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GETIFADDRS(3)		     Library Functions Manual		   GETIFADDRS(3)

NAME
     getifaddrs -- get interface addresses

SYNOPSIS
     #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 en-
     tries:

	 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 determine
     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 inter-
     faces,  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 in a pointer to
     the struct if_data (as defined in include file  <net/if.h>).   For  AF_LINK
     addresses,  it  contains  various interface attributes and statistics.  For
     all other address families, it 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 14.3			November 25, 2014		   GETIFADDRS(3)

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