HESIOD(3)                                                            HESIOD(3)



NAME
       hesiod,  hesiod_init, hesiod_resolve, hesiod_free_list, hesiod_to_bind,
       hesiod_end - Hesiod name server interface library

SYNOPSIS
       #include <hesiod.h>

       int hesiod_init(void ****context))
       char **hesiod_resolve(void **context,, const char **name,,
            const char **type))
       void hesiod_free_list(void **context,, char ****list));;
       char *hesiod_to_bind(void **context,, const char **name,,
            const char **type))
       void hesiod_end(void **context))

DESCRIPTION
       This family of functions allows you to perform lookups of Hesiod infor-
       mation, which is stored as text records in the Domain Name Service.  To
       perform lookups, you must first initialize a context, an opaque  object
       which  stores information used internally by the library between calls.
       hesiod__init initializes a context, storing a pointer to the context  in
       the  location pointed to by the context argument.  hesiod__end frees the
       resources used by a context.

       hesiod__resolve is the primary interface to the library.  If successful,
       it  returns  a  list of one or more strings giving the records matching
       name and type.  The last element of the list  is  followed  by  a  NULL
       pointer.  It is the caller's responsibility to call hesiod__free__list to
       free the resources used by the returned list.

       hesiod__to__bind converts name and type into the DNS name  used  by  hes-
       iod__resolve.   It  is  the caller's responsibility to free the returned
       string using free.

RETURN VALUES
       If successful, hesiod__init returns 0; otherwise it returns -1 and  sets
       errno  to  indicate  the  error.   On  failure, hesiod__resolve and hes-
       iod__to__bind return NULL and set the global variable errno  to  indicate
       the error.

ENVIRONMENT
       If  the  environment  variable  HES_DOMAIN is set, it will override the
       domain in the Hesiod configuration file.  If the  environment  variable
       HESIOD_CONFIG  is set, it specifies the location of the Hesiod configu-
       ration file.

SEE ALSO
       `Hesiod - Project Athena Technical Plan -- Name Service'

ERRORS
       Hesiod calls may fail because of:

       ENOMEM Insufficient memory was available to  carry  out  the  requested
              operation.

       ENOEXEC
              hesiod__init  failed  because  the  Hesiod configuration file was
              invalid.

       ECONNREFUSED
              hesiod__resolve failed because no name server could be  contacted
              to answer the query.

       EMSGSIZE
              hesiod__resolve  failed because the query or response was too big
              to fit into the packet buffers.

       ENOENT hesiod__resolve failed  because  the  name  server  had  no  text
              records matching name and type, or hesiod__to__bind failed because
              the name argument had a domain  extension  which  could  not  be
              resolved with type ``rhs-extension'' in the local Hesiod domain.

AUTHOR
       Steve Dyer, IBM/Project Athena
       Greg Hudson, MIT Team Athena
       Copyright 1987, 1988, 1995, 1996  by  the  Massachusetts  Institute  of
       Technology.

BUGS
       The  strings  corresponding to the errno values set by the Hesiod func-
       tions are not particularly indicative of what  went  wrong,  especially
       for ENOEXEC and ENOENT.



                               30 November 1996                      HESIOD(3)
