This is what system() (see perlfunc/system), `` (see perlop/``I/O Operators''), and open pipe (see perlfunc/open) are for. (Avoid exec() (see perlfunc/exec) unless you know what you do).

Note however that to use some of these operators you need to have a sh-syntax shell installed (see Pdksh, Frequently asked questions), and perl should be able to find it (see PERL_SH_DIR).

The cases when the shell is used are:

1. perldoc2tree.cgi: /usr/lib/perl5/5.8.8/pod/perlos2.pod: cannot resolve L in paragraph 86. perldoc2tree.cgi: /usr/lib/perl5/5.8.8/pod/perlos2.pod: cannot resolve L in paragraph 86.

   One-argument system() (see perlfunc/system), exec() (see perlfunc/exec) with redirection or shell meta-characters;

2. perldoc2tree.cgi: /usr/lib/perl5/5.8.8/pod/perlos2.pod: cannot resolve L in paragraph 88.

   Pipe-open (see perlfunc/open) with the command which contains redirection or shell meta-characters;

3. perldoc2tree.cgi: /usr/lib/perl5/5.8.8/pod/perlos2.pod: cannot resolve L in paragraph 90.

   Backticks `` (see perlop/``I/O Operators'') with the command which contains redirection or shell meta-characters;

4. If the executable called by system()/exec()/pipe-open()/`` is a script with the ``magic'' #! line or extproc line which specifies shell;

5. If the executable called by system()/exec()/pipe-open()/`` is a script without ``magic'' line, and $ENV{EXECSHELL} is set to shell;

6. If the executable called by system()/exec()/pipe-open()/`` is not found (is not this remark obsolete?);

7. perldoc2tree.cgi: /usr/lib/perl5/5.8.8/pod/perlos2.pod: cannot resolve L in paragraph 98. perldoc2tree.cgi: /usr/lib/perl5/5.8.8/pod/perlos2.pod: cannot resolve L in paragraph 98.

   For globbing (see perlfunc/glob, perlop/``I/O Operators'') (obsolete? Perl uses builtin globbing nowadays...).

For the sake of speed for a common case, in the above algorithms backslashes in the command name are not considered as shell metacharacters.

Perl starts scripts which begin with cookies extproc or #! directly, without an intervention of shell. Perl uses the same algorithm to find the executable as pdksh: if the path on #! line does not work, and contains /, then the directory part of the executable is ignored, and the executable is searched in . and on PATH. To find arguments for these scripts Perl uses a different algorithm than pdksh: up to 3 arguments are recognized, and trailing whitespace is stripped.

If a script does not contain such a cooky, then to avoid calling sh.exe, Perl uses the same algorithm as pdksh: if $ENV{EXECSHELL} is set, the script is given as the first argument to this command, if not set, then $ENV{COMSPEC} /c is used (or a hardwired guess if $ENV{COMSPEC} is not set).

When starting scripts directly, Perl uses exactly the same algorithm as for the search of script given by -S command-line option: it will look in the current directory, then on components of $ENV{PATH} using the following order of appended extensions: no extension, .cmd, .btm, .bat, .pl.

Note that Perl will start to look for scripts only if OS/2 cannot start the specified application, thus system 'blah' will not look for a script if there is an executable file blah.exe anywhere on PATH. In other words, PATH is essentially searched twice: once by the OS for an executable, then by Perl for scripts.

Note also that executable files on OS/2 can have an arbitrary extension, but .exe will be automatically appended if no dot is present in the name. The workaround is as simple as that: since blah. and blah denote the same file (at list on FAT and HPFS file systems), to start an executable residing in file n:/bin/blah (no extension) give an argument n:/bin/blah. (dot appended) to system().

Perl will start PM programs from VIO (=text-mode) Perl process in a separate PM session; the opposite is not true: when you start a non-PM program from a PM Perl process, Perl would not run it in a separate session. If a separate session is desired, either ensure that shell will be used, as in system 'cmd /c myprog', or start it using optional arguments to system() documented in OS2::Process module. This is considered to be a feature.

Frequently asked questions

``It does not work''

Perl binary distributions come with a testperl.cmd script which tries to detect common problems with misconfigured installations. There is a pretty large chance it will discover which step of the installation you managed to goof. ;-)

I cannot run external programs

• perldoc2tree.cgi: /usr/lib/perl5/5.8.8/pod/perlos2.pod: cannot resolve L in paragraph 113.

  Did you run your programs with -w switch? See Starting OS/2 (and DOS) programs under Perl.

• Do you try to run internal shell commands, like `copy a b` (internal for cmd.exe), or `glob a*b` (internal for ksh)? You need to specify your shell explicitly, like `cmd /c copy a b`, since Perl cannot deduce which commands are internal to your shell.

I cannot embed perl into my program, or use perl.dll from my program.

Is your program EMX-compiled with -Zmt -Zcrtdll?

Well, nowadays Perl DLL should be usable from a differently compiled program too... If you can run Perl code from REXX scripts (see the OS2::REXX manpage), then there are some other aspect of interaction which are overlooked by the current hackish code to support differently-compiled principal programs.

If everything else fails, you need to build a stand-alone DLL for perl. Contact me, I did it once. Sockets would not work, as a lot of other stuff.

Did you use the ExtUtils::Embed manpage?

Some time ago I had reports it does not work. Nowadays it is checked in the Perl test suite, so grep ./t subdirectory of the build tree (as well as *.t files in the ./lib subdirectory) to find how it should be done ``correctly''.

`` and pipe-open do not work under DOS.

This may a variant of just I cannot run external programs, or a deeper problem. Basically: you need RSX (see Prerequisites) for these commands to work, and you may need a port of sh.exe which understands command arguments. One of such ports is listed in Prerequisites under RSX. Do not forget to set variable "PERL_SH_DIR" as well.

DPMI is required for RSX.

Cannot start find.exe "pattern" file

The whole idea of the ``standard C API to start applications'' is that the forms foo and "foo" of program arguments are completely interchangable. find breaks this paradigm;

  find "pattern" file
  find pattern file

are not equivalent; find cannot be started directly using the above API. One needs a way to surround the doublequotes in some other quoting construction, necessarily having an extra non-Unixish shell in between.

Use one of

  system 'cmd', '/c', 'find "pattern" file';
  `cmd /c 'find "pattern" file'`

This would start find.exe via cmd.exe via sh.exe via perl.exe, but this is a price to pay if you want to use non-conforming program.

INSTALLATION

Automatic binary installation

The most convenient way of installing a binary distribution of perl is via perl installer install.exe. Just follow the instructions, and 99% of the installation blues would go away.

Note however, that you need to have unzip.exe on your path, and EMX environment running. The latter means that if you just installed EMX, and made all the needed changes to Config.sys, you may need to reboot in between. Check EMX runtime by running

        emxrev

Binary installer also creates a folder on your desktop with some useful objects. If you need to change some aspects of the work of the binary installer, feel free to edit the file Perl.pkg. This may be useful e.g., if you need to run the installer many times and do not want to make many interactive changes in the GUI.

PERL_BADLANG

may be needed if you change your codepage after perl installation, and the new value is not supported by EMX. See PERL_BADLANG.

PERL_BADFREE

see PERL_BADFREE.

Config.pm

This file resides somewhere deep in the location you installed your perl library, find it out by

  perl -MConfig -le "print $INC{'Config.pm'}"

While most important values in this file are updated by the binary installer, some of them may need to be hand-edited. I know no such data, please keep me informed if you find one. Moreover, manual changes to the installed version may need to be accompanied by an edit of this file.

NOTE. Because of a typo the binary installer of 5.00305 would install a variable PERL_SHPATH into Config.sys. Please remove this variable and put PERL_SH_DIR instead.

Manual binary installation

As of version 5.00305, OS/2 perl binary distribution comes split into 11 components. Unfortunately, to enable configurable binary installation, the file paths in the zip files are not absolute, but relative to some directory.

Note that the extraction with the stored paths is still necessary (default with unzip, specify -d to pkunzip). However, you need to know where to extract the files. You need also to manually change entries in Config.sys to reflect where did you put the files. Note that if you have some primitive unzipper (like pkunzip), you may get a lot of warnings/errors during unzipping. Upgrade to (w)unzip.

Below is the sample of what to do to reproduce the configuration on my machine. In VIEW.EXE you can press Ctrl-Insert now, and cut-and-paste from the resulting file - created in the directory you started VIEW.EXE from.

For each component, we mention environment variables related to each installation directory. Either choose directories to match your values of the variables, or create/append-to variables to take into account the directories.

Perl VIO and PM executables (dynamically linked)

  unzip perl_exc.zip *.exe *.ico -d f:/emx.add/bin
  unzip perl_exc.zip *.dll -d f:/emx.add/dll

(have the directories with *.exe on PATH, and *.dll on LIBPATH);

Perl_ VIO executable (statically linked)

  unzip perl_aou.zip -d f:/emx.add/bin

(have the directory on PATH);

Executables for Perl utilities

  unzip perl_utl.zip -d f:/emx.add/bin

(have the directory on PATH);

Main Perl library

  unzip perl_mlb.zip -d f:/perllib/lib

If this directory is exactly the same as the prefix which was compiled into perl.exe, you do not need to change anything. However, for perl to find the library if you use a different path, you need to set PERLLIB_PREFIX in Config.sys, see PERLLIB_PREFIX.

Additional Perl modules

  unzip perl_ste.zip -d f:/perllib/lib/site_perl/5.8.8/

perldoc2tree.cgi: /usr/lib/perl5/5.8.8/pod/perlos2.pod: cannot resolve L in paragraph 173.

Same remark as above applies. Additionally, if this directory is not one of directories on @INC (and @INC is influenced by PERLLIB_PREFIX), you need to put this directory and subdirectory ./os2 in PERLLIB or PERL5LIB variable. Do not use PERL5LIB unless you have it set already. See perl/``ENVIRONMENT''.

[Check whether this extraction directory is still applicable with the new directory structure layout!]

Tools to compile Perl modules

  unzip perl_blb.zip -d f:/perllib/lib

Same remark as for perl_ste.zip.

Manpages for Perl and utilities

  unzip perl_man.zip -d f:/perllib/man

This directory should better be on MANPATH. You need to have a working man to access these files.

Manpages for Perl modules

  unzip perl_mam.zip -d f:/perllib/man

This directory should better be on MANPATH. You need to have a working man to access these files.

Source for Perl documentation

  unzip perl_pod.zip -d f:/perllib/lib

perldoc2tree.cgi: /usr/lib/perl5/5.8.8/pod/perlos2.pod: cannot resolve L in paragraph 186.

This is used by the perldoc program (see perldoc), and may be used to generate HTML documentation usable by WWW browsers, and documentation in zillions of other formats: info, LaTeX, Acrobat, FrameMaker and so on. [Use programs such as pod2latex etc.]

Perl manual in .INF format

  unzip perl_inf.zip -d d:/os2/book

This directory should better be on BOOKSHELF.

Pdksh

  unzip perl_sh.zip -d f:/bin

This is used by perl to run external commands which explicitly require shell, like the commands using redirection and shell metacharacters. It is also used instead of explicit /bin/sh.

Set PERL_SH_DIR (see PERL_SH_DIR) if you move sh.exe from the above location.

Note. It may be possible to use some other sh-compatible shell (untested).

After you installed the components you needed and updated the Config.sys correspondingly, you need to hand-edit Config.pm. This file resides somewhere deep in the location you installed your perl library, find it out by

  perl -MConfig -le "print $INC{'Config.pm'}"

You need to correct all the entries which look like file paths (they currently start with f:/).

Warning

The automatic and manual perl installation leave precompiled paths inside perl executables. While these paths are overwriteable (see PERLLIB_PREFIX, PERL_SH_DIR), some people may prefer binary editing of paths inside the executables/DLLs.

Accessing documentation

Depending on how you built/installed perl you may have (otherwise identical) Perl documentation in the following formats:

OS/2 .INF file

Most probably the most convenient form. Under OS/2 view it as

  view perl
  view perl perlfunc
  view perl less   view perl ExtUtils::MakeMaker

(currently the last two may hit a wrong location, but this may improve soon). Under Win* see SYNOPSIS.

If you want to build the docs yourself, and have OS/2 toolkit, run

        pod2ipf > perl.ipf

in /perllib/lib/pod directory, then

        ipfc /inf perl.ipf

(Expect a lot of errors during the both steps.) Now move it on your BOOKSHELF path.

Plain text

If you have perl documentation in the source form, perl utilities installed, and GNU groff installed, you may use

        perldoc perlfunc
        perldoc less         perldoc ExtUtils::MakeMaker

to access the perl documentation in the text form (note that you may get better results using perl manpages).

Alternately, try running pod2text on .pod files.

Manpages

If you have man installed on your system, and you installed perl manpages, use something like this:

        man perlfunc
        man 3 less         man ExtUtils.MakeMaker

to access documentation for different components of Perl. Start with

        man perl

Note that dot (.) is used as a package separator for documentation for packages, and as usual, sometimes you need to give the section - 3 above - to avoid shadowing by the less(1) manpage.

Make sure that the directory above the directory with manpages is on our MANPATH, like this

  set MANPATH=c:/man;f:/perllib/man

for Perl manpages in f:/perllib/man/man1/ etc.

HTML

If you have some WWW browser available, installed the Perl documentation in the source form, and Perl utilities, you can build HTML docs. Cd to directory with .pod files, and do like this

        cd f:/perllib/lib/pod
        pod2html

After this you can direct your browser the file perl.html in this directory, and go ahead with reading docs, like this:

        explore file:///f:/perllib/lib/pod/perl.html

Alternatively you may be able to get these docs prebuilt from CPAN.

GNU info files

Users of Emacs would appreciate it very much, especially with CPerl mode loaded. You need to get latest pod2texi from CPAN, or, alternately, the prebuilt info pages.

PDF files

for Acrobat are available on CPAN (may be for slightly older version of perl).

LaTeX docs

can be constructed using pod2latex.

BUILD

Here we discuss how to build Perl under OS/2. There is an alternative (but maybe older) view on http://www.shadow.net/~troc/os2perl.html.

The short story

Assume that you are a seasoned porter, so are sure that all the necessary tools are already present on your system, and you know how to get the Perl source distribution. Untar it, change to the extract directory, and

  gnupatch -p0 < os2\diff.configure
  sh Configure -des -D prefix=f:/perllib
  make
  make test
  make install
  make aout_test
  make aout_install

This puts the executables in f:/perllib/bin. Manually move them to the PATH, manually move the built perl*.dll to LIBPATH (here for Perl DLL * is a not-very-meaningful hex checksum), and run

  make installcmd INSTALLCMDDIR=d:/ir/on/path

Assuming that the man-files were put on an appropriate location, this completes the installation of minimal Perl system. (The binary distribution contains also a lot of additional modules, and the documentation in INF format.)

What follows is a detailed guide through these steps.

Prerequisites

You need to have the latest EMX development environment, the full GNU tool suite (gawk renamed to awk, and GNU find.exe earlier on path than the OS/2 find.exe, same with sort.exe, to check use

  find --version
  sort --version

). You need the latest version of pdksh installed as sh.exe.

Check that you have BSD libraries and headers installed, and - optionally - Berkeley DB headers and libraries, and crypt.

Possible locations to get the files:

  ftp://hobbes.nmsu.edu/os2/unix/
  ftp://ftp.cdrom.com/pub/os2/unix/
  ftp://ftp.cdrom.com/pub/os2/dev32/
  ftp://ftp.cdrom.com/pub/os2/emx09c/

It is reported that the following archives contain enough utils to build perl: gnufutil.zip, gnusutil.zip, gnututil.zip, gnused.zip, gnupatch.zip, gnuawk.zip, gnumake.zip, gnugrep.zip, bsddev.zip and ksh527rt.zip (or a later version). Note that all these utilities are known to be available from LEO:

  ftp://ftp.leo.org/pub/comp/os/os2/leo/gnu

Note also that the db.lib and db.a from the EMX distribution are not suitable for multi-threaded compile (even single-threaded flavor of Perl uses multi-threaded C RTL, for compatibility with XFree86-OS/2). Get a corrected one from

  http://www.ilyaz.org/software/os2/db_mt.zip

If you have exactly the same version of Perl installed already, make sure that no copies or perl are currently running. Later steps of the build may fail since an older version of perl.dll loaded into memory may be found. Running make test becomes meaningless, since the test are checking a previous build of perl (this situation is detected and reported by lib/os2_base.t test). Do not forget to unset PERL_EMXLOAD_SEC in environment.

Also make sure that you have /tmp directory on the current drive, and . directory in your LIBPATH. One may try to correct the latter condition by

  set BEGINLIBPATH .\.

if you use something like CMD.EXE or latest versions of 4os2.exe. (Setting BEGINLIBPATH to just . is ignored by the OS/2 kernel.)

Make sure your gcc is good for -Zomf linking: run omflibs script in /emx/lib directory.

Check that you have link386 installed. It comes standard with OS/2, but may be not installed due to customization. If typing

  link386

shows you do not have it, do Selective install, and choose Link object modules in Optional system utilities/More. If you get into link386 prompts, press Ctrl-C to exit.

Getting perl source

You need to fetch the latest perl source (including developers releases). With some probability it is located in

  http://www.cpan.org/src/5.0
  http://www.cpan.org/src/5.0/unsupported

If not, you may need to dig in the indices to find it in the directory of the current maintainer.

Quick cycle of developers release may break the OS/2 build time to time, looking into

  http://www.cpan.org/ports/os2/

may indicate the latest release which was publicly released by the maintainer. Note that the release may include some additional patches to apply to the current source of perl.

Extract it like this

  tar vzxf perl5.00409.tar.gz

You may see a message about errors while extracting Configure. This is because there is a conflict with a similarly-named file configure.

Change to the directory of extraction.

Application of the patches

You need to apply the patches in ./os2/diff.* like this:

  gnupatch -p0 < os2\diff.configure

You may also need to apply the patches supplied with the binary distribution of perl. It also makes sense to look on the perl5-porters mailing list for the latest OS/2-related patches (see http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/). Such patches usually contain strings /os2/ and patch, so it makes sense looking for these strings.

Hand-editing

You may look into the file ./hints/os2.sh and correct anything wrong you find there. I do not expect it is needed anywhere.

Making

  sh Configure -des -D prefix=f:/perllib

prefix means: where to install the resulting perl library. Giving correct prefix you may avoid the need to specify PERLLIB_PREFIX, see PERLLIB_PREFIX.

Now

  make

At some moment the built may die, reporting a version mismatch or unable to run perl. This means that you do not have . in your LIBPATH, so perl.exe cannot find the needed perl67B2.dll (treat these hex digits as line noise). After this is fixed the build should finish without a lot of fuss.

Testing

Now run

  make test

All tests should succeed (with some of them skipped). If you have the same version of Perl installed, it is crucial that you have . early in your LIBPATH (or in BEGINLIBPATH), otherwise your tests will most probably test the wrong version of Perl.

Some tests may generate extra messages similar to

A lot of bad free

in database tests related to Berkeley DB. This should be fixed already. If it persists, you may disable this warnings, see PERL_BADFREE.

Process terminated by SIGTERM/SIGINT

This is a standard message issued by OS/2 applications. *nix applications die in silence. It is considered to be a feature. One can easily disable this by appropriate sighandlers.

However the test engine bleeds these message to screen in unexpected moments. Two messages of this kind should be present during testing.

To get finer test reports, call

  perl t/harness

The report with io/pipe.t failing may look like this:

  Failed Test  Status Wstat Total Fail  Failed  List of failed
  ------------------------------------------------------------
  io/pipe.t                    12    1   8.33%  9
  7 tests skipped, plus 56 subtests skipped.
  Failed 1/195 test scripts, 99.49% okay. 1/6542 subtests failed, 99.98% okay.

The reasons for most important skipped tests are:

op/fs.t

1. Checks atime and mtime of stat() - unfortunately, HPFS provides only 2sec time granularity (for compatibility with FAT?).

2. Checks truncate() on a filehandle just opened for write - I do not know why this should or should not work.

op/stat.t

Checks stat(). Tests:

1. Checks atime and mtime of stat() - unfortunately, HPFS provides only 2sec time granularity (for compatibility with FAT?).

Installing the built perl

If you haven't yet moved perl*.dll onto LIBPATH, do it now.

Run

  make install

It would put the generated files into needed locations. Manually put perl.exe, perl__.exe and perl___.exe to a location on your PATH, perl.dll to a location on your LIBPATH.

Run

  make installcmd INSTALLCMDDIR=d:/ir/on/path

  make perl_

  make aout_test
  make aout_install

  make perl_dll

  gcc -Wall -DDOSISH -DOS2=1 -O2 -s -Zomf -Zsys perl-starter.c -DPERL_DLL_BASENAME=\"perl312F\" -Zstack 8192 -Zlinker /PM:VIO

  #define INCL_DOS
  #define INCL_NOPM
  /* These are needed for compile if os2.h includes os2tk.h, not os2emx.h */
  #define INCL_DOSPROCESS
  #include <os2.h>

  #include "EXTERN.h"
  #define PERL_IN_MINIPERLMAIN_C
  #include "perl.h"

  static char *me;
  HMODULE handle;

  static void
  die_with(char *msg1, char *msg2, char *msg3, char *msg4)
  {
     ULONG c;
     char *s = " error: ";

     DosWrite(2, me, strlen(me), &c);
     DosWrite(2, s, strlen(s), &c);
     DosWrite(2, msg1, strlen(msg1), &c);
     DosWrite(2, msg2, strlen(msg2), &c);
     DosWrite(2, msg3, strlen(msg3), &c);
     DosWrite(2, msg4, strlen(msg4), &c);
     DosWrite(2, "\r\n", 2, &c);
     exit(255);
  }

  typedef ULONG (*fill_extLibpath_t)(int type, char *pre, char *post, int replace, char *msg);
  typedef int (*main_t)(int type, char *argv[], char *env[]);
  typedef int (*handler_t)(void* data, int which);

  #ifndef PERL_DLL_BASENAME
  #  define PERL_DLL_BASENAME "perl"
  #endif

  static HMODULE
  load_perl_dll(char *basename)
  {
      char buf[300], fail[260];
      STRLEN l, dirl;
      fill_extLibpath_t f;
      ULONG rc_fullname;
      HMODULE handle, handle1;

      if (_execname(buf, sizeof(buf) - 13) != 0)
          die_with("Can't find full path: ", strerror(errno), "", "");
      /* XXXX Fill `me' with new value */
      l = strlen(buf);
      while (l && buf[l-1] != '/' && buf[l-1] != '\\')
          l--;
      dirl = l - 1;
      strcpy(buf + l, basename);
      l += strlen(basename);
      strcpy(buf + l, ".dll");
      if ( (rc_fullname = DosLoadModule(fail, sizeof fail, buf, &handle)) != 0
           && DosLoadModule(fail, sizeof fail, basename, &handle) != 0 )
          die_with("Can't load DLL ", buf, "", "");
      if (rc_fullname)
          return handle;                /* was loaded with short name; all is fine */
      if (DosQueryProcAddr(handle, 0, "fill_extLibpath", (PFN*)&f))
          die_with(buf, ": DLL exports no symbol ", "fill_extLibpath", "");
      buf[dirl] = 0;
      if (f(0 /*BEGINLIBPATH*/, buf /* prepend */, NULL /* append */,
            0 /* keep old value */, me))
          die_with(me, ": prepending BEGINLIBPATH", "", "");
      if (DosLoadModule(fail, sizeof fail, basename, &handle1) != 0)
          die_with(me, ": finding perl DLL again via BEGINLIBPATH", "", "");
      buf[dirl] = '\\';     
      if (handle1 != handle) {
          if (DosQueryModuleName(handle1, sizeof(fail), fail))
              strcpy(fail, "???");
          die_with(buf, ":\n\tperl DLL via BEGINLIBPATH is different: \n\t",
                   fail,
                   "\n\tYou may need to manipulate global BEGINLIBPATH and LIBPATHSTRICT"
                   "\n\tso that the other copy is loaded via BEGINLIBPATH.");
      }
      return handle;
  }

  int
  main(int argc, char **argv, char **env)
  {
      main_t f;
      handler_t h;
    
      me = argv[0];
      /**/
      handle = load_perl_dll(PERL_DLL_BASENAME);

      if (DosQueryProcAddr(handle, 0, "Perl_OS2_handler_install", (PFN*)&h))
          die_with(PERL_DLL_BASENAME, ": DLL exports no symbol ", "Perl_OS2_handler_install", "");
      if ( !h((void *)"~installprefix", Perlos2_handler_perllib_from)
           || !h((void *)"~dll", Perlos2_handler_perllib_to)
           || !h((void *)"~dll/sh/ksh.exe", Perlos2_handler_perl_sh) )
          die_with(PERL_DLL_BASENAME, ": Can't install @INC manglers", "", "");

      if (DosQueryProcAddr(handle, 0, "dll_perlmain", (PFN*)&f))
          die_with(PERL_DLL_BASENAME, ": DLL exports no symbol ", "dll_perlmain", "");
      return f(argc, argv, env);
  }

 extproc /bin/bash    -x   -c

  system qw(C:/emx.add/bin/bash.exe -x -c C:/emx/bin/foo.cmd bar baz)

  CallORD(), DeclFuncByORD(), DeclVoidFuncByORD(),
  DeclOSFuncByORD(), DeclWinFuncByORD(), AssignFuncPByORD(),
  DeclWinFuncByORD_CACHE(), DeclWinFuncByORD_CACHE_survive(),
  DeclWinFuncByORD_CACHE_resetError_survive(),
  DeclWinFunc_CACHE(), DeclWinFunc_CACHE_resetError(),
  DeclWinFunc_CACHE_survive(), DeclWinFunc_CACHE_resetError_survive()

  pm_prog args 2>&1 | cat -

  open P, 'pm_prog args 2>&1 |' or die;
  print while <P>;

  path1;path2

  path1 path2

  set PERLLIB_PREFIX=f:/perllib/lib;h:/opt/gnu

  f:/perllib/lib/5.00553/os2
  f:/perllib/lib/5.00553
  f:/perllib/lib/site_perl/5.00553/os2
  f:/perllib/lib/site_perl/5.00553
  .

  h:/opt/gnu/5.00553/os2
  h:/opt/gnu/5.00553
  h:/opt/gnu/site_perl/5.00553/os2
  h:/opt/gnu/site_perl/5.00553
  .

  LIBRARY 'perlE0AC' INITINSTANCE TERMINSTANCE
  DESCRIPTION '@#perl5-porters@perl.org:5.006001#@ Perl module for 5.00553 -> Perl 5.6.1 forwarder'
  CODE LOADONCALL
  DATA LOADONCALL NONSHARED MULTIPLE
  EXPORTS

 perl -wnle "next if 0../EXPORTS/; print qq(  \"$1\") if /\"(\w+)\"/" perl5.def >lst

 cat perl5shim.def-leader lst >perl5shim.def
 gcc -Zomf -Zdll -o perlE0AC.dll perl5shim.def -s -llibperl

  system 'cmd', '/c', 'mycmd', 'arg1', 'arg2', ...

  use OS2::Cmd;