Re: Problem with LT 2.1a

[Bob Friesenhahn]

On Wed, 6 Sep 2006, Jeff Squyres wrote:

> Greetings.
>
> I'm a longtime Libtool user; we've used both Libtool and libltdl in LAM/MPI
> and Open MPI (among dozens of other packages!).  I've said it before, but
> I'll say it again -- thanks bunches for Libtool!  I have no idea what we'd
> do without it (and for all the help that Ralf W. and others have provided us
> over the years).
>
> We have run into a problem with LT 2.1a, however (no worries; we realize
> that it's as-yet unreleased).  It took a little poking around to realize
> what the problem really is: that LT 2.1a's libltdl is no longer
> lt_dlopen()'ing plugins on Linux with RTLD_GLOBAL.
>
> Short version: can libltdl be augmented to allow users to optionally specify
> using RTLD_GLOBAL?  This would solve our problem.

There was lengthy mailing list discussion before the RTLD_GLOBAL 
default was removed.  The main reason why it was removed is because it 
represents non-portable behavior.  Applications depending on it won't 
work in all libtool-supported environments.  Libtool is a portability 
tool.  The global namespace conflict issue is less significant (but 
exists).  Making it a specific libtool option (with a strong warning 
in the documentation) seems reasonable.

> I certainly understand the desire to not use RTLD_GLOBAL for everything;
> separate namespaces are generally a Good Thing.  I guess my appeal is to
> allow the caller of lt_dlopen() to optionally specify that they want to use
> RTLD_GLOBAL.  This would solve our problem.
>
> Are there any estimates of how many other applications will be hurt by this
> change to libltdl?  We might be among the first of many to ask about this.

This is probably the second or third complaint voiced on this list.

Bob
======================================
Bob Friesenhahn
address@hidden, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/