Technical Reference: Communications, Volume 1

lb_$lookup_object_local Library Routine

Purpose

Looks up information about an object in a Local Location Broker (LLB) database.

void lb_$lookup_object_local ( object, sockaddr, slength, lookup_handle) void lb_$lookup_object_local ( max_results, num_results, results, status) uuid_$t *object; socket_$addr_t *sockaddr; unsigned long slength; lb_$lookup_handle_t *lookup_handle; unsigned long max_results; unsigned long *num_results; lb_$entry_t results [ ]; status_$t *status;

Description

The lb_$lookup_object_local routine searches the specified LLB database and returns all entries whose fields in the object parameter match the specified object. It returns information about all replicas of an object and all interfaces to the object that are located on the specified host.

The lb_$lookup_interface routine cannot return more than the number of matching entries specified by the max_results parameter at one time. The lookup_handle parameter directs this routine to do sequential lookup calls to find all matching entries.

Notes:

The Location Broker does not prevent modification of the database between lookup calls. This can cause the locations of entries relative to a value of the lookup_handle parameter to change. If multiple calls are made to find all matching results in the database, the returned information may skip or duplicate entries from the database.
It is also possible for the results of a single lookup call to skip or duplicate entries. This can occur if the size of the results exceeds the size of a remote procedure call (RPC) packet (64KB).

Parameters

Input

object	Points to the Universal Unique Identifier (UUID) of the object being looked up.
sockaddr	Specifies the location of the LLB database to be searched. The socket address must specify the network address of a host. However, the port number in the socket address is ignored. The lookup request is always sent to the host's LLB port.
slength	Specifies the length, in bytes, of the socket address specified by the sockaddr parameter.
max_results	Specifies the maximum number of matching entries that can be returned by a single call. This should be the number of elements in the results parameter array.

Input/Output

lookup_handle

Specifies a location in the database. On input, the value of the lookup_handle parameter indicates the location in the database where the search begins. An input value of lb_$default_lookup_handle specifies that the search starts at the beginning of the database.

On return, the lookup_handle indicates the next unsearched part of the database (that is, the point at which the next search should begin). A return value of lb_$default_lookup_handle indicates that the search reached the end of the database. Any other value indicates that the search found at most the number of matching entries specified by the max_results parameter before it reached the end of the database.

Output

num_results	Points to the number of entries that were returned in the results parameter array.
results	Specifies the array that contains the matching GLB database entries, up to the number specified in the max_results parameter. If the array contains any entries for servers on the local network, those entries appear first.
status	Points to the completion status.

Examples

In the following example, the repob object is replicated, with only one replica located on any host. To look up information about the repob object, enter:

lb_$lookup_object_local (&repob_id, &location, location_length,
  &lookup_handle, 1, &num_results, myob_entry, &st);

Since there is only one replica located on any host, the routine returns at most one result.

Implementation Specifics

This Library Routine is part of Network Computing System in Network Support Facilities in Base Operating System (BOS) Runtime.

Related Information

Remote Procedure Call (RPC) Runtime Library (NCS).