Re: how to link with installed libltdl?

[Bob Friesenhahn]

On Thu, 1 Sep 2005, Howard Chu wrote:
> > I guess I should better probe for libdl and
> > link with it, too? anthing else?
>
> If you use libtool for linking, and the libltdl.la file is installed, then 
> dependencies are taken care of automatically. If you're not using libtool for 
> linking, then you're making a mistake. The point of using libtool and libltdl 
> is to avoid having to check for other system-specific dependencies. Checking 
> for libdl is (a) redundant since libtool's configure script would have 
> already looked for it and (b) insufficient since other platforms may use some 
> other name for their dynamic linking support library.

So it seems that a libtool-provided macro should be used in 
configure.ac to test for an installed libltdl.  Testing for it in a 
simple way could well indeed result in false negatives due to libltdl 
depending on some other library (e.g. -ldl).  It is not necessary for 
a package to include its own copy of libtool in order to make use of 
it.  Libtool may already be installed in a standard location.

I may be missing something, but all the libltdl-related macros I see 
are for the case of when libltdl is bundled with the package.  I don't 
see one for simply testing for an already installed libltdl.

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