ethers(3N)                                             ethers(3N)



NAME
     ethers, ether_ntoa, ether_aton, ether_ntohost,
     ether_hostton, ether_line - provide Ethernet address mapping
     operations

SYNOPSIS
     #include <sys/types.h>
     #include <sys/socket.h>
     #include <net/if.h>
     #include <netinet/in.h>
     #include <netinet/if_ether.h>

     char *ether_ntoa(e)
     struct ether_addr *e;

     struct ether_addr *ether_aton(s)
     char *s;

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

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

     ether_line(l, e, hostname)
     char *l;
     struct ether_addr *e;
     char *hostname;

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

     The function ether_ntoa converts a 48-bit Ethernet number
     pointed to by e to its standard ACSII 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 255.  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



January 1992                                                    1

ethers(3N)                                             ethers(3N)



     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.

     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
          Executable file
     /etc/ethers.byaddr
          Yellow Pages control file
     /etc/ethers.byname
          Yellow Pages control file

SEE ALSO
     ethers(4)































2                                                    January 1992