Compiling EPICS and Building IOC Applications on OpenVMS 
(OpenVMS-Alpha and OpenVMS-IA64)
========================================================

Please mail questions, comments, corrections, additional examples, etc.
to wermelsk@slac.stanford.edu

Tested under OpenVMS Alpha V7.3-2 using Multinet V4.4
and OpenVMS IA64 V8.2-1 using TCP/IP Services for OpenVMS V5.5

Tools needed
------------

 o GNV (Alpha or I64) (tested with V1.6-2)
 
 o Perl for OpenVMS (Alpha or I64) (tested with V5.8-6)

  - This version of Perl does not support full ODS-5 file names, resulting
    in changing O.OpenVMS_Alpha to O_OpenVMS_Alpha. Names with embedded "@"
    also not supported (files below base/src/makeBaseApp/top).  May change 
    in future versions.  

 o Recent version of C and C++ compiler (V7.1 or higher)

  - V6.5 will have a problem with templates.

 o Use gnutar to extract files from the delivered tar files.  Cannot use
   VMS tar.

 o Disk drive containing files must be ODS-5.


Environment
-----------

An os-specific repository directory is needed for CXX and CXXLINK.
The logical name CXX$DEMANGLER_DB is assigned to this directory.
Example: DEFINE CXX$DEMANGLER_DB EPICS_ROOT:[base.cxx_repository.OpenVMS_Alpha]
This directory is NOT created by the build and must be manually created before 
the build starts.

Assuming UCX (TCIP/IP Services for OpenVMS) can be installed, even if
not run, the include files will be used and will work for Multinet as
well. Other TCP/IP packages for VMS (like Wallongong(?)) have not been
tested and will be ignored.

A subset of DECC and GNV logical names must be set before the build starts.
An example setup file is base/startup/Site.vms - it will need modification
for your site.


Building
--------

Shareable library build is not yet implemented.  Before building,
edit base/configure/CONFIG_SITE so that:
	SHARED_LIBRARIES=NO
	STATIC_BUILD=YES
	USE_POSIX_THREAD_PRIORITY_SCHEDULING = YES

Add base/configure/os/CONFIG_SITE.*OpenVMS* files to override any 
definitions in CONFIG.*OpenVMS* files just like for any other platform.

Building must be done using the bash shell, delivered with gnv. 
There is a bug in GNV make that requires all MakefileInclude files
be built first.  So the build requires two steps:
$ set def <location of base>
$ @[.startup]Site.vms
$ bash
bash$ setenv EPICS_HOST_ARCH OpenVMS-<Alpha or IA64>
bash$ make MakefileInclude
bash$ make

Make sure any existing symbols for cc, cxx, and link are deassigned before
building.


Shared Libraries
----------------

Later.


Known Problems
--------------

 o Source changes are not yet made for auto-startup of CA repeater.
   CA repeater must be started manually.  Add it to your system startup.

 o base/config is not updated for VMS.  No 3.13 extension or
   application can be built for VMS.

 o GNV make has a problem where it can't find a file that is created by 
   a previous rule.  So a two-step make is required - one to create all
   the MakefileInclude files required by the build, and the second to do
   the build.  The base/configure/RULES* files were changed to allow a
   separate MakefileInclude build.

 o makeBaseApp.pl and makeBaseExt.pl do not work with the current version 
   of perl.  They also cannot be fully built since they have files with 
   embedded "@"s and those files cannot be installed by perl.