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From: erc@pai.UUCP (Eric Johnson)
Newsgroups: comp.sys.hp
Subject: Re: Behavior of Xterms...
Keywords: X11 R2 and R3 xterm
Message-ID: <1545@pai.UUCP>
Date: 21 Nov 90 23:07:22 GMT
Organization: Boulware Technologies, Inc., Burnsville, MN
Lines: 65

love@spruce.cs.uiuc.edu (Christopher Love) writes:

For the application I am working on (adding X selection support to Epoch),
I am observing that HP xterms are looking only to XA_CUT_BUFFER0, *not* to
the selection XA_PRIMARY.  This prevents "normal" communication between
clients in some situations.  This behavior is in contrast to behavior with 
xterms running on other platforms (386, Sun sparc), which look to the 
selection.

Is this a correct analysis of the situation?  

BTW: X running on HP is the distribution provided with the system 
HP 9000/345.

Christopher J. Love	||Epoch Development Team, University of Illinois
love@cs.uiuc.edu	||	"We are marching for dear old Illini..."

---
Here's my guess: The HP xterm is at X11 Release 2. The other systems are
at X11 Release 3 or higher. If you're running HP-UX 6.5 or below on the
345, then you're at Release 2 of X (unless you compiled an MIT release
yourself). HP-UX 7.0 provides X11 Release 3 (and I've heard rumors that
HP-UX 8.0 will offer X11 Release 4--which I hope comes soon, due to 
performance issues: R4 is much faster). Release 2-based xterms used cut 
buffers (at least the R2-based xterms I've seen). Release 3+ and all 
later-model xterms use the PRIMARY selection (XA_PRIMARY). It's a pain, 
I know.

The use of cut buffers is now officially discouraged, which is kind of 
a drag, since cut buffers are much easier to deal with than selections
(in C code). Even so, I strongly advise you design Epoch to use selections.

For now, you can look at the program xcutsel (cut buffers to selection
converter), which may provide a solution. From the man page for xcutsel:

             xcutsel - interchange between cut buffer and selection

             The xcutsel program is used to copy the current selection
             into a cut buffer and to make a selection that contains the
             current contents of the cut buffer.  It acts as a bridge
             between applications that don't support selections and those
             that do.

             By default, xcutsel will use the selection named PRIMARY and
             the cut buffer CUT_BUFFER0.  Either or both of these can be
             overridden by command line arguments or by resources.

For writing selection-handling code, Advanced X Window Applications 
Programming, a book I'm responsible for, has a very long chapter on
the subject of selections, with lots of example C code.

Advanced X Window Applications Programming, by Eric F. Johnson and Kevin 
Reichard, MIS: Press, Portland, Oregon, 1990. ISBN 1-55828-029-4.

For info, you can call (in the USA): 1-800-MANUALS, or send me email.

Hope this helps,
-Eric


-- 
Eric F. Johnson               phone: +1 612 894 0313    BTI: Industrial
Boulware Technologies, Inc.   fax:   +1 612 894 0316    automation systems
415 W. Travelers Trail        email: erc@pai.mn.org     and services
Burnsville, MN 55337 USA