GETHOSTENT(3N) NETWORK FUNCTIONS GETHOSTENT(3N) NAME gethostent, gethostbyaddr, gethostbyname, sethostent, endhostent - get network host entry SYNOPSIS #include #include #include struct hostent *gethostent() struct hostent *gethostbyname(name) char *name; struct hostent *gethostbyaddr(addr, len, type) char *addr; int len, type; sethostent(stayopen) int stayopen endhostent() DESCRIPTION gethostent, gethostbyname, and gethostbyaddr() each return a pointer to an object with the following structure containing the broken-out fields of a line in the network host data base, /etc/hosts. In the case of gethostbyaddr(), _a_d_d_r is a pointer to the binary format address of length _l_e_n (not a character string). struct hostent { char *h_name; /* official name of host */ char **h_aliases; /* alias list */ int h_addrtype; /* address type */ int h_length; /* length of address */ char **h_addr_list; /* list of addresses from name server */ }; The members of this structure are: h_name Official name of the host. h_aliases A zero terminated array of alternate names for the host. h_addrtype The type of address being returned; currently always AF_INET. h_length The length, in bytes, of the address. h_addr_list A pointer to a list of network addresses for the named host. Host addresses are Sun Release 4.1 Last change: 7 September 1988 1 GETHOSTENT(3N) NETWORK FUNCTIONS GETHOSTENT(3N) returned in network byte order. gethostent() reads the next line of the file, opening the file if necessary. sethostent() opens and rewinds the file. If the _s_t_a_y_o_p_e_n flag is non-zero, the host data base will not be closed after each call to gethostent() (either directly, or indirectly through one of the other "gethost" calls). endhostent() closes the file. gethostbyname() and gethostbyaddr() sequentially search from the beginning of the file until a matching host name or host address is found, or until end-of-file is encountered. Host addresses are supplied in network order. FILES /etc/hosts SEE ALSO hosts(5), ypserv(8) DIAGNOSTICS A NULL pointer is returned on end-of-file or error. BUGS All information is contained in a static area so it must be copied if it is to be saved. Only the Internet address for- mat is currently understood. Sun Release 4.1 Last change: 7 September 1988 2