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perlos390 - building and installing Perl for OS/390 and z/OS


This document will help you Configure, build, test and install Perl on OS/390 (aka z/OS) Unix System Services.

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This is a fully ported Perl for OS/390 Version 2 Release 3, 5, 6, 7, 8, and 9. It may work on other versions or releases, but those are the ones we've tested it on.

You may need to carry out some system configuration tasks before running the Configure script for Perl.


The z/OS Unix Tools and Toys list may prove helpful and contains links to ports of much of the software helpful for building Perl.

Unpacking Perl distribution on OS/390

If using ftp remember to transfer the distribution in binary format.

Gunzip/gzip for OS/390 is discussed at:

to extract an ASCII tar archive on OS/390, try this:

pax -o to=IBM-1047,from=ISO8859-1 -r < latest.tar


zcat latest.tar.Z | pax -o to=IBM-1047,from=ISO8859-1 -r

If you get lots of errors of the form

tar: FSUM7171 ...: cannot set uid/gid: EDC5139I Operation not permitted.

you didn't read the above and tried to use tar instead of pax, you'll first have to remove the (now corrupt) perl directory

rm -rf perl-...

and then use pax.

Setup and utilities for Perl on OS/390

Be sure that your yacc installation is in place including any necessary parser template files. If you have not already done so then be sure to:

cp /samples/yyparse.c /etc

This may also be a good time to ensure that your /etc/protocol file and either your /etc/resolv.conf or /etc/hosts files are in place. The IBM document that described such USS system setup issues was SC28-1890-07 "OS/390 UNIX System Services Planning", in particular Chapter 6 on customizing the OE shell.

GNU make for OS/390, which is recommended for the build of perl (as well as building CPAN modules and extensions), is available from the "Tools".

Some people have reported encountering "Out of memory!" errors while trying to build Perl using GNU make binaries. If you encounter such trouble then try to download the source code kit and build GNU make from source to eliminate any such trouble. You might also find GNU make (as well as Perl and Apache) in the red-piece/book "Open Source Software for OS/390 UNIX", SG24-5944-00 from IBM.

If instead of the recommended GNU make you would like to use the system supplied make program then be sure to install the default rules file properly via the shell command:

cp /samples/ /etc

and be sure to also set the environment variable _C89_CCMODE=1 (exporting _C89_CCMODE=1 is also a good idea for users of GNU make).

You might also want to have GNU groff for OS/390 installed before running the "make install" step for Perl.

There is a syntax error in the /usr/include/sys/socket.h header file that IBM supplies with USS V2R7, V2R8, and possibly V2R9. The problem with the header file is that near the definition of the SO_REUSEPORT constant there is a spurious extra '/' character outside of a comment like so:

#define SO_REUSEPORT    0x0200    /* allow local address & port
                                     reuse */                    /

You could edit that header yourself to remove that last '/', or you might note that Language Environment (LE) APAR PQ39997 describes the problem and PTF's UQ46272 and UQ46271 are the (R8 at least) fixes and apply them. If left unattended that syntax error will turn up as an inability for Perl to build its "Socket" extension.

For successful testing you may need to turn on the sticky bit for your world readable /tmp directory if you have not already done so (see man chmod).

Configure Perl on OS/390

Once you've unpacked the distribution, run "sh Configure" (see INSTALL for a full discussion of the Configure options). There is a "hints" file for os390 that specifies the correct values for most things. Some things to watch out for include:

Build, Test, Install Perl on OS/390

Simply put:

sh Configure
make test

if everything looks ok (see the next section for test/IVP diagnosis) then:

make install

this last step may or may not require UID=0 privileges depending on how you answered the questions that Configure asked and whether or not you have write access to the directories you specified.

Build Anomalies with Perl on OS/390

"Out of memory!" messages during the build of Perl are most often fixed by re building the GNU make utility for OS/390 from a source code kit.

Another memory limiting item to check is your MAXASSIZE parameter in your 'SYS1.PARMLIB(BPXPRMxx)' data set (note too that as of V2R8 address space limits can be set on a per user ID basis in the USS segment of a RACF profile). People have reported successful builds of Perl with MAXASSIZE parameters as small as 503316480 (and it may be possible to build Perl with a MAXASSIZE smaller than that).

Within USS your /etc/profile or $HOME/.profile may limit your ulimit settings. Check that the following command returns reasonable values:

ulimit -a

To conserve memory you should have your compiler modules loaded into the Link Pack Area (LPA/ELPA) rather than in a link list or step lib.

If the c89 compiler complains of syntax errors during the build of the Socket extension then be sure to fix the syntax error in the system header /usr/include/sys/socket.h.

Testing Anomalies with Perl on OS/390

The "make test" step runs a Perl Verification Procedure, usually before installation. You might encounter STDERR messages even during a successful run of "make test". Here is a guide to some of the more commonly seen anomalies:

Installation Anomalies with Perl on OS/390

The installman script will try to run on OS/390. There will be fewer errors if you have a roff utility installed. You can obtain GNU groff from the Redbook SG24-5944-00 ftp site.

Usage Hints for Perl on OS/390

When using perl on OS/390 please keep in mind that the EBCDIC and ASCII character sets are different. See perlebcdic.pod for more on such character set issues. Perl builtin functions that may behave differently under EBCDIC are also mentioned in the perlport.pod document.

Open Edition (UNIX System Services) from V2R8 onward does support #!/path/to/perl script invocation. There is a PTF available from IBM for V2R7 that will allow shell/kernel support for #!. USS releases prior to V2R7 did not support the #! means of script invocation. If you are running V2R6 or earlier then see:

head `whence perldoc`

for an example of how to use the "eval exec" trick to ask the shell to have Perl run your scripts on those older releases of Unix System Services.

If you are having trouble with square brackets then consider switching your rlogin or telnet client. Try to avoid older 3270 emulators and ISHELL for working with Perl on USS.

Floating Point Anomalies with Perl on OS/390

There appears to be a bug in the floating point implementation on S/390 systems such that calling int() on the product of a number and a small magnitude number is not the same as calling int() on the quotient of that number and a large magnitude number. For example, in the following Perl code:

my $x = 100000.0;
my $y = int($x * 1e-5) * 1e5; # '0'
my $z = int($x / 1e+5) * 1e5;  # '100000'
print "\$y is $y and \$z is $z\n"; # $y is 0 and $z is 100000

Although one would expect the quantities $y and $z to be the same and equal to 100000 they will differ and instead will be 0 and 100000 respectively.

The problem can be further examined in a roughly equivalent C program:

#include <stdio.h>
#include <math.h>
double r1,r2;
double x = 100000.0;
double y = 0.0;
double z = 0.0;
x = 100000.0 * 1e-5;
r1 = modf (x,&y);
x = 100000.0 / 1e+5;
r2 = modf (x,&z);
printf("y is %e and z is %e\n",y*1e5,z*1e5);
/* y is 0.000000e+00 and z is 1.000000e+05 (with c89) */

Modules and Extensions for Perl on OS/390

Pure pure (that is non xs) modules may be installed via the usual:

perl Makefile.PL
make test
make install

If you built perl with dynamic loading capability then that would also be the way to build xs based extensions. However, if you built perl with the default static linking you can still build xs based extensions for OS/390 but you will need to follow the instructions in ExtUtils::MakeMaker for building statically linked perl binaries. In the simplest configurations building a static perl + xs extension boils down to:

perl Makefile.PL
make perl
make test
make install
make -f Makefile.aperl inst_perl MAP_TARGET=perl

In most cases people have reported better results with GNU make rather than the system's /bin/make program, whether for plain modules or for xs based extensions.

If the make process encounters trouble with either compilation or linking then try setting the _C89_CCMODE to 1. Assuming sh is your login shell then run:

export _C89_CCMODE=1

If tcsh is your login shell then use the setenv command.


David Fiander and Peter Prymmer with thanks to Dennis Longnecker and William Raffloer for valuable reports, LPAR and PTF feedback. Thanks to Mike MacIsaac and Egon Terwedow for SG24-5944-00. Thanks to Ignasi Roca for pointing out the floating point problems. Thanks to John Goodyear for dynamic loading help.


INSTALL, perlport, perlebcdic, ExtUtils::MakeMaker.

Mailing list for Perl on OS/390

If you are interested in the z/OS (formerly known as OS/390) and POSIX-BC (BS2000) ports of Perl then see the perl-mvs mailing list. To subscribe, send an empty message to

See also:

There are web archives of the mailing list at:


This document was originally written by David Fiander for the 5.005 release of Perl.

This document was podified for the 5.005_03 release of Perl 11 March 1999.

Updated 28 November 2001 for broken URLs.

Updated 12 November 2000 for the 5.7.1 release of Perl.

Updated 15 January 2001 for the 5.7.1 release of Perl.

Updated 24 January 2001 to mention dynamic loading.

Updated 12 March 2001 to mention //'SYS1.TCPPARMS(TCPDATA)'.