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GETIFADDRS(3)	       FreeBSD Library Functions Manual		 GETIFADDRS(3)

NAME
     getifaddrs	-- get interface addresses

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

     int
     getifaddrs(struct ifaddrs **ifap);

     void
     freeifaddrs(struct	ifaddrs	*ifp);

DESCRIPTION
     The getifaddrs() function stores a	reference to a linked list of the net-
     work interfaces on	the local machine in the memory	referenced by ifap.
     The list consists of ifaddrs structures, as defined in the	include	file
     <ifaddrs.h>.  The ifaddrs structure contains at least the following
     entries:

	 struct	ifaddrs	  *ifa_next;	     /*	Pointer	to next	struct */
	 char		  *ifa_name;	     /*	Interface name */
	 u_int		   ifa_flags;	     /*	Interface flags	*/
	 struct	sockaddr  *ifa_addr;	     /*	Interface address */
	 struct	sockaddr  *ifa_netmask;	     /*	Interface netmask */
	 struct	sockaddr  *ifa_broadaddr;    /*	Interface broadcast address */
	 struct	sockaddr  *ifa_dstaddr;	     /*	P2P interface destination */
	 void		  *ifa_data;	     /*	Address	specific data */

     The ifa_next field	contains a pointer to the next structure on the	list.
     This field	is NULL	in last	structure on the list.

     The ifa_name field	contains the interface name.

     The ifa_flags field contains the interface	flags, as set by ifconfig(8)
     utility.

     The ifa_addr field	references either the address of the interface or the
     link level	address	of the interface, if one exists, otherwise it is NULL.
     (The sa_family field of the ifa_addr field	should be consulted to deter-
     mine the format of	the ifa_addr address.)

     The ifa_netmask field references the netmask associated with ifa_addr, if
     one is set, otherwise it is NULL.

     The ifa_broadaddr field, which should only	be referenced for non-P2P
     interfaces, references the	broadcast address associated with ifa_addr, if
     one exists, otherwise it is NULL.

     The ifa_dstaddr field references the destination address on a P2P inter-
     face, if one exists, otherwise it is NULL.

     The ifa_data field	references address family specific data.  For AF_LINK
     addresses it contains a pointer to	the struct if_data (as defined in
     include file <net/if.h>) which contains various interface attributes and
     statistics.  For all other	address	families, it contains a	pointer	to the
     struct ifa_data (as defined in include file <net/if.h>) which contains
     per-address interface statistics.

     The data returned by getifaddrs() is dynamically allocated	and should be
     freed using freeifaddrs() when no longer needed.

RETURN VALUES
     The getifaddrs() 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 getifaddrs() may fail and set errno for any of	the errors specified
     for the library routines ioctl(2),	socket(2), malloc(3) or	sysctl(3).

SEE ALSO
     ioctl(2), socket(2), sysctl(3), networking(4), ifconfig(8)

HISTORY
     The getifaddrs implementation first appeared in BSDi BSD/OS.

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

FreeBSD	9.3		       October 12, 1995			   FreeBSD 9.3

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | SEE ALSO | HISTORY | BUGS

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