perlos2 - Perl under OS/2, DOS, Win0.3*, Win0.95 and WinNT.
One can read this document in the following formats:
man perlos2view perl perlos2explorer perlos2.htmlinfo perlos2to list some (not all may be available simultaneously), or it may be readas is: either asREADME.os2, orpod/perlos2.pod.
To read the.INF version of documentation (very 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.zipin?:\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 havelynx.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 haveview emxbook working by settingEMXBOOK environment variable as it is described in EMX docs).
The target is to make OS/2 the best supported platform for using/building/developing Perl andPerl 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 nottoo hard).
The current state is quite close to this target. Known limitations:
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() afteruseing dynamically loading extensions would not work with very old versions of EMX.
You need a separate perl executableperl__.exe (seeperl__.exe) 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 standardperl.exe from a text-mode window is possible too, I have seen cases when this causes degradation of the system stability. Usingperl__.exe avoids such a degradation.
There is no simple way to access WPS objects. The only way I know is viaOS2::REXX extension (seeOS2::REXX), and we do not have access to convenience methods of Object-REXX. (Is it possible at all? I know of no Object-REXX API.) TheSOM extension (currently in alpha-text) may eventually remove this shortcoming.
Please keep this list up-to-date by informing me about other items.
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"perl_.exe".
Note that not all features of Perl are available under these environments. This depends on the features theextender - most probably RSX - decided to implement.
Cf.Prerequisites.
EMX runtime is required (may be substituted by RSX). Note that it is possible to makeperl_.exe to run under DOS without any external support by bindingemx.exe/rsx.exe to it, seeemxbind. Note that under DOS for best results one should use RSX runtime, which has much more functions working (likefork,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, currently0.9d 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 nameemxrt.zip.
NOTE. It is enough to haveemx.exe/rsx.exe on your path. One does not need to specify them explicitly (though this
emx perl_.exe -de 0will work as well.)
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"Other OSes"). RSX would not work with VCPI only, as EMX would, it requires DMPI.
Having RSX and the latestsh.exe one gets a fully functional*nix-ish environment under DOS, say,fork,`` and pipe-open 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/contribftp://ftp.uni-bielefeld.de/pub/systems/msdos/miscftp://ftp.leo.org/pub/comp/os/os2/leo/devtools/emx+gcc/contribContact the author onrainer@mathematik.uni-bielefeld.de.
The latestsh.exe with DOS hooks is available in
ftp://ftp.math.ohio-state.edu/pub/users/ilya/os2/assh_dos.zip or under similar names starting withsh,pdksh etc.
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.
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 namedsh.exe, and located either in the wired-in-during-compile locations (usuallyF:/bin), or in configurable location (see"PERL_SH_DIR").
For best results use EMX pdksh. The standard binary (5.2.14 or later) runs under DOS (withRSX) as well, see
ftp://ftp.math.ohio-state.edu/pub/users/ilya/os2/Start your Perl programfoo.pl with argumentsarg1 arg2 arg3 the same way as on any other platform, by
perl foo.pl arg1 arg2 arg3If 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 arg3Alternately, 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_optsrename your program tofoo.cmd, and start it by typing
foo arg1 arg2 arg3Note that because of stupid OS/2 limitations the full path of the perl script is not available when you useextproc, thus you are forced to use-S perl switch, and your script should be on thePATH. 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 theextproc line in your script, see"extproc on the first line").
To understand what the abovemagic does, read perl docs about-S switch - seeperlrun, and cmdref aboutextproc:
view perl perlrunman perlrunview cmdref extprochelp extprocor whatever method you prefer.
There are also endless possibilities to useexecutable extensions of 4os2,associations of WPS and so on... However, if you use *nixish shell (likesh.exe supplied in the binary distribution), you need to follow the syntax specified in"Switches" in perlrun.
Note that-S switch enables a search with additional extensions.cmd,.btm,.bat,.pl as well.
This is what system() (see"system" in perlfunc),`` (see"I/O Operators" in perlop), andopen pipe (see"open" in perlfunc) are for. (Avoid exec() (see"exec" in perlfunc) unless you know what you do).
Note however that to use some of these operators you need to have a sh-syntax shell installed (see"Pdksh","Frequently asked questions"), and perl should be able to find it (see"PERL_SH_DIR").
The cases when the shell is used are:
One-argument system() (see"system" in perlfunc), exec() (see"exec" in perlfunc) with redirection or shell meta-characters;
Pipe-open (see"open" in perlfunc) with the command which contains redirection or shell meta-characters;
Backticks`` (see"I/O Operators" in perlop) with the command which contains redirection or shell meta-characters;
If the executable called by system()/exec()/pipe-open()/`` is a script with the "magic"#! line orextproc line which specifies shell;
If the executable called by system()/exec()/pipe-open()/`` is a script without "magic" line, and$ENV{EXECSHELL} is set to shell;
If the executable called by system()/exec()/pipe-open()/`` is not found;
For globbing (see"glob" in perlfunc,"I/O Operators" in perlop).
For the sake of speed for a common case, in the above algorithms backslashes in the command name are not considered as shell metacharacters.
Perl starts scripts which begin with cookiesextproc or#! directly, without an intervention of shell. Perl uses the same algorithm to find the executable aspdksh: if the path on#! line does not work, and contains/, then the executable is searched in. and onPATH. To find arguments for these scripts Perl uses a different algorithm thanpdksh: up to 3 arguments are recognized, and trailing whitespace is stripped.
If a script does not contain such a cooky, then to avoid callingsh.exe, Perl uses the same algorithm aspdksh: if$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 directory, then on components of$ENV{PATH} using the following order of appended extensions: no extension,.cmd,.btm,.bat,.pl.
Note that Perl will start to look for scripts only if OS/2 cannot start the specified application, thussystem 'blah' will not look for a script if there is an executable fileblah.exeanywhere onPATH.
Note also that executable files on OS/2 can have an arbitrary extension, but.exe will be automatically appended if no dot is present in the name. The workaround as as simple as that: sinceblah. andblah denote the same file, to start an executable residing in filen:/bin/blah (no extension) give an argumentn:/bin/blah. (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 insystem 'cmd /c myprog', or start it using optional arguments to system() documented inOS2::Process module. This is considered to be a feature.
Perl binary distributions come with atestperl.cmd script which tries to detect common problems with misconfigured installations. There is a pretty large chance it will discover which step of the installation you managed to goof.;-)
Did you run your programs with-w switch? See"2 (and DOS) programs under Perl" in Starting OS.
Do you try to runinternal shell commands, like`copy a b` (internal forcmd.exe), or`glob a*b` (internal for ksh)? You need to specify your shell explicitly, like`cmd /c copy a b`, since Perl cannot deduce which commands are internal to your shell.
-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.
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"I cannot run external programs", or a deeper problem. Basically: youneed RSX (see"Prerequisites") for these commands to work, and you may need a port ofsh.exe which understands command arguments. One of such ports is listed in"Prerequisites" under RSX. Do not forget to set variable"PERL_SH_DIR" as well.
DPMI is required for RSX.
find.exe "pattern" fileUse one of
system 'cmd', '/c', 'find "pattern" file';`cmd /c 'find "pattern" file'`This would startfind.exe viacmd.exe viash.exe viaperl.exe, but this is a price to pay if you want to use non-conforming program. In factfind.exe cannot be started at all using C library API only. Otherwise the following command-lines would be equivalent:
find "pattern" filefind pattern fileThe most convenient way of installing a binary distribution of perl is via perl installerinstall.exe. Just follow the instructions, and 99% of the installation blues would go away.
Note however, that you need to haveunzip.exe on your path, and EMX environmentrunning. The latter means that if you just installed EMX, and made all the needed changes toConfig.sys, you may need to reboot in between. Check EMX runtime by running
emxrevA folder is created on your desktop which contains some useful objects.
Things not taken care of by automatic binary installation:
PERL_BADLANGmay be needed if you change your codepageafter perl installation, and the new value is not supported by EMX. See"PERL_BADLANG".
PERL_BADFREEsee"PERL_BADFREE".
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 fileare 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 variablePERL_SHPATH intoConfig.sys. Please remove this variable and putPERL_SH_DIR instead.
As of version 5.00305, OS/2 perl binary distribution comes split into 11 components. Unfortunately, to enable configurable binary installation, the file paths in the zip files are not absolute, but relative to some directory.
Note that the extraction with the stored paths is still necessary (default with unzip, specify-d to pkunzip). However, you need to know where to extract the files. You need also to manually change entries inConfig.sys to reflect where did you put the files. Note that if you have some primitive unzipper (like pkunzip), you may get a lot of warnings/errors during unzipping. Upgrade to(w)unzip.
Below is the sample of what to do to reproduce the configuration on my machine:
unzip perl_exc.zip *.exe *.ico -d f:/emx.add/binunzip perl_exc.zip *.dll -d f:/emx.add/dll(have the directories with*.exe on PATH, and*.dll on LIBPATH);
unzip perl_aou.zip -d f:/emx.add/bin(have the directory on PATH);
unzip perl_utl.zip -d f:/emx.add/bin(have the directory on PATH);
unzip perl_mlb.zip -d f:/perllib/libIf this directory is exactly the same as the prefix which was compiled intoperl.exe, you do not need to change anything. However, for perl to find the library if you use a different path, you need toset PERLLIB_PREFIX inConfig.sys, see"PERLLIB_PREFIX".
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 byPERLLIB_PREFIX), you need to put this directory and subdirectory./os2 inPERLLIB orPERL5LIB variable. Do not usePERL5LIB unless you have it set already. See"ENVIRONMENT" in perl.
unzip perl_blb.zip -d f:/perllib/libSame remark as forperl_ste.zip.
unzip perl_man.zip -d f:/perllib/manThis directory should better be onMANPATH. You need to have a working man to access these files.
unzip perl_mam.zip -d f:/perllib/manThis directory should better be onMANPATH. You need to have a working man to access these files.
unzip perl_pod.zip -d f:/perllib/libThis is used by theperldoc program (seeperldoc), and may be used to generate HTML documentation usable by WWW browsers, and documentation in zillions of other formats:info,LaTeX,Acrobat,FrameMaker and so on.
unzip perl_inf.zip -d d:/os2/bookThis directory should better be onBOOKSHELF.
unzip perl_sh.zip -d f:/binThis is used by perl to run external commands which explicitly require shell, like the commands usingredirection andshell metacharacters. It is also used instead of explicit/bin/sh.
SetPERL_SH_DIR (see"PERL_SH_DIR") if you movesh.exe from the above location.
Note. It may be possible to use some other sh-compatible shell (file globbing - if done via shell - may break).
After you installed the components you needed and updated theConfig.sys correspondingly, you need to hand-editConfig.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 withf:/).
The automatic and manual perl installation leave precompiled paths inside perl executables. While these paths are overwriteable (see"PERLLIB_PREFIX","PERL_SH_DIR"), one may get better results by binary editing of paths inside the executables/DLLs.
Depending on how you built/installed perl you may have (otherwise identical) Perl documentation in the following formats:
Most probably the most convenient form. Under OS/2 view it as
view perlview perl perlfuncview perl lessview perl ExtUtils::MakeMaker(currently the last two may hit a wrong location, but this may improve soon). Under Win* see"SYNOPSIS".
If you want to build the docs yourself, and haveOS/2 toolkit, run
pod2ipf > perl.ipfin/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.
If you have perl documentation in the source form, perl utilities installed, and GNU groff installed, you may use
perldoc perlfuncperldoc lessperldoc ExtUtils::MakeMakerto 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.
If you have man installed on your system, and you installed perl manpages, use something like this:
man perlfuncman 3 lessman ExtUtils.MakeMakerto access documentation for different components of Perl. Start with
man perlNote that dot (.) is used as a package separator for documentation for packages, and as usual, sometimes you need to give the section -3 above - to avoid shadowing by theless(1) manpage.
Make sure that the directoryabove the directory with manpages is on ourMANPATH, like this
set MANPATH=c:/man;f:/perllib/manfor Perl manpages inf:/perllib/man/man1/ etc.
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/podpod2htmlAfter this you can direct your browser the fileperl.html in this directory, and go ahead with reading docs, like this:
explore file:///f:/perllib/lib/pod/perl.htmlAlternatively you may be able to get these docs prebuilt from CPAN.
info filesUsers of Emacs would appreciate it very much, especially withCPerl mode loaded. You need to get latestpod2info fromCPAN, or, alternately, prebuilt info pages.
forAcrobat are available on CPAN (for slightly old version of perl).
LaTeX docscan be constructed usingpod2latex.
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
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.configuresh Configure -des -D prefix=f:/perllibmakemake testmake installmake aout_testmake aout_installThis puts the executables in f:/perllib/bin. Manually move them to thePATH, manually move the builtperl*.dll toLIBPATH (here* is a not-very-meaningful hex checksum), and run
make installcmd INSTALLCMDDIR=d:/ir/on/pathWhat follows is a detailed guide through these steps.
You need to have the latest EMX development environment, the full GNU tool suite (gawk renamed to awk, and GNUfind.exe earlier on path than the OS/2find.exe, same withsort.exe, to check use
find --versionsort --version). You need the latest version ofpdksh installed assh.exe.
Check that you haveBSD 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,gnututil.zip,gnused.zip,gnupatch.zip,gnuawk.zip,gnumake.zip,bsddev.zip andksh527rt.zip (or a later version). Note that all these utilities are known to be available from LEO:
ftp://ftp.leo.org/pub/comp/os/os2/leo/gnuIf you haveexactly the same version of Perl installed already, make sure that no copies or perl are currently running. Later steps of the build may fail since an older version ofperl.dll loaded into memory may be found.
Also make sure that you have/tmp directory on the current drive, and. directory in yourLIBPATH. One may try to correct the latter condition by
set BEGINLIBPATH .if you use something likeCMD.EXE or latest versions of4os2.exe.
Make sure your gcc is good for-Zomf linking: runomflibs 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
link386shows you do not have it, doSelective install, and chooseLink object modules inOptional system utilities/More. If you get into link386 prompts, pressCtrl-C to exit.
You need to fetch the latest perl source (including developers releases). With some probability it is located in
http://www.perl.com/CPAN/src/5.0http://www.perl.com/CPAN/src/5.0/unsupportedIf 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.gzYou may see a message about errors while extractingConfigure. This is because there is a conflict with a similarly-named fileconfigure.
Change to the directory of extraction.
You need to apply the patches in./os2/diff.* like this:
gnupatch -p0 < os2\diff.configureYou may also need to apply the patches supplied with the binary distribution of perl.
Note also that thedb.lib anddb.a from the EMX distribution are not suitable for multi-threaded compile (even single-threaded flavor of Perl uses multi-threaded C RTL, for compatibility with XFree86-OS/2). Get a corrected one from
ftp://ftp.math.ohio-state.edu/pub/users/ilya/os2/db_mt.zipYou may look into the file./hints/os2.sh and correct anything wrong you find there. I do not expect it is needed anywhere.
sh Configure -des -D prefix=f:/perllibprefix means: where to install the resulting perl library. Giving correct prefix you may avoid the need to specifyPERLLIB_PREFIX, see"PERLLIB_PREFIX".
Ignore the message about missingln, and about-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
makeAt some moment the built may die, reporting aversion mismatch orunable to runperl. This means that you do not have. in your LIBPATH, soperl.exe cannot find the neededperl67B2.dll (treat these hex digits as line noise). After this is fixed the build should finish without a lot of fuss.
Now run
make testAll tests should succeed (with some of them skipped).
Some tests may generate extra messages similar to
bad freein database tests related to Berkeley DB.This should be fixed already. If it persists, you may disable this warnings, see"PERL_BADFREE".
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 kindshould be present during testing.
To get finer test reports, call
perl t/harnessThe report withio/pipe.t failing may look like this:
Failed Test Status Wstat Total Fail Failed List of failed------------------------------------------------------------io/pipe.t 12 1 8.33% 97 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:
Checksstat(). Tests:
Checksatime andmtime ofstat() - unfortunately, HPFS provides only 2sec time granularity (for compatibility with FAT?).
If you haven't yet moved perl.dll onto LIBPATH, do it now.
Run
make installIt would put the generated files into needed locations. Manually putperl.exe,perl__.exe andperl___.exe to a location on your PATH,perl.dll to a location on your LIBPATH.
Run
make installcmd INSTALLCMDDIR=d:/ir/on/pathto 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 what you gave toConfigure, seeMaking.
a.out-style buildProceed as above, but makeperl_.exe (see"perl_.exe") by
make perl_test and install by
make aout_testmake aout_installManually putperl_.exe to a location on your PATH.
Note. The build process forperl_does not know about all the dependencies, so you should make sure that anything is up-to-date, say, by doing
make perl_dllfirst.
/ became\ in pdksh.You have a very old pdksh. SeePrerequisites.
'errno' - unresolved externalYou do not have MT-safedb.lib. SeePrerequisites.
reported with very old version of tr and sed.
You have an older version ofperl.dll on your LIBPATH, which broke the build of extensions.
You did not runomflibs. SeePrerequisites.
You use an old version of GNU make. SeePrerequisites.
This can result from a bug in emx sprintf which was fixed in 0.9d fix 03.
setpriority,getpriorityNote 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.
WARNING. Callinggetpriority on a non-existing process can lock the system before Warp3 fixpak22.
system()Multi-argument form ofsystem() allows an additional numeric argument. The meaning of this argument is described inOS2::Process.
When finding a program to run, Perl first asks the OS to look for executables onPATH. If not found, it looks for a script with possible extensions added in this order: no extension,.cmd,.btm,.bat,.pl. If found, Perl checks the start of the file for magic strings"#!" and"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.,system 'foo', 'bar', 'baz' may lead Perl to findingC:/emx/bin/foo.cmd with the first line being
extproc /bin/bash -x -cIf/bin/bash is not found, and appending of executable extensions to/bin/bash does not help either, then Perl looks for an executablebash onPATH. If found inC:/emx.add/bin/bash.exe, 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/bin/sh Perl uses the hardwired-or-customized shell (see"PERL_SH_DIR").
The above search for "interpreter" is recursive: ifbash executable is not found, butbash.btm 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 viaOS2::Process to disable this magic.
extproc on the first lineIf the first chars of a Perl 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). See"DESCRIPTION" in perlrun.
OS2::Process,OS2::DLL,OS2::REXX,OS2::PrfDB,OS2::ExtAttr. These modules provide access to additional numeric argument forsystem 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.INI format, and to Extended Attributes.
Two additional extensions by Andreas Kaiser,OS2::UPM, andOS2::FTP, are included intoILYAZ directory, mirrored on CPAN.
File::Copy::syscopyused byFile::Copy::copy, seeFile::Copy.
DynaLoader::mod2fnameused byDynaLoader for DLL name mangling.
Cwd::current_drive()Self explanatory.
Cwd::sys_chdir(name)leaves drive as it is.
Cwd::change_drive(name)chanes the "current" drive.
Cwd::sys_is_absolute(name)means has drive letter and is_rooted.
Cwd::sys_is_rooted(name)means has leading[/\\] (maybe after a drive-letter:).
Cwd::sys_is_relative(name)means changes with current dir.
Cwd::sys_cwd(name)Interface to cwd from EMX. Used byCwd::cwd.
Cwd::sys_abspath(name, dir)Really really odious function to implement. Returns absolute name of file which would havename if CWD weredir.Dir defaults to the current dir.
Cwd::extLibpath([type])Get current value of extended library search path. Iftype is present andtrue, works with END_LIBPATH, otherwise withBEGIN_LIBPATH.
Cwd::extLibpath_set( path [, type ] )Set current value of extended library search path. Iftype is present andtrue, works with END_LIBPATH, otherwise withBEGIN_LIBPATH.
OS2::Error(do_harderror,do_exception)Returnsundef 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 popupsbefore the first call to this function.
OS2::Errors2Drive(drive)Returnsundef 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 diskbefore the first call to this function.
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_PROCESSReturns a letter without colon.
OS2::MorphPM(serve),OS2::UnMorphPM(serve)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"Centralized management of resources" for additional details.
OS2::Serve_Messages(force)Fake on-demand retrieval of outstanding PM messages. Ifforce 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.
OS2::Process_Messages(force [, cnt])Retrieval of PM messages until window creation/destruction. Ifforce is false, will not dispatch messages if a real message loop is known to be present.
Returns change in number of windows. Ifcnt is given, it is incremented by the number of messages retrieved.
Dies with "QUITing..." if WM_QUIT message is obtained.
OS2::_control87(new,mask)the same as_control87(3) of EMX. Takes integers as arguments, returns the previous coprocessor control word as an integer. Only bits innew which are present inmask are changed in the control word.
gets the coprocessor control word as an integer.
OS2::set_control87_em(new=MCW_EM,mask=MCW_EM)The variant of OS2::_control87() with default values good for handling exception mask: if nomask, uses exception mask part ofnew only. If nonew, disables all the floating point exceptions.
See"Misfeatures" for details.
(Note that some of these may be moved to different libraries - eventually).
same as _emx_rev of EMX, a string similar to0.9c.
same as _emx_env of EMX, a number similar to 0x8001.
a numberOS_MAJOR + 0.001 * OS_MINOR.
Sinceflock(3) is present in EMX, but is not functional, it is emulated by perl. To disable the emulations, set environment variableUSE_PERL_FLOCK=0.
Here is the list of things which may be "broken" on EMX (from EMX docs):
The functionsrecvmsg(3),sendmsg(3), andsocketpair(3) are not implemented.
sock_init(3) is not required and not implemented.
flock(3) is not yet implemented (dummy function). (Perl has a workaround.)
kill(3): Special treatment of PID=0, PID=1 and PID=-1 is not implemented.
WUNTRACED Not implemented. waitpid() is not implemented for negative values of PID.Note thatkill -9 does not work with the current version of EMX.
Sincesh.exe is used for globing (see"glob" in perlfunc), the bugs ofsh.exe plague perl as well.
In particular, uppercase letters do not work in[...]-patterns with the current pdksh.
Unix-domain sockets on OS/2 live in a pseudo-file-system/sockets/.... To avoid a failure to create a socket with a name of a different form,"/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.
Apparently, IBM used a compiler (for some period of time around '95?) which changes FP mask right and left. This is notthat 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.,TCP32IP). This means that even if you do notcall 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 ofall the applications in the system, this means a complete unpredictablity of floating point flags on systems using such HOOK DLLs. E.g.,GAMESRVR.DLL ofDIVE 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 codeOpenGL 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 aSIGFPE and would die a horrible death.
To circumvent this, Perl uses two hacks. They help againstone 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.
Perl modifies some standard C library calls in the following ways:
popenmy_popen usessh.exe if shell is required, cf."PERL_SH_DIR".
tmpnamis created usingTMP orTEMP environment variable, viatempnam.
tmpfileIf the current directory is not writable, file is created using modifiedtmpnam, so there may be a race condition.
ctermida dummy implementation.
statos2_stat special-cases/dev/tty and/dev/con.
mkdir,rmdirthese EMX functions do not work if the path contains a trailing/. Perl contains a workaround for this.
flockSinceflock(3) is present in EMX, but is not functional, it is emulated by perl. To disable the emulations, set environment variableUSE_PERL_FLOCK=0.
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. Runbldlevel DLL-name to find this info.
Since to call certain OS/2 API one needs to have a correctly initializedWin subsystem, OS/2-specific extensions may require gettingHABs andHMQs. If an extension would do it on its own, another extension could fail to initialize.
Perl provides a centralized management of these resources:
HABTo get the HAB, the extension should callhab = perl_hab_GET() in C. After this call is performed,hab may be accessed asPerl_hab. There is no need to release the HAB after it is used.
If by some reasonsperl.h cannot be included, use
extern int Perl_hab_GET(void);instead.
HMQThere are two cases:
the extension needs anHMQ only because some API will not work otherwise. Useserve = 0 below.
the extension needs anHMQ since it wants to engage in a PM event loop. Useserve = 1 below.
To get anHMQ, the extension should callhmq = perl_hmq_GET(serve) in C. After this call is performed,hmq may be accessed asPerl_hmq.
To signal to Perl that HMQ is not needed any more, callperl_hmq_UNSET(serve). Perl process will automatically morph/unmorph itself into/from a PM process if HMQ is needed/not-needed. Perl will automatically enable/disableWM_QUIT message during shutdown if the message queue is served/not-served.
NOTE. 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 callperl_hmq_GET(1) unless you are going to process messages on an orderly basis.
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:
The main workhorse. This is a chimera executable: it is compiled as ana.out-style executable, but is linked withomf-style dynamic libraryperl.dll, and with dynamic CRT DLL. This executable is a VIO application.
It can load perl dynamic extensions, and it can fork().
Note. Keep in mind that fork() is needed to open a pipe to yourself.
This is a statically linkeda.out-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.
This is the only executable with does not require OS/2. The friends locked intoM$ world would appreciate the fact that this executable runs under DOS, Win0.3*, Win0.95 and WinNT with an appropriate extender. See"Other OSes".
This is the same executable asperl___.exe, but it is a PM application.
Note. Usually (unless explicitly redirected during the startup) STDIN, STDERR, and STDOUT of a PM application are redirected tonul. However, it is possible tosee them if you startperl__.exe from a PM program which emulates a console window, likeShell mode of Emacs or EPM. Thus itis possible to use Perl debugger (seeperldebug) 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 shelldifferent fromcmd.exe, so that it does not create a link between a VIO session and the session ofpm_porg. (Such a link closes the VIO window.) E.g., this works withsh.exe - or with Perl!
open P, 'pm_prog args 2>&1 |' or die;print while <P>;The flavorperl__.exe is required if you want to start your program without a VIO window present, but notdetached (runhelp detach for more info). Very useful for extensions which use PM, likePerl/Tk orOpenGL.
This is anomf-style executable which is dynamically linked toperl.dll and CRT DLL. I know no advantages of this executable overperl.exe, but it cannot fork() at all. Well, one advantage is that the build process is not so convoluted as withperl.exe.
It is a VIO application.
Since Perl processes the#!-line (cf."DESCRIPTION" in perlrun,"Switches" in perlrun,"Not a perl script" in perldiag,"No Perl script found in input" in perldiag), it should know when a programis 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).
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 ofperl.dll.
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.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.EXE file which just loads this DLL into memory and supplies command-arguments. The extension DLL cannot link to symbols in.EXE, but it has no problem linking to symbols in the.DLL.
Thisgreatly 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 runningperl.exe andperl__.exe simultaneously: they share the memory ofperl.dll.
NOTE. 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.EXE files is also shared by all the processes which use the particular.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.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.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 ofany of the loaded DLLs in the system to be availablein all the processes which did not load a particular DLL yet. This is why the DLLs are mapped to the shared memory region.
Current EMX environment does not allow DLLs compiled using Unixisha.out format to export symbols for data (or at least some types of data). This forcesomf-style compile ofperl.dll.
Current EMX environment does not allow.EXE files compiled inomf format to fork(). fork() is needed for exactly three Perl operations:
explicit fork() in the script,
open FH, "|-"
open FH, "-|", in other words, opening pipes to itself.
While these operations are not questions of life and death, they are needed for a lot of useful scripts. This forcesa.out-style compile ofperl.exe.
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_PREFIXSpecific for EMX port. Should have the form
path1;path2or
path1 path2If the beginning of some prebuilt path matchespath1, it is substituted withpath2.
Should be used if the perl library is moved from the default location in preference toPERL(5)LIB, since this would not leave wrong entries in @INC. For example, if the compiled version of perl looks for @INC inf:/perllib/lib, and you want to install the library inh:/opt/gnu, do
set PERLLIB_PREFIX=f:/perllib/lib;h:/opt/gnuThis will cause Perl with the prebuilt @INC of
f:/perllib/lib/5.00553/os2f:/perllib/lib/5.00553f:/perllib/lib/site_perl/5.00553/os2f:/perllib/lib/site_perl/5.00553.to use the following @INC:
h:/opt/gnu/5.00553/os2h:/opt/gnu/5.00553h:/opt/gnu/site_perl/5.00553/os2h:/opt/gnu/site_perl/5.00553.PERL_BADLANGIf 0, perl ignores setlocale() failing. May be useful with some strangelocales.
PERL_BADFREEIf 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 somereal problems.
PERL_SH_DIRSpecific for EMX port. Gives the directory part of the location forsh.exe.
USE_PERL_FLOCKSpecific for EMX port. Sinceflock(3) is present in EMX, but is not functional, it is emulated by perl. To disable the emulations, set environment variableUSE_PERL_FLOCK=0.
TMP orTEMPSpecific for EMX port. Used as storage place for temporary files.
Here we list major changes which could make you by surprise.
setpriority andgetpriority are not compatible with earlier ports by Andreas Kaiser. See"setpriority, getpriority".
With the release 5.003_01 the dynamically loadable libraries should be rebuilt when a different version of Perl is compiled. In particular, DLLs (includingperl.dll) 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
find the old DLLs looking through the old @INC;
mangle the names according to the scheme of new perl and copy the DLLs to these names;
edit the internalLX 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).
edit the internalIMPORT tables and change the name of the "old"perl????.dll to the "new"perl????.dll.
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 compilePerl/Tk for XFree86-OS/2 out-of-the-box, and link with DLLs for other useful libraries, which typically are compiled with-Zmt -Zcrtdll.
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 programvia shell, thef:/bin/sh.exe will be called, or whatever is the override, see"PERL_SH_DIR".
Thus means that you need to get some copy of ash.exe as well (I use one from pdksh). The pathF:/bin above is set up automatically during the build to a correct value on the builder machine, but is overridable at runtime,
Reasons: a consensus onperl5-porters was that perl should use one non-overridable shell per platform. The obvious choices for OS/2 arecmd.exe andsh.exe. Having perl build itself would be impossible withcmd.exe as a shell, thus I picked upsh.exe. 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"Prerequisites").
Disadvantages: currentlysh.exe of pdksh calls external programs via fork()/exec(), and there isno functioning exec() on OS/2. exec() is emulated by EMX by an asynchronous call while the caller waits for child completion (to pretend that thepid did not change). This means that 1extra copy ofsh.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 spawnsh.exe unless needed (metachars found).
One can always startcmd.exe explicitly via
system 'cmd', '/c', 'mycmd', 'arg1', 'arg2', ...If you need to usecmd.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(),``, andopen(,'...|'). 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() byCORE::system('cmd.exe', '/c', shift).
If you have some working code forOS2::Cmd, 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"2 (and DOS) programs under Perl" in Starting OS. Set us mention a couple of features:
External scripts may be called by their basename. Perl will try the same extensions as when processing-S command-line switch.
External scripts starting with#! orextproc will be executed directly, without calling the shell, by calling the program specified on the rest of the first line.
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 prefixemx_ added. (Currently only DLL perl has this, it should propagate toperl_.exe shortly.)
One can build perl with thread support enabled by providing-D usethreads option toConfigure. Currently OS/2 support of threads is very preliminary.
Most notable problems:
COND_WAITmay have a race condition. Needs a reimplementation (in terms of chaining waiting threads, with the linked list stored in per-thread structure?).
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 experimenting, since they have a low probability of affecting small programs.
Ilya Zakharevich, ilya@math.ohio-state.edu
perl(1).
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