{#addrof <path> #} retrieves the address of a field of a c structure, following <path>. It behaves much like get or set, but instead of marshalling the target it returns a pointer to it. This is useful e.g. when the associated Haskell type doesn't have a Storable instance, for example SockAddr. See also: http://www.haskell.org/pipermail/c2hs/2013-March/001113.html