If you read this file _as_is_, just ignore the funny characters you see. It is written in the POD format (see perlpod manpage) which is specially designed to be readable as is. =head1 NAME perlos2 - Perl under OS/2, DOS, Win0.3*, Win0.95 and WinNT. =head1 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 I: either as F, or F. To read the F<.INF> version of documentation (B recommended) 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 F. This gives one an access to EMX's F<.INF> docs as well (text form is available in F in EMX's distribution). Note that if you have F installed, you can follow WWW links from this document in F<.INF> format. If you have EMX docs installed correctly, you can follow library links (you need to have C working by setting C environment variable as it is described in EMX docs). =cut Contents perlos2 - Perl under OS/2, DOS, Win0.3*, Win0.95 and WinNT. NAME SYNOPSIS DESCRIPTION - Target - Other OSes - Prerequisites - Starting Perl programs under OS/2 (and DOS and...) - Starting OS/2 (and DOS) programs under Perl Frequently asked questions - I cannot run external programs - I cannot embed perl into my program, or use perl.dll from my program. - `` and pipe-open do not work under DOS. - Cannot start find.exe "pattern" file INSTALLATION - Automatic binary installation - Manual binary installation - Warning Accessing documentation - OS/2 .INF file - Plain text - Manpages - HTML - GNU info files - .PDF files - LaTeX docs BUILD - Prerequisites - Getting perl source - Application of the patches - Hand-editing - Making - Testing - Installing the built perl - a.out-style build Build FAQ - Some / became \ in pdksh. - 'errno' - unresolved external - Problems with tr - Some problem (forget which ;-) - Library ... not found - Segfault in make Specific (mis)features of EMX port - setpriority, getpriority - system() - extproc on the first line - Additional modules: - Prebuilt methods: - Misfeatures - Modifications Perl flavors - perl.exe - perl_.exe - perl__.exe - perl___.exe - Why strange names? - Why dynamic linking? - Why chimera build? ENVIRONMENT - PERLLIB_PREFIX - PERL_BADLANG - PERL_BADFREE - PERL_SH_DIR - TMP or TEMP Evolution - Priorities - DLL name mangling - Threading - Calls to external programs - Memory allocation - Threads AUTHOR SEE ALSO =head1 DESCRIPTION =head2 Target The target is to make OS/2 the best supported platform for using/building/developing Perl and I, 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 B hard). The current state is quite close to this target. Known limitations: =over 5 =item * Some *nix programs use fork() a lot; with the mostly useful flavors of perl for OS/2 (there are several built simultaneously) this is supported; some flavors do not. Using fork() after Iing dynamically loading extensions would not work with very old versions of EMX. =item * You need a separate perl executable F (see L) if you want to use PM code in your application (as Perl/Tk or OpenGL Perl modules do) without having a text-mode window present. While using the standard F from a text-mode window is possible too, I have seen cases when this causes degradation of the system stability. Using F avoids such a degradation. =item * There is no simple way to access WPS objects. The only way I know is via C extension (see L), and we do not have access to convenience methods of Object-REXX. (Is it possible at all? I know of no Object-REXX API.) The C extension (currently in alpha-text) may eventually remove this shortcoming. =back Please keep this list up-to-date by informing me about other items. =head2 Other OSes Since OS/2 port of perl uses a remarkable EMX environment, it can run (and build extensions, and - possibly - be built 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 L<"perl_.exe">. Note that not all features of Perl are available under these environments. This depends on the features the I - most probably RSX - decided to implement. Cf. L. =head2 Prerequisites =over 6 =item EMX EMX runtime is required (may be substituted by RSX). Note that it is possible to make F to run under DOS without any external support by binding F/F to it, see L. Note that under DOS for best results one should use RSX runtime, which has much more functions working (like C, C 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 C<0.9d fix 03>. Perl may run under earlier versions of EMX, but this is not tested. One can get different parts of EMX from, say http://www.leo.org/pub/comp/os/os2/leo/gnu/emx+gcc/ http://powerusersbbs.com/pub/os2/dev/ [EMX+GCC Development] http://hobbes.nmsu.edu/pub/os2/dev/emx/v0.9d/ The runtime component should have the name F. B. It is enough to have F/F on your path. One does not need to specify them explicitly (though this emx perl_.exe -de 0 will work as well.) =item 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 L<"Other OSes">). RSX would not work with VCPI only, as EMX would, it requires DMPI. Having RSX and the latest F one gets a fully functional B<*nix>-ish environment under DOS, say, C, C<``> and pipe-C work. In fact, MakeMaker 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 C. The latest F with DOS hooks is available in ftp://ftp.math.ohio-state.edu/pub/users/ilya/os2/ as F or under similar names starting with C, C etc. =item 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. =item 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 F, and located either in the wired-in-during-compile locations (usually F), or in configurable location (see L<"PERL_SH_DIR">). For best results use EMX pdksh. The standard binary (5.2.14 or later) runs under DOS (with L) as well, see ftp://ftp.math.ohio-state.edu/pub/users/ilya/os2/ =back =head2 Starting Perl programs under OS/2 (and DOS and...) Start your Perl program F with arguments C the same way as on any other platform, by perl foo.pl arg1 arg2 arg3 If you want to specify perl options C<-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 F, 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 C, thus you are forced to use C<-S> perl switch, and your script should be on the C. 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 C<-my_opts> is taken care of by the C line in your script, see L on the first line>). To understand what the above I does, read perl docs about C<-S> switch - see L, and cmdref about C: view perl perlrun man perlrun view cmdref extproc help extproc or whatever method you prefer. There are also endless possibilities to use I of 4os2, I of WPS and so on... However, if you use *nixish shell (like F supplied in the binary distribution), you need to follow the syntax specified in L. Note that B<-S> switch enables a search with additional extensions F<.cmd>, F<.btm>, F<.bat>, F<.pl> as well. =head2 Starting OS/2 (and DOS) programs under Perl This is what system() (see L), C<``> (see L), and I (see L) are for. (Avoid exec() (see L) 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 L<"Pdksh">, L<"Frequently asked questions">), and perl should be able to find it (see L<"PERL_SH_DIR">). The cases when the shell is used are: =over =item 1 One-argument system() (see L), exec() (see L) with redirection or shell meta-characters; =item 2 Pipe-open (see L) with the command which contains redirection or shell meta-characters; =item 3 Backticks C<``> (see L) with the command which contains redirection or shell meta-characters; =item 4 If the executable called by system()/exec()/pipe-open()/C<``> is a script with the "magic" C<#!> line or C line which specifies shell; =item 5 If the executable called by system()/exec()/pipe-open()/C<``> is a script without "magic" line, and C<$ENV{EXECSHELL}> is set to shell; =item 6 If the executable called by system()/exec()/pipe-open()/C<``> is not found; =item 7 For globbing (see L, L). =back For the sake of speed for a common case, in the above algorithms backslashes in the command name are not considered as shell metacharacters. Perl starts scripts which begin with cookies C or C<#!> directly, without an intervention of shell. Perl uses the same algorithm to find the executable as F: if the path on C<#!> line does not work, and contains C, then the executable is searched in F<.> and on C. To find arguments for these scripts Perl uses a different algorithm than F: up to 3 arguments are recognized, and trailing whitespace is stripped. If a script does not contain such a cooky, then to avoid calling F, Perl uses the same algorithm as F: if C<$ENV{EXECSHELL}> is set, the script is given as the first argument to this command, if not set, then C<$ENV{COMSPEC} /c> is used (or a hardwired guess if C<$ENV{COMSPEC}> is not set). If starting scripts directly, Perl will use exactly the same algorithm as for the search of script given by B<-S> command-line option: it will look in the current directory, then on components of C<$ENV{PATH}> using the following order of appended extensions: no extension, F<.cmd>, F<.btm>, F<.bat>, F<.pl>. Note that Perl will start to look for scripts only if OS/2 cannot start the specified application, thus C will not look for a script if there is an executable file F I on C. Note also that executable files on OS/2 can have an arbitrary extension, but F<.exe> will be automatically appended if no dot is present in the name. The workaround as as simple as that: since F and F denote the same file, to start an executable residing in file F (no extension) give an argument C (dot appended) to system(). Perl will correctly start PM programs from VIO (=text-mode) Perl process; the opposite is not true: when you start a non-PM program from a PM Perl process, it would not run it in a separate session. If a separate session is desired, either ensure that shell will be used, as in C, or start it using optional arguments to system() documented in C module. This is considered to be a feature. =head1 Frequently asked questions =head2 "It does not work" Perl binary distributions come with a F 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. C<;-)> =head2 I cannot run external programs =over 4 =item * Did you run your programs with C<-w> switch? See L. =item * Do you try to run I shell commands, like C<`copy a b`> (internal for F), or C<`glob a*b`> (internal for ksh)? You need to specify your shell explicitly, like C<`cmd /c copy a b`>, since Perl cannot deduce which commands are internal to your shell. =back =head2 I cannot embed perl into my program, or use F from my program. =over 4 =item Is your program EMX-compiled with C<-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. =item Did you use L? I had reports it does not work. Somebody would need to fix it. =back =head2 C<``> and pipe-C do not work under DOS. This may a variant of just L<"I cannot run external programs">, or a deeper problem. Basically: you I RSX (see L<"Prerequisites">) for these commands to work, and you may need a port of F which understands command arguments. One of such ports is listed in L<"Prerequisites"> under RSX. Do not forget to set variable C> as well. DPMI is required for RSX. =head2 Cannot start C Use one of system 'cmd', '/c', 'find "pattern" file'; `cmd /c 'find "pattern" file'` This would start F via F via C via C, but this is a price to pay if you want to use non-conforming program. In fact F cannot be started at all using C library API only. Otherwise the following command-lines would be equivalent: find "pattern" file find pattern file =head1 INSTALLATION =head2 Automatic binary installation The most convenient way of installing a binary distribution of perl is via perl installer F. Just follow the instructions, and 99% of the installation blues would go away. Note however, that you need to have F on your path, and EMX environment I. The latter means that if you just installed EMX, and made all the needed changes to F, you may need to reboot in between. Check EMX runtime by running emxrev A folder is created on your desktop which contains some useful objects. B =over 15 =item C may be needed if you change your codepage I perl installation, and the new value is not supported by EMX. See L<"PERL_BADLANG">. =item C see L<"PERL_BADFREE">. =item F 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 I 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. =back B. Because of a typo the binary installer of 5.00305 would install a variable C into F. Please remove this variable and put C> instead. =head2 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 C<-d> to pkunzip). However, you need to know where to extract the files. You need also to manually change entries in F 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 C<(w)unzip>. Below is the sample of what to do to reproduce the configuration on my machine: =over 3 =item 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 C<*.exe> on PATH, and C<*.dll> on LIBPATH); =item Perl_ VIO executable (statically linked) unzip perl_aou.zip -d f:/emx.add/bin (have the directory on PATH); =item Executables for Perl utilities unzip perl_utl.zip -d f:/emx.add/bin (have the directory on PATH); =item 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 F, you do not need to change anything. However, for perl to find the library if you use a different path, you need to C in F, see L<"PERLLIB_PREFIX">. =item Additional Perl modules unzip perl_ste.zip -d f:/perllib/lib/site_perl/5.8.3/ Same remark as above applies. Additionally, if this directory is not one of directories on @INC (and @INC is influenced by C), you need to put this directory and subdirectory F<./os2> in C or C variable. Do not use C unless you have it set already. See L. =item Tools to compile Perl modules unzip perl_blb.zip -d f:/perllib/lib Same remark as for F. =item Manpages for Perl and utilities unzip perl_man.zip -d f:/perllib/man This directory should better be on C. You need to have a working man to access these files. =item Manpages for Perl modules unzip perl_mam.zip -d f:/perllib/man This directory should better be on C. You need to have a working man to access these files. =item Source for Perl documentation unzip perl_pod.zip -d f:/perllib/lib This is used by the C program (see L), and may be used to generate HTML documentation usable by WWW browsers, and documentation in zillions of other formats: C, C, C, C and so on. =item Perl manual in F<.INF> format unzip perl_inf.zip -d d:/os2/book This directory should better be on C. =item 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 I and I. It is also used instead of explicit F. Set C (see L<"PERL_SH_DIR">) if you move F from the above location. B It may be possible to use some other sh-compatible shell (file globbing - if done via shell - may break). =back After you installed the components you needed and updated the F correspondingly, you need to hand-edit F. 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 C). =head2 B The automatic and manual perl installation leave precompiled paths inside perl executables. While these paths are overwriteable (see L<"PERLLIB_PREFIX">, L<"PERL_SH_DIR">), one may get better results by binary editing of paths inside the executables/DLLs. =head1 Accessing documentation Depending on how you built/installed perl you may have (otherwise identical) Perl documentation in the following formats: =head2 OS/2 F<.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 L<"SYNOPSIS">. If you want to build the docs yourself, and have I, run pod2ipf > perl.ipf in F directory, then ipfc /inf perl.ipf (Expect a lot of errors during the both steps.) Now move it on your BOOKSHELF path. =head2 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 F<.pod> files. =head2 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 (F<.>) is used as a package separator for documentation for packages, and as usual, sometimes you need to give the section - C<3> above - to avoid shadowing by the I. Make sure that the directory B the directory with manpages is on our C, like this set MANPATH=c:/man;f:/perllib/man for Perl manpages in C etc. =head2 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 F<.pod> files, and do like this cd f:/perllib/lib/pod pod2html After this you can direct your browser the file F 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. =head2 GNU C files Users of Emacs would appreciate it very much, especially with C mode loaded. You need to get latest C from C, or, alternately, prebuilt info pages. =head2 F<.PDF> files for C are available on CPAN (for slightly old version of perl). =head2 C docs can be constructed using C. =head1 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 =head2 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 C, manually move the built F to C (here F<*> is a not-very-meaningful hex checksum), and run make installcmd INSTALLCMDDIR=d:/ir/on/path What follows is a detailed guide through these steps. =head2 Prerequisites You need to have the latest EMX development environment, the full GNU tool suite (gawk renamed to awk, and GNU F earlier on path than the OS/2 F, same with F, to check use find --version sort --version ). You need the latest version of F installed as F. Check that you have B 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: F, F, F, F, F, F, F, F and F (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 If you have I installed already, make sure that no copies or perl are currently running. Later steps of the build may fail since an older version of F loaded into memory may be found. Also make sure that you have F directory on the current drive, and F<.> directory in your C. One may try to correct the latter condition by set BEGINLIBPATH . if you use something like F or latest versions of F<4os2.exe>. Make sure your gcc is good for C<-Zomf> linking: run C script in F 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 I, and choose C in I. If you get into link386 prompts, press C to exit. =head2 Getting perl source You need to fetch the latest perl source (including developers 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 F. This is because there is a conflict with a similarly-named file F. Change to the directory of extraction. =head2 Application of the patches You need to apply the patches in F<./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 F and F 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 ftp://ftp.math.ohio-state.edu/pub/users/ilya/os2/db_mt.zip =head2 Hand-editing You may look into the file F<./hints/os2.sh> and correct anything wrong you find there. I do not expect it is needed anywhere. =head2 Making sh Configure -des -D prefix=f:/perllib C means: where to install the resulting perl library. Giving correct prefix you may avoid the need to specify C, see L<"PERLLIB_PREFIX">. I, and about C<-c> option to tr>. The latter is most probably already fixed, if you see it and can trace where the latter spurious warning comes from, please inform me. Now make At some moment the built may die, reporting a I or I>. This means that you do not have F<.> in your LIBPATH, so F cannot find the needed F (treat these hex digits as line noise). After this is fixed the build should finish without a lot of fuss. =head2 Testing Now run make test All tests should succeed (with some of them skipped). Some tests may generate extra messages similar to =over 4 =item A lot of C in database tests related to Berkeley DB. I If it persists, you may disable this warnings, see L<"PERL_BADFREE">. =item 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 I be present during testing. =back To get finer test reports, call perl t/harness The report with F 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: =over 8 =item F =over 4 =item 18 Checks C and C of C - unfortunately, HPFS provides only 2sec time granularity (for compatibility with FAT?). =item 25 Checks C on a filehandle just opened for write - I do not know why this should or should not work. =back =item F Checks C. Tests: =over 4 =item 4 Checks C and C of C - unfortunately, HPFS provides only 2sec time granularity (for compatibility with FAT?). =back =back =head2 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 F, F and F to a location on your PATH, F to a location on your LIBPATH. Run make installcmd INSTALLCMDDIR=d:/ir/on/path to convert perl utilities to F<.cmd> files and put them on PATH. You need to put F<.EXE>-utilities on path manually. They are installed in C<$prefix/bin>, here C<$prefix> is what you gave to F, see L. =head2 C-style build Proceed as above, but make F (see L<"perl_.exe">) by make perl_ test and install by make aout_test make aout_install Manually put F to a location on your PATH. B The build process for C I about all the dependencies, so you should make sure that anything is up-to-date, say, by doing make perl_dll first. =head1 Build FAQ =head2 Some C became C<\> in pdksh. You have a very old pdksh. See L. =head2 C<'errno'> - unresolved external You do not have MT-safe F. See L. =head2 Problems with tr or sed reported with very old version of tr and sed. =head2 Some problem (forget which ;-) You have an older version of F on your LIBPATH, which broke the build of extensions. =head2 Library ... not found You did not run C. See L. =head2 Segfault in make You use an old version of GNU make. See L. =head2 op/sprintf test failure This can result from a bug in emx sprintf which was fixed in 0.9d fix 03. =head1 Specific (mis)features of OS/2 port =head2 C, C Note that these functions are compatible with *nix, not with the older ports of '94 - 95. The priorities are absolute, go from 32 to -95, lower is quicker. 0 is the default priority. B. Calling C on a non-existing process could lock the system before Warp3 fixpak22. Starting with Warp3, Perl will use a workaround: it aborts getpriority() if the process is not present. This is not possible on older versions C<2.*>, and has a race condition anyway. =head2 C Multi-argument form of C allows an additional numeric argument. The meaning of this argument is described in L. When finding a program to run, Perl first asks the OS to look for executables on C (OS/2 adds extension F<.exe> if no extension is present). If not found, it looks for a script with possible extensions added in this order: no extension, F<.cmd>, F<.btm>, F<.bat>, F<.pl>. If found, Perl checks the start of the file for magic strings C<"#!"> and C<"extproc ">. If found, Perl uses the rest of the first line as the beginning of the command line to run this script. The only mangling done to the first line is extraction of arguments (currently up to 3), and ignoring of the path-part of the "interpreter" name if it can't be found using the full path. E.g., C may lead Perl to finding F with the first line being extproc /bin/bash -x -c If F is not found, then Perl looks for an executable F on C. If found in F, then the above system() is translated to system qw(C:/emx.add/bin/bash.exe -x -c C:/emx/bin/foo.cmd bar baz) One additional translation is performed: instead of F Perl uses the hardwired-or-customized shell (see C>). The above search for "interpreter" is recursive: if F executable is not found, but F is found, Perl will investigate its first line etc. The only hardwired limit on the recursion depth is implicit: there is a limit 4 on the number of additional arguments inserted before the actual arguments given to system(). In particular, if no additional arguments are specified on the "magic" first lines, then the limit on the depth is 4. If Perl finds that the found executable is of different type than the current session, it will start the new process in a separate session of necessary type. Call via C to disable this magic. B. Due to the described logic, you need to explicitly specify F<.com> extension if needed. Moreover, if the executable F is requested, Perl will not look for F. [This may change in the future.] =head2 C on the first line If the first chars of a Perl script are C<"extproc ">, this line is treated as C<#!>-line, thus all the switches on this line are processed (twice if script was started via cmd.exe). See L. =head2 Additional modules: L, L, L, L, L. These modules provide access to additional numeric argument for C and to the information about the running process, to DLLs having functions with REXX signature and to the REXX runtime, to OS/2 databases in the F<.INI> format, and to Extended Attributes. Two additional extensions by Andreas Kaiser, C, and C, are included into C directory, mirrored on CPAN. =head2 Prebuilt methods: =over 4 =item C used by C, see L. =item C used by C for DLL name mangling. =item C Self explanatory. =item C leaves drive as it is. =item C chanes the "current" drive. =item C means has drive letter and is_rooted. =item C means has leading C<[/\\]> (maybe after a drive-letter:). =item C means changes with current dir. =item C Interface to cwd from EMX. Used by C. =item C Really really odious function to implement. Returns absolute name of file which would have C if CWD were C. C defaults to the current dir. =item C Get current value of extended library search path. If C is present and I, works with END_LIBPATH, otherwise with C. =item C Set current value of extended library search path. If C is present and I, works with END_LIBPATH, otherwise with C. =item C Returns C if it was not called yet, otherwise bit 1 is set if on the previous call do_harderror was enabled, bit 2 is set if if on previous call do_exception was enabled. This function enables/disables error popups associated with hardware errors (Disk not ready etc.) and software exceptions. I know of no way to find out the state of popups I the first call to this function. =item C Returns C if it was not called yet, otherwise return false if errors were not requested to be written to a hard drive, or the drive letter if this was requested. This function may redirect error popups associated with hardware errors (Disk not ready etc.) and software exceptions to the file POPUPLOG.OS2 at the root directory of the specified drive. Overrides OS2::Error() specified by individual programs. Given argument undef will disable redirection. Has global effect, persists after the application exits. I know of no way to find out the state of redirection of popups to the disk I the first call to this function. =item OS2::SysInfo() Returns a hash with system information. The keys of the hash are MAX_PATH_LENGTH, MAX_TEXT_SESSIONS, MAX_PM_SESSIONS, MAX_VDM_SESSIONS, BOOT_DRIVE, DYN_PRI_VARIATION, MAX_WAIT, MIN_SLICE, MAX_SLICE, PAGE_SIZE, VERSION_MAJOR, VERSION_MINOR, VERSION_REVISION, MS_COUNT, TIME_LOW, TIME_HIGH, TOTPHYSMEM, TOTRESMEM, TOTAVAILMEM, MAXPRMEM, MAXSHMEM, TIMER_INTERVAL, MAX_COMP_LENGTH, FOREGROUND_FS_SESSION, FOREGROUND_PROCESS =item OS2::BootDrive() Returns a letter without colon. =item C, C Transforms the current application into a PM application and back. The argument true means that a real message loop is going to be served. OS2::MorphPM() returns the PM message queue handle as an integer. See L<"Centralized management of resources"> for additional details. =item C Fake on-demand retrieval of outstanding PM messages. If C is false, will not dispatch messages if a real message loop is known to be present. Returns number of messages retrieved. Dies with "QUITing..." if WM_QUIT message is obtained. =item C Retrieval of PM messages until window creation/destruction. If C is false, will not dispatch messages if a real message loop is known to be present. Returns change in number of windows. If C is given, it is incremented by the number of messages retrieved. Dies with "QUITing..." if WM_QUIT message is obtained. =item C the same as L<_control87(3)> of EMX. Takes integers as arguments, returns the previous coprocessor control word as an integer. Only bits in C which are present in C are changed in the control word. =item OS2::get_control87() gets the coprocessor control word as an integer. =item C The variant of OS2::_control87() with default values good for handling exception mask: if no C, uses exception mask part of C only. If no C, disables all the floating point exceptions. See L<"Misfeatures"> for details. =back (Note that some of these may be moved to different libraries - eventually). =head2 Prebuilt variables: =over 4 =item $OS2::emx_rev same as _emx_rev of EMX, a string similar to C<0.9c>. =item $OS2::emx_env same as _emx_env of EMX, a number similar to 0x8001. =item $OS2::os_ver a number C. =back =head2 Misfeatures =over 4 =item * Since L is present in EMX, but is not functional, it is emulated by perl. To disable the emulations, set environment variable C. =item * Here is the list of things which may be "broken" on EMX (from EMX docs): =over 4 =item * The functions L, L, and L are not implemented. =item * L is not required and not implemented. =item * L is not yet implemented (dummy function). (Perl has a workaround.) =item * L: Special treatment of PID=0, PID=1 and PID=-1 is not implemented. =item * L: WUNTRACED Not implemented. waitpid() is not implemented for negative values of PID. =back Note that C does not work with the current version of EMX. =item * Since F is used for globing (see L), the bugs of F plague perl as well. In particular, uppercase letters do not work in C<[...]>-patterns with the current pdksh. =item * Unix-domain sockets on OS/2 live in a pseudo-file-system C. To avoid a failure to create a socket with a name of a different form, C<"/socket/"> is prepended to the socket name (unless it starts with this already). This may lead to problems later in case the socket is accessed via the "usual" file-system calls using the "initial" name. =item * Apparently, IBM used a compiler (for some period of time around '95?) which changes FP mask right and left. This is not I bad for IBM's programs, but the same compiler was used for DLLs which are used with general-purpose applications. When these DLLs are used, the state of floating-point flags in the application is not predictable. What is much worse, some DLLs change the floating point flags when in _DLLInitTerm() (e.g., F). This means that even if you do not I any function in the DLL, just the act of loading this DLL will reset your flags. What is worse, the same compiler was used to compile some HOOK DLLs. Given that HOOK dlls are executed in the context of I the applications in the system, this means a complete unpredictablity of floating point flags on systems using such HOOK DLLs. E.g., F of B origin changes the floating point flags on each write to the TTY of a VIO (windowed text-mode) applications. Some other (not completely debugged) situations when FP flags change include some video drivers (?), and some operations related to creation of the windows. People who code B may have more experience on this. Perl is generally used in the situation when all the floating-point exceptions are ignored, as is the default under EMX. If they are not ignored, some benign Perl programs would get a C and would die a horrible death. To circumvent this, Perl uses two hacks. They help against I type of damage only: FP flags changed when loading a DLL. One of the hacks is to disable floating point exceptions on startup (as is the default with EMX). This helps only with compile-time-linked DLLs changing the flags before main() had a chance to be called. The other hack is to restore FP flags after a call to dlopen(). This helps against similar damage done by DLLs _DLLInitTerm() at runtime. Currently no way to switch these hacks off is provided. =back =head2 Modifications Perl modifies some standard C library calls in the following ways: =over 9 =item C C uses F if shell is required, cf. L<"PERL_SH_DIR">. =item C is created using C or C environment variable, via C. =item C If the current directory is not writable, file is created using modified C, so there may be a race condition. =item C a dummy implementation. =item C C special-cases F and F. =item C, C these EMX functions do not work if the path contains a trailing C. Perl contains a workaround for this. =item C Since L is present in EMX, but is not functional, it is emulated by perl. To disable the emulations, set environment variable C. =back =head2 Identifying DLLs All the DLLs built with the current versions of Perl have ID strings identifying the name of the extension, its version, and the version of Perl required for this DLL. Run C to find this info. =head2 Centralized management of resources Since to call certain OS/2 API one needs to have a correctly initialized C subsystem, OS/2-specific extensions may require getting Cs and Cs. If an extension would do it on its own, another extension could fail to initialize. Perl provides a centralized management of these resources: =over =item C To get the HAB, the extension should call C in C. After this call is performed, C may be accessed as C. There is no need to release the HAB after it is used. If by some reasons F cannot be included, use extern int Perl_hab_GET(void); instead. =item C There are two cases: =over =item * the extension needs an C only because some API will not work otherwise. Use C below. =item * the extension needs an C since it wants to engage in a PM event loop. Use C below. =back To get an C, the extension should call C in C. After this call is performed, C may be accessed as C. To signal to Perl that HMQ is not needed any more, call C. Perl process will automatically morph/unmorph itself into/from a PM process if HMQ is needed/not-needed. Perl will automatically enable/disable C message during shutdown if the message queue is served/not-served. B. If during a shutdown there is a message queue which did not disable WM_QUIT, and which did not process the received WM_QUIT message, the shutdown will be automatically cancelled. Do not call C unless you are going to process messages on an orderly basis. =back =head1 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 distribution: =head2 F The main workhorse. This is a chimera executable: it is compiled as an C-style executable, but is linked with C-style dynamic library F, and with dynamic CRT DLL. This executable is a VIO application. It can load perl dynamic extensions, and it can fork(). B Keep in mind that fork() is needed to open a pipe to yourself. =head2 F This is a statically linked C-style executable. It cannot load dynamic Perl extensions. The executable supplied in binary distributions has a lot of extensions prebuilt, thus the above restriction is important only if you use custom-built extensions. This executable is a VIO application. I The friends locked into C world would appreciate the fact that this executable runs under DOS, Win0.3*, Win0.95 and WinNT with an appropriate extender. See L<"Other OSes">. =head2 F This is the same executable as F, but it is a PM application. B Usually (unless explicitly redirected during the startup) STDIN, STDERR, and STDOUT of a PM application are redirected to F. However, it is possible to I them if you start C from a PM program which emulates a console window, like I of Emacs or EPM. Thus it I to use Perl debugger (see L) to debug your PM application (but beware of the message loop lockups - this will not work if you have a message queue to serve, unless you hook the serving into the getc() function of the debugger). Another way to see the output of a PM program is to run it as pm_prog args 2>&1 | cat - with a shell I from F, so that it does not create a link between a VIO session and the session of C. (Such a link closes the VIO window.) E.g., this works with F - or with Perl! open P, 'pm_prog args 2>&1 |' or die; print while

; The flavor F is required if you want to start your program without a VIO window present, but not Ced (run C for more info). Very useful for extensions which use PM, like C or C. =head2 F This is an C-style executable which is dynamically linked to F and CRT DLL. I know no advantages of this executable over C, but it cannot fork() at all. Well, one advantage is that the build process is not so convoluted as with C. It is a VIO application. =head2 Why strange names? Since Perl processes the C<#!>-line (cf. L, L, L, L), it should know when a program I. 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). =head2 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 the complicated-to-developers but very quick and convenient-to-users "hard" dynamic linking used by OS/2. There are two distinctive features of the dyna-linking model of OS/2: all the references to external functions are resolved at the compile time; there is no runtime fixup of the DLLs after they are loaded into memory. The first feature is an enormous advantage over other models: it avoids conflicts when several DLLs used by an application export entries with the same name. In such cases "other" models of dyna-linking just choose between these two entry points using some random criterion - with predictable disasters as results. But it is the second feature which requires the build of F. The address tables of DLLs are patched only once, when they are loaded. The addresses of the entry points into DLLs are guaranteed to be the same for all the programs which use the same DLL. This removes the runtime fixup - once DLL is loaded, its code is read-only. While this allows some (significant?) performance advantages, this makes life much harder for developers, since the above scheme makes it impossible for a DLL to be "linked" to a symbol in the F<.EXE> file. Indeed, this would need a DLL to have different relocations tables for the (different) executables which use this DLL. However, a dynamically loaded Perl extension is forced to use some symbols from the perl executable, e.g., to know how to find the arguments to the functions: the arguments live on the perl internal evaluation stack. The solution is to put the main code of the interpreter into a DLL, and make the F<.EXE> file which just loads this DLL into memory and supplies command-arguments. The extension DLL cannot link to symbols in F<.EXE>, but it has no problem linking to symbols in the F<.DLL>. This I increases the load time for the application (as well as complexity of the compilation). Since interpreter is in a DLL, the C RTL is basically forced to reside in a DLL as well (otherwise extensions would not be able to use CRT). There are some advantages if you use different flavors of perl, such as running F and F simultaneously: they share the memory of F. B. There is one additional effect which makes DLLs more wasteful: DLLs are loaded in the shared memory region, which is a scarse resource given the 512M barrier of the "standard" OS/2 virtual memory. The code of F<.EXE> files is also shared by all the processes which use the particular F<.EXE>, but they are "shared in the private address space of the process"; this is possible because the address at which different sections of the F<.EXE> file are loaded is decided at compile-time, thus all the processes have these sections loaded at same addresses, and no fixup of internal links inside the F<.EXE> is needed. Since DLLs may be loaded at run time, to have the same mechanism for for DLLs one needs to have the address range of I DLLs in the system to be available I which did not load a particular DLL yet. This is why the DLLs are mapped to the shared memory region. =head2 Why chimera build? Current EMX environment does not allow DLLs compiled using Unixish C format to export symbols for data (or at least some types of data). This forces C-style compile of F. Current EMX environment does not allow F<.EXE> files compiled in C format to fork(). fork() is needed for exactly three Perl operations: =over 4 =item * explicit fork() in the script, =item * C =item * C, in other words, opening pipes to itself. =back While these operations are not questions of life and death, they are needed for a lot of useful scripts. This forces C-style compile of F. =head1 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. =head2 C Specific for EMX port. Should have the form path1;path2 or path1 path2 If the beginning of some prebuilt path matches F, it is substituted with F. Should be used if the perl library is moved from the default location in preference to C, since this would not leave wrong entries in @INC. For example, if the compiled version of perl looks for @INC in F, and you want to install the library in F, do set PERLLIB_PREFIX=f:/perllib/lib;h:/opt/gnu This will cause Perl with the prebuilt @INC of 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 . to use the following @INC: 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 . =head2 C If 0, perl ignores setlocale() failing. May be useful with some strange Is. =head2 C If 0, perl would not warn of in case of unwarranted free(). With older perls this might be useful in conjunction with the module DB_File, which was buggy when dynamically linked and OMF-built. Should not be set with newer Perls, since this may hide some I problems. =head2 C Specific for EMX port. Gives the directory part of the location for F. =head2 C Specific for EMX port. Since L is present in EMX, but is not functional, it is emulated by perl. To disable the emulations, set environment variable C. =head2 C or C Specific for EMX port. Used as storage place for temporary files. =head1 Evolution Here we list major changes which could make you by surprise. =head2 Priorities C and C are not compatible with earlier ports by Andreas Kaiser. See C<"setpriority, getpriority">. =head2 DLL name mangling: pre 5.6.2 With the release 5.003_01 the dynamically loadable libraries should be rebuilt when a different version of Perl is compiled. In particular, DLLs (including F) are now created with the names which contain a checksum, thus allowing workaround for OS/2 scheme of caching DLLs. It may be possible to code a simple workaround which would =over =item * find the old DLLs looking through the old @INC; =item * mangle the names according to the scheme of new perl and copy the DLLs to these names; =item * edit the internal C tables of DLL to reflect the change of the name (probably not needed for Perl extension DLLs, since the internally coded names are not used for "specific" DLLs, they used only for "global" DLLs). =item * edit the internal C tables and change the name of the "old" F to the "new" F. =back =head2 DLL name mangling: 5.6.2 and beyond In fact mangling of I DLLs was done due to misunderstanding of the OS/2 dynaloading model. OS/2 (effectively) maintains two different tables of loaded DLL: =over =item Global DLLs those loaded by the base name from C; including those associated at link time; =item specific DLLs loaded by the full name. =back When resolving a request for a global DLL, the table of already-loaded specific DLLs is (effectively) ignored; moreover, specific DLLs are I loaded from the prescribed path. There is/was a minor twist which makes this scheme fragile: what to do with DLLs loaded from =over =item C and C (which depend on the process) =item F<.> from C which I depends on the process (although C is the same for all the processes). =back Unless C is set to C (and the kernel is after 2000/09/01), such DLLs are considered to be global. When loading a global DLL it is first looked in the table of already-loaded global DLLs. Because of this the fact that one executable loaded a DLL from C and C, or F<.> from C may affect I DLL is loaded when I executable requests a DLL with the same name. I is the reason for version-specific mangling of the DLL name for perl DLL. Since the Perl extension DLLs are always loaded with the full path, there is no need to mangle their names in a version-specific ways: their directory already reflects the corresponding version of perl, and @INC takes into account binary compatibility with older version. Starting from C<5.6.2> the name mangling scheme is fixed to be the same as for Perl 5.005_53 (same as in a popular binary release). Thus new Perls will be able to I of old extension DLLs if @INC allows finding their directories. However, this still does not guarantie that these DLL may be loaded. The reason is the mangling of the name of the I. And since the extension DLLs link with the Perl DLL, extension DLLs for older versions would load an older Perl DLL, and would most probably segfault (since the data in this DLL is not properly initialized). There is a partial workaround (which can be made complete with newer OS/2 kernels): create a forwarder DLL with the same name as the DLL of the older version of Perl, which forwards the entry points to the newer Perl's DLL. Make this DLL accessible on (say) the C of the new Perl executable. When the new executable accesses old Perl's extension DLLs, they would request the old Perl's DLL by name, get the forwarder instead, so effectively will link with the currently running (new) Perl DLL. This may break in two ways: =over =item * Old perl executable is started when a new executable is running has loaded an extension compiled for the old executable (ouph!). In this case the old executable will get a forwarder DLL instead of the old perl DLL, so would link with the new perl DLL. While not directly fatal, it will behave the same as new excutable. This beats the whole purpose of explicitly starting an old executable. =item * A new executable loads an extension compiled for the old executable when an old perl executable is running. In this case the extension will not pick up the forwarder - with fatal results. =back With support for C this may be circumvented - unless one of DLLs is started from F<.> from C (I do not know whether C affects this case). B. Unless newer kernels allow F<.> in C (older do not), this mess cannot be completely cleaned. B. C, C and C are not environment variables, although F emulates them on C lines. From Perl they may be accessed by L and L. =head2 DLL forwarder generation Assume that the old DLL is named F (as is one for 5.005_53), and the new version is 5.6.1. Create a file F with 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 modifying the versions/names as needed. Run perl -wnle "next if 0../EXPORTS/; print qq( \"$1\") if /\"(\w+)\"/" perl5.def >lst in the Perl build directory (to make the DLL smaller replace perl5.def with the definition file for the older version of Perl if present). cat perl5shim.def-leader lst >perl5shim.def gcc -Zomf -Zdll -o perlE0AC.dll perl5shim.def -s -llibperl (ignore multiple C). =head2 Threading As of release 5.003_01 perl is linked to multithreaded C RTL DLL. If perl itself is not compiled multithread-enabled, so will not be perl's malloc(). However, extensions may use multiple thread on their own risk. This was needed to compile C for XFree86-OS/2 out-of-the-box, and link with DLLs for other useful libraries, which typically are compiled with C<-Zmt -Zcrtdll>. =head2 Calls to external programs Due to a popular demand the perl external program calling has been changed wrt Andreas Kaiser's port. I perl needs to call an external program I, the F will be called, or whatever is the override, see L<"PERL_SH_DIR">. Thus means that you need to get some copy of a F as well (I use one from pdksh). The path F above is set up automatically during the build to a correct value on the builder machine, but is overridable at runtime, B a consensus on C was that perl should use one non-overridable shell per platform. The obvious choices for OS/2 are F and F. Having perl build itself would be impossible with F as a shell, thus I picked up C. This 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 L<"Prerequisites">). B currently F of pdksh calls external programs via fork()/exec(), and there is I functioning exec() on OS/2. exec() is emulated by EMX by an asynchronous call while the caller waits for child completion (to pretend that the C did not change). This means that 1 I copy of F 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 F unless needed (metachars found). One can always start F explicitly via system 'cmd', '/c', 'mycmd', 'arg1', 'arg2', ... If you need to use F, 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(), C<``>, and C. With current perl you may override only system(), readpipe() - the explicit version of C<``>, and maybe exec(). The code will substitute the one-argument call to system() by C. If you have some working code for C, please send it to me, I will include it into distribution. I have no need for such a module, so cannot test it. For the details of the current situation with calling external programs, see L. Set us mention a couple of features: =over 4 =item * External scripts may be called by their basename. Perl will try the same extensions as when processing B<-S> command-line switch. =item * External scripts starting with C<#!> or C will be executed directly, without calling the shell, by calling the program specified on the rest of the first line. =back =head2 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 benchmarks show that Perl's malloc is 5 times quicker than EMX one. I do not have convincing data about memory footprint, but a (pretty random) benchmark showed that Perl's one is 5% better. Combination of perl's malloc() and rigid DLL name resolution 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 C added. (Currently only DLL perl has this, it should propagate to F shortly.) =head2 Threads One can build perl with thread support enabled by providing C<-D usethreads> option to F. Currently OS/2 support of threads is very preliminary. Most notable problems: =over 4 =item C may have a race condition. Needs a reimplementation (in terms of chaining waiting threads, with the linked list stored in per-thread structure?). =item F has a couple of static variables used in OS/2-specific functions. (Need to be moved to per-thread structure, or serialized?) =back Note that these problems should not discourage experimenting, since they have a low probability of affecting small programs. =head1 BUGS This description was not updated since 5.6.1, see F for more info. =cut OS/2 extensions ~~~~~~~~~~~~~~~ I include 3 extensions by Andreas Kaiser, OS2::REXX, OS2::UPM, and OS2::FTP, into my ftp directory, mirrored on CPAN. I made some minor changes needed to compile them by standard tools. I cannot test UPM and FTP, so I will appreciate your feedback. Other extensions there are OS2::ExtAttr, OS2::PrfDB for tied access to EAs and .INI files - and maybe some other extensions at the time you read it. Note that OS2 perl defines 2 pseudo-extension functions OS2::Copy::copy and DynaLoader::mod2fname (many more now, see L). The -R switch of older perl is deprecated. If you need to call a REXX code which needs access to variables, include the call into a REXX compartment created by REXX_call {...block...}; Two new functions are supported by REXX code, REXX_eval 'string'; REXX_eval_with 'string', REXX_function_name => \&perl_sub_reference; If you have some other extensions you want to share, send the code to me. At least two are available: tied access to EA's, and tied access to system databases. =head1 AUTHOR Ilya Zakharevich, ilya@math.ohio-state.edu =head1 SEE ALSO perl(1). =cut