 Both <code>-lcpgplot</code> and <code>-lpgplot</code> are required, in that order.</li>

<li>You may also need to specify additional libraries that are used by your program or by PGPLOT. For example, if your version of PGPLOT includes one of the X-window drivers, you will probably need to add <code>-L<i>directory</i> -lX11</code> to the command line.</li>
</ul>

<p>To give an indication of how difficult it can be to include the correct libraries when using the C compiler to do the linking, here is an examp