/* ifaddrs.h -- declarations for getting network interface addresses
Copyright (C) 2002-2018 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#ifndef _IFADDRS_H
#define _IFADDRS_H 1
#include <features.h>
#include <sys/socket.h>
__BEGIN_DECLS
/* The `getifaddrs' function generates a linked list of these structures.
Each element of the list describes one network interface. */
struct ifaddrs
{
struct ifaddrs *ifa_next; /* Pointer to the next structure. */
char *ifa_name; /* Name of this network interface. */
unsigned int ifa_flags; /* Flags as from SIOCGIFFLAGS ioctl. */
struct sockaddr *ifa_addr; /* Network address of this interface. */
struct sockaddr *ifa_netmask; /* Netmask of this interface. */
union
{
/* At most one of the following two is valid. If the IFF_BROADCAST
bit is set in `ifa_flags', then `ifa_broadaddr' is valid. If the
IFF_POINTOPOINT bit is set, then `ifa_dstaddr' is valid.
It is never the case that both these bits are set at once. */
struct sockaddr *ifu_broadaddr; /* Broadcast address of this interface. */
struct sockaddr *ifu_dstaddr; /* Point-to-point destination address. */
} ifa_ifu;
/* These very same macros are defined by <net/if.h> for `struct ifaddr'.
So if they are defined already, the existing definitions will be fine. */
# ifndef ifa_broadaddr
# define ifa_broadaddr ifa_ifu.ifu_broadaddr
# endif
# ifndef ifa_dstaddr
# define ifa_dstaddr ifa_ifu.ifu_dstaddr
# endif
void *ifa_data; /* Address-specific data (may be unused). */
};
/* Create a linked list of `struct ifaddrs' structures, one for each
network interface on the host machine. If successful, store the
list in *IFAP and return 0. On errors, return -1 and set `errno'.
The storage returned in *IFAP is allocated dynamically and can
only be properly freed by passing it to `freeifaddrs'. */
extern int getifaddrs (struct ifaddrs **__ifap) __THROW;
/* Reclaim the storage allocated by a previous `getifaddrs' call. */
extern void freeifaddrs (struct ifaddrs *__ifa) __THROW;
__END_DECLS
#endif /* ifaddrs.h */
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