On 30 Jan 2010, at 19:39, Ken Raeburn wrote:
The Mac OS X situation is a bit more complicated than on "normal" ELF-based UNIX systems; shared libraries and dynamically loadable objects are not the same thing. It's easy to assume they're equivalent when working mostly on ELF or Windows systems where .so or .dll files work for both, but it's not always true. GNU libtool even has options for creating loadable modules as distinct from regular shared libraries.
Sure, it would be best to only load .dylib, but I suspect that there might be .dylib libraries with the .so extension on Mac OS X, due to past practice. Then such programs will suddenly break. One program using Guile is LilyPond, and I have a vague memory of they mentioning the .so problem on Mac OS X, but I do not recall details.
If .dylib fails and it tries .so which isn't on the .dylib format, then the function should give an error. So it is harmless.