hesiod

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)

       cc file.c -lhesiod

DESCRIPTION
       This family of functions allows	you  to	 perform  lookups  of  Hesiod
       information,  which  is stored as text records in the Domain Name Ser-
       vice.  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  success-
       ful,  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	 hes-
       iod_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’,  named(8),
       hesiod.conf(5)

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 or hesiod_to_bind 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)