From: mahan@tgv.com (Patrick L. Mahan)
Newsgroups: fj.mail-lists.x-window
Subject: RE: Questions about DECWindows under VMS
Date: 10 Apr 92 00:54:33 GMT
Distribution: fj
Organization: Workstation Div., Supermicro Systems Group, Sony Corporation

Date:    Thu, 9 Apr 92 11:00:04 PDT
Message-Id: <920409110004.20e0013e@TGV.COM>
X-St-Vmsmail-To: ST%"xpert@expo.lcs.mit.edu"

#
#I have a few questions about DECWindows under VMS that hopefully
#someone can help me answer.
#
#I don't have access to any machines running DECWindows under VMS, so
#I'm kind of working in the dark here.
#
#1)  The information that I've seen implies that DECWindows under VMS is
#an X11 varient, but I haven't been able to find the relationship
#between various versions of DECWindows and the releases of X11.  Is
#there an easy way to tell whether a version of DECWindows is X11R3 or
#X11R4?
#

When DECwindows was first released with VMS 5.1 it was based on X11R2.
Currently DECwindows is fully compliant with X11R3.  To obtain the 
DECwindows release that is based on X11R4 you must obtain DECwindows/
Motif which is carried as a seperate layer product and not sent out
with the operating system.  Digital has no plans to upgrade the core
DECwindows (commonly refered to as XUI) to X11R4.

To tell what version of X11 DECwindows is compliant with use the following
guidelines:

	o If the operating system is pre-VMS 5.3 then you are running
	  X11R2 based DECwindows.

	o If the operating system is VMS 5.3 or later then you are running
	  X11R3.

	o If the logical LMF$DEC_DW-MOTIF is defined in the logical name
	  table LMF$LICENSE_TABLE then you are running DECwindows based
	  on X11R4.

#
#2) Is VMS DECWindows a full X11 distribution?  Does it support all of
#the XLib toolkit?  Are there any other toolkits that are always
#included?
#

DECwindows supports the full Xlib toolkit.  The toolkits available are
XUI (X User Interface) for DECwindows based on X11R3 and Motif and
XUI for DECwindows based on X11R4.  You may obtain the Athena widget
set for DECwindows from the DECUS library for both X11R3 and X11R4
of DECwindows.

#
#3) Is there any easy way for X programs running under VMS (with the
#DECNet protocol, I suppose) to communicate with X servers running under
#Unix? (either Ultrix or otherwise)
#

You will need to obtain either Digital's or a third-party supported 
release of TCP/IP for VMS.  A number of companies are in this market
(including the one I work for).  Or you could check with your Unix
vendor to see if they have DECnet support for their X Windows stuff.

#
#4) Are there any special issues that have to be addressed in porting an
#XLib-based program from Unix to VMS?
#

Mainly, handling the Unix-isms that most of the PD X Windows software uses
(eg, using select() to do timeouts).  If you obtain the X11 Client and
Demos tape from the DECUS Library, it will contain a number of 
"emulation" routines to help you port the Unix code to VMS.

Patrick L. Mahan

--- TGV Window Washer ------------------------------- Mahan@TGV.COM ---------

Waking a person unnecessarily should not be considered  - Lazarus Long
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