perlos2 - Perl under OS/2, DOS, Win0.3*, Win0.95 and WinNT.
One can read this document in the following formats:
man perlos2
view perl perlos2
explorer perlos2.html
info perlos2
to list some (not all may be available simultaneously), or it may be read as is: either as README.os2, or pod/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.zip
in ?:\JUST_ADD\view.exe. This gives one an access to EMX's .INF docs as well (text form is available in /emx/doc in EMX's distribution).
Note that if you have lynx.exe installed, you can follow
WWW links from this document in .INF format. If you have
EMX docs installed correctly, you can follow library
links (you need to have view emxbook
working by setting EMXBOOK 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 and Perl applications, as well as make Perl the best language to use under OS/2. The secondary target is to try to make this work under DOS and Win* as well (but not too hard).
The current state is quite close to this target. Known limitations:
Some *nix programs use
fork() a lot, but currently
fork() is not supported after
useing dynamically loaded extensions.
OS2::REXX extension (see 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.)
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 build itself) under any environment which can run EMX. The current list is DOS, DOS-inside-OS/2, Win0.3*, Win0.95 and WinNT. Out of many perl flavors, only one works, see perl_.exe.
Note that not all features of Perl are available under these environments. This depends on the features the extender - most probably RSX - decided to implement.
Cf. Prerequisites.
popen and so on). In fact
RSX is required if there is no
VCPI present. Note the
RSX requires
DPMI.
Only the latest runtime is supported, currently 0.9c. Perl may run under earlier versions of
EMX, but this is not tested.
One can get different parts of EMX from, say
ftp://ftp.cdrom.com/pub/os2/emx09c/ ftp://hobbes.nmsu.edu/os2/unix/emx09c/
The runtime component should have the name emxrt.zip.
NOTE. It is enough to have emx.exe/rsx.exe on your path. One does not need to specify them explicitly (though this
emx perl_.exe -de 0
will work as well.)
Having
RSX and the latest sh.exe one gets a fully functional
*nix-ish environment under
DOS, say, fork, `` and pipe-open work. In fact, 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 rainer@mathematik.uni-bielefeld.de.
The latest sh.exe with DOS hooks is available at
ftp://ftp.math.ohio-state.edu/pub/users/ilya/os2/sh_dos.zip
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.
For best results use EMX pdksh. The soon-to-be-available standard binary (5.2.12?) runs under DOS (with RSX) as well, meanwhile use the binary from
ftp://ftp.math.ohio-state.edu/pub/users/ilya/os2/sh_dos.zip
Start your Perl program foo.pl with arguments arg1 arg2 arg3 the same way as on any other platform, by
perl foo.pl arg1 arg2 arg3
If you want to specify perl options -my_opts to the perl itself (as opposed to to your program), use
perl -my_opts foo.pl arg1 arg2 arg3
Alternately, if you use OS/2-ish shell, like CMD or 4os2, put the following at the start of your perl script:
extproc perl -S -my_opts
rename your program to foo.cmd, and start it by typing
foo arg1 arg2 arg3
Note that because of stupid
OS/2 limitations the full path of the perl script is
not available when you use extproc, thus you are forced to use -S perl switch, and your script should be on path. As a plus side, if you know
a full path to your script, you may still start it with
perl ../../blah/foo.cmd arg1 arg2 arg3
(note that the argument -my_opts is taken care of by the extproc line in your script, see extproc on the first line).
To understand what the above magic does, read perl docs about -S
switch - see the perlrun manpage, and cmdref about extproc:
view perl perlrun
man perlrun
view cmdref extproc
help extproc
or whatever method you prefer.
There are also endless possibilities to use executable extensions of 4os2, associations of
WPS and so on... However, if you use
*nixish shell (like sh.exe supplied in the binary distribution), you need to follow the syntax
specified in Switches.
Note that -S switch enables a search with additional extensions .cmd, .btm, .bat, .pl as well.
This is what
system() (see system), `` (see
I/O Operators), and open pipe (see open) are for. (Avoid
exec() (see exec) unless you know what you do).
Note however that to use some of these operators you need to have a sh-syntax shell installed (see Pdksh, Frequently asked questions), and perl should be able to find it (see PERL_SH_DIR).
The cases when the shell is used are:
One-argument
system() (see system),
exec() (see exec) with redirection or shell meta-characters;
`` (see I/O Operators) with the command which contains redirection or shell meta-characters;
system()/exec()/pipe-open()/
`` is a script with the ``magic'' #! line or extproc line which specifies shell;
system()/exec()/pipe-open()/
`` is a script without ``magic'' line, and $ENV{EXECSHELL} is set to shell;
system()/exec()/pipe-open()/
`` is not found;
For the sake of speed for a common case, in the above algorithms backslashes in the command name are not considered as shell metacharacters.
Perl starts scripts which begin with cookies
extproc or #! directly, without an intervention of shell. Perl uses the same algorithm to
find the executable as pdksh: if the path on #! line does not work, and contains /, then the executable is searched in . and on PATH. To find arguments for these scripts Perl uses a different algorithm than pdksh: up to 3 arguments are recognized, and trailing whitespace is stripped.
If a script does not contain such a cooky, then to avoid calling sh.exe, Perl uses the same algorithm as pdksh: if $ENV{EXECSHELL} is set, the script is given as the first argument to this command, if not
set, then
$ENV{COMSPEC} /c is used (or a hardwired guess if $ENV{COMSPEC} is not set).
If starting scripts directly, Perl will use exactly the same algorithm as
for the search of script given by -S command-line option: it will look in the current directory, then on
components of $ENV{PATH} using the following order of appended extensions: no extension, .cmd, .btm,
.bat, .pl.
Note that Perl will start to look for scripts only if
OS/2 cannot start the specified application, thus system 'blah' will not look for a script if there is an executable file blah.exe anywhere on PATH.
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: since blah. and blah denote the same file, to start an executable residing in file n:/bin/blah (no extension) give an argument n:/bin/blah. to
system().
The last note is that currently it is not straightforward to start
PM programs from
VIO (=text-mode) Perl process and visa versa. Either ensure that shell will be used, as in
system 'cmd /c epm', or start it using optional arguments to
system() documented in OS2::Process module. This is considered a bug and should be fixed soon.
Did you run your programs with -w switch? See
Starting OS.
Do you try to run internal shell commands, like `copy a b`
(internal for cmd.exe), or `glob a*b` (internal for ksh)? You need to specify your shell explicitly, like `cmd /c copy a b`, since Perl cannot deduce which commands are internal to your shell.
`` and pipe-open do not work under DOS.
This may a variant of just I cannot run external programs, or a deeper problem. Basically: you need
RSX (see Prerequisites) for these commands to work, and you may need a port of sh.exe which understands command arguments. One of such ports is listed in
Prerequisites under
RSX. Do not forget to set variable
<A HREF="#PERL_SH_DIR">PERL_SH_DIR</A> 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 start find.exe via cmd.exe via sh.exe via
perl.exe, but this is a price to pay if you want to use non-conforming program. In
fact find.exe cannot be started at all using
C library
API only. Otherwise the following command-lines were equivalent:
find "pattern" file find pattern file
The most convenient way of installing perl is via perl installer install.exe. Just follow the instructions, and 99% of the installation blues would go away.
Note however, that you need to have unzip.exe on your path, and EMX environment running. The latter means that if you just installed EMX, and made all the needed changes to Config.sys, you may need to reboot in between. Check EMX runtime by running
emxrev
A folder is created on your desktop which contains some useful objects.
Things not taken care of by automatic binary installation:
perl -MConfig -le "print $INC{'Config.pm'}"
While most important values in this file are updated by the binary installer, some of them may need to be hand-edited. I know no such data, please keep me informed if you find one.
NOTE. Because of a typo the binary installer of 5.00305 would install a
variable PERL_SHPATH into Config.sys. Please remove this variable and put <EM>PERL_SH_DIR</EM> 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 in Config.sys to reflect where did you put the files. Note that if you have some
primitive unzipper (like pkunzip), you may get a lot of warnings/errors
during unzipping. Upgrade to (w)unzip.
Below is the sample of what to do to reproduce the configuration on my machine:
unzip perl_exc.zip *.exe *.ico -d f:/emx.add/bin unzip perl_exc.zip *.dll -d f:/emx.add/dll
(have the directories with *.exe on
PATH, and *.dll on
LIBPATH);
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/lib
If this directory is preserved, you do not need to change anything.
However, for perl to find it if it is changed, you need to
set PERLLIB_PREFIX in Config.sys, see PERLLIB_PREFIX.
unzip perl_ste.zip -d f:/perllib/lib/site_perl
If you do not change this directory, do nothing. Otherwise put this directory and subdirectory ./os2 in PERLLIB or PERL5LIB variable. Do not use PERL5LIB unless you have it set already. See ENVIRONMENT.
unzip perl_blb.zip -d f:/perllib/lib
If this directory is preserved, you do not need to change anything.
However, for perl to find it if it is changed, you need to
set PERLLIB_PREFIX in Config.sys, see PERLLIB_PREFIX.
unzip perl_man.zip -d f:/perllib/man
This directory should better be on MANPATH. You need to have a working man to access these files.
unzip perl_mam.zip -d f:/perllib/man
This directory should better be on MANPATH. You need to have a working man to access these files.
unzip perl_pod.zip -d f:/perllib/lib
This is used by by perldoc program (see the perldoc manpage), and may be used to generate
HTML 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/book
This directory should better be on BOOKSHELF.
unzip perl_sh.zip -d f:/bin
This is used by perl to run external commands which explicitly require shell, like the commands using redirection and shell metacharacters. It is also used instead of explicit /bin/sh.
Set PERL_SH_DIR (see PERL_SH_DIR) if you move sh.exe from the above location.
Note. It may be possible to use some other sh-compatible shell (not tested).
After you installed the components you needed and updated the Config.sys correspondingly, you need to hand-edit Config.pm. This file resides somewhere deep in the location you installed your perl library, find it out by
perl -MConfig -le "print $INC{'Config.pm'}"
You need to correct all the entries which look like file paths (they
currently start with f:/).
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 perl view perl perlfunc view perl less view perl ExtUtils::MakeMaker
(currently the last two may hit a wrong location, but this may improve soon). Under Win* see SYNOPSIS.
If you want to build the docs yourself, and have OS/2 toolkit, run
pod2ipf > perl.ipf
in /perllib/lib/pod directory, then
ipfc /inf perl.ipf
(Expect a lot of errors during the both steps.) Now move it on your BOOKSHELF path.
If you have perl documentation in the source form, perl utilities installed, and GNU groff installed, you may use
perldoc perlfunc
perldoc less
perldoc ExtUtils::MakeMaker
to access the perl documentation in the text form (note that you may get better results using perl manpages).
Alternately, try running pod2text on .pod files.
If you have man installed on your system, and you installed perl manpages, use something like this:
man perlfunc
man 3 less
man ExtUtils.MakeMaker
to access documentation for different components of Perl. Start with
man perl
Note that dot (.) is used as a package separator for documentation for packages, and as
usual, sometimes you need to give the section - 3
above - to avoid shadowing by the less(1) manpage.
Make sure that the directory above the directory with manpages is on our MANPATH, like this
set MANPATH=c:/man;f:/perllib/man
If you have some WWW browser available, installed the Perl documentation in the source form, and Perl utilities, you can build HTML docs. Cd to directory with .pod files, and do like this
cd f:/perllib/lib/pod
pod2html
After this you can direct your browser the file perl.html in this directory, and go ahead with reading docs, like this:
explore file:///f:/perllib/lib/pod/perl.html
Alternatively you may be able to get these docs prebuilt from CPAN.
info files
Users of Emacs would appreciate it very much, especially with
CPerl mode loaded. You need to get latest pod2info from CPAN, or, alternately, prebuilt info pages.
for Acrobat are available on
CPAN (for slightly old version of perl).
LaTeX docs
can be constructed using pod2latex.
Here we discuss how to build Perl under OS/2. There is an alternative (but maybe older) view on http:.
You need to have the latest EMX development environment, the full GNU tool suite (gawk renamed to awk, and GNU find.exe earlier on path than the OS/2 find.exe, same with sort.exe, to check use
find --version sort --version
). You need the latest version of pdksh installed as sh.exe.
Check that you have BSD libraries and headers installed, and - optionally - Berkeley DB headers and libraries, and crypt.
Possible locations to get 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 and ksh527rt.zip. Note that all these utilities are known to be available from LEO:
ftp://ftp.leo.org/pub/comp/os/os2/leo/gnu
Make sure that no copies or perl are currently running. Later steps of the build may fail since an older version of perl.dll loaded into memory may be found.
Also make sure that you have /tmp directory on the current drive, and . directory in your LIBPATH. One may try to correct the latter condition by
set BEGINLIBPATH .
if you use something like CMD.EXE or latest versions of 4os2.exe.
Make sure your gcc is good for -Zomf linking: run omflibs
script in /emx/lib directory.
Check that you have link386 installed. It comes standard with OS/2, but may be not installed due to customization. If typing
link386
shows you do not have it, do Selective install, and choose Link
object modules in Optional system utilities/More. If you get into link386, press Ctrl-C.
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 Configure. This is because there is a conflict with a similarly-named file configure.
Change to the directory of extraction.
You need to apply the patches in ./os2/diff.* and ./os2/POSIX.mkfifo like this:
gnupatch -p0 < os2\POSIX.mkfifo gnupatch -p0 < os2\diff.configure
You may also need to apply the patches supplied with the binary distribution of perl.
Note also that the db.lib and db.a from the EMX distribution are not suitable for multi-threaded compile (note that currently perl is not multithread-safe, but is compiled as multithreaded for compatibility with XFree86-OS/2). Get a corrected one from
ftp://ftp.math.ohio-state.edu/pub/users/ilya/os2/db_mt.zip
To make -p filetest work, one may also need to apply the following patch to
EMX headers:
--- /emx/include/sys/stat.h.orig Thu May 23 13:48:16 1996 +++ /emx/include/sys/stat.h Sun Jul 12 14:11:32 1998 @@ -53,7 +53,7 @@ struct stat #endif #if !defined (S_IFMT) -#define S_IFMT 0160000 /* Mask for file type */ +#define S_IFMT 0170000 /* Mask for file type */ #define S_IFIFO 0010000 /* Pipe */ #define S_IFCHR 0020000 /* Character device */ #define S_IFDIR 0040000 /* Directory */
You 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:/perllib
prefix means: where to install the resulting perl library. Giving correct prefix
you may avoid the need to specify PERLLIB_PREFIX, see PERLLIB_PREFIX.
Ignore the message about missing ln, and about -c option to
tr. In fact if you can trace where the latter spurious warning comes from,
please inform me.
Now
make
At some moment the built may die, reporting a version mismatch or unable to run perl. This means that most of the build has been finished, and it is the time to move the constructed perl.dll to some absolute location in LIBPATH. After this is done the build should finish without a lot of fuss. One can avoid the interruption if one has the correct prebuilt version of perl.dll on LIBPATH, but probably this is not needed anymore, since miniperl.exe is linked statically now.
Warnings which are safe to ignore: mkfifo() redefined inside POSIX.c.
If you haven't yet moved perl.dll onto LIBPATH, do it now (alternatively, if you have a previous perl installation you'd rather not disrupt until this one is installed, copy perl.dll to the t directory).
Now run
make test
All tests should succeed (with some of them skipped). Note that on one of the systems I see intermittent failures of io/pipe.t subtest 9. Any help to track what happens with this test is appreciated.
Some tests may generate extra messages similar to
There is not much we can do with it (but apparently it does not cause any real error with data).
*nix applications die
in silence. It is considered a feature. One can easily disable this by
appropriate sighandlers.
However the test engine bleeds these message to screen in unexpected moments. Two messages of this kind should be present during testing.
Two lib/io_* tests may generate popups (system error SYS3175), but should succeed anyway. This is due to a bug of
EMX related to
fork()ing with dynamically loaded libraries.
I submitted a patch to
EMX which makes it possible to
fork() with
EMX dynamic libraries loaded, which makes
lib/io* tests pass without skipping offended tests. This means that soon the number
of skipped tests may decrease yet more.
To get finer test reports, call
perl t/harness
The report with io/pipe.t failing may look like this:
Failed Test Status Wstat Total Fail Failed List of failed ------------------------------------------------------------ io/pipe.t 12 1 8.33% 9 7 tests skipped, plus 56 subtests skipped. Failed 1/195 test scripts, 99.49% okay. 1/6542 subtests failed, 99.98% okay.
The reasons for most important skipped tests are:
Checks atime and mtime of stat() - unfortunately,
HPFS provides only 2sec time granularity (for compatibility with
FAT?).
IO::Pipe module. Some feature of
EMX - test
fork()s with dynamic extension loaded - unsupported now.
IO::Socket module. Some feature of
EMX - test
fork()s with dynamic extension loaded - unsupported now.
Checks atime and mtime of stat() - 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 install
It would put the generated files into needed locations. Manually put perl.exe, perl__.exe and perl___.exe to a location on your PATH, perl.dll to a location on your LIBPATH.
Run
make cmdscripts INSTALLCMDDIR=d:/ir/on/path
to convert perl utilities to .cmd files and put them on
PATH. You need to put .EXE-utilities on path manually. They are installed in $prefix/bin, here $prefix is what you gave to
Configure, see Making.
a.out-style buildProceed as above, but make perl_.exe (see perl_.exe) by
make perl_
test and install by
make aout_test make aout_install
Manually put perl_.exe to a location on your PATH.
Since perl_ has the extensions prebuilt, it does not suffer from the dynamic extensions + fork() syndrome, thus the failing tests look like
Failed Test Status Wstat Total Fail Failed List of failed --------------------------------------------------------------- io/fs.t 26 11 42.31% 2-5, 7-11, 18, 25 op/stat.t 56 5 8.93% 3-4, 20, 35, 39 Failed 2/118 test scripts, 98.31% okay. 16/2445 subtests failed, 99.35% okay.
Note. The build process for perl_ does not know about all the dependencies, so you should make sure that anything is
up-to-date, say, by doing
make perl.dll
first.
/ became \ in pdksh.You have a very old pdksh. See Prerequisites.
'errno' - unresolved externalYou do not have MT-safe db.lib. See Prerequisites.
reported with very old version of tr and sed.
You have an older version of perl.dll on your LIBPATH, which broke the build of extensions.
You did not run omflibs. See Prerequisites.
You use an old version of GNU make. See Prerequisites.
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.
Multi-argument form of system() allows an additional numeric argument. The meaning of this argument is described in Process.
extproc on the first line
If the first chars of a script are "extproc ", this line is treated as #!-line, thus all the switches on this line are processed (twice if script
was started via cmd.exe).
Process, REXX, PrfDB, ExtAttr. These modules provide access to additional numeric argument for system and to the list of the running processes, to DLLs having functions with REXX signature and to REXX runtime, to OS/2 databases in the .INI format, and to Extended Attributes.
Two additional extensions by Andreas Kaiser, OS2::UPM, and
OS2::FTP, are included into my ftp directory, mirrored on
CPAN.
File::Copy::copy, see Copy.
DynaLoader for
DLL name mangling.
[/\\] (maybe after a drive-letter:).
Cwd::cwd.
name if
CWD were dir. Dir defaults to the current dir.
type is present and true, works with
END_LIBPATH, otherwise with
BEGIN_LIBPATH.
type is present and true, works with
END_LIBPATH, otherwise with
BEGIN_LIBPATH.
(Note that some of these may be moved to different libraries - eventually).
Since flock(3) is present in
EMX, but is not functional, it is emulated by perl. To
disable the emulations, set environment variable
USE_PERL_FLOCK=0.
Here is the list of things which may be ``broken'' on EMX (from EMX docs):
The functions recvmsg(3), sendmsg(3), and socketpair(3) are not implemented.
WUNTRACED
Not implemented.
waitpid() is not implemented for negative values of PID.
Note that kill -9 does not work with the current version of
EMX.
Since sh.exe is used for globing (see glob), the bugs of sh.exe plague perl as well.
In particular, uppercase letters do not work in [...]-patterns with the current pdksh.
Perl modifies some standard C library calls in the following ways:
my_popen uses sh.exe if shell is required, cf. PERL_SH_DIR.
TMP or TEMP environment variable, via
tempnam.
tmpnam, so there may be a race condition.
os2_stat special-cases /dev/tty and /dev/con.
USE_PERL_FLOCK=0.
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 an
a.out-style executable, but is linked with omf-style dynamic library perl.dll, and with dynamic
CRT
DLL. This executable is a
VIO application.
It can load perl dynamic extensions, and it can
fork(). Unfortunately, with the current version of
EMX it cannot
fork() with dynamic extensions loaded (may be fixed by patches to
EMX).
Note. Keep in mind that
fork() is needed to open a pipe
to yourself.
This is a statically linked a.out-style executable. It can
fork(), but cannot load dynamic
Perl extensions. The supplied executable has a lot of extensions prebuilt,
thus there are situations when it can perform tasks not possible using perl.exe, like
fork()ing when having some standard extension loaded. This executable is a
VIO application.
Note.
A better behaviour could be obtained from perl.exe if it were statically linked with standard Perl extensions, but dynamically linked with the Perl DLL and
CRT
DLL. Then it would be able to
fork() with standard extensions,
and would be able to dynamically load arbitrary extensions. Some changes to
Makefiles and hint files should be necessary to achieve this.
This is also the only executable with does not require OS/2. The friends locked into M$ world would appreciate the fact that this executable runs under
DOS, Win0.3*, Win0.95 and WinNT with an appropriate
extender. See Other OSes.
This is the same executable as perl___.exe, but it is a PM application.
Note. Usually
STDIN,
STDERR, and
STDOUT of a
PM application are redirected to
nul. However, it is possible to see them if you start perl__.exe from a
PM program which emulates a console window, like Shell mode of Emacs or
EPM. Thus it is
possible to use Perl debugger (see the perldebug manpage) to debug your
PM application.
This flavor is required if you load extensions which use
PM, like the forthcoming Perl/Tk.
This is an omf-style executable which is dynamically linked to
perl.dll and
CRT
DLL.
I know no advantages of this executable over
perl.exe, but it cannot
fork() at all. Well, one
advantage is that the build process is not so convoluted as with perl.exe.
It is a VIO application.
Since Perl processes the #!-line (cf.
DESCRIPTION, Switches,
Not a perl script,
No Perl script found in input), it should know when a program is a Perl. There is some naming convention which allows Perl to distinguish correct
lines from wrong ones. The above names are almost the only names allowed by
this convention which do not contain digits (which have absolutely
different semantics).
Well, having several executables dynamically linked to the same huge library has its advantages, but this would not substantiate the additional work to make it compile. The reason is stupid-but-quick ``hard'' dynamic linking used by OS/2.
The address tables of DLLs are patched only once, when they are loaded. The addresses of entry points into DLLs are guaranteed to be the same for all programs which use the same DLL, which reduces the amount of runtime patching - once DLL is loaded, its code is read-only.
While this allows some performance advantages, this makes life terrible for developers, since the above scheme makes it impossible for a DLL to be resolved to a symbol in the .EXE file, since this would need a DLL to have different relocations tables for the executables which use it.
However, a Perl extension is forced to use some symbols from the perl executable, say to know how to find the arguments provided on the perl internal evaluation stack. The solution is that the main code of interpreter should be contained in a DLL, and the .EXE file just loads this DLL into memory and supplies command-arguments.
This greatly increases the load time for the application (as well as the number of problems during compilation). Since interpreter is in a DLL, the CRT is basically forced to reside in a DLL as well (otherwise extensions would not be able to use CRT).
Current
EMX environment does not allow DLLs compiled using
Unixish
a.out format to export symbols for data. This forces omf-style compile of perl.dll.
Current
EMX environment does not allow .EXE files compiled in
omf format to
fork().
fork() is needed for exactly three Perl operations:
While these operations are not questions of life and death, a lot of useful
scripts use them. This forces a.out-style compile of
perl.exe.
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;path2
or
path1 path2
If the beginning of some prebuilt path matches path1, it is substituted with path2.
Should be used if the perl library is moved from the default location in
preference to PERL(5)LIB, since this would not leave wrong entries in
@INC. Say, if the compiled version of perl looks for
@INC in f:/perllib/lib, and you want to install the library in
h:/opt/gnu, do
set PERLLIB_PREFIX=f:/perllib/lib;h:/opt/gnu
PERL_BADLANG
If 1, perl ignores
setlocale() failing. May
be useful with some strange locales.
PERL_BADFREE
If 1, perl would not warn of in case of unwarranted
free(). May be useful in conjunction with the module DB_File, since Berkeley
DB memory handling code is buggy.
PERL_SH_DIRSpecific for EMX port. Gives the directory part of the location for sh.exe.
USE_PERL_FLOCK
Specific for
EMX port. Since flock(3) is present in
EMX, but is not functional, it is emulated by perl. To
disable the emulations, set environment variable USE_PERL_FLOCK=0.
TMP or TEMP
Specific for
EMX port. Used as storage place for temporary files,
most notably -e scripts.
Here we list major changes which could make you by surprise.
setpriority and getpriority 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. In particular, DLLs are now created with the names which contain a checksum, thus allowing workaround for OS/2 scheme of caching DLLs.
As of release 5.003_01 perl is linked to multithreaded
CRT
DLL. If perl itself is not compiled multithread-enabled, so will not be perl
malloc(). However, extensions may use multiple thread on their own risk.
Needed to compile Perl/Tk for XFree86-OS/2 out-of-the-box.
Due to a popular demand the perl external program calling has been changed wrt Andreas Kaiser's port. If perl needs to call an external program via shell, the f:/bin/sh.exe will be called, or whatever is the override, see PERL_SH_DIR.
Thus means that you need to get some copy of a sh.exe as well (I use one from pdksh). The drive F: above is set up automatically during the build to a correct value on the builder machine, but is overridable at runtime,
Reasons: a consensus on perl5-porters was that perl should use one non-overridable shell per platform. The obvious choices for
OS/2 are
cmd.exe and sh.exe. Having perl build itself would be impossible with cmd.exe as a shell, thus
I picked up sh.exe. Thus assures almost 100% compatibility with the scripts coming from *nix. As an added benefit this works as well under
DOS if you use DOS-enabled port of pdksh (see
Prerequisites).
Disadvantages: currently sh.exe of pdksh calls external programs via
fork()/exec(), and there
is no functioning
exec() on
OS/2.
exec() is emulated by
EMX by asyncroneous call while the caller waits for child completion (to pretend that the
pid did not change). This means that 1 extra copy of sh.exe is made active via
fork()/exec(), which may lead to some resources taken from the system (even if we do not count extra work needed for
fork()ing).
Note that this a lesser issue now when we do not spawn sh.exe unless needed (metachars found).
One can always start cmd.exe explicitly via
system 'cmd', '/c', 'mycmd', 'arg1', 'arg2', ...
If you need to use cmd.exe, and do not want to hand-edit thousands of your scripts, the long-term solution proposed on p5-p is to have a directive
use OS2::Cmd;
which will override
system(),
exec(),
``, and
open(,'...|'). With current perl you may override only
system(),
readpipe() - the explicit version of
``, and maybe
exec(). The code will substitute the one-argument call to
system() by
CORE::system('cmd.exe', '/c', shift).
If you have some working code for OS2::Cmd, please send it to me,
I will include it into distribution.
I have no need for such a module, so cannot test it.
For the details of the current situation with calling external programs, see Starting OS.
External scripts may be called by name. Perl will try the same extensions as when processing -S command-line switch.
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 quickier than
EMX one.
I do not have convincing data about memory footpring, but a (pretty random) benchmark showed that Perl 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
emx_ added. (Currently only
DLL perl has this, it should propagate to perl_.exe shortly.)
One can build perl with thread support enabled by providing -D usethreads
option to Configure. Currently
OS/2 support of threads is very preliminary.
Most notable problems:
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).
If rather than formatting bugs, you encounter substantive content errors in these documents, such as mistakes in the explanations or code, please use the perlbug utility included with the Perl distribution.