There are three kinds of lists liblx uses: host lists, which are lists
of host addresses such as are returned by ListHosts requests; string
lists, such as are returned by ListExtensions requests; and resource
(LX_XID) lists, such as are returned by ListInstalledColormaps
requests.  Each one has its own opaque type and suite of functions.
For each kind of list, entry indices range from 0 to one less than the
number of entries in the list.

Host lists use LX_HOSTLIST.  A host list entry is characterized by a
type, a data blob size, and a data blob.  (The size can vary from entry
to entry, though for most types it depends on only the type.)  It is up
to the application to interpret the <size,data> pair appropriately for
the type.

String lists use LX_STRLIST.  A string list entry is characterized by
its length and its data.  As a convenience for cases where the string
does not contain embedded NULs (which is most uses of LX_STRLISTs), the
data always has a '\0' appended to what the server returned; this is
not included in the length.

Resource lists use LX_XIDLIST.  A resource list entry is just an
LX_XID.

The functions for each of these are named with strings beginning with
lx_hostlist, lx_strlist, or lx_XIDlist, as appropriate for the list
type in question.

lx_hostlist_free
----------------

void lx_hostlist_free(LX_HOSTLIST *hl)

Frees the LX_HOSTLIST and everything it points to.

lx_hostlist_entries
-------------------

int lx_hostlist_entries(const LX_HOSTLIST *hl)

Returns the number of entries on the LX_HOSTLIST.  Valid index values
to the lx_hostlist_entry_* functions range from 0 to one less than this
value.

lx_hostlist_entry_type
----------------------

LX_HOSTTYPE lx_hostlist_entry_type(const LX_HOSTLIST *hl, int x)

Returns the type of the entry with index x in hl.  At this writing,
LX_HOSTTYPE values can be

	LX_HOSTTYPE_IPv4
	LX_HOSTTYPE_IPv6
	LX_HOSTTYPE_DECnet
	LX_HOSTTYPE_Chaos
	LX_HOSTTYPE_Other
	LX_HOSTTYPE_Error

For the first four, the <size,data> pair describes an address in
whatever form is appropriate for the protocol in question.  Other is
used for unrecognized host types; the type byte on the wire is
prepended to the data blob on the wire to give the data blob visible
through this API.  Error is returned for out-of-range x values.

lx_hostlist_entry_size
----------------------

int lx_hostlist_entry_size(const LX_HOSTLIST *hl, int x)

Returns the data blob size for the entry with index x in hl.  -1 is
returned for out-of-range x values.

lx_hostlist_entry_data
----------------------

const void *lx_hostlist_entry_data(const LX_HOSTLIST *hl, int x)

Returns a pointer to the data blob for the entry with index x in hl.
nil is returned for out-of-range x values.  The pointed-to data remains
valid until the LX_HOSTLIST is freed.  As indicated by the const on the
return value, the application must not try to write into the data blob.

lx_strlist_free
---------------

void lx_strlist_free(LX_STRLIST *sl)

Frees the LX_STRLIST and everything it points to.

lx_strlist_entries
-------------------

int lx_strlist_entries(const LX_STRLIST *sl)

Returns the number of entries on the LX_STRLIST.  Valid index values to
the lx_strlist_entry_* functions range from 0 to one less than this
value.

lx_strlist_entry_len
--------------------

int lx_strlist_entry_len(const LX_STRLIST *sl, int x)

Returns the length for the entry with index x in sl.  As mentioned
above, this does not include the '\0' appended by liblx.

lx_strlist_entry_data
---------------------

const void *lx_strlist_entry_data(const LX_STRLIST *sl, int x)

Returns the string pointer for the entry with index x in sl.  The
pointed-to string remains valid until the LX_STRLIST is freed.  As
indicated by the const on the return vlaue, the application must not
try to write into the string.

lx_XIDlist_free
---------------

void lx_XIDlist_free(LX_XIDLIST *xl)

Frees the LX_XIDLIST and everything it points to.

lx_XIDlist_entries
-------------------

int lx_XIDlist_entries(const LX_XIDLIST *xl)

Returns the number of entries on the LX_XIDLIST.  Valid index values to
the lx_XIDlist_entry_* functions range from 0 to one less than this
value.

lx_XIDlist_entry_id
-------------------

LX_XID lx_XIDlist_entry_id(const LX_XIDLIST *xl, int x)

Returns the list entry for index x in xl.