Re: Mac OS X .dylib not working

[Peter O'Gorman]

On 03/03/2011 01:56 PM, Michael Ellis wrote:
> On Thu, Mar 3, 2011 at 2:32 PM, Hans Åberg<address@hidden>  wrote:
> > [I'm not on the bug-libtool list, so please cc me.]
> >
> > Despite being reported a year ago, Guile can still not open dynamic libraries 
> > ending with .dylib on Mac OS X. Looking throw the past discussion, it looks as 
> > though developers of the one package hold the opinion that those of the other 
> > package should do the fix. So I am merely reporting it, cross-linking, so that 
> > you can figure out who guys should do the fix. :-)
> >
> > So guile-2.0.0 using libltdl.7.dylib of libtool-2.4, can on Mac OS X 10.6.6 
> > only open a dynamic library if the name of what it actually opens ends in .so 
> > (say by making a soft link using 'ln -s'); if it ends in .dylib, it cannot open 
> > it, even if the full name is given.
> >
> > See
> >   http://lists.gnu.org/archive/html/bug-guile/2011-03/msg00008.html
> >   http://lists.gnu.org/archive/html/guile-devel/2011-03/msg00021.html
> >
> > Mac OS X does not care about file name extensions; .dylib is just a convention 
> > for native dynamic libraries.

The static linker when it sees a -l flag will look for files beginning 
with "lib" and ending in ".dylib", ".so" (though this is recent and 
perhaps not documented) and ".a". So, I think you could say that it 
cares about file name extensions.

> > So the wanted behavior is to first try opening a library without adding an 
> > extension, and then try out different endings. On Mac OS X, it would be best 
> > trying out .dylib first - I haven't seen any other ending in use.

It does seem as though guile should sometimes be trying lt_dlopen() 
first - then libltdl will attempt to open whatever it's given.

>   -- the libtool archive extension .la
>   -- the extension used for native dynamically loadable modules on the
> host platform, e.g., .so, .sl, etc.

On Mac OS X, libtool's idea of the native dynamically loadable module 
extension is ".so", and it's not going to change.

However, I can see the point that libltdl should try .dylib as well as 
.so for lt_dlopenext on Mac OS X. I will come up with a patch for that.

Peter