f="ext_ffi_api.html#ffi_cdef"><tt>ffi.cdef</tt></a>. Then the
symbol address is resolved by searching for the symbol name in the
associated shared libraries or the default symbol namespace. Finally,
the resulting binding between the symbol name, the symbol type and its
address is cached. Missing symbol declarations or nonexistent symbol
names cause an error.
</p>
<p>
This is what happens on a <b>read access</b> for the different kinds of
symbols:
</p>
<ul>

<li>External functions: a cdata object with the ty