path: root/lib/et/doc/src/et_selector.xml

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  <header>
    <copyright>
      <year>2002</year><year>2009</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
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    </legalnotice>

    <title>et_selector</title>
    <prepared>H&aring;kan Mattsson</prepared>
    <responsible>H&aring;kan Mattsson</responsible>
    <docno></docno>
    <approved>H&aring;kan Mattsson</approved>
    <checked></checked>
    <date></date>
    <rev>%VSN%</rev>
  </header>
  <module>et_selector</module>
  <modulesummary>Define event transforms and trace patterns</modulesummary>
  <description>
    <p></p>
  </description>
  <funcs>
    <func>
      <name>make_pattern(RawPattern) -> TracePattern</name>
      <fsummary>Makes a trace pattern suitable to feed change_pattern/1</fsummary>
      <type>
        <v>RawPattern = detail_level()</v>
        <v>TracePattern = erlang_trace_pattern_match_spec()</v>
        <v>detail_level() = min | max | integer(X) when X =&lt; 0, X >= 100</v>
      </type>
      <desc>
        <p>Makes a trace pattern suitable to feed change_pattern/1</p>
        <p>Min detail level deactivates tracing of calls to phone_home/4,5</p>
        <p>Max detail level activates tracing of all calls to phone_home/4,5</p>
        <p>integer(X) detail level activates tracing of all calls to
          phone_home/4,5 whose detail level argument is lesser than X.</p>
        <p>See also erlang:trace_pattern/2 for more info about its match_spec()</p>
      </desc>
    </func>
    <func>
      <name>change_pattern(Pattern) -> ok</name>
      <fsummary>Activates/deactivates tracing by changing the current trace pattern</fsummary>
      <type>
        <v>Pattern = detail_level() | empty_match_spec() | erlang_trace_pattern_match_spec()</v>
        <v>detail_level() = min | max | integer(X) when X =&lt;0, X >= 100</v>
        <v>empty_match_spec() = [] </v>
      </type>
      <desc>
        <p>Activates/deactivates tracing by changing the current trace pattern.</p>
        <p>Min detail level deactivates tracing of calls to phone_home/4,5</p>
        <p>Max detail level activates tracing of all calls to phone_home/4,5</p>
        <p>integer(X) detail level activates tracing of all calls to
          phone_home/4,5 whose detail level argument is lesser than X.</p>
        <p>An empty match spec deactivates tracing of calls to phone_home/4,5</p>
        <p>Other match specs activates tracing of calls to phone_home/4,5
          accordingly with erlang:trace_pattern/2.</p>
      </desc>
    </func>
    <func>
      <name>parse_event(Mod, ValidTraceData) -> false | true | {true, Event}</name>
      <fsummary>Transforms trace data and makes an event record out of it</fsummary>
      <type>
        <v>Mod = module_name() | undefined &lt;v>module_name() = atom() &lt;v>ValidTraceData = erlang_trace_data() | record(event)</v>
        <v>erlang_trace_data() = {trace, Pid, Label, Info} |  {trace, Pid, Label, Info, Extra} |  {trace_ts, Pid, Label, Info, ReportedTS} |  {trace_ts, Pid, Label, Info, Extra, ReportedTS} |  {seq_trace, Label, Info} |  {seq_trace, Label, Info, ReportedTS} |  {drop, NumberOfDroppedItems}</v>
      </type>
      <desc>
        <p>Transforms trace data and makes an event record out of it.</p>
        <p>See erlang:trace/3 for more info about the semantics of
          the trace data.</p>
        <p>An event record consists of the following fields:
          detail_level - Noise has a high level as opposed to essentials.
          trace_ts     - Time when the trace was generated.
          Same as event_ts if omitted in trace data.
          event_ts     - Time when the event record was created.
          from         - From actor, such as sender of a message.
          to           - To actor, such as receiver of message.
          label        - Label intended to provide a brief event summary.
          contents     - All nitty gritty details of the event.</p>
        <p>See et:phone_home/4 and et:phone_home/5 for details.</p>
        <p>Returns: 
          {true, Event} - where Event is an #event{} record representing the
          trace data
          true          - means that the trace data already is an event
          record and that it is valid as it is.
          No transformation is needed.
          false         - means that the trace data is uninteresting and
          should be dropped</p>
      </desc>
    </func>
  </funcs>
  
</erlref>