[Swig-user] Most trivial example - failure

[Smith J. (E. - U. - U. Group) <jac...@un...>]

I am trying to understand how SWIG behaves.

I have a C++ project which creates a library
The project contains the class header and cpp files as follows.

// ------------- File a_lib.h
class a_lib {
public:
	a_lib(void);
	
	void func( );
};
-------------------------------
// ------------- File a_lib.cpp
a_lib::a_lib()
{
}

void a_lib::func()
{
	    
}
-------------------------------

I also have a swig interface file as follows

/* File a_lib_swig.i */
%module a_lib_swig
%{
	#include "a_lib.h"
%}

%include "a_lib.h"


>From the very beginning I am confused.

What is a module ?  Why is the %module declaration needed ?  What is it
telling swig to do ?
Why am I hash-including and percent-including the same file ? 
If I hash-include, surely swig now knows about the class, why would I
need to tell it again ?
Where is the definitive list of swig reserved words and their meanings ?
This does not seem to appear anywhere in any documentation I can find on
swig.