lb_lookup_type.3ncs

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 3NCS 代码 · 共 162 行

.TH lb_lookup_type 3ncs
.SH Name
lb_lookup_type \- look up information about a type in the
Global Location Broker database
.SH Syntax
#include <idl/c/lb.h>

void lb_$lookup_type(\fIobj_type, lookup_handle, max_num_results,\fP
				\fInum_results, results, status)\fP 
.nf
uuid_$t *\fIobj_type;\fP
lb_$lookup_handle_t *\fP\fIlookup_handle;\fP
unsigned long \fImax_num_results;\fP
unsigned long *\fInum_results;\fP 
lb_$entry_t \fIresults[ ];\fP
status_$t *\fIstatus;\fP
.fi
.\".SH SYNOPSIS (PASCAL)
.\".DS
.\"\fB%include '/usr/include/idl/pas/lb.ins.pas'\fR
.\"
.\"\fBprocedure lb_$lookup_type(\fR
.\"	\fBin \fIobj_type\fB: uuid_$t;\fR
.\"	\fBin out \fIlookup_handle\fB: lb_$lookup_handle_t;\fR
.\"	\fBin \fImax_num_results\fB: unsigned32;\fR
.\"	\fBout \fInum_results\fB: unsigned32;\fR
.\"	\fBout \fIresults\fB: array [1..*] of lb_$entry_t;\fR
.\"	\fBout \fIstatus\fB: status_$t);\fR
.\".DE
.SH Arguments
.TP 20
\fIobj_type\fR
The UUID of the type being looked up.
.TP 20
\fIlookup_handle\fR
A location in the database.
.if t .sp .5
On input, the \fIlookup_handle\fR
indicates the location in the database where the search begins.
An input value of \fBlb_$default_lookup_handle\fR
specifies that the search will start at the beginning of the database.  
.if t .sp .5
On return, the \fIlookup_handle\fR indicates the next unsearched 
part of the database (that is, the point at which the next search 
should begin).
A return value of \fBlb_$default_lookup_handle\fR
indicates that the search reached the end of the database;
any other return value
indicates that the search found at most \fImax_num_results\fR matching entries 
before it reached the end of the database.
.TP 20
\fImax_num_results\fR
The maximum number of entries that can be returned by a single routine.
This should be the number of elements in the \fIresults\fR array.
.TP 20
\fInum_results\fR
The number of entries that were returned in the \fIresults\fR array.
.TP 20
\fIresults\fR
An array that contains the matching GLB database entries,
up to the number specified by the \fImax_num_results\fR parameter.
If the array contains any entries for servers on the local network,
those entries appear first.
.TP 20
\fIstatus\fR
The completion status.
If the completion status returned in
.PN status\&.all
is equal to
.B status_$ok ,
then the routine that supplied it was successful.
.SH Description
The 
.PN lb_$lookup_type
routine returns GLB database entries 
whose 
.I obj_type
fields match the specified type. 
It returns information about all objects of that type
and about all interfaces to each of these objects.
.NXR "lb_lookup_type"
.PP
The 
.PN lb_$lookup_type
routine cannot return more than 
.I max_num_results
matching entries at a time.
The 
.I lookup_handle
parameter 
enables you to find all matching entries by doing sequential lookups. 
.PP
If you use a sequence of lookup routines to find entries in the database, 
it is possible that the returned results will skip or duplicate entries.
This is because
the Location Broker does not prevent modification of the database between lookups,
and such modification can change the locations of entries
relative to a 
.I lookup_handle
value.
.PP
It is also possible that the results of a single lookup routine
will skip or duplicate entries.
This can occur if the size of the results exceeds 
the size of an RPC packet (64K bytes).
.SH Examples
The following statement looks up information in the GLB database
about the type 
.B array
:
.EX
lb_$lookup_type (&array_id, &lookup_handle, max_results,
                     &num_results, &results, &status);
.EE
.SH Diagnostics 
This section lists status codes for errors returned by this 
.PN lb_$
routine in
.PN status\&.all .
.TP 20
\fBlb_$database_invalid\fR
The format of the Location Broker database is out of date.
The database may have been created by an old version of the Location Broker; 
in this case, delete the out-of-date database and reregister any entries
that it contained.
The LLB or GLB that was accessed may be running out-of-date software;
in this case, update all Location Brokers to the current software version.
.TP 20
\fBlb_$database_busy\fR
The Location Broker database is currently in use in an incompatible manner.
.TP 20
\fBlb_$not_registered\fR
The Location Broker does not have any entries that match
the criteria specified in the lookup or unregister routine.
The requested object, type, interface, or combination thereof
is not registered in the specified database.
If you are using
an 
.PN lb_$lookup_object_local
or
.PN lb_$lookup_range
routine specifying an LLB, check that you have specified the correct LLB.
.TP 20
\fBlb_$cant_access\fR
The Location Broker cannot access the database.
Among the possible reasons:
.IP
1. The database does not exist, 
and the Location Broker cannot create it.
.IP
2. The database exists, but the Location Broker cannot access it.
.IP
3. The GLB entry table is full.
.TP 20
\fBlb_$server_unavailable\fR
The Location Broker Client Agent cannot reach the requested GLB or LLB.
A communications failure occurred or the broker was not running.
.SH Files
.PN /usr/include/idl/c/glb.h
.SH See Also
intro(3ncs), lb_lookup_interface(3ncs), lb_lookup_object(3ncs), lb_lookup_range(3ncs)