source: trunk/third/perl/README.vos @ 14545

Perl 5 README file for the Stratus VOS operating system.
Paul Green (Paul_Green@stratus.com)
February 3, 2000


Introduction
------------
This is a port of Perl version 5, revision 005-63, to VOS.  Perl
is a scripting or macro language that is popular on many
systems.  See your local computer bookstore for a number of good
books on Perl.

Most of the Perl features should work on VOS.  However, any
attempt by perl.pm to call the following unimplemented POSIX
functions will result in an error message and an immediate and
fatal call to the VOS debugger.  They are "dup", "fork", and
"waitpid".  The lack of these functions pretty much prevents you
from starting VOS commands and grabbing their output in perl.
The workaround is to run the commands outside of perl, then have
perl process the output file.


Compiling Perl 5 on VOS
-----------------------
Before you can build Perl 5 on VOS, you need to have or acquire the
following additional items.

1.   The VOS Standard C Compiler and Runtime, or the VOS Standard C
     Cross-Compiler.  This is a standard Stratus product.

2.   The VOS OS TCP/IP product set.  While the necessary header
     files are included with VOS POSIX.1, you still need the
     appropriate object files in order to bind perl.pm.  This is
     a standard Stratus product.

3.   The VOS POSIX.1 environment.  As of this writing, this is
     available on the VOS FTP site.  Login anonymously to
     ftp.stratus.com and get the file
     /pub/vos/alpha/posix.save.evf.gz in binary file-transfer
     mode.  Or use the Uniform Resource Locator (URL)
     ftp://ftp.stratus.com/pub/vos/alpha/posix.save.evf.gz from
     your web browser.  This is not a standard Stratus product.

     Instructions for unbundling this file are at
     ftp://ftp.stratus.com/pub/vos/utility/utility.html.

4.   You must compile this version of Perl 5 on VOS Release
     14.1.0 or higher because some of the perl source files
     contain more than 32,767 source lines.  Due to VOS
     release-compatibility rules, this port of perl may not
     execute on VOS Release 12 or earlier.

To build perl 5, change to the "vos" subdirectory and type the
command "compile_perl -processor X", where X is the processor
type (mc68020, i80860, pa7100, pa8000) that you wish to use.
Note that code compiled for the pa7100 processor type can
execute on the PA7100, PA8000, and PA8500 processors, and that
code compiled for the pa8000 processor type can execute on the
PA8000 and PA8500 processors.


Installing Perl 5 on VOS
------------------------
1.   Create the directory >system>ported>command_library.

2.   Copy the appropriate version of the perl program module to
     this directory.  For example, with your current directory
     set to the top-level directory of Perl 5, to install the
     executable program module for the Motorola 68K
     architecture, enter:

          !copy_file vos>obj>perl.pm >system>ported>command_library>*

     (If you wish to use both Perl version 4 and Perl version 5,
     you must give them different names; for example, perl.pm
     and perl5.pm).

3.   Create the directory >system>ported>perl>lib.

4.   Copy all of the files and subdirectories from the lib
     subdirectory into this new directory.  For example, with
     the current directory set to the top-level directory of the
     perl distribution, enter:

          !copy_dir lib >system>ported>perl>lib>5.005

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

          >system>ported>perl>lib>5.005.68k
          >system>ported>perl>lib>5.005.860
          >system>ported>perl>lib>5.005.7100
          >system>ported>perl>lib>5.005.8000

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

          >system>ported>perl>lib>site>5.005

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

          >system>ported>perl>lib>site>5.005.68k
          >system>ported>perl>lib>site>5.005.860
          >system>ported>perl>lib>site>5.005.7100
          >system>ported>perl>lib>site>5.005.8000

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


Unimplemented Features
----------------------
If Perl 5 attempts to call an unimplemented VOS POSIX.1 function,
it will print a fatal error message and enter the VOS debugger.
This error is not recoverable.  See vos_dummies.c for a list of
the unimplemented POSIX.1 functions.  To see what functions are
unimplemented and what the error message looks like, compile and
execute "test_vos_dummies.c".


Restrictions
------------
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.


Support Status
--------------
I'm offering this port "as is".  You can ask me questions, but I
can't guarantee I'll be able to answer them; I don't know much
about Perl itself; I'm still learning that.  There are some
excellent books available on the Perl language; consult a book
seller.

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