The
cdata object is returned unchanged.
</p>
<p>
This function allows safe integration of unmanaged resources into the
automatic memory management of the LuaJIT garbage collector. Typical
usage:
</p>
<pre class="code">
local p = ffi.gc(ffi.C.malloc(n), ffi.C.free)
...
p = nil -- Last reference to p is gone.
-- GC will eventually run finalizer: ffi.C.free(p)
</pre>
<p>
A cdata finalizer works like the <tt>__gc</tt> metamethod for userdata
objects: when the last reference to a cdata object is gone, the
associ