atexit in modules

[Mike Gran]

I have a C library that I wrapped as gsubrs that get put into a Guile module.  
The C library wants a library_init() function called when it is initialized and 
a library_end() function called when it taken down.

(for the curious, it is specifically mysql_library_init() and 
mysql_library_end().)

The library_init() call is easy because it can be called automatically in the 
initialization function called by (load-extension "libfoo.so" "foo_init").

Since libraries are never unloaded, I guess I can wait until the program exit 
to call library_end().

I read this thread
http://thread.gmane.org/gmane.lisp.guile.user/6430/focus=6443

This suggests dynamic-wind is the way to go, but, I don't think it would work 
in my case because I want to keep this in a Guile wrapper module that gets 
loaded with use-module.

I've got one crazy idea.  I could create a new special SMOB type which calls 
library_end() as part of the SMOB's free function.  When the Guile library is 
loaded, it will define a single variable of that type in the module's 
environment.

But then I started think about what happens if the module is used in multiple 
threads, and it made my head hurt.

Any better ideas?

-Mike Gran