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HESIOD(3) BSD Library Functions Manual HESIOD(3)
NAME
hesiod, hesiod_init, hesiod_resolve, hesiod_free_list, hesiod_to_bind, hesiod_end -- Hesiod
name server interface library
LIBRARY
Standard C Library (libc, -lc)
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 information, which is
stored as text records in the Domain Name Service. To perform lookups, you must first ini-
tialize 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
The hesiod_init() function returns the value 0 if successful; otherwise the value -1 is re-
turned and the global variable errno is set to indicate the error. On failure,
hesiod_resolve() and hesiod_to_bind() return NULL and set the global variable errno to indi-
cate the error.
ENVIRONMENT
HES_DOMAIN If the environment variable HES_DOMAIN is set, it will override the domain in
the Hesiod configuration file.
HESIOD_CONFIG If the environment variable HESIOD_CONFIG is set, it specifies the location
of the Hesiod configuration file.
SEE ALSO
hesiod.conf(5), named(8)
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 an-
swer 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 argu-
ment had a domain extension which could not be resolved with type
"rhs-extension" in the local Hesiod domain.
AUTHORS
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 particu-
larly indicative of what went wrong, especially for ENOEXEC and ENOENT.
BSD November 30, 1996 BSD
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