Sockets Library Functions                         ethers(3SOCKET)

NAME
     ethers,     ether_ntoa,      ether_aton,      ether_ntohost,
     ether_hostton,  ether_line - Ethernet address mapping opera-
     tions

SYNOPSIS
     cc [ flag ... ] file ... -lsocket -lnsl [ library ... ]
     #include <sys/types.h>
     #include <sys/socket.h>
     #include <net/if.h>
     #include <netinet/in.h>
     #include <netinet/if_ether.h>

     char *ether_ntoa(struct ether_addr *e);

     struct ether_addr *ether_aton(char *s);

     int ether_ntohost(char *hostname, struct ether_addr *e);

     int ether_hostton(char *hostname, struct ether_addr *e);

     int ether_line(char *l, struct ether_addr  *e,  char  *host-
     name);

DESCRIPTION
     These routines  are  useful  for  mapping  48  bit  Ethernet
     numbers  to their ASCII representations or their correspond-
     ing  host names, and vice versa.

     The function ether_ntoa() converts a 48 bit Ethernet  number
     pointed  to  by  e to its standard  ASCII representation; it
     returns a pointer to the  ASCII string.  The  representation
     is of the form x:x:x: x:x:x where  x is a hexadecimal number
     between 0 and ff.  The function   ether_aton()  converts  an
     ASCII string in the standard representation back to a 48 bit
     Ethernet number;  the function returns  NULL if  the  string
     cannot be scanned successfully.

     The  function  ether_ntohost()  maps  an   Ethernet   number
     (pointed  to  by  e) to its associated hostname.  The string
     pointed to by hostname must  be  long  enough  to  hold  the
     hostname  and  a  NULL character.  The function returns zero
     upon success and  non-zero  upon  failure.   Inversely,  the
     function  ether_hostton()  maps  a  hostname  string  to its
     corresponding Ethernet number;  the  function  modifies  the
     Ethernet  number  pointed to by e. The function also returns
     zero upon  success and non-zero upon failure. In order to do
     the  mapping, both these functions may lookup one or more of
     the  following  sources:  the  ethers  file,  the  NIS  maps
     ``ethers.byname''  and  ``ethers.byaddr'' and the NIS+ table
     ``ethers''. The sources and their lookup order are specified
     in  the   /etc/nsswitch.conf  file (see nsswitch.conf(4) for

SunOS 5.8           Last change: 30 Dec 1996                    1

Sockets Library Functions                         ethers(3SOCKET)

     details).

     The function  ether_line() scans a line (pointed  to  by  l)
     and sets the hostname and the Ethernet number (pointed to by
     e).  The string pointed to by hostname must be  long  enough
     to  hold  the  hostname and a  NULL character.  The function
     returns zero upon success and non-zero  upon  failure.   The
     format of the scanned line is described by  ethers(4).

FILES
     /etc/ethers

     /etc/nsswitch.conf

ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|

SEE ALSO
     ethers(4), nsswitch.conf(4), attributes(5)

BUGS
     Programs that call ether_hostton() or  ether_ntohost()  rou-
     tines  cannot  be linked statically since the implementation
     of these routines requires dynamic linker  functionality  to
     access shared objects at run time.

SunOS 5.8           Last change: 30 Dec 1996                    2