res_init - Search for a default domain name and Internet
#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 information 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 contain 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 hostname into an Internet
Functions: dn_comp(3), dn_expand(3), dn_find(3), dn_skipname(3), _getlong(3), _getshort(3), putlong(3), putshort(3), res_mkquery(3), res_query(3), res_search(3),
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