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README.vos - Perl for Stratus VOS


This file contains notes for building perl on the Stratus VOS operating system. Perl is a scripting or macro language that is popular on many systems. See perlbook for a number of good books on Perl.

These are instructions for building Perl from source. Most people can simply download a pre-compiled distribution from the VOS anonymous FTP site. This version of Perl is not supported on VOS Release 14.2.0 or earlier releases. If you are running VOS Release 14.3.0 or later, download Perl from Instructions for unbundling the Perl distribution file are at

If you are running VOS Release 14.4.1 or later, you can obtain a pre-compiled, supported copy of perl by purchasing Release 2.0.1 (or later) of the VOS GNU C++ and GNU Tools product from Stratus Technologies.


To build perl from its source code, you must have a Continuum platform running VOS Release 14.5.0 or later, the STCP product, and the GNU C++ and GNU Tools, Release 2.0.1 or later.

To build full perl using the supplied Configure script and makefiles, change to the "vos" subdirectory and type the command "compile_full_perl" or "start_process compile_full_perl". This will configure, build, and test perl.


  1. If you have built perl using the Configure script, ensure that you have modify permission to >system>ported and type

    gmake install
  2. While there are currently no architecture-specific extensions or modules distributed with perl, the following directories can be used to hold such files:

  3. Site-specific perl extensions and modules can be installed in one of two places. Put architecture-independent files into:


    Put site-specific architecture-dependent files into one of the following directories:

  4. You can examine the @INC variable from within a perl program to see the order in which Perl searches these directories.


Restrictions of Perl on VOS

This port of Perl version 5 to VOS prefers Unix-style, slash-separated pathnames over VOS-style greater-than-separated pathnames. VOS-style pathnames should work in most contexts, but if you have trouble, replace all greater-than characters by slash characters. Because the slash character is used as a pathname delimiter, Perl cannot process VOS pathnames containing a slash character in a directory or file name; these must be renamed.

This port of Perl also uses Unix-epoch date values internally. As long as you are dealing with ASCII character string representations of dates, this should not be an issue. The supported epoch is January 1, 1980 to January 17, 2038.

See the file pod/perlport.pod for more information about the VOS port of Perl.

Handling of underflow and overflow

Prior to VOS Release 14.7.0, VOS does not support automatically mapping overflowed floating-point values to +infinity, nor automatically mapping underflowed floating-point values to zero, unlike many other platforms. The Perl pack function has been modified to perform such mapping in software on VOS. Performing other floating-point computations that underflow or overflow will probably result in SIGFPE. Don't push your luck.

As of VOS Release 14.7.0, the VOS POSIX runtime sets up the PA-RISC hardware floating-point status register so that the overflow and underflow exceptions do not trap, but instead automatically convert the result to infinity or zero, as appropriate. As of this writing, there are still floating-point operations that can trap, for example, subtracting two infinite values. This is recorded as suggestion posix-1022, which is not yet fixed.


When Perl 5.9.0 is built using the native build process on VOS Release 14.7.0 and GNU C++/GNU Tools 2.0.2a, all but nine attempted tests either pass or result in TODO (ignored) failures. The tests that fail are:

t/io/dup, test 2 t/io/tell, test 28 t/op/pack, test 0 ext/B/t/bytecode, test 1 ext/Devel/Peek/t/Peek, test 1 ext/Encode/t/enc_module, test 1 ext/IO/t/io_dup, test 2 lib/ExtUtils/t/MM_Unix, test 94 lib/Net/ing/t/450_service, test 8


I'm offering this port "as is". You can ask me questions, but I can't guarantee I'll be able to answer them. There are some excellent books available on the Perl language; consult a book seller.

If you want a supported version of perl for VOS, purchase the VOS GNU C++ and GNU Tools Release 2.0.1 (or later) product from Stratus Technologies, along with a support contract (or from anyone else who will sell you support).


Paul Green (


January 15, 2004