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NAME    [Toc]    [Back]

     getifmaddrs -- get multicast group memberships

SYNOPSIS    [Toc]    [Back]

     #include <sys/types.h>
     #include <sys/socket.h>
     #include <ifaddrs.h>

     getifmaddrs(struct ifmaddrs **ifmap);

     freeifmaddrs(struct ifmaddrs *ifmp);

DESCRIPTION    [Toc]    [Back]

     The getifmaddrs() 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    [Toc]    [Back]

     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    [Toc]    [Back]

     The getifmaddrs() may fail and set errno for any of the errors specified
     for the library routines malloc(3) or sysctl(3).

BUGS    [Toc]    [Back]

     If both <net/if.h> and <ifaddrs.h> are being included, <net/if.h> must be
     included before <ifaddrs.h>.

SEE ALSO    [Toc]    [Back]

     sysctl(3), networking(4), ifconfig(8)

HISTORY    [Toc]    [Back]

     The getifmaddrs implementation first appeared in FreeBSD 5.2.

FreeBSD 5.2.1		       October 12, 1995 		 FreeBSD 5.2.1
[ Back ]
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