NAME¶
perlos2 - Perl under OS/2, DOS, Win0.3*, Win0.95 and WinNT.
SYNOPSIS¶
One can read this document in the following formats:
man perlos2
view perl perlos2
explorer perlos2.html
info perlos2
to list some (not all may be available simultaneously), or it may be read
as
is: either as
README.os2, or
pod/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). There is also a different viewer named xview.
Note that if you have
lynx.exe or
netscape.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).
DESCRIPTION¶
Target¶
The target is to make OS/2 one of 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; with the mostly
useful flavors of perl for OS/2 (there are several built simultaneously)
this is supported; but some flavors do not support this (e.g., when Perl
is called from inside REXX). Using fork() after useing
dynamically loading extensions would not work with very old
versions of EMX.
- •
- You need a separate perl executable perl__.exe (see
perl__.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 standard perl.exe from a text-mode window is possible
too, I have seen cases when this causes degradation of the system
stability. Using perl__.exe avoids such a degradation.
- •
- There is no simple way to access WPS objects. The only way
I know is via "OS2::REXX" and "SOM" extensions (see
OS2::REXX, Som). However, we do not have access to convenience methods of
Object-REXX. (Is it possible at all? I know of no Object-REXX API.) The
"SOM" extension (currently in alpha-text) may eventually remove
this shortcoming; however, due to the fact that DII is not supported by
the "SOM" module, using "SOM" is not as convenient as
one would like it.
Please keep this list up-to-date by informing me about other items.
Other OSes¶
Since OS/2 port of perl uses a remarkable EMX environment, it can run (and build
extensions, and - possibly - be 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 the
extender - most probably RSX - decided to
implement.
Cf. Prerequisites.
Prerequisites¶
- EMX
- EMX runtime is required (may be substituted by RSX). Note
that it is possible to make perl_.exe to run under DOS without any
external support by binding emx.exe/rsx.exe to it, see
emxbind. Note that under DOS for best results one should use RSX runtime,
which has much more functions working (like "fork",
"popen" and so on). In fact RSX is required if there is no VCPI
present. Note the RSX requires DPMI. Many implementations of DPMI are
known to be very buggy, beware!
Only the latest runtime is supported, currently "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
ftp://crydee.sai.msu.ru/pub/comp/os/os2/leo/gnu/emx+gcc/
http://hobbes.nmsu.edu/h-browse.php?dir=/pub/os2/dev/emx/v0.9d/
The runtime component should have the name emxrt.zip.
NOTE. When using emx.exe/rsx.exe, it is enough to have
them on your path. One does not need to specify them explicitly (though
this
emx perl_.exe -de 0
will work as well.)
- RSX
- To run Perl on DPMI platforms one needs RSX runtime. This
is needed under DOS-inside-OS/2, Win0.3*, Win0.95 and WinNT (see
"Other OSes"). RSX would not work with VCPI only, as EMX would,
it requires DMPI.
Having RSX and the latest sh.exe one gets a fully functional
*nix-ish environment under DOS, say, "fork",
"``" and pipe-"open" work. In fact, MakeMaker works
(for static build), so one can have Perl development environment under
DOS.
One can get RSX from, say
http://cd.textfiles.com/hobbesos29804/disk1/EMX09C/
ftp://crydee.sai.msu.ru/pub/comp/os/os2/leo/gnu/emx+gcc/contrib/
Contact the author on "rainer@mathematik.uni-bielefeld.de".
The latest sh.exe with DOS hooks is available in
http://www.ilyaz.org/software/os2/
as sh_dos.zip or under similar names starting with "sh",
"pdksh" etc.
- HPFS
- Perl does not care about file systems, but the perl library
contains many files with long names, so to install it intact one needs a
file system which supports long file names.
Note that if you do not plan to build the perl itself, it may be possible to
fool EMX to truncate file names. This is not supported, read EMX docs to
see how to do it.
- pdksh
- To start external programs with complicated command lines
(like with pipes in between, and/or quoting of arguments), Perl uses an
external shell. With EMX port such shell should be named sh.exe,
and located either in the wired-in-during-compile locations (usually
F:/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 (with RSX) as well, see
http://www.ilyaz.org/software/os2/
Starting Perl programs under OS/2 (and DOS and...)¶
Start your Perl program
foo.pl with arguments "arg1 arg2 arg3"
the same way as on any other platform, by
perl foo.pl arg1 arg2 arg3
If you want to specify perl options "-my_opts" to the perl itself (as
opposed to 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 the "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 perlrun, 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" in perlrun.
Note that
-S switch supports scripts with additional extensions
.cmd,
.btm,
.bat,
.pl as well.
Starting OS/2 (and DOS) programs under Perl¶
This is what
system() (see "system" in perlfunc),
"``" (see "I/O Operators" in perlop), and
open 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:
- 1.
- One-argument system() (see "system" in
perlfunc), exec() (see "exec" in perlfunc) with
redirection or shell meta-characters;
- 2.
- Pipe-open (see "open" in perlfunc) with the
command which contains redirection or shell meta-characters;
- 3.
- Backticks "``" (see "I/O Operators" in
perlop) with the command which contains redirection or shell
meta-characters;
- 4.
- If the executable called by
system()/exec()/pipe- open()/"``" is a
script with the "magic" "#!" line or
"extproc" line which specifies shell;
- 5.
- If the executable called by
system()/exec()/pipe- open()/"``" is a
script without "magic" line, and $ENV{EXECSHELL} is set to
shell;
- 6.
- If the executable called by
system()/exec()/pipe- open()/"``" is not
found (is not this remark obsolete?);
- 7.
- For globbing (see "glob" in perlfunc, "I/O
Operators" in perlop) (obsolete? Perl uses builtin globbing
nowadays...).
For the sake of speed for a common case, in the above algorithms backslashes in
the command name are not considered as shell metacharacters.
Perl starts scripts which begin with cookies "extproc" or
"#!" directly, without an intervention of shell. Perl uses the same
algorithm to find the executable as
pdksh: if the path on
"#!" line does not work, and contains "/", then the
directory part of the executable is ignored, and the executable is searched in
. and on "PATH". To find arguments for these scripts Perl
uses a different algorithm than
pdksh: up to 3 arguments are
recognized, and trailing whitespace is stripped.
If a script does not contain such a cooky, then to avoid calling
sh.exe,
Perl uses the same algorithm as
pdksh: if $ENV{EXECSHELL} is set, the
script is given as the first argument to this command, if not set, then
"$ENV{COMSPEC} /c" is used (or a hardwired guess if $ENV{COMSPEC} is
not set).
When starting scripts directly, Perl uses exactly the same algorithm as for the
search of script given by
-S command-line option: it will look in the
current directory, then on components of $ENV{PATH} using the following order
of appended extensions: no extension,
.cmd,
.btm,
.bat,
.pl.
Note that Perl will start to look for scripts only if OS/2 cannot start the
specified application, thus "system 'blah'" will not look for a
script if there is an executable file
blah.exe anywhere on
"PATH". In other words, "PATH" is essentially searched
twice: once by the OS for an executable, then by Perl for scripts.
Note also that executable files on OS/2 can have an arbitrary extension, but
.exe will be automatically appended if no dot is present in the name.
The workaround is as simple as that: since
blah. and
blah denote
the same file (at list on FAT and HPFS file systems), to start an executable
residing in file
n:/bin/blah (no extension) give an argument
"n:/bin/blah." (dot appended) to
system().
Perl will start PM programs from VIO (=text-mode) Perl process in a separate PM
session; the opposite is not true: when you start a non-PM program from a PM
Perl process, Perl would not run it in a separate session. If a separate
session is desired, either ensure that shell will be used, as in "system
'cmd /c myprog'", or start it using optional arguments to
system()
documented in "OS2::Process" module. This is considered to be a
feature.
Frequently asked questions¶
"It does not work"¶
Perl binary distributions come with a
testperl.cmd script which tries to
detect common problems with misconfigured installations. There is a pretty
large chance it will discover which step of the installation you managed to
goof. ";-)"
I cannot run external programs¶
- •
- Did you run your programs with "-w" switch? See
"2 (and DOS) programs under Perl" in 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.
I cannot embed perl into my program, or use perl.dll from
my program.¶
- Is your program EMX-compiled with "-Zmt
-Zcrtdll"?
- Well, nowadays Perl DLL should be usable from a differently
compiled program too... If you can run Perl code from REXX scripts (see
OS2::REXX), then there are some other aspect of interaction which are
overlooked by the current hackish code to support differently-compiled
principal programs.
If everything else fails, you need to build a stand-alone DLL for perl.
Contact me, I did it once. Sockets would not work, as a lot of other
stuff.
- Did you use ExtUtils::Embed?
- Some time ago I had reports it does not work. Nowadays it
is checked in the Perl test suite, so grep ./t subdirectory of the
build tree (as well as *.t files in the ./lib subdirectory)
to find how it should be done "correctly".
"``" and pipe-"open" do not work under
DOS.¶
This may a variant of just "I cannot run external programs", or a
deeper problem. Basically: you
need RSX (see "Prerequisites")
for these commands to work, and you may need a port of
sh.exe which
understands command arguments. One of such ports is listed in
"Prerequisites" under RSX. Do not forget to set variable
"PERL_SH_DIR" as well.
DPMI is required for RSX.
Cannot start "find.exe "pattern" file"¶
The whole idea of the "standard C API to start applications" is that
the forms "foo" and "foo" of program arguments are
completely interchangeable.
find breaks this paradigm;
find "pattern" file
find pattern file
are not equivalent;
find cannot be started directly using the above API.
One needs a way to surround the doublequotes in some other quoting
construction, necessarily having an extra non-Unixish shell in between.
Use one of
system 'cmd', '/c', 'find "pattern" file';
`cmd /c 'find "pattern" file'`
This would start
find.exe via
cmd.exe via "sh.exe" via
"perl.exe", but this is a price to pay if you want to use
non-conforming program.
INSTALLATION¶
Automatic binary installation¶
The most convenient way of installing a binary distribution of perl is via perl
installer
install.exe. Just follow the instructions, and 99% of the
installation blues would go away.
Note however, that you need to have
unzip.exe on your path, and EMX
environment
running. The latter means that if you just installed EMX,
and made all the needed changes to
Config.sys, you may need to reboot
in between. Check EMX runtime by running
emxrev
Binary installer also creates a folder on your desktop with some useful objects.
If you need to change some aspects of the work of the binary installer, feel
free to edit the file
Perl.pkg. This may be useful e.g., if you need to
run the installer many times and do not want to make many interactive changes
in the GUI.
Things not taken care of by automatic binary installation:
- "PERL_BADLANG"
- may be needed if you change your codepage after perl
installation, and the new value is not supported by EMX. See
"PERL_BADLANG".
- "PERL_BADFREE"
- see "PERL_BADFREE".
- Config.pm
- This file resides somewhere deep in the location you
installed your perl library, find it out by
perl -MConfig -le "print $INC{'Config.pm'}"
While most important values in this file are updated by the binary
installer, some of them may need to be hand-edited. I know no such data,
please keep me informed if you find one. Moreover, manual changes to the
installed version may need to be accompanied by an edit of this file.
NOTE. Because of a typo the binary installer of 5.00305 would install a
variable "PERL_SHPATH" into
Config.sys. Please remove this
variable and put "PERL_SH_DIR" instead.
Manual binary installation¶
As of version 5.00305, OS/2 perl binary distribution comes split into 11
components. Unfortunately, to enable configurable binary installation, the
file paths in the zip files are not absolute, but relative to some directory.
Note that the extraction with the stored paths is still necessary (default with
unzip, specify "-d" to pkunzip). However, you need to know where to
extract the files. You need also to manually change entries in
Config.sys to reflect where did you put the files. Note that if you
have some primitive unzipper (like "pkunzip"), you may get a lot of
warnings/errors during unzipping. Upgrade to "(w)unzip".
Below is the sample of what to do to reproduce the configuration on my machine.
In
VIEW.EXE you can press "Ctrl-Insert" now, and
cut-and-paste from the resulting file - created in the directory you started
VIEW.EXE from.
For each component, we mention environment variables related to each
installation directory. Either choose directories to match your values of the
variables, or create/append-to variables to take into account the directories.
- Perl VIO and PM executables (dynamically linked)
-
unzip perl_exc.zip *.exe *.ico -d f:/emx.add/bin
unzip perl_exc.zip *.dll -d f:/emx.add/dll
(have the directories with "*.exe" on PATH, and "*.dll"
on LIBPATH);
- Perl_ VIO executable (statically linked)
-
unzip perl_aou.zip -d f:/emx.add/bin
(have the directory on PATH);
- Executables for Perl utilities
-
unzip perl_utl.zip -d f:/emx.add/bin
(have the directory on PATH);
- Main Perl library
-
unzip perl_mlb.zip -d f:/perllib/lib
If this directory is exactly the same as the prefix which was compiled into
perl.exe, you do not need to change anything. However, for perl to
find the library if you use a different path, you need to "set
PERLLIB_PREFIX" in Config.sys, see
"PERLLIB_PREFIX".
- Additional Perl modules
-
unzip perl_ste.zip -d f:/perllib/lib/site_perl/5.14.2/
Same remark as above applies. Additionally, if this directory is not one of
directories on @INC (and @INC is influenced by
"PERLLIB_PREFIX"), you need to put this directory and
subdirectory ./os2 in "PERLLIB" or "PERL5LIB"
variable. Do not use "PERL5LIB" unless you have it set already.
See "ENVIRONMENT" in perl.
[Check whether this extraction directory is still applicable with
the new directory structure layout!]
- Tools to compile Perl modules
-
unzip perl_blb.zip -d f:/perllib/lib
Same remark as for perl_ste.zip.
- Manpages for Perl and utilities
-
unzip perl_man.zip -d f:/perllib/man
This directory should better be on "MANPATH". You need to have a
working man to access these files.
- Manpages for Perl modules
-
unzip perl_mam.zip -d f:/perllib/man
This directory should better be on "MANPATH". You need to have a
working man to access these files.
- Source for Perl documentation
-
unzip perl_pod.zip -d f:/perllib/lib
This is used by the "perldoc" program (see perldoc), and may be
used to generate HTML documentation usable by WWW browsers, and
documentation in zillions of other formats: "info",
"LaTeX", "Acrobat", "FrameMaker" and so on.
[Use programs such as pod2latex etc.]
- Perl manual in .INF format
-
unzip perl_inf.zip -d d:/os2/book
This directory should better be on "BOOKSHELF".
- Pdksh
-
unzip perl_sh.zip -d f:/bin
This is used by perl to run external commands which explicitly require
shell, like the commands using redirection and shell
metacharacters. It is also used instead of explicit /bin/sh.
Set "PERL_SH_DIR" (see "PERL_SH_DIR") if you move
sh.exe from the above location.
Note. It may be possible to use some other sh-compatible shell
(untested).
After you installed the components you needed and updated the
Config.sys
correspondingly, you need to hand-edit
Config.pm. This file resides
somewhere deep in the location you installed your perl library, find it out by
perl -MConfig -le "print $INC{'Config.pm'}"
You need to correct all the entries which look like file paths (they currently
start with "f:/").
Warning¶
The automatic and manual perl installation leave precompiled paths inside perl
executables. While these paths are overwriteable (see
"PERLLIB_PREFIX", "PERL_SH_DIR"), some people may prefer
binary editing of paths inside the executables/DLLs.
Accessing documentation¶
Depending on how you built/installed perl you may have (otherwise identical)
Perl documentation in the following formats:
OS/2 .INF file¶
Most probably the most convenient form. Under OS/2 view it as
view perl
view perl perlfunc
view perl less
view perl ExtUtils::MakeMaker
(currently the last two may hit a wrong location, but this may improve soon).
Under Win* see "SYNOPSIS".
If you want to build the docs yourself, and have
OS/2 toolkit, run
pod2ipf > perl.ipf
in
/perllib/lib/pod directory, then
ipfc /inf perl.ipf
(Expect a lot of errors during the both steps.) Now move it on your BOOKSHELF
path.
Plain text¶
If you have perl documentation in the source form, perl utilities installed, and
GNU groff installed, you may use
perldoc perlfunc
perldoc less
perldoc ExtUtils::MakeMaker
to access the perl documentation in the text form (note that you may get better
results using perl manpages).
Alternately, try running pod2text on
.pod files.
Manpages¶
If you have
man installed on your system, and you installed perl
manpages, use something like this:
man perlfunc
man 3 less
man ExtUtils.MakeMaker
to access documentation for different components of Perl. Start with
man perl
Note that dot (
.) is used as a package separator for documentation for
packages, and as usual, sometimes you need to give the section - 3 above - to
avoid shadowing by the
less(1) manpage.
Make sure that the directory
above the directory with manpages is on our
"MANPATH", like this
set MANPATH=c:/man;f:/perllib/man
for Perl manpages in "f:/perllib/man/man1/" etc.
HTML¶
If you have some WWW browser available, installed the Perl documentation in the
source form, and Perl utilities, you can build HTML docs. Cd to directory with
.pod files, and do like this
cd f:/perllib/lib/pod
pod2html
After this you can direct your browser the file
perl.html in this
directory, and go ahead with reading docs, like this:
explore file:///f:/perllib/lib/pod/perl.html
Alternatively you may be able to get these docs prebuilt from CPAN.
GNU "info" files¶
Users of Emacs would appreciate it very much, especially with "CPerl"
mode loaded. You need to get latest "pod2texi" from
"CPAN", or, alternately, the prebuilt info pages.
PDF files¶
for "Acrobat" are available on CPAN (may be for slightly older version
of perl).
"LaTeX" docs¶
can be constructed using "pod2latex".
BUILD¶
Here we discuss how to build Perl under OS/2.
The short story¶
Assume that you are a seasoned porter, so are sure that all the necessary tools
are already present on your system, and you know how to get the Perl source
distribution. Untar it, change to the extract directory, and
gnupatch -p0 < os2\diff.configure
sh Configure -des -D prefix=f:/perllib
make
make test
make install
make aout_test
make aout_install
This puts the executables in f:/perllib/bin. Manually move them to the
"PATH", manually move the built
perl*.dll to
"LIBPATH" (here for Perl DLL
* is a not-very-meaningful hex
checksum), and run
make installcmd INSTALLCMDDIR=d:/ir/on/path
Assuming that the "man"-files were put on an appropriate location,
this completes the installation of minimal Perl system. (The binary
distribution contains also a lot of additional modules, and the documentation
in INF format.)
What follows is a detailed guide through these steps.
Prerequisites¶
You need to have the latest EMX development environment, the full GNU tool suite
(gawk renamed to awk, and GNU
find.exe earlier on path than the OS/2
find.exe, same with
sort.exe, to check use
find --version
sort --version
). You need the latest version of
pdksh installed as
sh.exe.
Check that you have
BSD libraries and headers installed, and - optionally
- Berkeley DB headers and libraries, and crypt.
Possible locations to get the files:
ftp://ftp.uni-heidelberg.de/pub/os2/unix/
http://hobbes.nmsu.edu/h-browse.php?dir=/pub/os2
http://cd.textfiles.com/hobbesos29804/disk1/DEV32/
http://cd.textfiles.com/hobbesos29804/disk1/EMX09C/
It is reported that the following archives contain enough utils to build perl:
gnufutil.zip,
gnusutil.zip,
gnututil.zip,
gnused.zip,
gnupatch.zip,
gnuawk.zip,
gnumake.zip,
gnugrep.zip,
bsddev.zip and
ksh527rt.zip (or a later
version). Note that all these utilities are known to be available from LEO:
ftp://crydee.sai.msu.ru/pub/comp/os/os2/leo/gnu/
Note also that the
db.lib and
db.a from the EMX distribution are
not suitable for multi-threaded compile (even single-threaded flavor of Perl
uses multi-threaded C RTL, for compatibility with XFree86-OS/2). Get a
corrected one from
http://www.ilyaz.org/software/os2/db_mt.zip
If you have
exactly the same version of Perl installed already, make sure
that no copies or perl are currently running. Later steps of the build may
fail since an older version of
perl.dll loaded into memory may be
found. Running "make test" becomes meaningless, since the test are
checking a previous build of perl (this situation is detected and reported by
lib/os2_base.t test). Do not forget to unset
"PERL_EMXLOAD_SEC" in environment.
Also make sure that you have
/tmp directory on the current drive, and
. directory in your "LIBPATH". One may try to correct the
latter condition by
set BEGINLIBPATH .\.
if you use something like
CMD.EXE or latest versions of
4os2.exe.
(Setting BEGINLIBPATH to just "." is ignored by the OS/2 kernel.)
Make sure your gcc is good for "-Zomf" linking: run
"omflibs" script in
/emx/lib directory.
Check that you have link386 installed. It comes standard with OS/2, but may be
not installed due to customization. If typing
link386
shows you do not have it, do
Selective install, and choose "Link
object modules" in
Optional system utilities/More. If you get into
link386 prompts, press "Ctrl-C" to exit.
Getting perl source¶
You need to fetch the latest perl source (including developers releases). With
some probability it is located in
http://www.cpan.org/src/
http://www.cpan.org/src/unsupported
If not, you may need to dig in the indices to find it in the directory of the
current maintainer.
Quick cycle of developers release may break the OS/2 build time to time, looking
into
http://www.cpan.org/ports/os2/
may indicate the latest release which was publicly released by the maintainer.
Note that the release may include some additional patches to apply to the
current source of perl.
Extract it like this
tar vzxf perl5.00409.tar.gz
You may see a message about errors while extracting
Configure. This is
because there is a conflict with a similarly-named file
configure.
Change to the directory of extraction.
Application of the patches¶
You need to apply the patches in
./os2/diff.* like this:
gnupatch -p0 < os2\diff.configure
You may also need to apply the patches supplied with the binary distribution of
perl. It also makes sense to look on the perl5-porters mailing list for the
latest OS/2-related patches (see
http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/
<
http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/>). Such patches
usually contain strings "/os2/" and "patch", so it makes
sense looking for these strings.
Hand-editing¶
You may look into the file
./hints/os2.sh and correct anything wrong you
find there. I do not expect it is needed anywhere.
Making¶
sh Configure -des -D prefix=f:/perllib
"prefix" means: where to install the resulting perl library. Giving
correct prefix you may avoid the need to specify "PERLLIB_PREFIX",
see "PERLLIB_PREFIX".
Ignore the message about missing "ln", 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
make
At some moment the built may die, reporting a
version mismatch or
unable to run perl. This means that you do not have
. in your LIBPATH, so
perl.exe cannot find the needed
perl67B2.dll (treat these hex digits as line noise). After this is
fixed the build should finish without a lot of fuss.
Testing¶
Now run
make test
All tests should succeed (with some of them skipped). If you have the same
version of Perl installed, it is crucial that you have "." early in
your LIBPATH (or in BEGINLIBPATH), otherwise your tests will most probably
test the wrong version of Perl.
Some tests may generate extra messages similar to
- A lot of "bad free"
- in database tests related to Berkeley DB. This should be
fixed already. If it persists, you may disable this warnings, see
"PERL_BADFREE".
- Process terminated by SIGTERM/SIGINT
- This is a standard message issued by OS/2 applications.
*nix applications die in silence. It is considered to be a feature. One
can easily disable this by appropriate sighandlers.
However the test engine bleeds these message to screen in unexpected
moments. Two messages of this kind should be present during
testing.
To get finer test reports, call
perl t/harness
The report with
io/pipe.t failing may look like this:
Failed Test Status Wstat Total Fail Failed List of failed
------------------------------------------------------------
io/pipe.t 12 1 8.33% 9
7 tests skipped, plus 56 subtests skipped.
Failed 1/195 test scripts, 99.49% okay. 1/6542 subtests failed, 99.98% okay.
The reasons for most important skipped tests are:
- op/fs.t
- 18
- Checks "atime" and "mtime" of
"stat()" - unfortunately, HPFS provides only 2sec time
granularity (for compatibility with FAT?).
- 25
- Checks "truncate()" on a filehandle just opened
for write - I do not know why this should or should not work.
- op/stat.t
- Checks "stat()". Tests:
- 4
- Checks "atime" and "mtime" of
"stat()" - unfortunately, HPFS provides only 2sec time
granularity (for compatibility with FAT?).
Installing the built perl¶
If you haven't yet moved "perl*.dll" onto LIBPATH, do it now.
Run
make install
It would put the generated files into needed locations. Manually put
perl.exe,
perl__.exe and
perl___.exe to a location on
your PATH,
perl.dll to a location on your LIBPATH.
Run
make installcmd INSTALLCMDDIR=d:/ir/on/path
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.
If you use "man", either move the installed
*/man/ directories
to your "MANPATH", or modify "MANPATH" to match the
location. (One could have avoided this by providing a correct
"manpath" option to
./Configure, or editing
./config.sh between configuring and making steps.)
"a.out"-style build¶
Proceed 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.
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.
Building a binary distribution¶
[This section provides a short overview only...]
Building should proceed differently depending on whether the version of perl you
install is already present and used on your system, or is a new version not
yet used. The description below assumes that the version is new, so installing
its DLLs and
.pm files will not disrupt the operation of your system
even if some intermediate steps are not yet fully working.
The other cases require a little bit more convoluted procedures. Below I suppose
that the current version of Perl is 5.8.2, so the executables are named
accordingly.
- 1.
- Fully build and test the Perl distribution. Make sure that
no tests are failing with "test" and "aout_test"
targets; fix the bugs in Perl and the Perl test suite detected by these
tests. Make sure that "all_test" make target runs as clean as
possible. Check that "os2/perlrexx.cmd" runs fine.
- 2.
- Fully install Perl, including "installcmd"
target. Copy the generated DLLs to "LIBPATH"; copy the numbered
Perl executables (as in perl5.8.2.exe) to "PATH"; copy
"perl_.exe" to "PATH" as "perl_5.8.2.exe".
Think whether you need backward-compatibility DLLs. In most cases you do
not need to install them yet; but sometime this may simplify the following
steps.
- 3.
- Make sure that "CPAN.pm" can download files from
CPAN. If not, you may need to manually install "Net::FTP".
- 4.
- Install the bundle "Bundle::OS2_default"
perl5.8.2 -MCPAN -e "install Bundle::OS2_default" < nul |& tee 00cpan_i_1
This may take a couple of hours on 1GHz processor (when run the first time).
And this should not be necessarily a smooth procedure. Some modules may
not specify required dependencies, so one may need to repeat this
procedure several times until the results stabilize.
perl5.8.2 -MCPAN -e "install Bundle::OS2_default" < nul |& tee 00cpan_i_2
perl5.8.2 -MCPAN -e "install Bundle::OS2_default" < nul |& tee 00cpan_i_3
Even after they stabilize, some tests may fail.
Fix as many discovered bugs as possible. Document all the bugs which are not
fixed, and all the failures with unknown reasons. Inspect the produced
logs 00cpan_i_1 to find suspiciously skipped tests, and other fishy
events.
Keep in mind that installation of some modules may fail too: for
example, the DLLs to update may be already loaded by CPAN.pm.
Inspect the "install" logs (in the example above
00cpan_i_1 etc) for errors, and install things manually, as in
cd $CPANHOME/.cpan/build/Digest-MD5-2.31
make install
Some distributions may fail some tests, but you may want to install them
anyway (as above, or via "force install" command of
"CPAN.pm" shell-mode).
Since this procedure may take quite a long time to complete, it makes sense
to "freeze" your CPAN configuration by disabling periodic
updates of the local copy of CPAN index: set "index_expire" to
some big value (I use 365), then save the settings
CPAN> o conf index_expire 365
CPAN> o conf commit
Reset back to the default value 1 when you are finished.
- 5.
- When satisfied with the results, rerun the
"installcmd" target. Now you can copy "perl5.8.2.exe"
to "perl.exe", and install the other OMF-build executables:
"perl__.exe" etc. They are ready to be used.
- 6.
- Change to the "./pod" directory of the build
tree, download the Perl logo CamelGrayBig.BMP, and run
( perl2ipf > perl.ipf ) |& tee 00ipf
ipfc /INF perl.ipf |& tee 00inf
This produces the Perl docs online book "perl.INF". Install in on
"BOOKSHELF" path.
- 7.
- Now is the time to build statically linked executable
perl_.exe which includes newly-installed via
"Bundle::OS2_default" modules. Doing testing via
"CPAN.pm" is going to be painfully slow, since it statically
links a new executable per XS extension.
Here is a possible workaround: create a toplevel Makefile.PL in
$CPANHOME/.cpan/build/ with contents being (compare
with "Making executables with a custom collection of statically
loaded extensions")
use ExtUtils::MakeMaker;
WriteMakefile NAME => 'dummy';
execute this as
perl_5.8.2.exe Makefile.PL <nul |& tee 00aout_c1
make -k all test <nul |& 00aout_t1
Again, this procedure should not be absolutely smooth. Some
"Makefile.PL"'s in subdirectories may be buggy, and would not
run as "child" scripts. The interdependency of modules can
strike you; however, since non-XS modules are already installed, the
prerequisites of most modules have a very good chance to be present.
If you discover some glitches, move directories of problematic modules to a
different location; if these modules are non-XS modules, you may just
ignore them - they are already installed; the remaining, XS, modules you
need to install manually one by one.
After each such removal you need to rerun the
"Makefile.PL"/"make" process; usually this procedure
converges soon. (But be sure to convert all the necessary external C
libraries from .lib format to .a format: run one of
emxaout foo.lib
emximp -o foo.a foo.lib
whichever is appropriate.) Also, make sure that the DLLs for external
libraries are usable with with executables compiled without
"-Zmtd" options.
When you are sure that only a few subdirectories lead to failures, you may
want to add "-j4" option to "make" to speed up
skipping subdirectories with already finished build.
When you are satisfied with the results of tests, install the build C
libraries for extensions:
make install |& tee 00aout_i
Now you can rename the file ./perl.exe generated during the last
phase to perl_5.8.2.exe; place it on "PATH"; if there is
an inter-dependency between some XS modules, you may need to repeat the
"test"/"install" loop with this new executable and
some excluded modules - until the procedure converges.
Now you have all the necessary .a libraries for these Perl modules in
the places where Perl builder can find it. Use the perl builder: change to
an empty directory, create a "dummy" Makefile.PL again,
and run
perl_5.8.2.exe Makefile.PL |& tee 00c
make perl |& tee 00p
This should create an executable ./perl.exe with all the statically
loaded extensions built in. Compare the generated perlmain.c files
to make sure that during the iterations the number of loaded extensions
only increases. Rename ./perl.exe to perl_5.8.2.exe on
"PATH".
When it converges, you got a functional variant of perl_5.8.2.exe;
copy it to "perl_.exe". You are done with generation of the
local Perl installation.
- 8.
- Make sure that the installed modules are actually installed
in the location of the new Perl, and are not inherited from entries of
@INC given for inheritance from the older versions of Perl: set
"PERLLIB_582_PREFIX" to redirect the new version of Perl to a
new location, and copy the installed files to this new location. Redo the
tests to make sure that the versions of modules inherited from older
versions of Perl are not needed.
Actually, the log output of pod2ipf during the step 6 gives a very detailed
info about which modules are loaded from which place; so you may use it as
an additional verification tool.
Check that some temporary files did not make into the perl install tree. Run
something like this
pfind . -f "!(/\.(pm|pl|ix|al|h|a|lib|txt|pod|imp|bs|dll|ld|bs|inc|xbm|yml|cgi|uu|e2x|skip|packlist|eg|cfg|html|pub|enc|all|ini|po|pot)$/i or /^\w+$/") | less
in the install tree (both top one and sitelib one).
Compress all the DLLs with lxlite. The tiny .exe can be
compressed with "/c:max" (the bug only appears when there is a
fixup in the last 6 bytes of a page (?); since the tiny executables are
much smaller than a page, the bug will not hit). Do not compress
"perl_.exe" - it would not work under DOS.
- 9.
- Now you can generate the binary distribution. This is done
by running the test of the CPAN distribution
"OS2::SoftInstaller". Tune up the file test.pl to suit
the layout of current version of Perl first. Do not forget to pack the
necessary external DLLs accordingly. Include the description of the bugs
and test suite failures you could not fix. Include the small-stack
versions of Perl executables from Perl build directory.
Include perl5.def so that people can relink the perl DLL preserving
the binary compatibility, or can create compatibility DLLs. Include the
diff files ("diff -pu old new") of fixes you did so that people
can rebuild your version. Include perl5.map so that one can use
remote debugging.
- 10.
- Share what you did with the other people. Relax. Enjoy
fruits of your work.
- 11.
- Brace yourself for thanks, bug reports, hate mail and spam
coming as result of the previous step. No good deed should remain
unpunished!
Building custom .EXE files¶
The Perl executables can be easily rebuilt at any moment. Moreover, one can use
the
embedding interface (see perlembed) to make very customized
executables.
Making executables with a custom collection of statically loaded
extensions¶
It is a little bit easier to do so while
decreasing the list of
statically loaded extensions. We discuss this case only here.
- 1.
- Change to an empty directory, and create a placeholder
<Makefile.PL>:
use ExtUtils::MakeMaker;
WriteMakefile NAME => 'dummy';
- 2.
- Run it with the flavor of Perl (perl.exe or
perl_.exe) you want to rebuild.
perl_ Makefile.PL
- 3.
- Ask it to create new Perl executable:
make perl
(you may need to manually add "PERLTYPE=-DPERL_CORE" to this
commandline on some versions of Perl; the symptom is that the command-line
globbing does not work from OS/2 shells with the newly-compiled
executable; check with
.\perl.exe -wle "print for @ARGV" *
).
- 4.
- The previous step created perlmain.c which contains
a list of newXS() calls near the end. Removing unnecessary calls,
and rerunning
make perl
will produce a customized executable.
Making executables with a custom search-paths¶
The default perl executable is flexible enough to support most usages. However,
one may want something yet more flexible; for example, one may want to find
Perl DLL relatively to the location of the EXE file; or one may want to ignore
the environment when setting the Perl-library search patch, etc.
If you fill comfortable with
embedding interface (see perlembed), such
things are easy to do repeating the steps outlined in "Making executables
with a custom collection of statically loaded extensions", and doing more
comprehensive edits to
main() of
perlmain.c. The people with
little desire to understand Perl can just rename
main(), and do
necessary modification in a custom
main() which calls the renamed
function in appropriate time.
However, there is a third way: perl DLL exports the
main() function and
several callbacks to customize the search path. Below is a complete example of
a "Perl loader" which
- 1.
- Looks for Perl DLL in the directory
"$exedir/../dll";
- 2.
- Prepends the above directory to
"BEGINLIBPATH";
- 3.
- Fails if the Perl DLL found via "BEGINLIBPATH" is
different from what was loaded on step 1; e.g., another process could have
loaded it from "LIBPATH" or from a different value of
"BEGINLIBPATH". In these cases one needs to modify the setting
of the system so that this other process either does not run, or loads the
DLL from "BEGINLIBPATH" with "LIBPATHSTRICT=T"
(available with kernels after September 2000).
- 4.
- Loads Perl library from
"$exedir/../dll/lib/".
- 5.
- Uses Bourne shell from
"$exedir/../dll/sh/ksh.exe".
For best results compile the C file below with the same options as the Perl DLL.
However, a lot of functionality will work even if the executable is not an EMX
applications, e.g., if compiled with
gcc -Wall -DDOSISH -DOS2=1 -O2 -s -Zomf -Zsys perl-starter.c -DPERL_DLL_BASENAME=\"perl312F\" -Zstack 8192 -Zlinker /PM:VIO
Here is the sample C file:
#define INCL_DOS
#define INCL_NOPM
/* These are needed for compile if os2.h includes os2tk.h, not os2emx.h */
#define INCL_DOSPROCESS
#include <os2.h>
#include "EXTERN.h"
#define PERL_IN_MINIPERLMAIN_C
#include "perl.h"
static char *me;
HMODULE handle;
static void
die_with(char *msg1, char *msg2, char *msg3, char *msg4)
{
ULONG c;
char *s = " error: ";
DosWrite(2, me, strlen(me), &c);
DosWrite(2, s, strlen(s), &c);
DosWrite(2, msg1, strlen(msg1), &c);
DosWrite(2, msg2, strlen(msg2), &c);
DosWrite(2, msg3, strlen(msg3), &c);
DosWrite(2, msg4, strlen(msg4), &c);
DosWrite(2, "\r\n", 2, &c);
exit(255);
}
typedef ULONG (*fill_extLibpath_t)(int type, char *pre, char *post, int replace, char *msg);
typedef int (*main_t)(int type, char *argv[], char *env[]);
typedef int (*handler_t)(void* data, int which);
#ifndef PERL_DLL_BASENAME
# define PERL_DLL_BASENAME "perl"
#endif
static HMODULE
load_perl_dll(char *basename)
{
char buf[300], fail[260];
STRLEN l, dirl;
fill_extLibpath_t f;
ULONG rc_fullname;
HMODULE handle, handle1;
if (_execname(buf, sizeof(buf) - 13) != 0)
die_with("Can't find full path: ", strerror(errno), "", "");
/* XXXX Fill `me' with new value */
l = strlen(buf);
while (l && buf[l-1] != '/' && buf[l-1] != '\\')
l--;
dirl = l - 1;
strcpy(buf + l, basename);
l += strlen(basename);
strcpy(buf + l, ".dll");
if ( (rc_fullname = DosLoadModule(fail, sizeof fail, buf, &handle)) != 0
&& DosLoadModule(fail, sizeof fail, basename, &handle) != 0 )
die_with("Can't load DLL ", buf, "", "");
if (rc_fullname)
return handle; /* was loaded with short name; all is fine */
if (DosQueryProcAddr(handle, 0, "fill_extLibpath", (PFN*)&f))
die_with(buf, ": DLL exports no symbol ", "fill_extLibpath", "");
buf[dirl] = 0;
if (f(0 /*BEGINLIBPATH*/, buf /* prepend */, NULL /* append */,
0 /* keep old value */, me))
die_with(me, ": prepending BEGINLIBPATH", "", "");
if (DosLoadModule(fail, sizeof fail, basename, &handle1) != 0)
die_with(me, ": finding perl DLL again via BEGINLIBPATH", "", "");
buf[dirl] = '\\';
if (handle1 != handle) {
if (DosQueryModuleName(handle1, sizeof(fail), fail))
strcpy(fail, "???");
die_with(buf, ":\n\tperl DLL via BEGINLIBPATH is different: \n\t",
fail,
"\n\tYou may need to manipulate global BEGINLIBPATH and LIBPATHSTRICT"
"\n\tso that the other copy is loaded via BEGINLIBPATH.");
}
return handle;
}
int
main(int argc, char **argv, char **env)
{
main_t f;
handler_t h;
me = argv[0];
/**/
handle = load_perl_dll(PERL_DLL_BASENAME);
if (DosQueryProcAddr(handle, 0, "Perl_OS2_handler_install", (PFN*)&h))
die_with(PERL_DLL_BASENAME, ": DLL exports no symbol ", "Perl_OS2_handler_install", "");
if ( !h((void *)"~installprefix", Perlos2_handler_perllib_from)
|| !h((void *)"~dll", Perlos2_handler_perllib_to)
|| !h((void *)"~dll/sh/ksh.exe", Perlos2_handler_perl_sh) )
die_with(PERL_DLL_BASENAME, ": Can't install @INC manglers", "", "");
if (DosQueryProcAddr(handle, 0, "dll_perlmain", (PFN*)&f))
die_with(PERL_DLL_BASENAME, ": DLL exports no symbol ", "dll_perlmain", "");
return f(argc, argv, env);
}
Build FAQ¶
Some "/" became "\" in pdksh.¶
You have a very old pdksh. See Prerequisites.
'errno' - unresolved external¶
You do not have MT-safe
db.lib. See Prerequisites.
Problems with tr or sed¶
reported with very old version of tr and sed.
Some problem (forget which ;-)¶
You have an older version of
perl.dll on your LIBPATH, which broke the
build of extensions.
Library ... not found¶
You did not run "omflibs". See Prerequisites.
Segfault in make¶
You use an old version of GNU make. See Prerequisites.
op/sprintf test failure¶
This can result from a bug in emx sprintf which was fixed in 0.9d fix 03.
Specific (mis)features of OS/2 port¶
"setpriority", "getpriority"¶
Note that these functions are compatible with *nix, not with the older ports of
'94 - 95. The priorities are absolute, go from 32 to -95, lower is quicker. 0
is the default priority.
WARNING. Calling "getpriority" 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 "2.*", and has a race condition
anyway.
"system()"¶
Multi-argument form of "system()" allows an additional numeric
argument. The meaning of this argument is described in OS2::Process.
When finding a program to run, Perl first asks the OS to look for executables on
"PATH" (OS/2 adds extension
.exe if no extension is present).
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 finding
C:/emx/bin/foo.cmd with the first line being
extproc /bin/bash -x -c
If
/bin/bash.exe is not found, then Perl looks for an executable
bash.exe on "PATH". If found in
C:/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: if
bash
executable is not found, but
bash.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 PM type when the current session
is not, it will start the new process in a separate session of necessary type.
Call via "OS2::Process" to disable this magic.
WARNING. Due to the described logic, you need to explicitly specify
.com extension if needed. Moreover, if the executable
perl5.6.1
is requested, Perl will not look for
perl5.6.1.exe. [This may change in
the future.]
"extproc" on the first line¶
If 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.
Additional modules:¶
OS2::Process, OS2::DLL, OS2::REXX, OS2::PrfDB, OS2::ExtAttr. These modules
provide access to additional numeric argument for "system" 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", and
"OS2::FTP", are included into "ILYAZ" directory, mirrored
on CPAN. Other OS/2-related extensions are available too.
Prebuilt methods:¶
- "File::Copy::syscopy"
- used by "File::Copy::copy", see File::Copy.
- "DynaLoader::mod2fname"
- used by "DynaLoader" for DLL name mangling.
- "Cwd::current_drive()"
- Self explanatory.
- "Cwd::sys_chdir(name)"
- leaves drive as it is.
- "Cwd::change_drive(name)"
- changes 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 by
"Cwd::cwd".
- "Cwd::sys_abspath(name, dir)"
- Really really odious function to implement. Returns
absolute name of file which would have "name" if CWD were
"dir". "Dir" defaults to the current dir.
- "Cwd::extLibpath([type])"
- Get current value of extended library search path. If
"type" is present and positive, works with
"END_LIBPATH", if negative, works with
"LIBPATHSTRICT", otherwise with "BEGIN_LIBPATH".
- "Cwd::extLibpath_set( path [, type ] )"
- Set current value of extended library search path. If
"type" is present and positive, works with <END_LIBPATH>,
if negative, works with "LIBPATHSTRICT", otherwise with
"BEGIN_LIBPATH".
- "OS2::Error(do_harderror,do_exception)"
- Returns "undef" 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 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 before the first
call to this function.
- "OS2::Errors2Drive(drive)"
- Returns "undef" 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
before the first call to this function.
- 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
- OS2::BootDrive()
- Returns 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. If
"force" 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.
If "force" is false, will not dispatch messages if a real
message loop is known to be present.
Returns change in number of windows. If "cnt" 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 in "new" which are present in "mask" are
changed in the control word.
- OS2::get_control87()
- 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 no "mask", uses exception
mask part of "new" only. If no "new", disables all the
floating point exceptions.
See "Misfeatures" for details.
- "OS2::DLLname([how [, \&xsub]])"
- Gives the information about the Perl DLL or the DLL
containing the C function bound to by &xsub. The meaning of
"how" is: default (2): full name; 0: handle; 1: module
name.
(Note that some of these may be moved to different libraries - eventually).
Prebuilt variables:¶
- $OS2::emx_rev
- numeric value is the same as _emx_rev of EMX, a string
value the same as _emx_vprt (similar to "0.9c").
- $OS2::emx_env
- same as _emx_env of EMX, a number similar to 0x8001.
- $OS2::os_ver
- a number "OS_MAJOR + 0.001 * OS_MINOR".
- $OS2::is_aout
- true if the Perl library was compiled in AOUT format.
- $OS2::can_fork
- true if the current executable is an AOUT EMX executable,
so Perl can fork. Do not use this, use the portable check for
$Config::Config{dfork}.
- $OS2::nsyserror
- This variable (default is 1) controls whether to enforce
the contents of $^E to start with "SYS0003"-like id. If set to
0, then the string value of $^E is what is available from the OS/2 message
file. (Some messages in this file have an "SYS0003"-like id
prepended, some not.)
Misfeatures¶
- •
- 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.
- •
- 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.
- •
- waitpid(3):
WUNTRACED
Not implemented.
waitpid() is not implemented for negative values of PID.
Note that "kill -9" does not work with the current version of
EMX.
- •
- See "Text-mode filehandles".
- •
- 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 not that
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 not call 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 all the applications in the system, this means a complete
unpredictability of floating point flags on systems using such HOOK DLLs.
E.g., GAMESRVR.DLL of DIVE 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 OpenGL 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 "SIGFPE" and
would die a horrible death.
To circumvent this, Perl uses two hacks. They help against one type
of damage only: FP flags changed when loading a DLL.
One of the hacks is to disable floating point exceptions on Perl 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.
Modifications¶
Perl modifies some standard C library calls in the following ways:
- "popen"
- "my_popen" uses sh.exe if shell is
required, cf. "PERL_SH_DIR".
- "tmpnam"
- is created using "TMP" or "TEMP"
environment variable, via "tempnam".
- "tmpfile"
- If the current directory is not writable, file is created
using modified "tmpnam", so there may be a race condition.
- "ctermid"
- a dummy implementation.
- "stat"
- "os2_stat" special-cases /dev/tty and
/dev/con.
- "mkdir", "rmdir"
- these EMX functions do not work if the path contains a
trailing "/". Perl contains a workaround for this.
- "flock"
- Since flock(3) is present in EMX, but is not
functional, it is emulated by perl. To disable the emulations, set
environment variable "USE_PERL_FLOCK=0".
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 "bldlevel DLL-name" to find this info.
Centralized management of resources¶
Since to call certain OS/2 API one needs to have a correctly initialized
"Win" subsystem, OS/2-specific extensions may require getting
"HAB"s and "HMQ"s. If an extension would do it on its own,
another extension could fail to initialize.
Perl provides a centralized management of these resources:
- "HAB"
- To get the HAB, the extension should call "hab =
perl_hab_GET()" in C. After this call is performed, "hab"
may be accessed as "Perl_hab". There is no need to release the
HAB after it is used.
If by some reasons perl.h cannot be included, use
extern int Perl_hab_GET(void);
instead.
- "HMQ"
- There are two cases:
- •
- the extension needs an "HMQ" only because some
API will not work otherwise. Use "serve = 0" below.
- •
- the extension needs an "HMQ" since it wants to
engage in a PM event loop. Use "serve = 1" below.
To get an "HMQ", the extension should call "hmq =
perl_hmq_GET(serve)" in C. After this call is performed, "hmq"
may be accessed as "Perl_hmq".
To signal to Perl that HMQ is not needed any more, call
"perl_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/disable "WM_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 call perl_hmq_GET(1) unless you are
going to process messages on an orderly basis.
- Treating errors reported by OS/2 API
- There are two principal conventions (it is useful to call
them "Dos*" and "Win*" - though this part of the
function signature is not always determined by the name of the API) of
reporting the error conditions of OS/2 API. Most of "Dos*" APIs
report the error code as the result of the call (so 0 means success, and
there are many types of errors). Most of "Win*" API report
success/fail via the result being "TRUE"/"FALSE"; to
find the reason for the failure one should call WinGetLastError()
API.
Some "Win*" entry points also overload a "meaningful"
return value with the error indicator; having a 0 return value indicates
an error. Yet some other "Win*" entry points overload things
even more, and 0 return value may mean a successful call returning a valid
value 0, as well as an error condition; in the case of a 0 return value
one should call WinGetLastError() API to distinguish a successful
call from a failing one.
By convention, all the calls to OS/2 API should indicate their failures by
resetting $^E. All the Perl-accessible functions which call OS/2 API may
be broken into two classes: some die()s when an API error is
encountered, the other report the error via a false return value (of
course, this does not concern Perl-accessible functions which
expect a failure of the OS/2 API call, having some workarounds
coded).
Obviously, in the situation of the last type of the signature of an OS/2
API, it is must more convenient for the users if the failure is indicated
by die()ing: one does not need to check $^E to know that something
went wrong. If, however, this solution is not desirable by some reason,
the code in question should reset $^E to 0 before making this OS/2 API
call, so that the caller of this Perl-accessible function has a chance to
distinguish a success-but-0-return value from a failure. (One may return
undef as an alternative way of reporting an error.)
The macros to simplify this type of error propagation are
- "CheckOSError(expr)"
- Returns true on error, sets $^E. Expects expr() be a
call of "Dos*"-style API.
- "CheckWinError(expr)"
- Returns true on error, sets $^E. Expects expr() be a
call of "Win*"-style API.
- "SaveWinError(expr)"
- Returns "expr", sets $^E from
WinGetLastError() if "expr" is false.
- "SaveCroakWinError(expr,die,name1,name2)"
- Returns "expr", sets $^E from
WinGetLastError() if "expr" is false, and die()s
if "die" and $^E are true. The message to die is the
concatenated strings "name1" and "name2", separated by
": " from the contents of $^E.
- "WinError_2_Perl_rc"
- Sets "Perl_rc" to the return value of
WinGetLastError().
- "FillWinError"
- Sets "Perl_rc" to the return value of
WinGetLastError(), and sets $^E to the corresponding value.
- "FillOSError(rc)"
- Sets "Perl_rc" to "rc", and sets $^E to
the corresponding value.
- Loading DLLs and ordinals in DLLs
- Some DLLs are only present in some versions of OS/2, or in
some configurations of OS/2. Some exported entry points are present only
in DLLs shipped with some versions of OS/2. If these DLLs and entry points
were linked directly for a Perl executable/DLL or from a Perl extensions,
this binary would work only with the specified versions/setups. Even if
these entry points were not needed, the load of the executable (or
DLL) would fail.
For example, many newer useful APIs are not present in OS/2 v2; many
PM-related APIs require DLLs not available on floppy-boot setup.
To make these calls fail only when the calls are executed, one should
call these API via a dynamic linking API. There is a subsystem in Perl to
simplify such type of calls. A large number of entry points available for
such linking is provided (see "entries_ordinals" - and also
"PMWIN_entries" - in os2ish.h). These ordinals can be
accessed via the APIs:
CallORD(), DeclFuncByORD(), DeclVoidFuncByORD(),
DeclOSFuncByORD(), DeclWinFuncByORD(), AssignFuncPByORD(),
DeclWinFuncByORD_CACHE(), DeclWinFuncByORD_CACHE_survive(),
DeclWinFuncByORD_CACHE_resetError_survive(),
DeclWinFunc_CACHE(), DeclWinFunc_CACHE_resetError(),
DeclWinFunc_CACHE_survive(), DeclWinFunc_CACHE_resetError_survive()
See the header files and the C code in the supplied OS/2-related modules for
the details on usage of these functions.
Some of these functions also combine dynaloading semantic with the
error-propagation semantic discussed above.
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:
perl.exe¶
The main workhorse. This is a chimera executable: it is compiled as an
"a.out"-style executable, but is linked with "omf"-style
dynamic library
perl.dll, and with dynamic CRT DLL. This executable is
a VIO application.
It can load perl dynamic extensions, and it can
fork().
Note. Keep in mind that
fork() is needed to open a pipe to
yourself.
perl_.exe¶
This is a statically linked "a.out"-style executable. It 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 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".
perl__.exe¶
This is the same executable as
perl___.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 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 perldebug) 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
different from
cmd.exe, so that it does not create a
link between a VIO session and the session of "pm_porg". (Such a
link closes the VIO window.) E.g., this works with
sh.exe - or with
Perl!
open P, 'pm_prog args 2>&1 |' or die;
print while <P>;
The flavor
perl__.exe is required if you want to start your program
without a VIO window present, but not "detach"ed (run "help
detach" for more info). Very useful for extensions which use PM, like
"Perl/Tk" or "OpenGL".
Note also that the differences between PM and VIO executables are only in the
default behaviour. One can start
any executable in
any
kind of session by using the arguments "/fs", "/pm" or
"/win" switches of the command "start" (of
CMD.EXE
or a similar shell). Alternatively, one can use the numeric first argument of
the "system" Perl function (see OS2::Process).
perl___.exe¶
This is an "omf"-style executable which is dynamically linked to
perl.dll and CRT DLL. I know no advantages of this executable over
"perl.exe", but it cannot
fork() at all. Well, one advantage
is that the build process is not so convoluted as with "perl.exe".
It is a VIO application.
Why strange names?¶
Since Perl processes the "#!"-line (cf. "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 program
is a Perl. There is some naming convention which
allows Perl to distinguish correct lines from wrong ones. The above names are
almost the only names allowed by this convention which do not contain digits
(which have absolutely different semantics).
Why dynamic linking?¶
Well, having several executables dynamically linked to the same huge library has
its advantages, but this would not substantiate the additional work to make it
compile. The reason is 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: first, all
the references to external functions are resolved at the compile time; second,
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
perl.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.
This
greatly 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
perl.exe and
perl__.exe simultaneously:
they share the memory of
perl.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 DLLs one
needs to have the address range of
any of the loaded DLLs in the system
to be available
in all the processes which did not load a particular
DLL yet. This is why the DLLs are mapped to the shared memory region.
Why chimera build?¶
Current EMX environment does not allow DLLs compiled using Unixish
"a.out" format to export symbols for data (or at least some types of
data). This forces "omf"-style compile of
perl.dll.
Current EMX environment does not allow
.EXE files compiled in
"omf" format to
fork().
fork() is needed for exactly
three Perl operations:
- •
- explicit fork() in the script,
- •
- "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 forces "a.out"-style compile of
perl.exe.
ENVIRONMENT¶
Here we list environment variables with are either OS/2- and DOS- and
Win*-specific, or are more important under OS/2 than under other OSes.
"PERLLIB_PREFIX"¶
Specific for EMX port. Should have the form
path1;path2
or
path1 path2
If the beginning of some prebuilt path matches
path1, it is substituted
with
path2.
Should be used if the perl library is moved from the default location in
preference to "PERL(5)LIB", since this would not leave wrong entries
in @INC. For example, 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
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
.
"PERL_BADLANG"¶
If 0, perl ignores
setlocale() failing. May be useful with some strange
locales.
"PERL_BADFREE"¶
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
real
problems.
"PERL_SH_DIR"¶
Specific for EMX port. Gives the directory part of the location for
sh.exe.
"USE_PERL_FLOCK"¶
Specific for EMX port. Since
flock(3) is present in EMX, but is not
functional, it is emulated by perl. To disable the emulations, set environment
variable "USE_PERL_FLOCK=0".
"TMP" or "TEMP"¶
Specific for EMX port. Used as storage place for temporary files.
Evolution¶
Here we list major changes which could make you by surprise.
Text-mode filehandles¶
Starting from version 5.8, Perl uses a builtin translation layer for text-mode
files. This replaces the efficient well-tested EMX layer by some code which
should be best characterized as a "quick hack".
In addition to possible bugs and an inability to follow changes to the
translation policy with off/on switches of TERMIO translation, this introduces
a serious incompatible change: before
sysread() on text-mode
filehandles would go through the translation layer, now it would not.
Priorities¶
"setpriority" and "getpriority" are not compatible with
earlier ports by Andreas Kaiser. See "setpriority, getpriority".
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
perl.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 internal "LX" 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 internal "IMPORT" tables and change the
name of the "old" perl????.dll to the "new"
perl????.dll.
DLL name mangling: 5.6.2 and beyond¶
In fact mangling of
extension DLLs was done due to misunderstanding of
the OS/2 dynaloading model. OS/2 (effectively) maintains two different tables
of loaded DLL:
- Global DLLs
- those loaded by the base name from "LIBPATH";
including those associated at link time;
- specific DLLs
- loaded by the full name.
When resolving a request for a global DLL, the table of already-loaded specific
DLLs is (effectively) ignored; moreover, specific DLLs are
always
loaded from the prescribed path.
There is/was a minor twist which makes this scheme fragile: what to do with DLLs
loaded from
- "BEGINLIBPATH" and "ENDLIBPATH"
- (which depend on the process)
- . from "LIBPATH"
- which effectively depends on the process (although
"LIBPATH" is the same for all the processes).
Unless "LIBPATHSTRICT" is set to "T" (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
"BEGINLIBPATH" and "ENDLIBPATH", or
. from
"LIBPATH" may affect
which DLL is loaded when
another
executable requests a DLL with the same name.
This 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 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
resolve the names of old
extension DLLs if @INC allows finding their directories.
However, this still does not guarantee that these DLL may be loaded. The reason
is the mangling of the name of the
Perl DLL. 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 "BEGINLIBPATH" 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:
- •
- 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 executable. This beats the whole
purpose of explicitly starting an old executable.
- •
- 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.
With support for "LIBPATHSTRICT" this may be circumvented - unless one
of DLLs is started from
. from "LIBPATH" (I do not know
whether "LIBPATHSTRICT" affects this case).
REMARK. Unless newer kernels allow
. in "BEGINLIBPATH"
(older do not), this mess cannot be completely cleaned. (It turns out that as
of the beginning of 2002,
. is not allowed, but
.\. is - and it
has the same effect.)
REMARK. "LIBPATHSTRICT", "BEGINLIBPATH" and
"ENDLIBPATH" are not environment variables, although
cmd.exe
emulates them on "SET ..." lines. From Perl they may be accessed by
Cwd::extLibpath and Cwd::extLibpath_set.
DLL forwarder generation¶
Assume that the old DLL is named
perlE0AC.dll (as is one for 5.005_53),
and the new version is 5.6.1. Create a file
perl5shim.def-leader 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 "warning L4085").
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 "Perl/Tk" for XFree86-OS/2 out-of-the-box,
and link with DLLs for other useful libraries, which typically are compiled
with "-Zmt -Zcrtdll".
Calls to external programs¶
Due to a popular demand the perl external program calling has been changed wrt
Andreas Kaiser's port.
If perl needs to call an external program
via
shell, the
f:/bin/sh.exe will be called, or whatever is the
override, see "PERL_SH_DIR".
Thus means that you need to get some copy of a
sh.exe as well (I use one
from pdksh). The path
F:/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 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". 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: 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 an asynchronous
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
"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 "#!" or
"extproc " will be executed directly, without calling the shell,
by calling the program specified on the rest of the first line.
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 "emx_" added. (Currently only DLL perl has this, it
should propagate to
perl_.exe shortly.)
Threads¶
One can build perl with thread support enabled by providing "-D
usethreads" option to
Configure. Currently OS/2 support of threads
is very preliminary.
Most notable problems:
- "COND_WAIT"
- may have a race condition (but probably does not due to
edge-triggered nature of OS/2 Event semaphores). (Needs a reimplementation
(in terms of chaining waiting threads, with the linked list stored in
per-thread structure?)?)
- os2.c
- has a couple of static variables used in OS/2-specific
functions. (Need to be moved to per-thread structure, or serialized?)
Note that these problems should not discourage experimenting, since they have a
low probability of affecting small programs.
BUGS¶
This description is not updated often (since 5.6.1?), see
./os2/Changes
(perlos2delta) for more info.
AUTHOR¶
Ilya Zakharevich, cpan@ilyaz.org
SEE ALSO¶
perl(1).