omniORB2 on OpenVMS platforms
=============================

This file contains information on building omniORB2 on OpenVMS (Alpha and
and VAX) platforms.

Changes in 2.8.0
----------------

Starting with the 2.8.0 release, shareable images can be created and used for
the Alpha platform.  Shareable images are currently not supported for the VAX
platform.

To simplify linking, separate omniORB floating point libraries are no longer
required.

There are additional configuration parameters in [.config]config.mms.

Downloading the distribution
----------------------------

Refer to http://www.uk.research.att.com/omniORB/VMSDownload.html for
downloading and unpacking the distribution.


Building the distribution
-------------------------

This distribution requires the use of MMS.  It has been tested on Compaq C++ 6.2
for OpenVMS Alpha 7.1, DEC C++ 5.6 for OpenVMS Alpha 7.1, and DEC C++ 5.6 for
OpenVMS VAX 6.1.

The MMS files assume the use of the MMS /Skip qualifier.  You should define a
"make" symbol as follows:

	$ make=="mms/skip"

Before starting the build, you should configure your system to the platform you
are using by editing the file [.config]config.mms.

Next, set your default working directory to [.src] and type:

	$ make/macro=(initialize_mms=1)

You should now be ready to build. Just type 'make export'.  If you use the
"veryclean" rule you will need to repeat the above initialization step.

To build debug versions of the library and/or executables, type:

	$ make/macro=(debug=1)

This will create libraries and executables with a "d" suffix.  For example,
omniORB2d.olb.

Setting up your environment
---------------------------

If your operating system is 6.2 or above, you should add the directory:
mydisk:[myroot.bin.platform] to the logical name DCL$PATH (where platform is
openvms_{alpha|vax}_6_{1|2} and mydisk:[myroot] is the directory containing the
file you are reading).  DCL$PATH should be defined as a search list logical.

If your operating system is 6.1 or below, you should define each of the
executables in that directory as foreign commands.  E.g.:

	$ omniidl2=="mydisk:[myroot.bin.openvms_vax_6_1]omniidl2.exe"

You will also need to define the logical OMNICFG to point to an existing
directory for name service configuration information.  The omniNames server
will use this directory.

You will need to create a file called "omnicfg:omniorb.cfg" to contain the
nameservice IOR as described in the omniORB2 documentation.  The file
contains the single record:

NAMESERVICE <stringified IOR>

Once you have created this file, you should startup the omniNames server as a
detached process.  This should be added to your system startup procedure.  One
way to accomplish this is to configure the port as a UCX (or TCPIP services)
service with the listen flag.

Building omniORB2 applications
-----------------------------

To compile and link against the omniORB2 libraries, you should define the
following logical names:

	$ define <qualifiers> omni mydisk:[myroot.include]
	$ define <qualifiers> omniORB2 mydisk:[myroot.include.omniORB2]
	$ define <qualifiers> omniVms mydisk:[myroot.include.omniVms]
	$ define <qualifiers> omnithread mydisk:[myroot.include.omnithread]
	$ define <qualifiers> omnilib mydisk:[myroot.lib.platform]

(Note that the resulting logical names and translations will be in all upper
case.)  With the above definitions in place, you should add
/include=([],omni:)/exceptions to your CXX compiles.  In addition, if the
compiler version is 5.6 or below, you may need to add
/Warnings=(Disable=CANTCOMPLETE) to your command line.

The logical name omnilib is used as a convenience for the cxxlink command line.
You will link against omnilib:omniORB2.olb/library, and the POSIX threads
shareable image for your platform (you should use omnilib:share.opt/options for
this).

To link against the shareable images, you should use the omnilib:omni_share.olb
(or omnilib:omni_shared.olb) library.  To run the resulting executable, you will
need to redefine sys$share.  E.g.,

	$ define sys$share omnilib,sys$library

You may wish to use or adapt the development environment provided in the DCL 
and MMS files contained in [.etc]openvms.zip to accomplish the above.

Floating point support
----------------------

The CORBA standard mandates that an implementation should use the IEEE standard
for floating point types (CORBA::Float and CORBA::Double).  Since native IEEE
floating point is not available on the VAX platform and to provide additional
flexibility for the Alpha platform, these types are proxy types.

The omniORB2 for VMS development environment provides for different floating
point formats by allowing one of:

	make /macro=(D_FLOAT=1)
	make /macro=(G_FLOAT=1)
	make /macro=(IEEE_FLOAT=1)

to explicitly build for D, G, or IEEE floating point support.  The default is
G_Float and D_FLOAT on Alpha and VAX, respectively (consistent with the CXX
default).  You do not need to supply these qualifiers when building the
distribution.

Notes
-----

If you are running OpenVMS version 6.1, please ensure that you have
installed the latest ECOs for the DEC C RTL and C++ Class Library.

This release of omniORB2 is incompatible with the backport library supplied with
DEC C++ version 5.6 (however, see "Using tcpSocketVaxRoutines.cc on OpenVMS
6.x", below).  Therefore, if your operating system is below 7.0 and you use DEC
C++ version 5.6 or above, be sure that the logical name DECC$CRTLMAP is not
defined.

Building the examples
=====================

You are strongly encouraged to try out the examples provided in
[.src.examples]. Go into [.src.examples] and type 'make all' (where make is
defined as above).

Study the documentations in [.doc] (in the omniORB 2.5.0 distribution) before
you run any of the example programs.

Documentation
=============

You must read the omniORB2 and the OMNI naming service user guides. Follow
the instructions in the guides to complete the configuration process.

Performance
===========

omniORB is implemented using synchronous socket calls in threads rather than
asynchronous socket calls.  Thus, performance of omniORB relies heavily on the
ability of the O/S to perform I/Os that block only the thread of execution
(rather than the whole process) pending I/O completion.

Alpha
-----

For OpenVMS Alpha platforms, the best way to achieve this behavior is to use
link with /Thread=upcalls.  This requires at least 7.1 of OpenVMS.  Ideally, you
should upgrade (if necessary) to 7.1 or 7.2 and use /Thread=upcalls.  If for
some reason you cannot upgrade the O/S you can use the tcpSocketVaxRoutines.cc
enhancement below.

VAX
---

The OpenVMS VAX platform (effectively) ignores the /Thread=upcalls (at least as
of 7.2).  Therefore you should use the tcpSocketVaxRoutines.cc enhancement
below. However, since this enhancement relies on a DEC CRTL 7.0 feature, it
requires using the backport libraries on versions of VMS prior to 7.1. 
Therefore, upgrading to at least OpenVMS 7.1 is advised.

tcpSocketVaxRoutines.cc
-----------------------

The file [.etc]openvms.zip file contains the module
[.src.lib.omniORB2.orbcore]tcpSocketVaxRoutines.cc.  By default, this module is
not compiled into the omniORB2[d].olb library.  In order to use this
enhancement, you should (after a clean build of the source tree):

	$ useTcpSocketVaxRoutines==1
	$ set default [.src.lib.omniorb2.orbcore]
	$ lib/delete=tcpsocketmtfactory omniorb2.olb ! repeat for omniorb2d.olb
	$ make export	! make/macro=(debug=1) export

Using tcpSocketVaxRoutines.cc on OpenVMS 6.x
--------------------------------------------

This requires the use of the DEC CRTL backport library (see
sys$library:decc$crtl.readme) for OpenVMS versions older than 7.1. The backport
library is incompatible with the DEC C++ class library and with VAXCRTL so this
is going to be painful.  Numerous multiply defined external references will
occur at link time.  In addition, if you need to link against code compiled
under the VAX C compiler you will need to add statements like:

PSECT_ATTR=ENVIRON,LCL
PSECT_ATTR=STDERR,LCL
PSECT_ATTR=STDIN,LCL
PSECT_ATTR=STDOUT,LCL
PSECT_ATTR=_CTYPE_,LCL
PSECT_ATTR=RANDX,LCL
PSECT_ATTR=ERRNO,LCL
PSECT_ATTR=VAXC$ERRNO,LCL

to a linker options file in order to create an executable.  It should be safe to
ignore the multiply defined symbols that conflict with DECC$CRTL.OLB, but any
other errors or warnings should be heeded.
