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
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
hesiod_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
hesiod_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
configuration 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
functions are not particularly indicative of what went wrong,
especially for ENOEXEC and ENOENT.
30 November 1996