text: /* ifaddrs.h -- declarations for getting network interface addresses
     Copyright (C) 2002-2016 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 */
  