res_init(3)res_init(3)NAMEres_init - Search for a default domain name and Internet address
#include <sys/types.h> #include <netinet/in.h> #include
<arpa/nameser.h> #include <resolv.h>
Standard C Library (libc)
The res_init() function reads the /etc/resolv.conf file for the default
domain name and the Internet address of the initial hosts running the
name server, even if the name server is not functioning.
The res_init() function is one of a set of subroutines that form the
resolver, a set of functions that resolve domain names. All resolver
functions use the /usr/include/resolv.h header file, which defines the
_res data structure. The res_init() function stores domain name infor‐
mation in the _res data structure.
If the /etc/resolv.conf file does not exist, the res_init() function
attempts name resolution using the local /etc/hostsfile. If the system
is not using a domain name server, the /etc/resolv.conf file should not
exist. The /etc/host file should be present on the system even if the
system is using a name server. In this instance, the file should con‐
tain the host IDs that the system requires to function even if the name
server is not functioning.
Contains the name server and domain name. Contains hostnames and their
addresses for hosts in a network. This file is used to resolve a host‐
name into an Internet address.
Functions: dn_comp(3), dn_expand(3), dn_find(3), dn_skipname(3), _get‐
long(3), _getshort(3), putlong(3), putshort(3), res_mkquery(3),
res_query(3), res_search(3), res_send(3).