


PERLOS2(1)       Perl Programmers Reference Guide      PERLOS2(1)


NAME
       perlos2 - Perl under OS/2, DOS, Win0.3*, Win0.95 and
       WinNT.

SYNOPSIS
       One can read this document in the following formats:

               man perlos2
               view perl perlos2
               explorer perlos2.html
               info perlos2

       to list some (not all may be available simultaneously), or
       it may be read as is: either as README.os2, or pod/per-
       los2.pod.

       To read the .INF version of documentation (very recom-
       mended) outside of OS/2, one needs an IBM's reader (may be
       available on IBM ftp sites (?)  (URL anyone?)) or shipped
       with PC DOS 7.0 and IBM's Visual Age C++ 3.5.

       A copy of a Win* viewer is contained in the "Just add OS/2
       Warp" package

         ftp://ftp.software.ibm.com/ps/products/os2/tools/jaow/jaow.zip

       in ?:\JUST_ADD\view.exe. This gives one an access to EMX's
       .INF docs as well (text form is available in /emx/doc in
       EMX's distribution).

       Note that if you have lynx.exe installed, you can follow
       WWW links from this document in .INF format. If you have
       EMX docs installed correctly, you can follow library links
       (you need to have `view emxbook' working by setting `EMX-
       BOOK' environment variable as it is described in EMX
       docs).

DESCRIPTION
       Target

       The target is to make OS/2 the best supported platform for
       using/building/developing Perl and Perl applications, as
       well as make Perl the best language to use under OS/2. The
       secondary target is to try to make this work under DOS and
       Win* as well (but not too hard).

       The current state is quite close to this target. Known
       limitations:

       o    Some *nix programs use fork() a lot, but currently
            fork() is not supported after useing dynamically
            loaded extensions.





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       o    You need a separate perl executable perl__.exe (see
            the perl__.exe manpage) to use PM code in your appli-
            cation (like the forthcoming Perl/Tk).

       o    There is no simple way to access WPS objects. The
            only way I know is via `OS2::REXX' extension (see the
            OS2::REXX manpage), and we do not have access to con-
            venience methods of Object-REXX. (Is it possible at
            all? I know of no Object-REXX API.)

       Please keep this list up-to-date by informing me about
       other items.

       Other OSes

       Since OS/2 port of perl uses a remarkable EMX environment,
       it can run (and build extensions, and - possibly - be
       build itself) under any environment which can run EMX. The
       current list is DOS, DOS-inside-OS/2, Win0.3*, Win0.95 and
       WinNT. Out of many perl flavors, only one works, see the
       section on "perl_.exe".

       Note that not all features of Perl are available under
       these environments. This depends on the features the
       extender - most probably RSX - decided to implement.

       Cf. the Prerequisites manpage.

       Prerequisites


       EMX   EMX runtime is required (may be substituted by RSX).
             Note that it is possible to make perl_.exe to run
             under DOS without any external support by binding
             emx.exe/rsx.exe to it, see the emxbind manpage. Note
             that under DOS for best results one should use RSX
             runtime, which has much more functions working (like
             `fork', `popen' and so on). In fact RSX is required
             if there is no VCPI present. Note the RSX requires
             DPMI.

             Only the latest runtime is supported, currently
             `0.9c'. Perl may run under earlier versions of EMX,
             but this is not tested.

             One can get different parts of EMX from, say

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

             The runtime component should have the name
             emxrt.zip.

             NOTE. It is enough to have emx.exe/rsx.exe on your



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             path. One does not need to specify them explicitly
             (though this

               emx perl_.exe -de 0

             will work as well.)

       RSX   To run Perl on DPMI platforms one needs RSX runtime.
             This is needed under DOS-inside-OS/2, Win0.3*,
             Win0.95 and WinNT (see the section on "Other OSes").
             RSX would not work with VCPI only, as EMX would, it
             requires DMPI.

             Having RSX and the latest sh.exe one gets a fully
             functional *nix-ish environment under DOS, say,
             `fork', ```' and pipe-`open' work. In fact, Make-
             Maker works (for static build), so one can have Perl
             development environment under DOS.

             One can get RSX from, say

               ftp://ftp.cdrom.com/pub/os2/emx09c/contrib
               ftp://ftp.uni-bielefeld.de/pub/systems/msdos/misc
               ftp://ftp.leo.org/pub/comp/os/os2/leo/devtools/emx+gcc/contrib

             Contact the author on `rainer@mathematik.uni-biele-
             feld.de'.

             The latest sh.exe with DOS hooks is available at

               ftp://ftp.math.ohio-state.edu/pub/users/ilya/os2/sh_dos.zip


       HPFS  Perl does not care about file systems, but to
             install the whole perl library intact one needs a
             file system which supports long file names.

             Note that if you do not plan to build the perl
             itself, it may be possible to fool EMX to truncate
             file names. This is not supported, read EMX docs to
             see how to do it.

       pdksh To start external programs with complicated command
             lines (like with pipes in between, and/or quoting of
             arguments), Perl uses an external shell. With EMX
             port such shell should be named <sh.exe>, and
             located either in the wired-in-during-compile loca-
             tions (usually F:/bin), or in configurable location
             (see the section on "PERL_SH_DIR").

             For best results use EMX pdksh. The soon-to-be-
             available standard binary (5.2.12?) runs under DOS
             (with the RSX manpage) as well, meanwhile use the
             binary from



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               ftp://ftp.math.ohio-state.edu/pub/users/ilya/os2/sh_dos.zip


       Starting Perl programs under OS/2 (and DOS and...)

       Start your Perl program foo.pl with arguments `arg1 arg2
       arg3' the same way as on any other platform, by

               perl foo.pl arg1 arg2 arg3

       If you want to specify perl options `-my_opts' to the perl
       itself (as opposed to to your program), use

               perl -my_opts foo.pl arg1 arg2 arg3

       Alternately, if you use OS/2-ish shell, like CMD or 4os2,
       put the following at the start of your perl script:

               extproc perl -S -my_opts

       rename your program to foo.cmd, and start it by typing

               foo arg1 arg2 arg3

       Note that because of stupid OS/2 limitations the full path
       of the perl script is not available when you use
       `extproc', thus you are forced to use `-S' perl switch,
       and your script should be on path. As a plus side, if you
       know a full path to your script, you may still start it
       with

               perl ../../blah/foo.cmd arg1 arg2 arg3

       (note that the argument `-my_opts' is taken care of by the
       `extproc' line in your script, see the section on
       "`extproc' on the first line").

       To understand what the above magic does, read perl docs
       about `-S' switch - see the perlrun manpage, and cmdref
       about `extproc':

               view perl perlrun
               man perlrun
               view cmdref extproc
               help extproc

       or whatever method you prefer.

       There are also endless possibilities to use executable
       extensions of 4os2, associations of WPS and so on... How-
       ever, if you use *nixish shell (like sh.exe supplied in
       the binary distribution), you need to follow the syntax
       specified in the Switches entry in the perlrun manpage.




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       Note that -S switch enables a search with additional
       extensions .cmd, .btm, .bat, .pl as well.

       Starting OS/2 (and DOS) programs under Perl

       This is what system() (see the system entry in the perl-
       func manpage), ```' (see the I/O Operators entry in the
       perlop manpage), and open pipe (see the open entry in the
       perlfunc manpage) are for. (Avoid exec() (see the exec
       entry in the perlfunc manpage) 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 the section on
       "Pdksh", the section on "Frequently asked questions"), and
       perl should be able to find it (see the section on
       "PERL_SH_DIR").

       The cases when the shell is used are:

       1   One-argument system() (see the system entry in the
           perlfunc manpage), exec() (see the exec entry in the
           perlfunc manpage) with redirection or shell meta-char-
           acters;

       2   Pipe-open (see the open entry in the perlfunc manpage)
           with the command which contains redirection or shell
           meta-characters;

       3   Backticks ```' (see the I/O Operators entry in the
           perlop manpage) with the command which contains redi-
           rection 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;

       7   For globbing (see the glob entry in the perlfunc man-
           page, the I/O Operators entry in the perlop manpage).

       For the sake of speed for a common case, in the above
       algorithms backslashes in the command name are not consid-
       ered 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:



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       if the path on `#!' line does not work, and contains `/',
       then 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).

       If starting scripts directly, Perl will use exactly the
       same algorithm as for the search of script given by -S
       command-line option: it will look in the current direc-
       tory, then on components of `$ENV{PATH}' using the follow-
       ing 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 exe-
       cutable file blah.exe anywhere on `PATH'.

       Note also that executable files on OS/2 can have an arbi-
       trary extension, but .exe will be automatically appended
       if no dot is present in the name.  The workaround as as
       simple as that:  since blah. and blah denote the same
       file, to start an executable residing in file n:/bin/blah
       (no extension) give an argument `n:/bin/blah.' to sys-
       tem().

       The last note is that currently it is not straightforward
       to start PM programs from VIO (=text-mode) Perl process
       and visa versa.  Either ensure that shell will be used, as
       in `system 'cmd /c epm'', or start it using optional argu-
       ments to system() documented in `OS2::Process' module.
       This is considered a bug and should be fixed soon.

Frequently asked questions
       I cannot run external programs


           Did you run your programs with `-w' switch? See the 2
           (and DOS) programs under Perl entry in the Starting OS
           manpage.

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




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

       program."  program."

       Is your program EMX-compiled with `-Zmt -Zcrtdll'?
           If not, 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?
           I had reports it does not work. Somebody would need to
           fix it.

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

       This may a variant of just the section on "I cannot run
       external programs", or a deeper problem. Basically: you
       need RSX (see the section on "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 the section on "Prerequisites" under RSX. Do not forget
       to set variable `the section on "PERL_SH_DIR"' as well.

       DPMI is required for RSX.

       Cannot start `find.exe "pattern" file'

       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. In fact find.exe cannot be started
       at all using C library API only. Otherwise the following
       command-lines were equivalent:

         find "pattern" file
         find pattern file


INSTALLATION
       Automatic binary installation

       The most convenient way of installing 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



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       EMX runtime by running

               emxrev

       A folder is created on your desktop which contains some
       useful objects.

       Things not taken care of by automatic binary installation:

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

       `PERL_BADFREE' see the section on "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.

       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 `the PERL_SH_DIR man-
       page' instead.

       Manual binary installation

       As of version 5.00305, OS/2 perl binary distribution comes
       split into 11 components. Unfortunately, to enable config-
       urable 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 config-
       uration on my machine:

       Perl VIO and PM executables (dynamically linked)




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            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 preserved, you do not need to
          change anything. However, for perl to find it if it is
          changed, you need to `set PERLLIB_PREFIX' in Con-
          fig.sys, see the section on "PERLLIB_PREFIX".

       Additional Perl modules
            unzip perl_ste.zip -d f:/perllib/lib/site_perl

          If you do not change this directory, do nothing. Other-
          wise put this directory and subdirectory ./os2 in `PER-
          LLIB' or `PERL5LIB' variable. Do not use `PERL5LIB'
          unless you have it set already. See the ENVIRONMENT
          entry in the perl manpage.

       Tools to compile Perl modules
            unzip perl_blb.zip -d f:/perllib/lib

          If this directory is preserved, you do not need to
          change anything. However, for perl to find it if it is
          changed, you need to `set PERLLIB_PREFIX' in Con-
          fig.sys, see the section on "PERLLIB_PREFIX".

       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.





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       Source for Perl documentation
            unzip perl_pod.zip -d f:/perllib/lib

          This is used by by `perldoc' program (see the perldoc
          manpage), and may be used to generate HTML documenta-
          tion usable by WWW browsers, and documentation in zil-
          lions of other formats: `info', `LaTeX', `Acrobat',
          `FrameMaker' and so on.

       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 redi-
          rection and shell metacharacters. It is also used
          instead of explicit /bin/sh.

          Set `PERL_SH_DIR' (see the section on "PERL_SH_DIR") if
          you move sh.exe from the above location.

          Note. It may be possible to use some other sh-compati-
          ble shell (not tested).

       After you installed the components you needed and updated
       the Config.sys correspondingly, you need to hand-edit Con-
       fig.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 precom-
       piled paths inside perl executables. While these paths are
       overwriteable (see the section on "PERLLIB_PREFIX", the
       section on "PERL_SH_DIR"), one may get better results by
       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:







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       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 the section on "SYNOP-
       SIS".

       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




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       Note that dot (.) is used as a package separator for docu-
       mentation 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 man-
       pages is on our `MANPATH', like this

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


       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
       `pod2info' from `CPAN', or, alternately, prebuilt info
       pages.


       for `Acrobat' are available on CPAN (for slightly old ver-
       sion 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 the section on
       "/www.shadow.net/~troc/os2perl.html" in the http: manpage.

       Prerequisites

       You need to have the latest EMX development environment,
       the full GNU tool suite (gawk renamed to awk, and GNU



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       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 this from are

         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, gnutu-
       til.zip, gnused.zip, gnupatch.zip, gnuawk.zip, gnumake.zip
       and ksh527rt.zip.  Note that all these utilities are known
       to be available from LEO:

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

       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.

       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.

       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, press `Ctrl-C'.




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       Getting perl source

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

         http://www.perl.com/CPAN/src/5.0
         http://www.perl.com/CPAN/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.perl.com/CPAN/ports/os2/ilyaz/

       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 Con-
       figure. This is because there is a conflict with a simi-
       larly-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.

       Note also that the db.lib and db.a from the EMX distribu-
       tion are not suitable for multi-threaded compile (note
       that currently perl is not multithread-safe, but is com-
       piled as multithreaded for compatibility with
       XFree86-OS/2). Get a corrected one from

         ftp://ftp.math.ohio-state.edu/pub/users/ilya/os2/db_mt.zip

       To make `-p' filetest work, one may also need to apply the
       following patch to EMX headers:







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         --- /emx/include/sys/stat.h.orig      Thu May 23 13:48:16 1996
         +++ /emx/include/sys/stat.h   Sun Jul 12 14:11:32 1998
         @@ -53,7 +53,7 @@ struct stat
          #endif

          #if !defined (S_IFMT)
         -#define S_IFMT   0160000  /* Mask for file type */
         +#define S_IFMT   0170000  /* Mask for file type */
          #define S_IFIFO  0010000  /* Pipe */
          #define S_IFCHR  0020000  /* Character device */
          #define S_IFDIR  0040000  /* Directory */


       Hand-editing

       You may look into the file ./hints/os2.sh and correct any-
       thing 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 the section on "PERLLIB_PRE-
       FIX".

       Ignore the message about missing `ln', and about `-c'
       option to tr. In fact if you can trace where the latter
       spurious warning comes from, please inform me.

       Now

         make

       At some moment the built may die, reporting a version mis-
       match or unable to run perl. This means that most of the
       build has been finished, and it is the time to move the
       constructed perl.dll to some absolute location in LIBPATH.
       After this is done the build should finish without a lot
       of fuss. One can avoid the interruption if one has the
       correct prebuilt version of perl.dll on LIBPATH, but prob-
       ably this is not needed anymore, since miniperl.exe is
       linked statically now.

       Warnings which are safe to ignore: mkfifo() redefined
       inside POSIX.c.

       Testing

       If you haven't yet moved perl.dll onto LIBPATH, do it now
       (alternatively, if you have a previous perl installation
       you'd rather not disrupt until this one is installed, copy



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       perl.dll to the t directory).

       Now run

         make test

       All tests should succeed (with some of them skipped).
       Note that on one of the systems I see intermittent fail-
       ures of io/pipe.t subtest 9.  Any help to track what hap-
       pens with this test is appreciated.

       Some tests may generate extra messages similar to

       A lot of `bad free'
           in database tests related to Berkeley DB. This is a
           confirmed bug of DB. You may disable this warnings,
           see the section on "PERL_BADFREE".

           There is not much we can do with it (but apparently it
           does not cause any real error with data).

       Process terminated by SIGTERM/SIGINT
           This is a standard message issued by OS/2 applica-
           tions. *nix applications die in silence. It is consid-
           ered a feature. One can easily disable this by appro-
           priate sighandlers.

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

       Two lib/io_* tests may generate popups (system error
       `SYS3175'), but should succeed anyway.  This is due to a
       bug of EMX related to fork()ing with dynamically loaded
       libraries.

       I submitted a patch to EMX which makes it possible to
       fork() with EMX dynamic libraries loaded, which makes
       lib/io* tests pass without skipping offended tests. This
       means that soon the number of skipped tests may decrease
       yet more.

       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.




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       The reasons for most important skipped tests are:

       op/fs.t

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

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

       lib/io_pipe.t
               Checks `IO::Pipe' module. Some feature of EMX -
               test fork()s with dynamic extension loaded -
               unsupported now.

       lib/io_sock.t
               Checks `IO::Socket' module. Some feature of EMX -
               test fork()s with dynamic extension loaded -
               unsupported now.

       op/stat.t
               Checks `stat()'. Tests:

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

       lib/io_udp.t
               It never terminates, apparently some bug in stor-
               ing the last socket from which we obtained a mes-
               sage.

       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 LIB-
       PATH.

       Run

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

       to convert perl utilities to .cmd files and put them on
       PATH. You need to put .EXE-utilities on path manually.
       They are installed in `$prefix/bin', here `$prefix' is



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       what you gave to Configure, see the Making manpage.

       `a.out'-style build

       Proceed as above, but make perl_.exe (see the section on
       "perl_.exe") by

         make perl_

       test and install by

         make aout_test
         make aout_install

       Manually put perl_.exe to a location on your PATH.

       Since `perl_' has the extensions prebuilt, it does not
       suffer from the dynamic extensions + fork() syndrome, thus
       the failing tests look like

         Failed Test  Status Wstat Total Fail  Failed  List of failed
         ---------------------------------------------------------------
         io/fs.t                      26   11  42.31%  2-5, 7-11, 18, 25
         op/stat.t                    56    5   8.93%  3-4, 20, 35, 39
         Failed 2/118 test scripts, 98.31% okay. 16/2445 subtests failed, 99.35% okay.

       Note. The build process for `perl_' does not know about
       all the dependencies, so you should make sure that any-
       thing is up-to-date, say, by doing

         make perl.dll

       first.

Build FAQ
       Some `/' became `\' in pdksh.

       You have a very old pdksh. See the Prerequisites manpage.

       `'errno'' - unresolved external

       You do not have MT-safe db.lib. See the Prerequisites man-
       page.

       Problems with tr or sed

       reported with very old version of tr and sed.

       Some problem (forget which ;-)

       You have an older version of perl.dll on your LIBPATH,
       which broke the build of extensions.





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       Library ... not found

       You did not run `omflibs'. See the Prerequisites manpage.

       Segfault in make

       You use an old version of GNU make. See the Prerequisites
       manpage.

Specific (mis)features of OS/2 port
       `setpriority', `getpriority'

       Note that these functions are compatible with *nix, not
       with the older ports of '94 - 95. The priorities are abso-
       lute, go from 32 to -95, lower is quicker. 0 is the
       default priority.

       `system()'

       Multi-argument form of `system()' allows an additional
       numeric argument. The meaning of this argument is
       described in the OS2::Process manpage.

       `extproc' on the first line

       If the first chars of a script are `"extproc "', this line
       is treated as `#!'-line, thus all the switches on this
       line are processed (twice if script was started via
       cmd.exe).

       Additional modules:

       the OS2::Process manpage, the OS2::REXX manpage, the
       OS2::PrfDB manpage, the OS2::ExtAttr manpage. These mod-
       ules provide access to additional numeric argument for
       `system' and to the list of the running processes, to DLLs
       having functions with REXX signature and to REXX runtime,
       to OS/2 databases in the .INI format, and to Extended
       Attributes.

       Two additional extensions by Andreas Kaiser, `OS2::UPM',
       and `OS2::FTP', are included into my ftp directory, mir-
       rored on CPAN.

       Prebuilt methods:


       `File::Copy::syscopy'
           used by `File::Copy::copy', see the File::Copy man-
           page.

       `DynaLoader::mod2fname'
           used by `DynaLoader' for DLL name mangling.




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       `Cwd::current_drive()'
           Self explanatory.

       `Cwd::sys_chdir(name)'
           leaves drive as it is.

       `Cwd::change_drive(name)'

       `Cwd::sys_is_absolute(name)'
           means has drive letter and is_rooted.

       `Cwd::sys_is_rooted(name)'
           means has leading `[/\\]' (maybe after a drive-let-
           ter:).

       `Cwd::sys_is_relative(name)'
           means changes with current dir.

       `Cwd::sys_cwd(name)'
           Interface to cwd from EMX. Used by `Cwd::cwd'.

       `Cwd::sys_abspath(name, dir)'
           Really really odious function to implement. Returns
           absolute name of file which would have `name' if CWD
           were `dir'.  `Dir' defaults to the current dir.

       `Cwd::extLibpath([type])'
           Get current value of extended library search path. If
           `type' is present and true, works with END_LIBPATH,
           otherwise with `BEGIN_LIBPATH'.

       `Cwd::extLibpath_set( path [, type ] )'
           Set current value of extended library search path. If
           `type' is present and true, works with END_LIBPATH,
           otherwise with `BEGIN_LIBPATH'.

       (Note that some of these may be moved to different
       libraries - eventually).

       Misfeatures


           Since flock(3) is present in EMX, but is not func-
           tional, it is emulated by perl.  To disable the emula-
           tions, set environment variable `USE_PERL_FLOCK=0'.

           Here is the list of things which may be "broken" on
           EMX (from EMX docs):

           o   The functions recvmsg(3), sendmsg(3), and
               socketpair(3) are not implemented.

           o   sock_init(3) is not required and not implemented.




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           o   flock(3) is not yet implemented (dummy function).
               (Perl has a workaround.)

           o   kill(3):  Special treatment of PID=0, PID=1 and
               PID=-1 is not implemented.

           o   waitpid(3):

                     WUNTRACED
                             Not implemented.
                     waitpid() is not implemented for negative values of PID.


           Note that `kill -9' does not work with the current
           version of EMX.

           Since sh.exe is used for globing (see the glob entry
           in the perlfunc manpage), the bugs of sh.exe plague
           perl as well.

           In particular, uppercase letters do not work in
           `[...]'-patterns with the current pdksh.

       Modifications

       Perl modifies some standard C library calls in the follow-
       ing ways:

       `popen'  `my_popen' uses sh.exe if shell is required, cf.
                the section on "PERL_SH_DIR".

       `tmpnam' is created using `TMP' or `TEMP' environment
                variable, via `tempnam'.

       `tmpfile'
                If the current directory is not writable, file is
                created using modified `tmpnam', so there may be
                a race condition.

       `ctermid'
                a dummy implementation.

       `stat'   `os2_stat' special-cases /dev/tty and /dev/con.

       `flock'  Since flock(3) is present in EMX, but is not
                functional, it is emulated by perl.  To disable
                the emulations, set environment variable
                `USE_PERL_FLOCK=0'.

Perl flavors
       Because of idiosyncrasies of OS/2 one cannot have all the
       eggs in the same basket (though EMX environment tries hard
       to overcome this limitations, so the situation may somehow
       improve). There are 4 executables for Perl provided by the



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       distribution:

       perl.exe

       The main workhorse. This is a chimera executable: it is
       compiled as an `a.out'-style executable, but is linked
       with `omf'-style dynamic library perl.dll, and with
       dynamic CRT DLL. This executable is a VIO application.

       It can load perl dynamic extensions, and it can fork().
       Unfortunately, with the current version of EMX it cannot
       fork() with dynamic extensions loaded (may be fixed by
       patches to EMX).

       Note. Keep in mind that fork() is needed to open a pipe to
       yourself.

       perl_.exe

       This is a statically linked `a.out'-style executable. It
       can fork(), but cannot load dynamic Perl extensions. The
       supplied executable has a lot of extensions prebuilt, thus
       there are situations when it can perform tasks not possi-
       ble using perl.exe, like fork()ing when having some stan-
       dard extension loaded. This executable is a VIO applica-
       tion.

       Note. A better behaviour could be obtained from `perl.exe'
       if it were statically linked with standard Perl exten-
       sions, but dynamically linked with the Perl DLL and CRT
       DLL. Then it would be able to fork() with standard exten-
       sions, and would be able to dynamically load arbitrary
       extensions. Some changes to Makefiles and hint files
       should be necessary to achieve this.

       This is also the only executable with does not require
       OS/2. The friends locked into `M$' world would appreciate
       the fact that this executable runs under DOS, Win0.3*,
       Win0.95 and WinNT with an appropriate extender. See the
       section on "Other OSes".

       perl__.exe

       This is the same executable as perl___.exe, but it is a PM
       application.

       Note. Usually STDIN, STDERR, and STDOUT of a PM applica-
       tion are redirected to `nul'. However, it is possible to
       see them if you start `perl__.exe' from a PM program which
       emulates a console window, like Shell mode of Emacs or
       EPM. Thus it is possible to use Perl debugger (see the
       perldebug manpage) to debug your PM application.

       This flavor is required if you load extensions which use



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       PM, like the forthcoming `Perl/Tk'.

       perl___.exe

       This is an `omf'-style executable which is dynamically
       linked to perl.dll and CRT DLL. I know no advantages of
       this executable over `perl.exe', but it cannot fork() at
       all. Well, one advantage is that the build process is not
       so convoluted as with `perl.exe'.

       It is a VIO application.

       Why strange names?

       Since Perl processes the `#!'-line (cf.  the DESCRIPTION
       entry in the perlrun manpage, the Switches entry in the
       perlrun manpage, the Not a perl script entry in the perl-
       diag manpage, the No Perl script found in input entry in
       the perldiag manpage), it should know when a program is a
       Perl. There is some naming convention which allows Perl to
       distinguish correct lines from wrong ones. The above names
       are almost the only names allowed by this convention which
       do not contain digits (which have absolutely different
       semantics).

       Why dynamic linking?

       Well, having several executables dynamically linked to the
       same huge library has its advantages, but this would not
       substantiate the additional work to make it compile. The
       reason is stupid-but-quick "hard" dynamic linking used by
       OS/2.

       The address tables of DLLs are patched only once, when
       they are loaded. The addresses of entry points into DLLs
       are guaranteed to be the same for all programs which use
       the same DLL, which reduces the amount of runtime patching
       - once DLL is loaded, its code is read-only.

       While this allows some performance advantages, this makes
       life terrible for developers, since the above scheme makes
       it impossible for a DLL to be resolved to a symbol in the
       .EXE file, since this would need a DLL to have different
       relocations tables for the executables which use it.

       However, a Perl extension is forced to use some symbols
       from the perl executable, say to know how to find the
       arguments provided on the perl internal evaluation stack.
       The solution is that the main code of interpreter should
       be contained in a DLL, and the .EXE file just loads this
       DLL into memory and supplies command-arguments.

       This greatly increases the load time for the application
       (as well as the number of problems during compilation).



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       Since interpreter is in a DLL, the CRT is basically forced
       to reside in a DLL as well (otherwise extensions would not
       be able to use CRT).

       Why chimera build?

       Current EMX environment does not allow DLLs compiled using
       Unixish `a.out' format to export symbols for data. This
       forces `omf'-style compile of perl.dll.

       Current EMX environment does not allow .EXE files compiled
       in `omf' format to fork(). fork() is needed for exactly
       three Perl operations:

       explicit fork()
           in the script, and

       open FH, ""|-""

       open FH, ""-|""
           opening pipes to itself.

       While these operations are not questions of life and
       death, a lot of useful scripts use them. This forces
       `a.out'-style compile of perl.exe.

ENVIRONMENT
       Here we list environment variables with are either OS/2-
       and DOS- and Win*-specific, or are more important under
       OS/2 than under other OSes.

       `PERLLIB_PREFIX'

       Specific for EMX port. Should have the form

         path1;path2

       or

         path1 path2

       If the beginning of some prebuilt path matches path1, it
       is substituted with path2.

       Should be used if the perl library is moved from the
       default location in preference to `PERL(5)LIB', since this
       would not leave wrong entries in @INC.  Say, if the com-
       piled version of perl looks for @INC in f:/perllib/lib,
       and you want to install the library in h:/opt/gnu, do

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






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       `PERL_BADLANG'

       If 1, perl ignores setlocale() failing. May be useful with
       some strange locales.

       `PERL_BADFREE'

       If 1, perl would not warn of in case of unwarranted
       free(). May be useful in conjunction with the module
       DB_File, since Berkeley DB memory handling code is buggy.

       `PERL_SH_DIR'

       Specific for EMX port. Gives the directory part of the
       location for sh.exe.

       `USE_PERL_FLOCK'

       Specific for EMX port. Since flock(3) is present in EMX,
       but is not functional, it is emulated by perl.  To disable
       the emulations, set environment variable
       `USE_PERL_FLOCK=0'.

       `TMP' or `TEMP'

       Specific for EMX port. Used as storage place for temporary
       files, most notably `-e' scripts.

Evolution
       Here we list major changes which could make you by sur-
       prise.

       Priorities

       `setpriority' and `getpriority' are not compatible with
       earlier ports by Andreas Kaiser. See `"setpriority, get-
       priority"'.

       DLL name mangling

       With the release 5.003_01 the dynamically loadable
       libraries should be rebuilt. In particular, DLLs are now
       created with the names which contain a checksum, thus
       allowing workaround for OS/2 scheme of caching DLLs.

       Threading

       As of release 5.003_01 perl is linked to multithreaded CRT
       DLL.  If perl itself is not compiled multithread-enabled,
       so will not be perl malloc(). However, extensions may use
       multiple thread on their own risk.

       Needed to compile `Perl/Tk' for XFree86-OS/2 out-of-the-
       box.



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       Calls to external programs

       Due to a popular demand the perl external program calling
       has been changed wrt Andreas Kaiser's port.  If perl needs
       to call an external program via shell, the f:/bin/sh.exe
       will be called, or whatever is the override, see the sec-
       tion on "PERL_SH_DIR".

       Thus means that you need to get some copy of a sh.exe as
       well (I use one from pdksh). The drive F: above is set up
       automatically during the build to a correct value on the
       builder machine, but is overridable at runtime,

       Reasons: a consensus on `perl5-porters' was that perl
       should use one non-overridable shell per platform. The
       obvious choices for OS/2 are cmd.exe and sh.exe. Having
       perl build itself would be impossible with cmd.exe as a
       shell, thus I picked up `sh.exe'. Thus assures almost 100%
       compatibility with the scripts coming from *nix. As an
       added benefit this works as well under DOS if you use DOS-
       enabled port of pdksh (see the section on "Prerequi-
       sites").

       Disadvantages: currently sh.exe of pdksh calls external
       programs via fork()/exec(), and there is no functioning
       exec() on OS/2. exec() is emulated by EMX by asyncroneous
       call while the caller waits for child completion (to pre-
       tend that the `pid' did not change). This means that 1
       extra copy of sh.exe is made active via fork()/exec(),
       which may lead to some resources taken from the system
       (even if we do not count extra work needed for fork()ing).

       Note that this a lesser issue now when we do not spawn
       sh.exe unless needed (metachars found).

       One can always start cmd.exe explicitly via

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

       If you need to use cmd.exe, and do not want to hand-edit
       thousands of your scripts, the long-term solution proposed
       on p5-p is to have a directive

         use OS2::Cmd;

       which will override system(), exec(), ```', and
       `open(,'...|')'. With current perl you may override only
       system(), readpipe() - the explicit version of ```', and
       maybe exec(). The code will substitute the one-argument
       call to system() by `CORE::system('cmd.exe', '/c',
       shift)'.

       If you have some working code for `OS2::Cmd', please send
       it to me, I will include it into distribution. I have no



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       need for such a module, so cannot test it.

       For the details of the current situation with calling
       external programs, see the 2 (and DOS) programs under Perl
       entry in the Starting OS manpage.

           External scripts may be called by name.  Perl will try
           the same extensions as when processing -S command-line
           switch.

       Memory allocation

       Perl uses its own malloc() under OS/2 - interpreters are
       usually malloc-bound for speed, but perl is not, since its
       malloc is lightning-fast.  Perl-memory-usage-tuned bench-
       marks show that Perl's malloc is 5 times quickier than EMX
       one.  I do not have convincing data about memory foot-
       pring, but a (pretty random) benchmark showed that Perl
       one is 5% better.

       Combination of perl's malloc() and rigid DLL name resolu-
       tion creates a special problem with library functions
       which expect their return value to be free()d by system's
       free(). To facilitate extensions which need to call such
       functions, system memory-allocation functions are still
       available with the prefix `emx_' added. (Currently only
       DLL perl has this, it should propagate to perl_.exe
       shortly.)

       Threads

       One can build perl with thread support enabled by provid-
       ing `-D usethreads' option to Configure.  Currently OS/2
       support of threads is very preliminary.

       Most notable problems:

       `COND_WAIT'
           may have a race condition.  Needs a reimplementation
           (in terms of chaining waiting threads, with linker
           list stored in per-thread structure?).

       os2.c
           has a couple of static variables used in OS/2-specific
           functions.  (Need to be moved to per-thread structure,
           or serialized?)

       Note that these problems should not discourage experiment-
       ing, since they have a low probability of affecting small
       programs.

AUTHOR
       Ilya Zakharevich, ilya@math.ohio-state.edu




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SEE ALSO
       perl(1).























































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