The ether_line function returns zero on success and non-zero if it was unable to parse any part of the supplied line l. It returns the extracted ethernet address in the supplied
.Vt ether_addr structure e and the hostname in the supplied string h.
On success, ether_ntoa returns a pointer to a string containing an ASCII representation of an ethernet address. If it is unable to convert the supplied
.Vt ether_addr structure, it returns a NULL pointer. Likewise, ether_aton returns a pointer to an
.Vt ether_addr structure on success and a NULL pointer on failure.
The ether_ntohost and ether_hostton functions both return zero on success or non-zero if they were unable to find a match in the /etc/ethers database.
The user must insure that the hostname strings passed to the ether_line, ether_ntohost and ether_hostton functions are large enough to contain the returned hostnames.
If the /etc/ethers contains a line with a single + in it, the ether_ntohost and ether_hostton functions will attempt to consult the NIS ethers.byname and ethers.byaddr maps in addition to the data in the /etc/ethers file.