This example shows how one might handle exceptions generated by
C functions.  It's certainly incomplete, but the idea is simple.
Within a C function, you can call the function

	SWIG_Raise("Exception message.");

We then have a special Tcl wrapper function that checks the status
of a SWIG exception variable and returns TCL_ERROR if it's set.  This
command is then called from Tcl as

	% swig_catch { tcl command }

While it's certainly not perfect, an approach like this could probably
be extended to other things.     

To test it out, compile and run as follows. 

	unix > my_tclsh
	% mod 4 0
	0
	% swig_catch {mod 4 0}
	0**SWIG Exception. Division by zero
	%


