Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!uupsi!sunic!news.funet.fi!funic!santra!santra!sja
From: sja@sirius.hut.fi (Sakari Jalovaara)
Newsgroups: comp.windows.x.motif
Subject: Re: Shared Motif libraries on RISC System/6000
Message-ID: <1991Mar23.181817.18575@santra.uucp>
Date: 23 Mar 91 19:17:51 GMT
References: <1991Mar22.121625.29734@santra.uucp>
Sender: news@santra.uucp (Cnews - USENET news system)
Organization: Helsinki University of X-nology
Lines: 48
In-Reply-To: sja@sirius.hut.fi's message of 22 Mar 91 14:16:03

I wrote:
> Has anyone made shared Motif 1.1.1 libraries on an IBM RS/6000?
>
> I don't seem to be able to make them work.  If Motif programs are
> linked statically they work but if any or all of Mrm, Xm or Xt are
> shared libraries some programs give errors [...]

Two people, Kaleb Keithley at JPL and Kee Hinckley at Alfalfa Software
Inc, knew what was happening: Xm redefines VendorShell and the AIX
linker put _both_ Xm's and Xt's VendorShell into programs.


When an AIX shared library is created as many references inside the
library are resolved as possible.  If the symbol vendorShellClassRec
is defined in libXt and referenced, say, from a function XtFoo() also
in libXt, the "ld" run that creates the shared library resolves the
reference:

	XtFoo() -> vendorShellClassRec

Then I create the Motif library that has its own vendorShellClassRec
and an XmBar() function that uses it; libXm will also contain a
resolved reference to vendorShellClassRec:

	XmBar() -> vendorShellClassRec

Finally, I link a program that uses both XtFoo() and XmBar() and the
program will end up with _two_ independent "vendorShellClassRec"s:

	XtFoo() -> vendorShellClassRec [Xt version]
	XmBar() -> vendorShellClassRec [Xm version]

Instand schizo zaphod mode.  In reality, vendorShellClassRec is not
referenced from functions but from other widget class records.


I can't just pull Vendor.o out from the shared Xt (Vendor.o appears to
define the only external symbols redefined by libXm) because AIX
shared libraries apparently can't contain unresolved external
references.  If I take out Vendor.o I have to take out every other
file that uses symbols defined there - and then files that need those
files, etc.  I tried it and ended up with three or four object files
in libXt and the res non-sharable.

I kludged around this by putting all of libXt (minus Vendor.o) into
the shared libXm.  It isn't a pretty solution but it works - and beats
having a statically linked two-megabyte "periodic" demo...
									++sja