NAME
getifmaddrs —
get multicast group
memberships
SYNOPSIS
#include
<ifaddrs.h>
int
getifmaddrs(struct
ifmaddrs **ifmap);
void
freeifmaddrs(struct
ifmaddrs *ifmp);
DESCRIPTION
Thegetifmaddrs()
function stores a reference to a linked list of the multicast memberships on
the local machine in the memory referenced by ifmap. The
list consists of ifmaddrs structures, as defined in the
include file <ifaddrs.h>. The
ifmaddrs structure contains at least the following
entries:
struct ifmaddrs *ifma_next; /* Pointer to next struct */
struct sockaddr *ifma_name; /* Interface name (AF_LINK) */
struct sockaddr *ifma_addr; /* Multicast address */
struct sockaddr *ifma_lladdr; /* Link-layer translation, if any */
The ifma_next field contains a pointer to
the next structure on the list. This field is NULL
in last structure on the list.
The ifma_name field references an
AF_LINK address structure, containing the name of
the interface where the membership exists.
The ifma_addr references the address that this membership is for.
The ifma_lladdr field references a
link-layer translation for the protocol-level address in
ifma_addr, if one is set, otherwise it is
NULL.
The data returned by
getifmaddrs()
is dynamically allocated and should be freed using
freeifmaddrs()
when no longer needed.
RETURN VALUES
The getifmaddrs() function returns the
value 0 if successful; otherwise the value -1 is returned and
the global variable errno is set to indicate the
error.
ERRORS
The getifmaddrs() may fail and set
errno for any of the errors specified for the library
routines malloc(3) or
sysctl(3).
SEE ALSO
HISTORY
The getifmaddrs() function first appeared
in FreeBSD 5.2.
BUGS
If both <net/if.h>
and <ifaddrs.h> are being
included, <net/if.h>
must be
included before
<ifaddrs.h>.