Re: tlug: Acrobat reader and libXt

["Stephen J. Turnbull" <turnbull@example.com>]

>>>>> "kyomu" writes:

    kyomu> On Sun, 17 Jan 1999, Jonathan Byrne wrote:

    >> I just installed Acrobat reaader for Linux 3.01, and when I run
    >> it, it says "can't load libary 'libXt.s0.6' and dies.  Can
    >> somebody clue me in as to what libXt.so.6 is, where it should
    >> be, and if it's normal for that to not be in TurboLinux
    >> (3.0-J)?

Just blow off the libXt stuff and wait for Adobe to get its shit
together and put out a glibc version of Acrobat is my advice.  There
may already be one on the server, go look.

Or use gv over Aladdin Ghostscript >= 5.10.

If you really want to know, "read on, MacDuff".

    >> Oh, and what to do about getting libXt.so.6, too :-)

    kyomu>         i am not really sure but....  but it should be in
    kyomu> your /usr/X11R6/lib/ or in your /usr/ix86-linuxaout/lib/.

    kyomu>         It usually gos in /usr/ix86-linuxaout/lib, and it is
    kyomu> used to provide backwards compatibility for dynamically
    kyomu> linked a.out format X binaries.  (i think...)

I beg to differ :-)  First of all, it has nothing to do with a.out
format.  There probably is a backwards-compatibility issue here, but
it's H.J.Liu libc5 against the forces of Good and Light, aka Uli
Drepper's GNU libc "ta da!" Version Two-point-X.

(1) Where do libraries live?

Libraries can live almost anywhere.  Fortunately, the ones that do
live in arbitrary places are either statically linked or come with
wrapper scripts to load them up (eg the original liblocale.so for
muriyari Netscrap).

DLLs (.so) live where the dynamic linker ld.so can find them.  This is
configured via /etc/ld.so.conf.  `cat /etc/ld.so.conf' will give you a
list of the standard directories where .so's are found.  `man ld.so'
should (and does on Debian systems) give you details about hairy
options and environment variables to modify this basic behavior, but
probably will not (TurboLinux should be taken out behind the woodshed
about its documentation, /usr/doc is populated with all sorts of
wonderful information about window managers I don't use, but nothing
about ld.so, and `man' and `info' often come up empty...).

To find out if ld.so knows about a particular library, and if so where
the versions it will use live, use `ldconfig -p' (a non-root user may
need to do `/sbin/ldconfig -p'):

		     ldconfig -p | fgrep libXt.so

Output is omitted to encourage you to try this out at home.  It's not
dangerous, really.

(2) What does "can't load library ..." mean?

It means "I can't find a file with the name ... that matches the
object format (a.out DLL or ELF) and version information (major should
match exactly, IIRC, and minor should be no smaller) requested by the
executable being loaded."  This is particularly confusing with respect
to the X11 libraries, since the major number of the .so did not get
incremented when the shift to glibc was made.  It is often the case
that an apparently appropriate library exists but does not satisfy
version information.

(3) What is libXt.so?

This is the library implementing the Xt "X toolkit" library, the
granddaddy of all X toolkits.  Most X toolkits are built either on top
of Xt (the MIT Athena widgets) or on a modified version of Xt (Motif).
Without this library, your mouse won't point, your events won't
happen, and in general you may as well give up, or you're stuck
programming in Xlib calls (the GUI equivalent of assembly language).

(4) Where does libXt.so live?

Normally in /usr/X11R6/lib/.  Possibly in /usr/lib/libc5-compat (IIRC,
I know the theory, not the practice, and that may be a Debianism) if
you have a system which is primarily glibc but is supporting binaries
linked with libc5.

(5) Is it normal for that not to be in TL-3.0J?

No, that's very abnormal.  However, the message didn't say it couldn't 
_find_ libXt.so, it said it couldn't _load_ it.  Probably due to the
libc5 vs. glibc conflict.  TL-3.x systems are glibc through-and-through;
(since I accidentally got dropped from the J-beta list) I don't have
one to check how (if) it supports libc5 backward compatibility,
which is especially difficult for X.

But Scott will be by shortly to explain and/or fix all this, I'm sure.

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