Historical Name-vs-Address Translation Functions (2)

• Name to address

• struct hostent *getipnodebyname(const char *name, int af, int flags,

• int *error_num);

• Address to name

• struct hostent *getipnodebyaddr(const void *src, size_t len, int af,

• int *error_num);

• Pros

• Support both IPv6/IPv4 in similar semantics of gethostby{name,addr}()

• Searching options

  • AI_DEFAULT to the flags for standard query

• Numeric address, IPv4-mapped address

• MT-Safe

  • Free memory be freehostent()

• Cons

• No scopes

• Uneasy to create socket

• Not widely deployed, deprecated now

Notes: