[2742] in SIPB_Linux_Development
Re: third/wcl
daemon@ATHENA.MIT.EDU (Aaron M. Ucko)
Wed Jun 2 12:11:07 1999
To: Greg Hudson <ghudson@MIT.EDU>
Cc: linux-dev@MIT.EDU
From: amu@MIT.EDU (Aaron M. Ucko)
Date: 02 Jun 1999 11:02:41 -0500
In-Reply-To: Greg Hudson's message of "Wed, 2 Jun 1999 00:20:05 -0400 (EDT)"
Greg Hudson <ghudson@MIT.EDU> writes:
> ld: warning: libSM.so.6, needed by /usr/X11R6/lib/libXmu.so, not found (try using --rpath)
> ld: warning: libICE.so.6, needed by /usr/X11R6/lib/libXmu.so, not found (try using --rpath)
Oh, I think I know what's happening. Because the dynamic loader can't
tell whether an ELF shared library with no dependency information was
built with libc5 or libc6, some programs were getting libraries built
with the wrong version of libc. For Red Hat-Athena 5.2/8.2, we worked
around this problem by switching to a version of ldconfig that
supported an extended ld.so.conf syntax that allowed us to associate a
default library generation with each directory, solving the runtime
problem.
What we forgot was that ld uses ld.so.conf when linking in shared
libraries containing dependency information and the version of ld
we're using *doesn't* support the extended syntax mentioned above and
ends up not looking in /usr/X11R6/lib when trying to resolve
shared-library dependencies.
Here are some solutions which strike me as at least vaguely
reasonable, from most preferred to least preferred:
* Replace ld, like ldconfig, with a version that can deal with the
extended ld.so.conf syntax.
This is the best solution in most ways, but kind of feels like
overkill.
* Change /usr/X11R6/lib=libc6 back to /usr/X11R6/lib in /etc/ld.so.conf.
This unconfuses ld about /usr/X11R6/lib, and should be safe
unless people install poorly built third-party libraries in
that directory. (Every library a Red Hat 5.2 package installs
in /usr/X11R6/lib contains proper dependency information; I
*assume* the same is true of 6.0, but would need to check to
be sure.)
* Work around the problem in the build system.
These "solutions" all leave the problem around for people not
using our build system, and are included only for completeness.
** Have do.sh set LD_LIBRARY_PATH to /usr/X11R6/lib on Linux.
** Arrange for the wcl Makefiles to run ld with the flag
"-rpath-link /usr/X11R6/lib"
** Arrange for the wcl Makefiles to link against -lSM -lICE
explicitly.
