Historical Name-vs-Address Translation Functions

• Name to address

• struct hostent *gethostbyname(const char *name);

• Address to name

• struct hostent *gethostbyaddr(const char *addr,

• int len, int type);

• Host entry structure

• struct hostent {

• char *h_name; /* official name */

• char **h_aliases; /* alias list */

• char h_addrtype; /* type of address: AF_xxx */

• int h_length; /* length of the address: 4 for IPv4 */

• char **h_addr_list; /* list of addresses from name server */

• };

• Issues

  • The structure itself is af-independent, but gethostbyname().
  • Unflexible – no searching options
  • Not MT-safe

Notes: