resolver(3)                DG/UX 4.30                 resolver(3)



     NAME
          res_mkquery, res_send, res_init, dn_comp, dn_expand -
          resolver routines

     SYNOPSIS
          #include <sys/types.h>
          #include <netinet/in.h>
          #include <arpa/nameser.h>
          #include <resolv.h>

          resmkquery(op, dname, class, type, data, datalen, newrr,
          buf, buflen)
          int op;
          char *dname;
          int class, type;
          char *data;
          int datalen;
          struct rrec *newrr;
          char *buf;
          int buflen;

          ressend(msg, msglen, answer, anslen)
          char *msg;
          int msglen;
          char *answer;
          int anslen;

          resinit()

          dncomp(expdn, compdn, length, dnptrs, lastdnptr)
          char *expdn, *compdn;
          int length;
          char **dnptrs, **lastdnptr;

          dnexpand(msg, eomorig, compdn, expdn, length)
          char *msg, *eomorig, *compdn, expdn;
          int length;

     DESCRIPTION
          These routines are used for making, sending and interpreting
          packets to Internet domain name servers. Global information
          that is used by the resolver routines is kept in the
          variable _res.  Most of the values have reasonable defaults
          and can be ignored. Options stored in _res.options are
          defined in resolv.h and are as follows. Options are a simple
          bit mask and are or'ed in to enable.

          RES_INIT
               True if the initial name server address and default
               domain name are initialized (i.e., resinit has been
               called).




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     resolver(3)                DG/UX 4.30                 resolver(3)



          RES_DEBUG
               Print debugging messages.

          RES_AAONLY
               Accept authoritative answers only.  Ressend will
               continue until it finds an authoritative answer or
               finds an error.  Currently this is not implemented.

          RES_USEVC
               Use TCP connections for queries instead of UDP.

          RES_STAYOPEN
               Used with RES_USEVC to keep the TCP connection open
               between queries.  This is useful only in programs that
               regularly do many queries.  UDP should be the normal
               mode used.

          RES_IGNTC
               Unused currently (ignore truncation errors, i.e., don't
               retry with TCP).

          RES_RECURSE
               Set the recursion desired bit in queries. This is the
               default.  ( ressend does not do iterative queries and
               expects the name server to handle recursion.)

          RES_DEFNAMES
               Append the default domain name to single label queries.
               This is the default.

          Resinit

          reads the initialization file to get the default domain name
          and the Internet address of the initial hosts running the
          name server. If this line does not exist, the host running
          the resolver is tried.  Resmkquery makes a standard query
          message and places it in buf.  Resmkquery will return the
          size of the query or -1 if the query is larger than buflen.
          Op is usually QUERY but can be any of the query types
          defined in nameser.h.  Dname is the domain name. If dname
          consists of a single label and the RES_DEFNAMES flag is
          enabled (the default), dname will be appended with the
          current domain name. The current domain name is defined in a
          system file and can be overridden by the environment
          variable LOCALDOMAIN.  Newrr is currently unused but is
          intended for making update messages.

          Ressend sends a query to name servers and returns an
          answer.  It will call resinit if RES_INIT is not set, send
          the query to the local name server, and handle timeouts and
          retries. The length of the message is returned or -1 if
          there were errors.



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     resolver(3)                DG/UX 4.30                 resolver(3)



          Dnexpand expands the compressed domain name comp_dn to a
          full domain name.  Expanded names are converted to upper
          case.  Msg is a pointer to the beginning of the message,
          exp_dn is a pointer to a buffer of size length for the
          result.  The size of compressed name is returned or -1 if
          there was an error.

          Dncomp compresses the domain name exp_dn and stores it in
          compdn.  The size of the compressed name is returned or -1
          if there were errors.  length is the size of the array
          pointed to by comp_dn.  Dnptrs is a list of pointers to
          previously compressed names in the current message.  The
          first pointer points to to the beginning of the message and
          the list ends with NULL.  lastdnptr is a pointer to the end
          of the array pointed to dnptrs.  A side effect is to update
          the list of pointers for labels inserted into the message by
          dncomp as the name is compressed.  If dnptr is NULL, we
          don't try to compress names. If lastdnptr is NULL, we don't
          update the list.

     FILES
          /etc/resolv.conf

     SEE ALSO
          named(1m), resolve.conf(5)






























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