path: root/lib/snmp/doc/src/snmpa.xml

<?xml version="1.0" encoding="iso-8859-1" ?>
<!DOCTYPE erlref SYSTEM "erlref.dtd">

<erlref>
  <header>
    <copyright>
      <year>2004</year><year>2012</year>
      <holder>Ericsson AB. All Rights Reserved.</holder>
    </copyright>
    <legalnotice>
      The contents of this file are subject to the Erlang Public License,
      Version 1.1, (the "License"); you may not use this file except in
      compliance with the License. You should have received a copy of the
      Erlang Public License along with this software. If not, it can be
      retrieved online at http://www.erlang.org/.

      Software distributed under the License is distributed on an "AS IS"
      basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
      the License for the specific language governing rights and limitations
      under the License.

    </legalnotice>

    <title>snmpa</title>
    <prepared></prepared>
    <responsible></responsible>
    <docno></docno>
    <approved></approved>
    <checked></checked>
    <date></date>
    <rev></rev>
    <file>snmpa.xml</file>
  </header>
  <module>snmpa</module>
  <modulesummary>Interface Functions to the SNMP toolkit agent</modulesummary>
  <description>
    <p>The module <c>snmpa</c> contains interface functions to the 
      SNMP agent.</p>

    <marker id="data_types"></marker>
  </description>

  <section>
    <title>DATA TYPES</title>
    <code type="none"><![CDATA[
oid() = [byte()] 
atl_type() = read | write | read_write
notification_delivery_info() = #snmpa_notification_delivery_info{}
    ]]></code>

    <p>The <c>oid()</c> type is used to represent an ASN.1 OBJECT IDENTIFIER. </p>

    <p>The record <c><![CDATA[snmpa_notification_delivery_info]]></c> contains the following fields: </p>
    <taglist>
      <tag><c><![CDATA[tag = term()]]></c></tag>
      <item>
        <p>A user defined identity representing this notification send 
          operation.</p>
      </item>
      <tag><c><![CDATA[mod = module()]]></c></tag>
      <item>
        <p>A module implementing the 
          <seealso marker="snmpa_notification_delivery_info_receiver">snmpa_notification_delivery_info_receiver</seealso> 
          behaviour. The info functions of this module will be called at 
          various stages of delivery. </p>
      </item>
      <tag><c><![CDATA[extra = term()]]></c></tag>
      <item>
        <p>This is any extra info the user wants to have supplied 
          when the functions in the callback module is called. </p>
      </item>
    </taglist>
    
    <marker id="add_agent_caps"></marker>
  </section>

  <funcs>
    <func>
      <name>add_agent_caps(SysORID, SysORDescr) -> SysORIndex</name>
      <fsummary>Add an AGENT-CAPABILITY definition to the agent</fsummary>
      <type>
        <v>SysORID = oid()</v>
        <v>SysORDescr = string()</v>
        <v>SysORIndex = integer()</v>
      </type>
      <desc>
        <p>This function can be used to add an AGENT-CAPABILITY
          statement to the sysORTable in the agent.  The table is
          defined in the SNMPv2-MIB.</p>
        <marker id="del_agent_caps"></marker>
      </desc>
    </func>

    <func>
      <name>del_agent_caps(SysORIndex) -> void()</name>
      <fsummary>Delete an AGENT-CAPABILITY definition from the agent</fsummary>
      <type>
        <v>SysORIndex = integer()</v>
      </type>
      <desc>
        <p>This function can be used to delete an AGENT-CAPABILITY
          statement to the sysORTable in the agent.  This table is
          defined in the SNMPv2-MIB. </p>

          <marker id="get_agent_caps"></marker>
      </desc>
    </func>

    <func>
      <name>get_agent_caps() -> [[SysORIndex, SysORID, SysORDescr, SysORUpTime]]</name>
      <fsummary>Return all AGENT-CAPABILITY definitions in the agent</fsummary>
      <type>
        <v>SysORIndex = integer()</v>
        <v>SysORId = oid()</v>
        <v>SysORDescr = string()</v>
        <v>SysORUpTime = integer()</v>
      </type>
      <desc>
        <p>Returns all AGENT-CAPABILITY statements in the sysORTable
          in the agent.  This table is defined in the SNMPv2-MIB. </p>

        <marker id="get"></marker>
      </desc>
    </func>

    <func>
      <name>get(Agent, Vars) -> Values | {error, Reason}</name>
      <name>get(Agent, Vars, Context) -> Values | {error, Reason}</name>
      <fsummary>Perform a get operation on the agent</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
        <v>Vars = [oid()]</v>
        <v>Context = string()</v>
        <v>Values = [term()]</v>
        <v>Reason = {atom(), oid()}</v>
      </type>
      <desc>
        <p>Performs a GET operation on the agent.  All loaded MIB
          objects are visible in this operation.  The agent calls the
          corresponding instrumentation functions just as if it was a
          GET request coming from a manager. </p>
        <p>Note that the request specific parameters (such as 
          <seealso marker="#current_request_id">current_request_id</seealso>) 
          are not accessible for the instrumentation functions if this 
          function is used. </p>

          <marker id="get_next"></marker>
      </desc>
    </func>

    <func>
      <name>get_next(Agent, Vars) -> Values | {error, Reason}</name>
      <name>get_next(Agent, Vars, Context) -> Values | {error, Reason}</name>
      <fsummary>Perform a get-next operation on the agent</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
        <v>Vars = [oid()]</v>
        <v>Context = string()</v>
        <v>Values = [{oid(), term()}]</v>
        <v>Reason = {atom(), oid()}</v>
      </type>
      <desc>
        <p>Performs a GET-NEXT operation on the agent.  All loaded MIB
          objects are visible in this operation.  The agent calls the
          corresponding instrumentation functions just as if it was a
          GET request coming from a manager. </p>
        <p>Note that the request specific parameters (such as 
          <c>snmpa:current_request_id/0</c> are not accessible for the 
          instrumentation functions if this function is used. </p>

        <marker id="backup"></marker>
        <!-- <marker id="get_symbolic_store_db"></marker> -->
      </desc>
    </func>

<!--
    <func>
      <name>get_symbolic_store_db() -> Db</name>
      <fsummary>Retrieve the symbolic store database reference</fsummary>
      <type>
        <v>Db = term()</v>
      </type>
      <desc>
        <p>Retrieve the symbolic store database reference. This is used 
          for faster access to the database using the functions: 
          <c>int_to_enum/3</c>, <c>enum_to_int/3</c>, <c>name_to_oid/2</c>, 
          <c>oid_to_name/2</c>. </p>

        <marker id="backup"></marker>
      </desc>
    </func>

-->
    <func>
      <name>backup(BackupDir) -> ok | {error, Reason}</name>
      <name>backup(Agent, BackupDir) -> ok | {error, Reason}</name>
      <fsummary>Backup agent data</fsummary>
      <type>
        <v>BackupDir = string()</v>
        <v>Agent = pid() | atom()</v>
        <v>Reason = backup_in_progress | term()</v>
      </type>
      <desc>
        <p>Backup persistent/permanent data handled by the agent
          (such as local-db, mib-data and vacm). </p>
        <p>Data stored by mnesia is not handled. </p>
        <p>BackupDir cannot be identical to DbDir. </p>
        <p>Simultaneous backup calls are <em>not</em> allowed. 
	That is, two different processes cannot simultaneously 
	successfully call this function. One of them will be first, 
	and succeed. The second will fail with the error reason
	<c>backup_in_progress</c>. </p>

        <marker id="info"></marker>
      </desc>
    </func>
    <func>
      <name>info() -> [{Key, Value}]</name>
      <name>info(Agent) -> [{Key, Value}]</name>
      <fsummary>Return information about the agent</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
      </type>
      <desc>
        <p>Returns a list (a dictionary) containing information about
	the agent. Information includes loaded MIBs, registered
	sub-agents, some information about the memory allocation. </p>
	<p>As of version 4.4 the format of the info has been changed. 
	To convert the info to the old format, call the 
	<seealso marker="#old_info_format">old_info_format</seealso> 
	function. </p>
	
        <marker id="old_info_format"></marker>
      </desc>
    </func>

    <func>
      <name>old_info_format(NewInfo) -> OldInfo</name>
      <fsummary>Return information about the agent</fsummary>
      <type>
        <v>OldInfo = NewInfo = [{Key, Value}]</v>
      </type>
      <desc>
        <p>As of version 4.4 the format of the info has been changed. 
          This function is used to convert to the old (pre-4.4) info 
          format. </p>

        <marker id="load_mibs"></marker>
      </desc>
    </func>

    <func>
      <name>load_mibs(Mibs) -> ok | {error, Reason}</name>
      <name>load_mibs(Agent,Mibs) -> ok | {error, Reason}</name>
      <fsummary>Load MIBs into the agent</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
        <v>Mibs = [MibName]</v>
        <v>MibName = string()</v>
        <v>Reason = term()</v>
      </type>
      <desc>
        <p>Loads <c>Mibs</c> into an agent.  If the agent cannot load
          all MIBs, it will indicate where loading was aborted.  The
          <c>MibName</c> is the name of the Mib, including the path to
          where the compiled mib is found.  For example,</p>
        <code type="none">
          Dir = code:priv_dir(my_app) ++ "/mibs/",
          snmpa:load_mibs(snmp_master_agent, [Dir ++ "MY-MIB"]).
        </code>

        <marker id="unload_mibs"></marker>
      </desc>
    </func>

    <func>
      <name>unload_mibs(Mibs) -> ok | {error, Reason}</name>
      <name>unload_mibs(Agent,Mibs) -> ok | {error, Reason}</name>
      <fsummary>Unload MIBs from the agent</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
        <v>Mibs = [MibName]</v>
        <v>MibName = string()</v>
      </type>
      <desc>
        <p>Unloads MIBs into an agent.  If it cannot unload all MIBs,
          it will indicate where unloading was aborted. </p>

        <marker id="which_mibs"></marker>
      </desc>
    </func>

    <func>
      <name>which_mibs() -> Mibs</name>
      <name>which_mibs(Agent) -> Mibs</name>
      <fsummary>Get a list of all the loaded mibs</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
        <v>Mibs = [{MibName, MibFile}]</v>
        <v>MibName = atom()</v>
        <v>MibFile = string()</v>
      </type>
      <desc>
        <p>Retrieve the list of all the mibs loaded into this agent. Default 
          is the master agent. </p>
                    
        <marker id="whereis_mib"></marker>
      </desc>
    </func>

    <func>
      <name>whereis_mib(MibName) -> {ok, MibFile} | {error, Reason}</name>
      <name>whereis_mib(Agent, MibName) -> {ok, MibFile} | {error, Reason}</name>
      <fsummary>Get the path to the mib file</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
        <v>MibName = atom()</v>
        <v>MibFile = string()</v>
        <v>Reason = term()</v>
      </type>
      <desc>
        <p>Get the full path to the (compiled) mib-file. </p>

        <marker id="current_request_id"></marker>
        <marker id="current_context"></marker>
        <marker id="current_community"></marker>
        <marker id="current_address"></marker>
      </desc>
    </func>

    <func>
      <name>current_request_id() -> {value, RequestId} | false</name>
      <name>current_context() -> {value, Context} | false</name>
      <name>current_community() -> {value, Community} | false</name>
      <name>current_address() -> {value, Address} | false</name>
      <fsummary>Get the request-id, context, community and address of the current request</fsummary>
      <type>
        <v>RequestId = integer()</v>
        <v>Context = string()</v>
        <v>Community = string()</v>
        <v>Address = term()</v>
      </type>
      <desc>
        <p>Get the request-id, context, community and address of the 
          request currently being processed by the agent. </p>
        <p>Note that these functions is intended to be called by the 
          instrumentation functions and <em>only</em> if they are 
          executed in the context of the agent process (e.g. it does 
          not work if called from a spawned process).</p>

        <marker id="enum_to_int"></marker>
      </desc>
    </func>

    <func>
      <name>enum_to_int(Name, Enum) -> {value, Int} | false</name>
      <name>enum_to_int(Db, Name, Enum) -> {value, Int} | false</name>
      <fsummary>Convert an enum value to an integer</fsummary>
      <type>
        <v>Db   = term()</v>
        <v>Name = atom()</v>
        <v>Enum = atom()</v>
        <v>Int  = int()</v>
      </type>
      <desc>
        <p>Converts the symbolic value <c>Enum</c> to the
          corresponding integer of the enumerated object or type
          <c>Name</c> in a MIB.  The MIB must be loaded. 
          </p>
        <p><c>false</c> is returned if the object or type is not
          defined in any loaded MIB, or if it does not define the
          symbolic value as enumerated.
          </p>
        <p><c>Db</c> is a reference to the symbolic store database 
          (retrieved by a call to <c>get_symbolic_store_db/0</c>). </p>

        <marker id="int_to_enum"></marker>
      </desc>
    </func>

    <func>
      <name>int_to_enum(Name, Int) -> {value, Enum} | false</name>
      <name>int_to_enum(Db, Name, Int) -> {value, Enum} | false</name>
      <fsummary>Convert an integer to an enum value</fsummary>
      <type>
        <v>Db   = term()</v>
        <v>Name = atom()</v>
        <v>Int  = int()</v>
        <v>Enum = atom()</v>
      </type>
      <desc>
        <p>Converts the integer <c>Int</c> to the corresponding
          symbolic value of the enumerated object or type <c>Name</c> in
          a MIB.  The MIB must be loaded. 
          </p>
        <p><c>false</c> is returned if the object or type is not
          defined in any loaded MIB, or if it does not define the
          symbolic value as enumerated.
          </p>
        <p><c>Db</c> is a reference to the symbolic store database 
          (retrieved by a call to <c>get_symbolic_store_db/0</c>). </p>

        <marker id="name_to_oid"></marker>
      </desc>
    </func>

    <func>
      <name>name_to_oid(Name) -> {value, oid()} | false</name>
      <name>name_to_oid(Db, Name) -> {value, oid()} | false</name>
      <fsummary>Convert a symbolic name to an OID</fsummary>
      <type>
        <v>Db   = term()</v>
        <v>Name = atom()</v>
      </type>
      <desc>
        <p>Looks up the OBJECT IDENTIFIER of a MIB object, given the
          symbolic name.  Note, the OBJECT IDENTIFIER is given for the
          object, not for an instance. </p>
        <p><c>false</c> is returned if the object is not defined in any
          loaded MIB. </p>
        <p><c>Db</c> is a reference to the symbolic store database 
          (retrieved by a call to <c>get_symbolic_store_db/0</c>). </p>

        <marker id="oid_to_name"></marker>
      </desc>
    </func>

    <func>
      <name>oid_to_name(OID) -> {value, Name} | false</name>
      <name>oid_to_name(Db, OID) -> {value, Name} | false</name>
      <fsummary>Convert an OID to a symbolic name</fsummary>
      <type>
        <v>Db   = term()</v>
        <v>OID  = oid()</v>
        <v>Name = atom()</v>
      </type>
      <desc>
        <p>Looks up the symbolic name of a MIB object, given OBJECT
          IDENTIFIER. </p>
        <p><c>false</c> is returned if the object is not defined in any
          loaded MIB. </p>
        <p><c>Db</c> is a reference to the symbolic store database 
          (retrieved by a call to <c>get_symbolic_store_db/0</c>). </p>

        <marker id="which_aliasnames"></marker>
      </desc>
    </func>

    <func>
      <name>which_aliasnames() -> Result</name>
      <fsummary>Get all alias-names known to the agent</fsummary>
      <type>
        <v>Result = [atom()]</v>
      </type>
      <desc>
        <p>Retrieve all alias-names known to the agent.</p>
        <marker id="which_tables"></marker>
      </desc>
    </func>

    <func>
      <name>which_tables() -> Result</name>
      <fsummary>Get all tables known to the agent</fsummary>
      <type>
        <v>Result = [atom()]</v>
      </type>
      <desc>
        <p>Retrieve all tables known to the agent.</p>

        <marker id="which_variables"></marker>
      </desc>
    </func>

    <func>
      <name>which_variables() -> Result</name>
      <fsummary>Get all variables known to the agent</fsummary>
      <type>
        <v>Result = [atom()]</v>
      </type>
      <desc>
        <p>Retrieve all variables known to the agent.</p>

        <marker id="which_notifications"></marker>
      </desc>
    </func>

    <func>
      <name>which_notifications() -> Result</name>
      <fsummary>Get all notifications known to the agent</fsummary>
      <type>
        <v>Result = [{Name, MibName, Info}]</v>
        <v>Name = atom()</v>
        <v>MibName = atom()</v>
        <v>Info = term()</v>
      </type>
      <desc>
        <p>Retrieve all notifications (and traps) known to the agent.</p>

        <marker id="log_to_txt"></marker>
      </desc>
    </func>

    <func>
      <name>log_to_txt(LogDir, Mibs)</name>
      <name>log_to_txt(LogDir, Mibs, OutFile) -> ok | {error, Reason}</name>
      <name>log_to_txt(LogDir, Mibs, OutFile, LogName) ->  ok | {error, Reason}</name>
      <name>log_to_txt(LogDir, Mibs, OutFile, LogName, LogFile) ->  ok | {error, Reason}</name>
      <name>log_to_txt(LogDir, Mibs, OutFile, LogName, LogFile, Start) ->  ok | {error, Reason}</name>
      <name>log_to_txt(LogDir, Mibs, OutFile, LogName, LogFile, Start, Stop)  -> ok | {error, Reason}</name>
      <fsummary>Convert an Audit Trail Log to text format</fsummary>
      <type>
        <v>LogDir = string()</v>
        <v>Mibs = [MibName]</v>
        <v>MibName = string()</v>
        <v>OutFile = string()</v>
        <v>LogName = string()</v>
        <v>LogFile = string()</v>
        <v>Start = Stop = null | datetime() | {local_time,datetime()} |  {universal_time,datetime()} </v>
        <v>Reason = disk_log_open_error() | file_open_error() | term()</v>
        <v>disk_log_open_error() = {LogName, term()}</v>
        <v>file_open_error() = {OutFile, term()}</v>
      </type>
      <desc>
        <p>Converts an Audit Trail Log to a readable text file. 
          <c>OutFile</c> defaults to "./snmpa_log.txt". 
          <c>LogName</c> defaults to "snmpa_log". 
          <c>LogFile</c> defaults to "snmpa.log". 
          See <seealso marker="snmp#log_to_txt">snmp:log_to_txt</seealso> 
          for more info.</p>

        <marker id="change_log_size"></marker>
      </desc>
    </func>

    <func>
      <name>change_log_size(NewSize) -> ok | {error, Reason}</name>
      <fsummary>Change the size of the Audit Trail Log</fsummary>
      <type>
        <v>NewSize = {MaxBytes, MaxFiles}</v>
        <v>MaxBytes = integer()</v>
        <v>MaxFiles = integer()</v>
        <v>Reason = term()</v>
      </type>
      <desc>
        <p>Changes the log size of the Audit Trail Log. The application must 
          be configured to use the audit trail log function. Please refer to 
          disk_log(3) in Kernel Reference Manual for a description of how to 
          change the log size. </p>
        <p>The change is permanent, as long as the log is not deleted. 
          That means, the log size is remembered across reboots. </p>

        <marker id="set_log_type"></marker>
      </desc>
    </func>

    <func>
      <name>set_log_type(NewType) -> {ok, OldType} | {error, Reason}</name>
      <name>set_log_type(Agent, NewType) -> {ok, OldType} | {error, Reason}</name>
      <fsummary>Change the type of the Audit Trail Log</fsummary>
      <type>
        <v>NewType = OldType = atl_type()</v>
        <v>Agent = pid() | atom()</v>
        <v>Reason = term()</v>
      </type>
      <desc>
        <p>Changes the run-time Audit Trail log type. </p>
        <p>Note that this has no effect on the application configuration as
          defined by configuration files, so a node restart will revert the 
          config to whatever is in those files. </p>
        <p>This function is primarily useful in testing/debugging 
          scenarios. </p>

        <marker id="mib_of"></marker>
      </desc>

    </func>

    <func>
      <name>mib_of(Oid) -> {ok, MibName} | {error, Reason}</name>
      <name>mib_of(Agent, Oid) -> {ok, MibName} | {error, Reason}</name>
      <fsummary>Which mib an Oid belongs to</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
        <v>Oid = oid()</v>
        <v>MibName = atom()</v>
        <v>Reason = term()</v>
      </type>
      <desc>
        <p>Finds the mib corresponding to the <c>Oid</c>. If it is a
          variable, the Oid must be 
          &lt;Oid for var&gt;.0 and if it is a table, Oid must be 
          &lt;table&gt;.&lt;entry&gt;.&lt;col&gt;.&lt;any&gt;</p>

        <marker id="me_of"></marker>
      </desc>
    </func>

    <func>
      <name>me_of(Oid) -> {ok, Me} | {error, Reason}</name>
      <name>me_of(Agent, Oid) -> {ok, Me} | {error, Reason}</name>
      <fsummary>Retrieve the mib-entry of an Oid</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
        <v>Oid = oid()</v>
        <v>Me = #me{}</v>
        <v>Reason = term()</v>
      </type>
      <desc>
        <p>Finds the mib entry corresponding to the <c>Oid</c>. If it is a
          variable, the Oid must be 
          &lt;Oid for var&gt;.0 and if it is a table, Oid must be 
          &lt;table&gt;.&lt;entry&gt;.&lt;col&gt;.&lt;any&gt;</p>

        <marker id="invalidate_mibs_cache"></marker>
      </desc>
    </func>

    <func>
      <name>invalidate_mibs_cache() -> void()</name>
      <name>invalidate_mibs_cache(Agent) -> void()</name>
      <fsummary>Invalidate the mib server cache</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
      </type>
      <desc>
        <p>Invalidate the mib server cache. </p>
        <p>The entire contents of the cache will be deleted. </p>

        <marker id="enable_mibs_cache"></marker>
      </desc>
    </func>

    <func>
      <name>enable_mibs_cache() -> void()</name>
      <name>enable_mibs_cache(Agent) -> void()</name>
      <fsummary>Enable the mib server cache</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
      </type>
      <desc>
        <p>Enable the mib server cache. </p>

        <marker id="disable_mibs_cache"></marker>
      </desc>
    </func>

    <func>
      <name>disable_mibs_cache() -> void()</name>
      <name>disable_mibs_cache(Agent) -> void()</name>
      <fsummary>Disable the mib server cache</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
      </type>
      <desc>
        <p>Disable the mib server cache. </p>

        <marker id="which_mibs_cache_size"></marker>
      </desc>
    </func>

    <func>
      <name>which_mibs_cache_size() -> void()</name>
      <name>which_mibs_cache_size(Agent) -> void()</name>
      <fsummary>The size of the mib server cache</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
      </type>
      <desc>
        <p>Retreive the size of the mib server cache. </p>

        <marker id="gc_mibs_cache"></marker>
      </desc>
    </func>

    <func>
      <name>gc_mibs_cache() -> {ok, NumElementsGCed} | {error, Reason}</name>
      <name>gc_mibs_cache(Agent) -> {ok, NumElementsGCed} | {error, Reason}</name>
      <name>gc_mibs_cache(Age) -> {ok, NumElementsGCed} | {error, Reason}</name>
      <name>gc_mibs_cache(Agent, Age) -> {ok, NumElementsGCed} | {error, Reason}</name>
      <name>gc_mibs_cache(Age, GcLimit) -> {ok, NumElementsGCed} | {error, Reason}</name>
      <name>gc_mibs_cache(Agent, Age, GcLimit) -> {ok, NumElementsGCed} | {error, Reason}</name>
      <fsummary>Perform mib server cache gc</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
        <v>Age = integer() > 0</v>
        <v>GcLimit = integer() > 0 | infinity</v>
        <v>NumElementsGCed = integer() >= 0</v>
        <v>Reason = term()</v>
      </type>
      <desc>
        <p>Perform mib server cache gc. </p>
        <p>Manually performs a mib server cache gc. 
          This can be done regardless of the value of the 
          <c>autogc</c> option. 
          The <c>NumElementsGCed</c> value indicates how many 
          elements where actually removed from the cache. </p>

        <marker id="enable_mibs_cache_autogc"></marker>
      </desc>
    </func>

    <func>
      <name>enable_mibs_cache_autogc() -> void()</name>
      <name>enable_mibs_cache_autogc(Agent) -> void()</name>
      <fsummary>Enable automatic gc of the mib server cache</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
      </type>
      <desc>
        <p>Enable automatic gc of the mib server cache. </p>

        <marker id="disable_mibs_cache_autogc"></marker>
      </desc>
    </func>

    <func>
      <name>disable_mibs_cache_autogc() -> void()</name>
      <name>disable_mibs_cache_autogc(Agent) -> void()</name>
      <fsummary>Disable automatic gc of the mib server cache</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
      </type>
      <desc>
        <p>Disable automatic gc of the mib server cache. </p>

        <marker id="update_mibs_cache_age"></marker>
      </desc>
    </func>

    <func>
      <name>update_mibs_cache_age(NewAge) -> ok | {error, Reason}</name>
      <name>update_mibs_cache_age(Agent, NewAge) -> ok | {error, Reason}</name>
      <fsummary>Change the mib server cache age property</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
        <v>NewAge = integer() > 0</v>
        <v>Reason = term()</v>
      </type>
      <desc>
        <p>Change the mib server cache <c>age</c> property. </p>

        <marker id="update_mibs_cache_gclimit"></marker>
      </desc>
    </func>

    <func>
      <name>update_mibs_cache_gclimit(NewGcLimit) -> ok | {error, Reason}</name>
      <name>update_mibs_cache_gclimit(Agent, NewGCLimit) -> ok | {error, Reason}</name>
      <fsummary>Change the mib server cache gclimit property</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
        <v>NewGcLimit = integer() > 0 | infinity</v>
        <v>Reason = term()</v>
      </type>
      <desc>
        <p>Change the mib server cache <c>gclimit</c> property. </p>

        <marker id="register_notification_filter"></marker>
      </desc>
    </func>


    <func>
      <name>register_notification_filter(Id, Mod, Data) -> ok | {error, Reason}</name>
      <name>register_notification_filter(Agent, Id, Mod, Data) -> ok | {error, Reason}</name>
      <name>register_notification_filter(Id, Mod, Data, Where) -> ok | {error, Reason}</name>
      <name>register_notification_filter(Agent, Id, Mod, Data, Where) -> ok | {error, Reason}</name>
      <fsummary>Register a notification filter</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
        <v>Id = filter_id()</v>
        <v>filter_id() = term()</v>
        <v>Mod = atom()</v>
        <v>Data = term()</v>
        <v>Where = filter_position()</v>
        <v>Reason = term()</v>
        <v>filter_position() = first | last | {insert_before, filter_id()} | {insert_after, filter_id()} </v>
      </type>
      <desc>
        <p>Registers a notification filter.
          </p>
        <p><c>Mod</c> is a module implementing the 
          <c>snmpa_notification_filter</c> behaviour.</p>
        <p><c>Data</c> will be passed on to the filter when calling the
          functions of the behaviour.</p>

        <marker id="unregister_notification_filter"></marker>
      </desc>
    </func>

    <func>
      <name>unregister_notification_filter(Id) -> ok | {error, Reason}</name>
      <name>unregister_notification_filter(Agent, Id) -> ok | {error, Reason}</name>
      <fsummary>Unregister a notification filter</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
        <v>Id = filter_id()</v>
        <v>filter_id() = term()</v>
      </type>
      <desc>
        <p>Unregister a notification filter. </p>

        <marker id="which_notification_filter"></marker>
      </desc>
    </func>

    <func>
      <name>which_notification_filter() -> Filters</name>
      <name>which_notification_filter(Agent) -> Filters</name>
      <fsummary>Which notification filter</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
        <v>Filters = [filter_id()]</v>
        <v>filter_id() = term()</v>
      </type>
      <desc>
        <p>List all notification filters in an agent.</p>

        <marker id="set_request_limit"></marker>
      </desc>
    </func>

   <func>
      <name>set_request_limit(NewLimit) -> {ok, OldLimit} | {error, Reason}</name>
      <name>set_request_limit(Agent, NewLimit) -> {ok, OldLimit} | {error, Reason}</name>
      <fsummary>Change the request limit</fsummary>
      <type>
        <v>NewLimit = OldLimit = infinity | integer() >= 0</v>
        <v>Agent = pid() | atom()</v>
        <v>Reason = term()</v>
      </type>
      <desc>
        <p>Changes the request limit. </p>
        <p>Note that this has no effect on the application configuration as
          defined by configuration files, so a node restart will revert the 
          config to whatever is in those files. </p>
        <p>This function is primarily useful in load regulation 
          scenarios. </p>

        <marker id="register_subagent"></marker>
      </desc>
    </func>

    <func>
      <name>register_subagent(Agent, SubTreeOid, Subagent) -> ok | {error, Reason}</name>
      <fsummary>Register a sub-agent under a sub-tree</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
        <v>SubTreeOid = oid()</v>
        <v>SubAgent = pid()</v>
      </type>
      <desc>
        <p>Registers a sub-agent under a sub-tree of another agent. </p>
        <p>It is easy to make mistakes when registering sub-agents and
          this activity should be done carefully.  For example, a
          strange behaviour would result from the following
          configuration:</p>
        <pre>
snmp_agent:register_subagent(MAPid,[1,2,3,4],SA1),
snmp_agent:register_subagent(SA1,[1,2,3], SA2).
        </pre>
        <p><c>SA2</c> will not get requests starting with object
          identifier <c>[1,2,3]</c> since <c>SA1</c> does not. </p>

        <marker id="unregister_subagent"></marker>
      </desc>
    </func>

    <func>
      <name>unregister_subagent(Agent, SubagentOidOrPid) -> ok | {ok, SubAgentPid} | {error, Reason}</name>
      <fsummary>Unregister a sub-agent</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
        <v>SubTreeOidorPid = oid() | pid()</v>
      </type>
      <desc>
        <p>Unregister a sub-agent.  If the second argument is a pid,
          then that sub-agent will be unregistered from all trees in
          <c>Agent</c>. </p>

          <marker id="send_notification"></marker>
      </desc>
    </func>

    <func>
      <name>send_notification(Agent, Notification, Receiver)</name>
      <name>send_notification(Agent, Notification, Receiver, Varbinds)</name>
      <name>send_notification(Agent, Notification, Receiver, NotifyName, Varbinds)</name>
      <name>send_notification(Agent, Notification, Receiver, NotifyName, ContextName, Varbinds) -> void() </name>
      <name>send_notification(Agent, Notification, Receiver, NotifyName, ContextName, Varbinds, LocalEngineID) -> void() </name>
      <fsummary>Send a notification</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
        <v>Notification = atom()</v>
        <v>Receiver = no_receiver | {Tag, Recv} | notification_delivery_info()</v>
        <v>Tag = term()</v>
        <v>Recv = receiver()</v>
        <v>receiver() = pid() | atom() | {Mod, Func, Args}</v>
        <v>Mod = atom()</v>
        <v>Func = atom()</v>
        <v>Args = list()</v>
        <v>NotifyName = string()</v>
        <v>ContextName = string()</v>
        <v>Varbinds = varbinds()</v>
        <v>varbinds() = [varbind()]</v>
        <v>varbind() = {Variable, Value} | {Column, RowIndex, Value} | {OID, Value}</v>
        <v>Variable = atom()</v>
        <v>Column = atom()</v>
        <v>OID = oid()</v>
        <v>Value = term()</v>
        <v>RowIndex = [int()]</v>
        <v>LocalEngineID = string()</v>
      </type>
      <desc>
        <p>Sends the notification <c>Notification</c> to the
          management targets defined for <c>NotifyName</c> in the
          <c>snmpNotifyTable</c> in SNMP-NOTIFICATION-MIB from the
          specified context.  If no <c>NotifyName</c> is specified (or
          if it is <c>""</c>), the notification is sent to all
          management targets (<c>Addresses</c> below).  If no <c>ContextName</c> 
          is specified, the default <c>""</c> context is used.
          </p>

        <p>The parameter <c>Receiver</c> specifies where information
          about delivery of Inform-Requests should be sent.  The agent
          sends Inform-Requests and waits for acknowledgments from the
          managers. <c>Receiver</c> can have three values: </p>

	<list type="bulleted">
          <item>
            <p><c>no_receiver</c> - No information is delivered. </p>
	  </item>

          <item>
            <p><c>{Tag, Recv}</c> - The information is delivered either via messages 
              or via a function call according to the value of <c>Recv</c>. </p>
	  </item>

          <item>
            <p><c>notification_delivery_info()</c> - The information is 
              delivered via a function call according to this data. See the 
              <seealso marker="#data_types">DATA TYPES</seealso> section 
              above for details. </p>
	  </item>

        </list>


        <p>If <c>Receiver</c> has the value <c>{Tag, Recv}</c>, the delivery is
          done according to <c>Recv</c>: </p>

        <list>
          <item>
            <p><c>pid() | atom()</c> - The info will be delivered in  
              the following messages: </p>
            <list>
              <item>
                <p><c>{snmp_targets, Tag, Addresses}</c></p>
                <p>This inform the user which target addresses the 
                  notification was sent to. </p>
		  </item>
              <item>
                <p><c>{snmp_notification, Tag, {got_response, Address}}</c></p>
                <p>This informs the user that this target address 
                  acknowledged the notification. </p>
		  </item>
              <item>
                <p><c>{snmp_notification, Tag, {no_response, Address}}</c></p>
                <p>This informs the user that this target address 
                  did not acknowledge notification. </p>
		  </item>
		</list>
            <p>The notification is sent as an Inform-Request to each 
              target address in <c>Addresses</c> and if there are no 
              targets for which an Inform-Request is sent, <c>Addresses</c> 
              is the empty list <c>[]</c>. </p>
            <p>The <c>receiver</c> will first be sent the <c>snmp_targets</c> 
              message, and then for each address in <c>Addresses</c> list, 
              one of the two <c>snmp_notification</c> messages. </p>
	  </item>
          <item>
            <p><c>{Mod, Func, Args}</c> - The info will be delivered via
              the function call: </p>
            <p><c>Mod:Func([Msg | Args])</c></p>
            <p>where <c>Msg</c> has the same content and purpose as the 
              messages descrived above.</p>
	  </item>
	</list>

        <p><c>Address</c> is a management target address and <c>Addresses</c> is a 
          list of management target addresses. They are defined as followes: </p>

<pre>
        Addresses  = [address()]
        Address    = address()
        address()  = v1_address() | v3_address()
        v1_address() = {TDomain, TAddress}
        v3_address() = {{TDomain, TAddress}, V3MsgData}
        TDomain    = tdoamin()
        TAddress   = taddress()
        tdomain()  = The oid of snmpUDPDomain 
                     This is the only supported transport domain.
        taddress() = [A1, A2, A3, A4, P1, P3]
                     The 4 first bytes makes up the IP-address and the last 2,
                     the UDP-port number.
        V3MsgData  = v3_msg_data()
        v3_msg_data() = term()
</pre>

        <p>If <c>Receiver</c> is a <c>notification_delivery_info()</c> record,
          then the information about the notification delivery will be delivered 
          to the <c>receiver</c> via the callback functions defined by the 
          <seealso marker="snmpa_notification_delivery_info_receiver">snmpa_notification_delivery_info_receiver</seealso> 
          behaviour according to the content of the <c>notification_delivery_info()</c> 
          record. </p>

        <p>The optional argument <c>Varbinds</c> defines
          values for the objects in the notification.  If no value is
          given for an object, the <c>Agent</c> performs a get-operation
          to retrieve the value.
          </p>
        <p><c>Varbinds</c> is a list of <c>Varbind</c>, where each
          <c>Varbind</c> is one of:
          </p>
        <list type="bulleted">
          <item><c>{Variable, Value}</c>, where <c>Variable</c> is the
           symbolic name of a scalar variable referred to in the notification
           specification.
          </item>
          <item><c>{Column, RowIndex, Value}</c>, where <c>Column</c>
           is the symbolic name of a column variable.
          <c>RowIndex</c> is a list of indices for the specified
           element.  If this is the case, the OBJECT IDENTIFIER sent
           in the notification is the <c>RowIndex</c> appended to the OBJECT
           IDENTIFIER for the table column. This is the OBJECT
           IDENTIFIER which specifies the element.
          </item>
          <item><c>{OID, Value}</c>, where <c>OID</c> is the OBJECT
           IDENTIFIER for an instance of an object, scalar variable,
           or column variable.
          </item>
        </list>
        <p>For example, to specify that <c>sysLocation</c> should have the
          value <c>"upstairs"</c> in the notification, we could use one of:
          </p>
        <list type="bulleted">
          <item><c>{sysLocation, "upstairs"}</c> or</item>
          <item><c>{[1,3,6,1,2,1,1,6,0], "upstairs"}</c> or</item>
          <item><c>{?sysLocation_instance, "upstairs"}</c> (provided
           that the generated <c>.hrl</c> file is included)</item>
        </list>

        <p>If a variable in the notification is a table element, the
          <c>RowIndex</c> for the element must be given in the
          <c>Varbinds</c> list. In this case, the OBJECT IDENTIFIER sent
          in the notification is the OBJECT IDENTIFIER that identifies this
          element.  This OBJECT IDENTIFIER could be used in a get
          operation later.
          </p>

        <p>This function is asynchronous, and does not return any
          information.  If an error occurs, <c>user_err/2</c> of the error
          report module is called and the notification is discarded.
          </p>

        <note>
          <p>Note that the use of the LocalEngineID argument is only intended 
            for special cases, if the agent is to "emulate" multiple EngineIDs!
            By default, the agent uses the value of <c>SnmpEngineID</c> 
            (see SNMP-FRAMEWORK-MIB). </p>
	</note>

<!--
          <marker id="send_trap"></marker>
-->
	  <marker id="discovery"></marker>
      </desc>
    </func>

<!--
    <func>
      <name>send_trap(Agent,Trap,Community)</name>
      <name>send_trap(Agent,Trap,Community,Varbinds) -> void()</name>
      <fsummary>Send a trap</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
        <v>Trap = atom()</v>
        <v>Community = string()</v>
        <v>Varbinds = [Varbind]</v>
        <v>Varbind = {Variable, Value} | {Column, RowIndex, Value} | {OID, Value}</v>
        <v>Variable = atom()</v>
        <v>Column = atom()</v>
        <v>OID = oid()</v>
        <v>Value = term()</v>
        <v>RowIndex = [int()]</v>
      </type>
      <desc>
        <p>Note!  This function is only kept for backwards
          compatibility reasons.  Use <c>send_notification</c> instead.
          </p>
        <p>Sends the trap <c>Trap</c> to the managers defined for
          <c>Community</c> in the <c>intTrapDestTable</c> in
          OTP-SNMPEA-MIB.  The optional argument <c>Varbinds</c> defines
          values for the objects in the trap.  If no value is given for
          an object, the <c>Agent</c> performs a get-operation to
          retrieve the value.
          </p>
        <p><c>Varbinds</c> is a list of <c>Varbind</c>, where each
          <c>Varbind</c> is one of:
          </p>
        <list type="bulleted">
          <item><c>{Variable, Value}</c>, where <c>Variable</c> is the
           symbolic name of a scalar variable referred to in the trap
           specification.
          </item>
          <item><c>{Column, RowIndex, Value}</c>, where <c>Column</c>
           is the symbolic name of a column variable.
          <c>RowIndex</c> is a list of indices for the specified
           element.  If this is the case, the OBJECT IDENTIFIER sent
           in the trap is the <c>RowIndex</c> appended to the OBJECT
           IDENTIFIER for the table column. This is the OBJECT
           IDENTIFIER which specifies the element.
          </item>
          <item><c>{OID, Value}</c>, where <c>OID</c> is the OBJECT
           IDENTIFIER for an instance of an object, scalar variable,
           or column variable.
          </item>
        </list>
        <p>For example, to specify that <c>sysLocation</c> should have the
          value <c>"upstairs"</c> in the trap, we could use one of:
          </p>
        <list type="bulleted">
          <item><c>{sysLocation, "upstairs"}</c> or</item>
          <item><c>{[1,3,6,1,2,1,1,6,0], "upstairs"}</c> or</item>
          <item><c>{?sysLocation_instance, "upstairs"}</c> (provided
           that the generated <c>.hrl</c> file is included)</item>
        </list>
        <p>If a variable in the trap is a table element, the
          <c>RowIndex</c> for the element must be given in the
          <c>Varbinds</c> list. In this case, the OBJECT IDENTIFIER sent
          in the trap is the OBJECT IDENTIFIER that identifies this
          element.  This OBJECT IDENTIFIER could be used in a get
          operation later.
          </p>
        <p>This function is asynchronous, and does not return any
          information.  If an error occurs, <c>snmp_error:user_err/2</c>
          is called and the trap is discarded. </p>

        <marker id="discovery"></marker>
      </desc>
    </func>
-->

    <func>
      <name>discovery(TargetName, Notification) -> {ok, ManagerEngineID} | {error, Reason}</name>
      <name>discovery(TargetName, Notification, Varbinds) -> {ok, ManagerEngineID} | {error, Reason}</name>
      <name>discovery(TargetName, Notification, DiscoHandler) -> {ok, ManagerEngineID} | {error, Reason}</name>
      <name>discovery(TargetName, Notification, ContextName, Varbinds) -> {ok, ManagerEngineID} | {error, Reason}</name>
      <name>discovery(TargetName, Notification, Varbinds, DiscoHandler) -> {ok, ManagerEngineID} | {error, Reason}</name>
      <name>discovery(TargetName, Notification, ContextName, Varbinds, DiscoHandler) -> {ok, ManagerEngineID} | {error, Reason}</name>
      <name>discovery(TargetName, Notification, ContextName, Varbinds, DiscoHandler, ExtraInfo) -> {ok, ManagerEngineID} | {error, Reason}</name>
      <fsummary>Initiate the discovery process with a manager</fsummary>
      <type>
        <v>TargetName = string()</v>
        <v>Notification = atom()</v>
        <v>ContextName = string() (defaults to "")</v>
        <v>Varbinds = varbinds()</v>
        <v>varbinds() = [varbind()]</v>
        <v>DiscoHandler = snmpa_discovery_handler()</v>
        <v>ExtraInfo = term()</v>
        <v>snmpa_discovery_handler() = Module implementing the snmpa_discovery_handler behaviour</v>
        <v>ManagerEngineID = string()</v>
        <v>varbind() = {Variable, Value} | {Column, RowIndex, Value} | {OID, Value}</v>
        <v>Variable = atom()</v>
        <v>Column = atom()</v>
        <v>OID = oid()</v>
        <v>Value = term()</v>
        <v>RowIndex = [int()]</v>
        <v>Reason = term()</v>
      </type>
      <desc>
        <p>Initiate the discovery process with the manager identified by
          <c>TargetName</c> using the notification <c>Notification</c>. </p>

        <p>This function is synchronous, which means that it will return when
          the discovery process has been completed or failed. </p>

        <p>The <c>DiscoHandler</c> module is used during the discovery 
          process. See 
          <seealso marker="snmpa_discovery_handler">discovery handler</seealso>
          for more info. </p>

        <p>The <c>ExtraInfo</c> argument is passed on to the callback functions
          of the <c>DiscoHandler</c>. </p>

        <note><p>If we are not at security-level <c>noAuthNoPriv</c>,
          this could be complicated, since the agent will then continue 
          with stage 2, before which the usm-related updates must be 
          done. </p></note>

        <note><p>The default discovery handler will require 
          additional actions by the caller and the discovery will not work
          if the security-level is higher then <c>noAuthNoPriv</c>. </p></note>

          <marker id="convert_config"></marker>
      </desc>
    </func>

    <func>
      <name>convert_config(OldConfig) -> AgentConfig</name>
      <fsummary>Convert old snmp config to new agent config</fsummary>
      <type>
        <v>OldConfig = list()</v>
        <v>AgentConfig = list()</v>
      </type>
      <desc>
        <p>This off-line utility function can be used to convert
          the old snmp application config (pre snmp-4.0) to the 
          new snmp agent config (as of snmp-4.0).</p>
        <p>For information about the old config (<c>OldConfig</c>) 
          see the OTP R9C documentation.</p>
        <p>For information about the current agent config 
          (<c>AgentConfig</c>), see either
          the <seealso marker="snmp_app">SNMP application</seealso> 
          part of the reference manual or the 
          <seealso marker="snmp_config">Configuring the application</seealso> 
          chapter of the SNMP user's guide.</p>

        <marker id="restart_worker"></marker>
      </desc>
    </func>

    <func>
      <name>restart_worker() -> void()</name>
      <name>restart_worker(Agent) -> void()</name>
      <fsummary>Restart the worker process of a multi-threaded agent</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
      </type>
      <desc>
        <p>Restart the worker process of a multi-threaded agent.</p>
        <p>This is a utility function, that can be usefull when 
          e.g. debugging instrumentation functions.</p>

        <marker id="restart_set_worker"></marker>
      </desc>
    </func>

    <func>
      <name>restart_set_worker() -> void()</name>
      <name>restart_set_worker(Agent) -> void()</name>
      <fsummary>Restart the set worker process of a multi-threaded agent</fsummary>
      <type>
        <v>Agent = pid() | atom()</v>
      </type>
      <desc>
        <p>Restart the set worker process of a multi-threaded agent.</p>
        <p>This is a utility function, that can be usefull when 
          e.g. debugging instrumentation functions.</p>

        <marker id="verbosity"></marker>
      </desc>
    </func>

    <func>
      <name>verbosity(Ref,Verbosity) -> void()</name>
      <fsummary>Assign a new verbosity for the process</fsummary>
      <type>
        <v>Ref = pid() | sub_agents | master_agent | net_if | mib_server | symbolic_store | note_store | local_db</v>
        <v>Verbosity = verbosity() | {subagents, verbosity()}</v>
        <v>verbosity() = silence | info | log | debug | trace </v>
      </type>
      <desc>
        <p>Sets verbosity for the designated process. For the lowest 
          verbosity <c>silence</c>, nothing is printed. The higher the
          verbosity, the more is printed. </p>
      </desc>
    </func>
  </funcs>

  <section>
    <title>See Also</title>
    <p>calendar(3), erlc(1) </p>
  </section>

  
</erlref>