ed above---as long as you link your extension 
modules with these libraries, it should not be necessary to rebuild Tcl.
</p>

<p>
If you aren't entirely sure about the linking of a C++ extension, you
might look at an existing C++ program.  On many Unix machines, the
<tt>ldd</tt> command will list library dependencies.  This should give
you some clues about what you might have to include when you link your
extension module. For example:
</p>

<div class="code">
<pre>
$ ldd swig
        libstdc++-libc6.1-1.so