg4), &c);
1443 DosWrite(2, "\r\n", 2, &c);
1447 typedef ULONG (*fill_extLibpath_t)(int type, char *pre, char *post, int replace, char *msg);
1448 typedef int (*main_t)(int type, char *argv[], char *env[]);
1449 typedef int (*handler_t)(void* data, int which);
1451 #ifndef PERL_DLL_BASENAME
1452 # define PERL_DLL_BASENAME "perl"
1456 load_perl_dll(char *basename)
1458 char buf[300], fail[260];
1460 fill_extLibpath_t f;
1462 HMODULE handle, handle1;
1464 if (_execname(buf, sizeof(buf) - 13) != 0)
1465 die_with("Can't find full path: ", strerror(errno), "", "");
1466 /* XXXX Fill 'me' with new value */
1468 while (l && buf[l-1] != '/' && buf[l-1] != '\\')
1471 strcpy(buf + l, basename);
1472 l += strlen(basename);
1473 strcpy(buf + l, ".dll");
1474 if ( (rc_fullname = DosLoadModule(fail, sizeof fail, buf, &handle)) != 0
1475 && DosLoadModule(fail, sizeof fail, basename, &handle) != 0 )
1476 die_with("Can't load DLL ", buf, "", "");
1478 return handle; /* was loaded with short name; all is fine */
1479 if (DosQueryProcAddr(handle, 0, "fill_extLibpath", (PFN*)&f))
1480 die_with(buf, ": DLL exports no symbol ", "fill_extLibpath", "");
1482 if (f(0 /*BEGINLIBPATH*/, buf /* prepend */, NULL /* append */,
1483 0 /* keep old value */, me))
1484 die_with(me, ": prepending BEGINLIBPATH", "", "");
1485 if (DosLoadModule(fail, sizeof fail, basename, &handle1) != 0)
1486 die_with(me, ": finding perl DLL again via BEGINLIBPATH", "", "");
1488 if (handle1 != handle) {
1489 if (DosQueryModuleName(handle1, sizeof(fail), fail))
1490 strcpy(fail, "???");
1491 die_with(buf, ":\n\tperl DLL via BEGINLIBPATH is different: \n\t",
1493 "\n\tYou may need to manipulate global BEGINLIBPATH and LIBPATHSTRICT"
1494 "\n\tso that the other copy is loaded via BEGINLIBPATH.");
1500 main(int argc, char **argv, char **env)
1507 handle = load_perl_dll(PERL_DLL_BASENAME);
1509 if (DosQueryProcAddr(handle, 0, "Perl_OS2_handler_install", (PFN*)&h))
1510 die_with(PERL_DLL_BASENAME, ": DLL exports no symbol ", "Perl_OS2_handler_install", "");
1511 if ( !h((void *)"~installprefix", Perlos2_handler_perllib_from)
1512 || !h((void *)"~dll", Perlos2_handler_perllib_to)
1513 || !h((void *)"~dll/sh/ksh.exe", Perlos2_handler_perl_sh) )
1514 die_with(PERL_DLL_BASENAME, ": Can't install @INC manglers", "", "");
1516 if (DosQueryProcAddr(handle, 0, "dll_perlmain", (PFN*)&f))
1517 die_with(PERL_DLL_BASENAME, ": DLL exports no symbol ", "dll_perlmain", "");
1518 return f(argc, argv, env);
1524 =head2 Some C</> became C<\> in pdksh.
1526 You have a very old pdksh. See L</Prerequisites>.
1528 =head2 C<'errno'> - unresolved external
1530 You do not have MT-safe F<db.lib>. See L</Prerequisites>.
1532 =head2 Problems with tr or sed
1534 reported with very old version of tr and sed.
1536 =head2 Some problem (forget which ;-)
1538 You have an older version of F<perl.dll> on your LIBPATH, which
1539 broke the build of extensions.
1541 =head2 Library ... not found
1543 You did not run C<omflibs>. See L</Prerequisites>.
1545 =head2 Segfault in make
1547 You use an old version of GNU make. See L</Prerequisites>.
1549 =head2 op/sprintf test failure
1551 This can result from a bug in emx sprintf which was fixed in 0.9d fix 03.
1553 =head1 Specific (mis)features of OS/2 port
1555 =head2 C<setpriority>, C<getpriority>
1557 Note that these functions are compatible with *nix, not with the older
1558 ports of '94 - 95. The priorities are absolute, go from 32 to -95,
1559 lower is quicker. 0 is the default priority.
1561 B<WARNING>. Calling C<getpriority> on a non-existing process could lock
1562 the system before Warp3 fixpak22. Starting with Warp3, Perl will use
1563 a workaround: it aborts getpriority() if the process is not present.
1564 This is not possible on older versions C<2.*>, and has a race
1569 Multi-argument form of C<system()> allows an additional numeric
1570 argument. The meaning of this argument is described in
1573 When finding a program to run, Perl first asks the OS to look for executables
1574 on C<PATH> (OS/2 adds extension F<.exe> if no extension is present).
1575 If not found, it looks for a script with possible extensions
1576 added in this order: no extension, F<.cmd>, F<.btm>,
1577 F<.bat>, F<.pl>. If found, Perl checks the start of the file for magic
1578 strings C<"#!"> and C<"extproc ">. If found, Perl uses the rest of the
1579 first line as the beginning of the command line to run this script. The
1580 only mangling done to the first line is extraction of arguments (currently
1581 up to 3), and ignoring of the path-part of the "interpreter" name if it can't
1582 be found using the full path.
1584 E.g., C<system 'foo', 'bar', 'baz'> may lead Perl to finding
1585 F<C:/emx/bin/foo.cmd> with the first line being
1587 extproc /bin/bash -x -c
1589 If F</bin/bash.exe> is not found, then Perl looks for an executable F<bash.exe> on
1590 C<PATH>. If found in F<C:/emx.add/bin/bash.exe>, then the above system() is
1593 system qw(C:/emx.add/bin/bash.exe -x -c C:/emx/bin/foo.cmd bar baz)
1595 One additional translation is performed: instead of F</bin/sh> Perl uses
1596 the hardwired-or-customized shell (see C<L<"PERL_SH_DIR">>).
1598 The above search for "interpreter" is recursive: if F<bash> executable is not
1599 found, but F<bash.btm> is found, Perl will investigate its first line etc.
1600 The only hardwired limit on the recursion depth is implicit: there is a limit
1601 4 on the number of additional arguments inserted before the actual arguments
1602 given to system(). In particular, if no additional arguments are specified
1603 on the "magic" first lines, then the limit on the depth is 4.
1605 If Perl finds that the found executable is of PM type when the
1606 current session is not, it will start the new process in a separate session of
1607 necessary type. Call via C<OS2::Process> to disable this magic.
1609 B<WARNING>. Due to the described logic, you need to explicitly
1610 specify F<.com> extension if needed. Moreover, if the executable
1611 F<perl5.6.1> is requested, Perl will not look for F<perl5.6.1.exe>.
1612 [This may change in the future.]
1614 =head2 C<extproc> on the first line
1616 If the first chars of a Perl script are C<"extproc ">, this line is treated
1617 as C<#!>-line, thus all the switches on this line are processed (twice
1618 if script was started via cmd.exe). See L<perlrun/DESCRIPTION>.
1620 =head2 Additional modules:
1622 L<OS2::Process>, L<OS2::DLL>, L<OS2::REXX>, L<OS2::PrfDB>, L<OS2::ExtAttr>. These
1623 modules provide access to additional numeric argument for C<system>
1624 and to the information about the running process,
1625 to DLLs having functions with REXX signature and to the REXX runtime, to
1626 OS/2 databases in the F<.INI> format, and to Extended Attributes.
1628 Two additional extensions by Andreas Kaiser, C<OS2::UPM>, and
1629 C<OS2::FTP>, are included into C<ILYAZ> directory, mirrored on CPAN.
1630 Other OS/2-related extensions are available too.
1632 =head2 Prebuilt methods:
1636 =item C<File::Copy::syscopy>
1638 used by C<File::Copy::copy>, see L<File::Copy>.
1640 =item C<DynaLoader::mod2fname>
1642 used by C<DynaLoader> for DLL name mangling.
1644 =item C<Cwd::current_drive()>
1648 =item C<Cwd::sys_chdir(name)>
1650 leaves drive as it is.
1652 =item C<Cwd::change_drive(name)>
1654 changes the "current" drive.
1656 =item C<Cwd::sys_is_absolute(name)>
1658 means has drive letter and is_rooted.
1660 =item C<Cwd::sys_is_rooted(name)>
1662 means has leading C<[/\\]> (maybe after a drive-letter:).
1664 =item C<Cwd::sys_is_relative(name)>
1666 means changes with current dir.
1668 =item C<Cwd::sys_cwd(name)>
1670 Interface to cwd from EMX. Used by C<Cwd::cwd>.
1672 =item C<Cwd::sys_abspath(name, dir)>
1674 Really really odious function to implement. Returns absolute name of
1675 file which would have C<name> if CWD were C<dir>. C<Dir> defaults to the
1678 =item C<Cwd::extLibpath([type])>
1680 Get current value of extended library search path. If C<type> is
1681 present and positive, works with C<END_LIBPATH>, if negative, works
1682 with C<LIBPATHSTRICT>, otherwise with C<BEGIN_LIBPATH>.
1684 =item C<Cwd::extLibpath_set( path [, type ] )>
1686 Set current value of extended library search path. If C<type> is
1687 present and positive, works with <END_LIBPATH>, if negative, works
1688 with C<LIBPATHSTRICT>, otherwise with C<BEGIN_LIBPATH>.
1690 =item C<OS2::Error(do_harderror,do_exception)>
1692 Returns C<undef> if it was not called yet, otherwise bit 1 is
1693 set if on the previous call do_harderror was enabled, bit
1694 2 is set if on previous call do_exception was enabled.
1696 This function enables/disables error popups associated with
1697 hardware errors (Disk not ready etc.) and software exceptions.
1699 I know of no way to find out the state of popups I<before> the first call
1702 =item C<OS2::Errors2Drive(drive)>
1704 Returns C<undef> if it was not called yet, otherwise return false if errors
1705 were not requested to be written to a hard drive, or the drive letter if
1708 This function may redirect error popups associated with hardware errors
1709 (Disk not ready etc.) and software exceptions to the file POPUPLOG.OS2 at
1710 the root directory of the specified drive. Overrides OS2::Error() specified
1711 by individual programs. Given argument undef will disable redirection.
1713 Has global effect, persists after the application exits.
1715 I know of no way to find out the state of redirection of popups to the disk
1716 I<before> the first call to this function.
1718 =item OS2::SysInfo()
1720 Returns a hash with system information. The keys of the hash are
1722 MAX_PATH_LENGTH, MAX_TEXT_SESSIONS, MAX_PM_SESSIONS,
1723 MAX_VDM_SESSIONS, BOOT_DRIVE, DYN_PRI_VARIATION,
1724 MAX_WAIT, MIN_SLICE, MAX_SLICE, PAGE_SIZE,
1725 VERSION_MAJOR, VERSION_MINOR, VERSION_REVISION,
1726 MS_COUNT, TIME_LOW, TIME_HIGH, TOTPHYSMEM, TOTRESMEM,
1727 TOTAVAILMEM, MAXPRMEM, MAXSHMEM, TIMER_INTERVAL,
1728 MAX_COMP_LENGTH, FOREGROUND_FS_SESSION,
1731 =item OS2::BootDrive()
1733 Returns a letter without colon.
1735 =item C<OS2::MorphPM(serve)>, C<OS2::UnMorphPM(serve)>
1737 Transforms the current application into a PM application and back.
1738 The argument true means that a real message loop is going to be served.
1739 OS2::MorphPM() returns the PM message queue handle as an integer.
1741 See L<"Centralized management of resources"> for additional details.
1743 =item C<OS2::Serve_Messages(force)>
1745 Fake on-demand retrieval of outstanding PM messages. If C<force> is false,
1746 will not dispatch messages if a real message loop is known to
1747 be present. Returns number of messages retrieved.
1749 Dies with "QUITing..." if WM_QUIT message is obtained.
1751 =item C<OS2::Process_Messages(force [, cnt])>
1753 Retrieval of PM messages until window creation/destruction.
1754 If C<force> is false, will not dispatch messages if a real message loop
1755 is known to be present.
1757 Returns change in number of windows. If C<cnt> is given,
1758 it is incremented by the number of messages retrieved.
1760 Dies with "QUITing..." if WM_QUIT message is obtained.
1762 =item C<OS2::_control87(new,mask)>
1764 the same as L<_control87(3)> of EMX. Takes integers as arguments, returns
1765 the previous coprocessor control word as an integer. Only bits in C<new> which
1766 are present in C<mask> are changed in the control word.
1768 =item OS2::get_control87()
1770 gets the coprocessor control word as an integer.
1772 =item C<OS2::set_control87_em(new=MCW_EM,mask=MCW_EM)>
1774 The variant of OS2::_control87() with default values good for
1775 handling exception mask: if no C<mask>, uses exception mask part of C<new>
1776 only. If no C<new>, disables all the floating point exceptions.
1778 See L<"Misfeatures"> for details.
1780 =item C<OS2::DLLname([how [, \&xsub]])>
1782 Gives the information about the Perl DLL or the DLL containing the C
1783 function bound to by C<&xsub>. The meaning of C<how> is: default (2):
1784 full name; 0: handle; 1: module name.
1788 (Note that some of these may be moved to different libraries -
1792 =head2 Prebuilt variables:
1798 numeric value is the same as _emx_rev of EMX, a string value the same
1799 as _emx_vprt (similar to C<0.9c>).
1803 same as _emx_env of EMX, a number similar to 0x8001.
1807 a number C<OS_MAJOR + 0.001 * OS_MINOR>.
1811 true if the Perl library was compiled in AOUT format.
1813 =item $OS2::can_fork
1815 true if the current executable is an AOUT EMX executable, so Perl can
1816 fork. Do not use this, use the portable check for
1817 $Config::Config{dfork}.
1819 =item $OS2::nsyserror
1821 This variable (default is 1) controls whether to enforce the contents
1822 of $^E to start with C<SYS0003>-like id. If set to 0, then the string
1823 value of $^E is what is available from the OS/2 message file. (Some
1824 messages in this file have an C<SYS0003>-like id prepended, some not.)
1834 Since L<flock(3)> is present in EMX, but is not functional, it is
1835 emulated by perl. To disable the emulations, set environment variable
1836 C<USE_PERL_FLOCK=0>.
1840 Here is the list of things which may be "broken" on
1841 EMX (from EMX docs):
1847 The functions L<recvmsg(3)>, L<sendmsg(3)>, and L<socketpair(3)> are not
1852 L<sock_init(3)> is not required and not implemented.
1856 L<flock(3)> is not yet implemented (dummy function). (Perl has a workaround.)
1860 L<kill(3)>: Special treatment of PID=0, PID=1 and PID=-1 is not implemented.
1868 waitpid() is not implemented for negative values of PID.
1872 Note that C<kill -9> does not work with the current version of EMX.
1876 See L<"Text-mode filehandles">.
1880 Unix-domain sockets on OS/2 live in a pseudo-file-system C</sockets/...>.
1881 To avoid a failure to create a socket with a name of a different form,
1882 C<"/socket/"> is prepended to the socket name (unless it starts with this
1885 This may lead to problems later in case the socket is accessed via the
1886 "usual" file-system calls using the "initial" name.
1890 Apparently, IBM used a compiler (for some period of time around '95?) which
1891 changes FP mask right and left. This is not I<that> bad for IBM's
1892 programs, but the same compiler was used for DLLs which are used with
1893 general-purpose applications. When these DLLs are used, the state of
1894 floating-point flags in the application is not predictable.
1896 What is much worse, some DLLs change the floating point flags when in
1897 _DLLInitTerm() (e.g., F<TCP32IP>). This means that even if you do not I<call>
1898 any function in the DLL, just the act of loading this DLL will reset your
1899 flags. What is worse, the same compiler was used to compile some HOOK DLLs.
1900 Given that HOOK dlls are executed in the context of I<all> the applications
1901 in the system, this means a complete unpredictability of floating point
1902 flags on systems using such HOOK DLLs. E.g., F<GAMESRVR.DLL> of B<DIVE>
1903 origin changes the floating point flags on each write to the TTY of a VIO
1904 (windowed text-mode) applications.
1906 Some other (not completely debugged) situations when FP flags change include
1907 some video drivers (?), and some operations related to creation of the windows.
1908 People who code B<OpenGL> may have more experience on this.
1910 Perl is generally used in the situation when all the floating-point
1911 exceptions are ignored, as is the default under EMX. If they are not ignored,
1912 some benign Perl programs would get a C<SIGFPE> and would die a horrible death.
1914 To circumvent this, Perl uses two hacks. They help against I<one> type of
1915 damage only: FP flags changed when loading a DLL.
1917 One of the hacks is to disable floating point exceptions on Perl startup (as
1918 is the default with EMX). This helps only with compile-time-linked DLLs
1919 changing the flags before main() had a chance to be called.
1921 The other hack is to restore FP flags after a call to dlopen(). This helps
1922 against similar damage done by DLLs _DLLInitTerm() at runtime. Currently
1923 no way to switch these hacks off is provided.
1927 =head2 Modifications
1929 Perl modifies some standard C library calls in the following ways:
1935 C<my_popen> uses F<sh.exe> if shell is required, cf. L<"PERL_SH_DIR">.
1939 is created using C<TMP> or C<TEMP> environment variable, via
1944 If the current directory is not writable, file is created using modified
1945 C<tmpnam>, so there may be a race condition.
1949 a dummy implementation.
1953 C<os2_stat> special-cases F</dev/tty> and F</dev/con>.
1955 =item C<mkdir>, C<rmdir>
1957 these EMX functions do not work if the path contains a trailing C</>.
1958 Perl contains a workaround for this.
1962 Since L<flock(3)> is present in EMX, but is not functional, it is
1963 emulated by perl. To disable the emulations, set environment variable
1964 C<USE_PERL_FLOCK=0>.
1968 =head2 Identifying DLLs
1970 All the DLLs built with the current versions of Perl have ID strings
1971 identifying the name of the extension, its version, and the version
1972 of Perl required for this DLL. Run C<bldlevel DLL-name> to find this
1975 =head2 Centralized management of resources
1977 Since to call certain OS/2 API one needs to have a correctly initialized
1978 C<Win> subsystem, OS/2-specific extensions may require getting C<HAB>s and
1979 C<HMQ>s. If an extension would do it on its own, another extension could
1982 Perl provides a centralized management of these resources:
1988 To get the HAB, the extension should call C<hab = perl_hab_GET()> in C. After
1989 this call is performed, C<hab> may be accessed as C<Perl_hab>. There is
1990 no need to release the HAB after it is used.
1992 If by some reasons F<perl.h> cannot be included, use
1994 extern int Perl_hab_GET(void);
2000 There are two cases:
2006 the extension needs an C<HMQ> only because some API will not work otherwise.
2007 Use C<serve = 0> below.
2011 the extension needs an C<HMQ> since it wants to engage in a PM event loop.
2012 Use C<serve = 1> below.
2016 To get an C<HMQ>, the extension should call C<hmq = perl_hmq_GET(serve)> in C.
2017 After this call is performed, C<hmq> may be accessed as C<Perl_hmq>.
2019 To signal to Perl that HMQ is not needed any more, call
2020 C<perl_hmq_UNSET(serve)>. Perl process will automatically morph/unmorph itself
2021 into/from a PM process if HMQ is needed/not-needed. Perl will automatically
2022 enable/disable C<WM_QUIT> message during shutdown if the message queue is
2025 B<NOTE>. If during a shutdown there is a message queue which did not disable
2026 WM_QUIT, and which did not process the received WM_QUIT message, the
2027 shutdown will be automatically cancelled. Do not call C<perl_hmq_GET(1)>
2028 unless you are going to process messages on an orderly basis.
2030 =item Treating errors reported by OS/2 API
2032 There are two principal conventions (it is useful to call them C<Dos*>
2033 and C<Win*> - though this part of the function signature is not always
2034 determined by the name of the API) of reporting the error conditions
2035 of OS/2 API. Most of C<Dos*> APIs report the error code as the result
2036 of the call (so 0 means success, and there are many types of errors).
2037 Most of C<Win*> API report success/fail via the result being
2038 C<TRUE>/C<FALSE>; to find the reason for the failure one should call
2039 WinGetLastError() API.
2041 Some C<Win*> entry points also overload a "meaningful" return value
2042 with the error indicator; having a 0 return value indicates an error.
2043 Yet some other C<Win*> entry points overload things even more, and 0
2044 return value may mean a successful call returning a valid value 0, as
2045 well as an error condition; in the case of a 0 return value one should
2046 call WinGetLastError() API to distinguish a successful call from a
2049 By convention, all the calls to OS/2 API should indicate their
2050 failures by resetting $^E. All the Perl-accessible functions which
2051 call OS/2 API may be broken into two classes: some die()s when an API
2052 error is encountered, the other report the error via a false return
2053 value (of course, this does not concern Perl-accessible functions
2054 which I<expect> a failure of the OS/2 API call, having some workarounds
2057 Obviously, in the situation of the last type of the signature of an OS/2
2058 API, it is must more convenient for the users if the failure is
2059 indicated by die()ing: one does not need to check $^E to know that
2060 something went wrong. If, however, this solution is not desirable by
2061 some reason, the code in question should reset $^E to 0 before making
2062 this OS/2 API call, so that the caller of this Perl-accessible
2063 function has a chance to distinguish a success-but-0-return value from
2064 a failure. (One may return undef as an alternative way of reporting
2067 The macros to simplify this type of error propagation are
2071 =item C<CheckOSError(expr)>
2073 Returns true on error, sets $^E. Expects expr() be a call of
2076 =item C<CheckWinError(expr)>
2078 Returns true on error, sets $^E. Expects expr() be a call of
2081 =item C<SaveWinError(expr)>
2083 Returns C<expr>, sets $^E from WinGetLastError() if C<expr> is false.
2085 =item C<SaveCroakWinError(expr,die,name1,name2)>
2087 Returns C<expr>, sets $^E from WinGetLastError() if C<expr> is false,
2088 and die()s if C<die> and $^E are true. The message to die is the
2089 concatenated strings C<name1> and C<name2>, separated by C<": "> from
2090 the contents of $^E.
2092 =item C<WinError_2_Perl_rc>
2094 Sets C<Perl_rc> to the return value of WinGetLastError().
2096 =item C<FillWinError>
2098 Sets C<Perl_rc> to the return value of WinGetLastError(), and sets $^E
2099 to the corresponding value.
2101 =item C<FillOSError(rc)>
2103 Sets C<Perl_rc> to C<rc>, and sets $^E to the corresponding value.
2107 =item Loading DLLs and ordinals in DLLs
2109 Some DLLs are only present in some versions of OS/2, or in some
2110 configurations of OS/2. Some exported entry points are present only
2111 in DLLs shipped with some versions of OS/2. If these DLLs and entry
2112 points were linked directly for a Perl executable/DLL or from a Perl
2113 extensions, this binary would work only with the specified
2114 versions/setups. Even if these entry points were not needed, the
2115 I<load> of the executable (or DLL) would fail.
2117 For example, many newer useful APIs are not present in OS/2 v2; many
2118 PM-related APIs require DLLs not available on floppy-boot setup.
2120 To make these calls fail I<only when the calls are executed>, one
2121 should call these API via a dynamic linking API. There is a subsystem
2122 in Perl to simplify such type of calls. A large number of entry
2123 points available for such linking is provided (see C<entries_ordinals>
2124 - and also C<PMWIN_entries> - in F<os2ish.h>). These ordinals can be
2125 accessed via the APIs:
2127 CallORD(), DeclFuncByORD(), DeclVoidFuncByORD(),
2128 DeclOSFuncByORD(), DeclWinFuncByORD(), AssignFuncPByORD(),
2129 DeclWinFuncByORD_CACHE(), DeclWinFuncByORD_CACHE_survive(),
2130 DeclWinFuncByORD_CACHE_resetError_survive(),
2131 DeclWinFunc_CACHE(), DeclWinFunc_CACHE_resetError(),
2132 DeclWinFunc_CACHE_survive(), DeclWinFunc_CACHE_resetError_survive()
2134 See the header files and the C code in the supplied OS/2-related
2135 modules for the details on usage of these functions.
2137 Some of these functions also combine dynaloading semantic with the
2138 error-propagation semantic discussed above.
2144 Because of idiosyncrasies of OS/2 one cannot have all the eggs in the
2145 same basket (though EMX environment tries hard to overcome this
2146 limitations, so the situation may somehow improve). There are 4
2147 executables for Perl provided by the distribution:
2151 The main workhorse. This is a chimera executable: it is compiled as an
2152 C<a.out>-style executable, but is linked with C<omf>-style dynamic
2153 library F<perl.dll>, and with dynamic CRT DLL. This executable is a
2156 It can load perl dynamic extensions, and it can fork().
2158 B<Note.> Keep in mind that fork() is needed to open a pipe to yourself.
2162 This is a statically linked C<a.out>-style executable. It cannot
2163 load dynamic Perl extensions. The executable supplied in binary
2164 distributions has a lot of extensions prebuilt, thus the above restriction is
2165 important only if you use custom-built extensions. This executable is a VIO
2168 I<This is the only executable with does not require OS/2.> The
2169 friends locked into C<M$> world would appreciate the fact that this
2170 executable runs under DOS, Win0.3*, Win0.95 and WinNT with an
2171 appropriate extender. See L<"Other OSes">.
2173 =head2 F<perl__.exe>
2175 This is the same executable as F<perl___.exe>, but it is a PM
2178 B<Note.> Usually (unless explicitly redirected during the startup)
2179 STDIN, STDERR, and STDOUT of a PM
2180 application are redirected to F<nul>. However, it is possible to I<see>
2181 them if you start C<perl__.exe> from a PM program which emulates a
2182 console window, like I<Shell mode> of Emacs or EPM. Thus it I<is
2183 possible> to use Perl debugger (see L<perldebug>) to debug your PM
2184 application (but beware of the message loop lockups - this will not
2185 work if you have a message queue to serve, unless you hook the serving
2186 into the getc() function of the debugger).
2188 Another way to see the output of a PM program is to run it as
2190 pm_prog args 2>&1 | cat -
2192 with a shell I<different> from F<cmd.exe>, so that it does not create
2193 a link between a VIO session and the session of C<pm_porg>. (Such a link
2194 closes the VIO window.) E.g., this works with F<sh.exe> - or with Perl!
2196 open P, 'pm_prog args 2>&1 |' or die;
2199 The flavor F<perl__.exe> is required if you want to start your program without
2200 a VIO window present, but not C<detach>ed (run C<help detach> for more info).
2201 Very useful for extensions which use PM, like C<Perl/Tk> or C<OpenGL>.
2203 Note also that the differences between PM and VIO executables are only
2204 in the I<default> behaviour. One can start I<any> executable in
2205 I<any> kind of session by using the arguments C</fs>, C</pm> or
2206 C</win> switches of the command C<start> (of F<CMD.EXE> or a similar
2207 shell). Alternatively, one can use the numeric first argument of the
2208 C<system> Perl function (see L<OS2::Process>).
2210 =head2 F<perl___.exe>
2212 This is an C<omf>-style executable which is dynamically linked to
2213 F<perl.dll> and CRT DLL. I know no advantages of this executable
2214 over C<perl.exe>, but it cannot fork() at all. Well, one advantage is
2215 that the build process is not so convoluted as with C<perl.exe>.
2217 It is a VIO application.
2219 =head2 Why strange names?
2221 Since Perl processes the C<#!>-line (cf.
2222 L<perlrun/DESCRIPTION>, L<perlrun/Command Switches>,
2223 L<perldiag/"No Perl script found in input">), it should know when a
2224 program I<is a Perl>. There is some naming convention which allows
2225 Perl to distinguish correct lines from wrong ones. The above names are
2226 almost the only names allowed by this convention which do not contain
2227 digits (which have absolutely different semantics).
2229 =head2 Why dynamic linking?
2231 Well, having several executables dynamically linked to the same huge
2232 library has its advantages, but this would not substantiate the
2233 additional work to make it compile. The reason is the complicated-to-developers
2234 but very quick and convenient-to-users "hard" dynamic linking used by OS/2.
2236 There are two distinctive features of the dyna-linking model of OS/2:
2237 first, all the references to external functions are resolved at the compile time;
2238 second, there is no runtime fixup of the DLLs after they are loaded into memory.
2239 The first feature is an enormous advantage over other models: it avoids
2240 conflicts when several DLLs used by an application export entries with
2241 the same name. In such cases "other" models of dyna-linking just choose
2242 between these two entry points using some random criterion - with predictable
2243 disasters as results. But it is the second feature which requires the build
2246 The address tables of DLLs are patched only once, when they are
2247 loaded. The addresses of the entry points into DLLs are guaranteed to be
2248 the same for all the programs which use the same DLL. This removes the
2249 runtime fixup - once DLL is loaded, its code is read-only.
2251 While this allows some (significant?) performance advantages, this makes life
2252 much harder for developers, since the above scheme makes it impossible
2253 for a DLL to be "linked" to a symbol in the F<.EXE> file. Indeed, this
2254 would need a DLL to have different relocations tables for the
2255 (different) executables which use this DLL.
2257 However, a dynamically loaded Perl extension is forced to use some symbols
2259 executable, e.g., to know how to find the arguments to the functions:
2260 the arguments live on the perl
2261 internal evaluation stack. The solution is to put the main code of
2262 the interpreter into a DLL, and make the F<.EXE> file which just loads
2263 this DLL into memory and supplies command-arguments. The extension DLL
2264 cannot link to symbols in F<.EXE>, but it has no problem linking
2265 to symbols in the F<.DLL>.
2267 This I<greatly> increases the load time for the application (as well as
2268 complexity of the compilation). Since interpreter is in a DLL,
2269 the C RTL is basically forced to reside in a DLL as well (otherwise
2270 extensions would not be able to use CRT). There are some advantages if
2271 you use different flavors of perl, such as running F<perl.exe> and
2272 F<perl__.exe> simultaneously: they share the memory of F<perl.dll>.
2274 B<NOTE>. There is one additional effect which makes DLLs more wasteful:
2275 DLLs are loaded in the shared memory region, which is a scarse resource
2276 given the 512M barrier of the "standard" OS/2 virtual memory. The code of
2277 F<.EXE> files is also shared by all the processes which use the particular
2278 F<.EXE>, but they are "shared in the private address space of the process";
2279 this is possible because the address at which different sections
2280 of the F<.EXE> file are loaded is decided at compile-time, thus all the
2281 processes have these sections loaded at same addresses, and no fixup
2282 of internal links inside the F<.EXE> is needed.
2284 Since DLLs may be loaded at run time, to have the same mechanism for DLLs
2285 one needs to have the address range of I<any of the loaded> DLLs in the
2286 system to be available I<in all the processes> which did not load a particular
2287 DLL yet. This is why the DLLs are mapped to the shared memory region.
2289 =head2 Why chimera build?
2291 Current EMX environment does not allow DLLs compiled using Unixish
2292 C<a.out> format to export symbols for data (or at least some types of
2293 data). This forces C<omf>-style compile of F<perl.dll>.
2295 Current EMX environment does not allow F<.EXE> files compiled in
2296 C<omf> format to fork(). fork() is needed for exactly three Perl
2303 explicit fork() in the script,
2311 C<open FH, "-|">, in other words, opening pipes to itself.
2315 While these operations are not questions of life and death, they are
2317 useful scripts. This forces C<a.out>-style compile of
2323 Here we list environment variables with are either OS/2- and DOS- and
2324 Win*-specific, or are more important under OS/2 than under other OSes.
2326 =head2 C<PERLLIB_PREFIX>
2328 Specific for EMX port. Should have the form
2336 If the beginning of some prebuilt path matches F<path1>, it is
2337 substituted with F<path2>.
2339 Should be used if the perl library is moved from the default
2340 location in preference to C<PERL(5)LIB>, since this would not leave wrong
2341 entries in @INC. For example, if the compiled version of perl looks for @INC
2342 in F<f:/perllib/lib>, and you want to install the library in
2345 set PERLLIB_PREFIX=f:/perllib/lib;h:/opt/gnu
2347 This will cause Perl with the prebuilt @INC of
2349 f:/perllib/lib/5.00553/os2
2350 f:/perllib/lib/5.00553
2351 f:/perllib/lib/site_perl/5.00553/os2
2352 f:/perllib/lib/site_perl/5.00553
2355 to use the following @INC:
2357 h:/opt/gnu/5.00553/os2
2359 h:/opt/gnu/site_perl/5.00553/os2
2360 h:/opt/gnu/site_perl/5.00553
2363 =head2 C<PERL_BADLANG>
2365 If 0, perl ignores setlocale() failing. May be useful with some
2368 =head2 C<PERL_BADFREE>
2370 If 0, perl would not warn of in case of unwarranted free(). With older
2372 useful in conjunction with the module DB_File, which was buggy when
2373 dynamically linked and OMF-built.
2375 Should not be set with newer Perls, since this may hide some I<real> problems.
2377 =head2 C<PERL_SH_DIR>
2379 Specific for EMX port. Gives the directory part of the location for
2382 =head2 C<USE_PERL_FLOCK>
2384 Specific for EMX port. Since L<flock(3)> is present in EMX, but is not
2385 functional, it is emulated by perl. To disable the emulations, set
2386 environment variable C<USE_PERL_FLOCK=0>.
2388 =head2 C<TMP> or C<TEMP>
2390 Specific for EMX port. Used as storage place for temporary files.
2394 Here we list major changes which could make you by surprise.
2396 =head2 Text-mode filehandles
2398 Starting from version 5.8, Perl uses a builtin translation layer for
2399 text-mode files. This replaces the efficient well-tested EMX layer by
2400 some code which should be best characterized as a "quick hack".
2402 In addition to possible bugs and an inability to follow changes to the
2403 translation policy with off/on switches of TERMIO translation, this
2404 introduces a serious incompatible change: before sysread() on
2405 text-mode filehandles would go through the translation layer, now it
2410 C<setpriority> and C<getpriority> are not compatible with earlier
2411 ports by Andreas Kaiser. See C<"setpriority, getpriority">.
2413 =head2 DLL name mangling: pre 5.6.2
2415 With the release 5.003_01 the dynamically loadable libraries
2416 should be rebuilt when a different version of Perl is compiled. In particular,
2417 DLLs (including F<perl.dll>) are now created with the names
2418 which contain a checksum, thus allowing workaround for OS/2 scheme of
2421 It may be possible to code a simple workaround which would
2427 find the old DLLs looking through the old @INC;
2431 mangle the names according to the scheme of new perl and copy the DLLs to
2436 edit the internal C<LX> tables of DLL to reflect the change of the name
2437 (probably not needed for Perl extension DLLs, since the internally coded names
2438 are not used for "specific" DLLs, they used only for "global" DLLs).
2442 edit the internal C<IMPORT> tables and change the name of the "old"
2443 F<perl????.dll> to the "new" F<perl????.dll>.
2447 =head2 DLL name mangling: 5.6.2 and beyond
2449 In fact mangling of I<extension> DLLs was done due to misunderstanding
2450 of the OS/2 dynaloading model. OS/2 (effectively) maintains two
2451 different tables of loaded DLL:
2457 those loaded by the base name from C<LIBPATH>; including those
2458 associated at link time;
2462 loaded by the full name.
2466 When resolving a request for a global DLL, the table of already-loaded
2467 specific DLLs is (effectively) ignored; moreover, specific DLLs are
2468 I<always> loaded from the prescribed path.
2470 There is/was a minor twist which makes this scheme fragile: what to do
2471 with DLLs loaded from
2475 =item C<BEGINLIBPATH> and C<ENDLIBPATH>
2477 (which depend on the process)
2479 =item F<.> from C<LIBPATH>
2481 which I<effectively> depends on the process (although C<LIBPATH> is the
2482 same for all the processes).
2486 Unless C<LIBPATHSTRICT> is set to C<T> (and the kernel is after
2487 2000/09/01), such DLLs are considered to be global. When loading a
2488 global DLL it is first looked in the table of already-loaded global
2489 DLLs. Because of this the fact that one executable loaded a DLL from
2490 C<BEGINLIBPATH> and C<ENDLIBPATH>, or F<.> from C<LIBPATH> may affect
2491 I<which> DLL is loaded when I<another> executable requests a DLL with
2492 the same name. I<This> is the reason for version-specific mangling of
2493 the DLL name for perl DLL.
2495 Since the Perl extension DLLs are always loaded with the full path,
2496 there is no need to mangle their names in a version-specific ways:
2497 their directory already reflects the corresponding version of perl,
2498 and @INC takes into account binary compatibility with older version.
2499 Starting from C<5.6.2> the name mangling scheme is fixed to be the
2500 same as for Perl 5.005_53 (same as in a popular binary release). Thus
2501 new Perls will be able to I<resolve the names> of old extension DLLs
2502 if @INC allows finding their directories.
2504 However, this still does not guarantee that these DLL may be loaded.
2505 The reason is the mangling of the name of the I<Perl DLL>. And since
2506 the extension DLLs link with the Perl DLL, extension DLLs for older
2507 versions would load an older Perl DLL, and would most probably
2508 segfault (since the data in this DLL is not properly initialized).
2510 There is a partial workaround (which can be made complete with newer
2511 OS/2 kernels): create a forwarder DLL with the same name as the DLL of
2512 the older version of Perl, which forwards the entry points to the
2513 newer Perl's DLL. Make this DLL accessible on (say) the C<BEGINLIBPATH> of
2514 the new Perl executable. When the new executable accesses old Perl's
2515 extension DLLs, they would request the old Perl's DLL by name, get the
2516 forwarder instead, so effectively will link with the currently running
2519 This may break in two ways:
2525 Old perl executable is started when a new executable is running has
2526 loaded an extension compiled for the old executable (ouph!). In this
2527 case the old executable will get a forwarder DLL instead of the old
2528 perl DLL, so would link with the new perl DLL. While not directly
2529 fatal, it will behave the same as new executable. This beats the whole
2530 purpose of explicitly starting an old executable.
2534 A new executable loads an extension compiled for the old executable
2535 when an old perl executable is running. In this case the extension
2536 will not pick up the forwarder - with fatal results.
2540 With support for C<LIBPATHSTRICT> this may be circumvented - unless
2541 one of DLLs is started from F<.> from C<LIBPATH> (I do not know
2542 whether C<LIBPATHSTRICT> affects this case).
2544 B<REMARK>. Unless newer kernels allow F<.> in C<BEGINLIBPATH> (older
2545 do not), this mess cannot be completely cleaned. (It turns out that
2546 as of the beginning of 2002, F<.> is not allowed, but F<.\.> is - and
2547 it has the same effect.)
2550 B<REMARK>. C<LIBPATHSTRICT>, C<BEGINLIBPATH> and C<ENDLIBPATH> are
2551 not environment variables, although F<cmd.exe> emulates them on C<SET
2552 ...> lines. From Perl they may be accessed by
2553 L<Cwd::extLibpath|/Cwd::extLibpath([type])> and
2554 L<Cwd::extLibpath_set|/Cwd::extLibpath_set( path [, type ] )>.
2556 =head2 DLL forwarder generation
2558 Assume that the old DLL is named F<perlE0AC.dll> (as is one for
2559 5.005_53), and the new version is 5.6.1. Create a file
2560 F<perl5shim.def-leader> with
2562 LIBRARY 'perlE0AC' INITINSTANCE TERMINSTANCE
2563 DESCRIPTION '@#perl5-porters@perl.org:5.006001#@ Perl module for 5.00553 -> Perl 5.6.1 forwarder'
2565 DATA LOADONCALL NONSHARED MULTIPLE
2568 modifying the versions/names as needed. Run
2570 perl -wnle "next if 0../EXPORTS/; print qq( \"$1\") if /\"(\w+)\"/" perl5.def >lst
2572 in the Perl build directory (to make the DLL smaller replace perl5.def
2573 with the definition file for the older version of Perl if present).
2575 cat perl5shim.def-leader lst >perl5shim.def
2576 gcc -Zomf -Zdll -o perlE0AC.dll perl5shim.def -s -llibperl
2578 (ignore multiple C<warning L4085>).
2582 As of release 5.003_01 perl is linked to multithreaded C RTL
2583 DLL. If perl itself is not compiled multithread-enabled, so will not be perl's
2584 malloc(). However, extensions may use multiple thread on their own
2587 This was needed to compile C<Perl/Tk> for XFree86-OS/2 out-of-the-box, and
2588 link with DLLs for other useful libraries, which typically are compiled
2589 with C<-Zmt -Zcrtdll>.
2591 =head2 Calls to external programs
2593 Due to a popular demand the perl external program calling has been
2594 changed wrt Andreas Kaiser's port. I<If> perl needs to call an
2595 external program I<via shell>, the F<f:/bin/sh.exe> will be called, or
2596 whatever is the override, see L<"PERL_SH_DIR">.
2598 Thus means that you need to get some copy of a F<sh.exe> as well (I
2599 use one from pdksh). The path F<F:/bin> above is set up automatically during
2600 the build to a correct value on the builder machine, but is
2601 overridable at runtime,
2603 B<Reasons:> a consensus on C<perl5-porters> was that perl should use
2604 one non-overridable shell per platform. The obvious choices for OS/2
2605 are F<cmd.exe> and F<sh.exe>. Having perl build itself would be impossible
2606 with F<cmd.exe> as a shell, thus I picked up C<sh.exe>. This assures almost
2607 100% compatibility with the scripts coming from *nix. As an added benefit
2608 this works as well under DOS if you use DOS-enabled port of pdksh
2609 (see L</Prerequisites>).
2611 B<Disadvantages:> currently F<sh.exe> of pdksh calls external programs
2612 via fork()/exec(), and there is I<no> functioning exec() on
2613 OS/2. exec() is emulated by EMX by an asynchronous call while the caller
2614 waits for child completion (to pretend that the C<pid> did not change). This
2615 means that 1 I<extra> copy of F<sh.exe> is made active via fork()/exec(),
2616 which may lead to some resources taken from the system (even if we do
2617 not count extra work needed for fork()ing).
2619 Note that this a lesser issue now when we do not spawn F<sh.exe>
2620 unless needed (metachars found).
2622 One can always start F<cmd.exe> explicitly via
2624 system 'cmd', '/c', 'mycmd', 'arg1', 'arg2', ...
2626 If you need to use F<cmd.exe>, and do not want to hand-edit thousands of your
2627 scripts, the long-term solution proposed on p5-p is to have a directive
2631 which will override system(), exec(), C<``>, and
2632 C<open(,'...|')>. With current perl you may override only system(),
2633 readpipe() - the explicit version of C<``>, and maybe exec(). The code
2634 will substitute the one-argument call to system() by
2635 C<CORE::system('cmd.exe', '/c', shift)>.
2637 If you have some working code for C<OS2::Cmd>, please send it to me,
2638 I will include it into distribution. I have no need for such a module, so
2641 For the details of the current situation with calling external programs,
2642 see L<Starting OSE<sol>2 (and DOS) programs under Perl>. Set us mention a couple
2649 External scripts may be called by their basename. Perl will try the same
2650 extensions as when processing B<-S> command-line switch.
2654 External scripts starting with C<#!> or C<extproc > will be executed directly,
2655 without calling the shell, by calling the program specified on the rest of
2660 =head2 Memory allocation
2662 Perl uses its own malloc() under OS/2 - interpreters are usually malloc-bound
2663 for speed, but perl is not, since its malloc is lightning-fast.
2664 Perl-memory-usage-tuned benchmarks show that Perl's malloc is 5 times quicker
2665 than EMX one. I do not have convincing data about memory footprint, but
2666 a (pretty random) benchmark showed that Perl's one is 5% better.
2668 Combination of perl's malloc() and rigid DLL name resolution creates
2669 a special problem with library functions which expect their return value to
2670 be free()d by system's free(). To facilitate extensions which need to call
2671 such functions, system memory-allocation functions are still available with
2672 the prefix C<emx_> added. (Currently only DLL perl has this, it should
2673 propagate to F<perl_.exe> shortly.)
2677 One can build perl with thread support enabled by providing C<-D usethreads>
2678 option to F<Configure>. Currently OS/2 support of threads is very
2681 Most notable problems:
2687 may have a race condition (but probably does not due to edge-triggered
2688 nature of OS/2 Event semaphores). (Needs a reimplementation (in terms of chaining
2689 waiting threads, with the linked list stored in per-thread structure?)?)
2693 has a couple of static variables used in OS/2-specific functions. (Need to be
2694 moved to per-thread structure, or serialized?)
2698 Note that these problems should not discourage experimenting, since they
2699 have a low probability of affecting small programs.
2703 This description is not updated often (since 5.6.1?), see F<./os2/Changes>
2710 I include 3 extensions by Andreas Kaiser, OS2::REXX, OS2::UPM, and OS2::FTP,
2711 into my ftp directory, mirrored on CPAN. I made
2712 some minor changes needed to compile them by standard tools. I cannot
2713 test UPM and FTP, so I will appreciate your feedback. Other extensions
2714 there are OS2::ExtAttr, OS2::PrfDB for tied access to EAs and .INI
2715 files - and maybe some other extensions at the time you read it.
2717 Note that OS2 perl defines 2 pseudo-extension functions
2718 OS2::Copy::copy and DynaLoader::mod2fname (many more now, see
2719 L<Prebuilt methods>).
2721 The -R switch of older perl is deprecated. If you need to call a REXX code
2722 which needs access to variables, include the call into a REXX compartment
2724 REXX_call {...block...};
2726 Two new functions are supported by REXX code,
2728 REXX_eval_with 'string', REXX_function_name => \&perl_sub_reference;
2730 If you have some other extensions you want to share, send the code to
2731 me. At least two are available: tied access to EA's, and tied access
2732 to system databases.
2736 Ilya Zakharevich, cpan@ilyaz.org