erts: Editorial changes

1 files changed, 502 insertions, 371 deletions

diff --git a/erts/doc/src/erl_tracer.xml b/erts/doc/src/erl_tracer.xml
index e2852ce49d..a2cfed684b 100644
--- a/erts/doc/src/erl_tracer.xml
+++ b/erts/doc/src/erl_tracer.xml
@@ -29,488 +29,618 @@
     <rev></rev>
   </header>
   <module>erl_tracer</module>
-  <modulesummary>Erlang Tracer Behaviour</modulesummary>
+  <modulesummary>Erlang tracer behavior.</modulesummary>
   <description>
-    <p>A behaviour module for implementing the back end of the erlang
-    tracing system. The functions in this module will be called whenever
-    a trace probe is triggered. Both the <c>enabled</c> and <c>trace</c>
-    functions are called in the context of the entity that triggered the
-    trace probe.
-    This means that the overhead by having the tracing enabled will be
-    greatly effected by how much time is spent in these functions. So do as
-    little work as possible in these functions.</p>
+    <p>This behavior module implements the back end of the Erlang
+      tracing system. The functions in this module are called whenever
+      a trace probe is triggered. Both the <c>enabled</c> and <c>trace</c>
+      functions are called in the context of the entity that triggered the
+      trace probe.
+      This means that the overhead by having the tracing enabled is
+      greatly effected by how much time is spent in these functions. So, do as
+      little work as possible in these functions.</p>
+
     <note>
-      <p>All functions in this behaviour have to be implemented as NIF's.
-      This is a limitation that may the lifted in the future.
-      There is an <seealso marker="#example">example tracer module nif</seealso>
-      implementation at the end of this page.</p>
+      <p>All functions in this behavior must be implemented as NIFs.
+        This limitation can be removed in a future releases.
+        An <seealso marker="#example">example tracer module NIF</seealso>
+        implementation is provided at the end of this page.</p>
     </note>
+
     <warning>
       <p>Do not send messages or issue port commands to the <c>Tracee</c>
-      in any of the callbacks. Doing so is not allowed and can cause all
-      sorts of strange behaviour, including but not limited to infinite
-      recursions.</p>
+        in any of the callbacks. This is not allowed and can cause all
+        sorts of strange behavior, including, but not limited to, infinite
+        recursions.</p>
     </warning>
   </description>
 
   <datatypes>
-      <datatype> <name name="trace_tag_send" /> </datatype>
-      <datatype> <name name="trace_tag_receive" /> </datatype>
-      <datatype> <name name="trace_tag_call" /> </datatype>
-      <datatype> <name name="trace_tag_procs" /> </datatype>
-      <datatype> <name name="trace_tag_ports" /> </datatype>
-      <datatype> <name name="trace_tag_running_procs" /> </datatype>
-      <datatype> <name name="trace_tag_running_ports" /> </datatype>
-      <datatype> <name name="trace_tag_gc" /> </datatype>
     <datatype>
-      <name name="trace_tag" />
+      <name name="trace_tag_call"/>
+    </datatype>
+    <datatype>
+      <name name="trace_tag_gc"/>
+    </datatype>
+    <datatype>
+      <name name="trace_tag_ports"/>
+    </datatype>
+    <datatype>
+      <name name="trace_tag_procs"/>
+    </datatype>
+    <datatype>
+      <name name="trace_tag_receive"/>
+    </datatype>
+    <datatype>
+      <name name="trace_tag_running_ports"/>
+    </datatype>
+    <datatype>
+      <name name="trace_tag_running_procs"/>
+    </datatype>
+    <datatype>
+      <name name="trace_tag_send"/>
+    </datatype>
+    <datatype>
+      <name name="trace_tag"/>
       <desc>
-	<p>The different trace tags that the tracer will be called with.
-        Each trace tag is described in greater detail in
-        <seealso marker="#Module:trace/5">Module:trace/5</seealso>
-        </p>
+        <p>The different trace tags that the tracer is called with.
+          Each trace tag is described in detail in
+          <seealso marker="#Module:trace/5"><c>Module:trace/5</c></seealso>.</p>
       </desc>
     </datatype>
     <datatype>
-      <name name="tracee" />
+      <name name="tracee"/>
       <desc>
-	<p>The process or port that the trace belongs to.
-        </p>
+        <p>The process or port that the trace belongs to.</p>
       </desc>
     </datatype>
     <datatype>
-      <name name="trace_opts" />
+      <name name="trace_opts"/>
       <desc>
-	<p>The options for the tracee.</p>
+        <p>The options for the tracee:</p>
         <taglist>
           <tag><c>timestamp</c></tag>
-          <item>If set the tracer has been requested to include a timestamp.</item>
+          <item>If set the tracer has been requested to include a
+            time stamp.</item>
           <tag><c>extra</c></tag>
           <item>If set the tracepoint has included additonal data about
-          the trace event. What the additional data is depends on which
-          <c>TraceTag</c> has been triggered. The <c>extra</c> trace data
-          corresponds to the fifth elemnt in the trace tuples described in
-          <seealso marker="erlang#trace_3_trace_messages">erlang:trace/3</seealso>.</item>
+            the trace event. What the additional data is depends on which
+            <c>TraceTag</c> has been triggered. The <c>extra</c> trace data
+            corresponds to the fifth element in the trace tuples described in
+            <seealso marker="erlang#trace_3_trace_messages">
+              erlang:trace/3</seealso>.</item>
           <tag><c>match_spec_result</c></tag>
           <item>If set the tracer has been requested to include the output
-          of a match specification that was run.</item>
+            of a match specification that was run.</item>
           <tag><c>scheduler_id</c></tag>
-          <item>Set the scheduler id is to be included by the tracer.</item>
+          <item>If set the scheduler id is to be included by the tracer.</item>
         </taglist>
       </desc>
     </datatype>
     <datatype>
-      <name name="tracer_state" />
+      <name name="tracer_state"/>
       <desc>
-        <p>
-          The state which is given when calling
-          <seealso marker="erlang#trace-3"><c>erlang:trace(PidPortSpec,true,[{tracer,Module,TracerState}])</c></seealso>.
-          The tracer state is an immutable value that is passed to erl_tracer callbacks and should
-          contain all the data that is needed to generate the trace event.
-        </p>
+        <p>The state specified when calling
+          <seealso marker="erlang#trace-3">
+          <c>erlang:trace(PidPortSpec,true,[{tracer,Module,TracerState}])</c></seealso>.
+          The tracer state is an immutable value that is passed to
+          <c>erl_tracer</c> callbacks and is to
+          contain all the data that is needed to generate the trace event.</p>
       </desc>
     </datatype>
   </datatypes>
 
   <section>
-    <title>CALLBACK FUNCTIONS</title>
-    <p>The following functions
-      should be exported from a <c>erl_tracer</c> callback module.</p>
-   <taglist>
-       <tag><seealso marker="#Module:enabled/3"><c>Module:enabled/3</c></seealso></tag>
-       <item>Mandatory</item>
-       <tag><seealso marker="#Module:trace/5"><c>Module:trace/5</c></seealso></tag>
-       <item>Mandatory</item>
-       <tag><seealso marker="#Module:enabled_procs/3"><c>Module:enabled_procs/3</c></seealso></tag>
-       <item>Optional</item>
-       <tag><seealso marker="#Module:trace_procs/5"><c>Module:trace_procs/5</c></seealso></tag>
-       <item>Optional</item>
-       <tag><seealso marker="#Module:enabled_ports/3"><c>Module:enabled_ports/3</c></seealso></tag>
-       <item>Optional</item>
-       <tag><seealso marker="#Module:trace_ports/5"><c>Module:trace_ports/5</c></seealso></tag>
-       <item>Optional</item>
-       <tag><seealso marker="#Module:enabled_running_ports/3"><c>Module:enabled_running_ports/3</c></seealso></tag>
-       <item>Optional</item>
-       <tag><seealso marker="#Module:trace_running_ports/5"><c>Module:trace_running_ports/5</c></seealso></tag>
-       <item>Optional</item>
-       <tag><seealso marker="#Module:enabled_running_procs/3"><c>Module:enabled_running_procs/3</c></seealso></tag>
-       <item>Optional</item>
-       <tag><seealso marker="#Module:trace_running_procs/5"><c>Module:trace_running_procs/5</c></seealso></tag>
-       <item>Optional</item>
+    <title>Callback Functions</title>
+    <p>The following functions are to be exported from an <c>erl_tracer</c>
+      callback module:</p>
+
+    <taglist>
+      <tag><seealso marker="#Module:enabled/3">
+        <c>Module:enabled/3</c></seealso></tag>
+      <item>Mandatory</item>
+      <tag><seealso marker="#Module:trace/5">
+        <c>Module:trace/5</c></seealso></tag>
+      <item>Mandatory</item>
+      <tag><seealso marker="#Module:enabled_call/3">
+        <c>Module:enabled_call/3</c></seealso></tag>
+      <item>Optional</item>
+      <tag><seealso marker="#Module:trace_call/5">
+        <c>Module:trace_call/5</c></seealso></tag>
+      <item>Optional</item>
+      <tag><seealso marker="#Module:enabled_garbage_collection/3">
+        <c>Module:enabled_garbage_collection/3</c></seealso></tag>
+      <item>Optional</item>
+      <tag><seealso marker="#Module:trace_garbage_collection/5">
+        <c>Module:trace_garbage_collection/5</c></seealso></tag>
+      <item>Optional</item>
+      <tag><seealso marker="#Module:enabled_ports/3">
+        <c>Module:enabled_ports/3</c></seealso></tag>
+      <item>Optional</item>
+      <tag><seealso marker="#Module:trace_ports/5">
+        <c>Module:trace_ports/5</c></seealso></tag>
+      <item>Optional</item>
+      <tag><seealso marker="#Module:enabled_procs/3">
+        <c>Module:enabled_procs/3</c></seealso></tag>
+      <item>Optional</item>
+      <tag><seealso marker="#Module:trace_procs/5">
+        <c>Module:trace_procs/5</c></seealso></tag>
+      <item>Optional</item>
+      <tag><seealso marker="#Module:enabled_receive/3">
+        <c>Module:enabled_receive/3</c></seealso></tag>
+      <item>Optional</item>
+      <tag><seealso marker="#Module:trace_receive/5">
+        <c>Module:trace_receive/5</c></seealso></tag>
+      <item>Optional</item>
+      <tag><seealso marker="#Module:enabled_running_ports/3">
+        <c>Module:enabled_running_ports/3</c></seealso></tag>
+      <item>Optional</item>
+      <tag><seealso marker="#Module:trace_running_ports/5">
+        <c>Module:trace_running_ports/5</c></seealso></tag>
+      <item>Optional</item>
+      <tag><seealso marker="#Module:enabled_running_procs/3">
+        <c>Module:enabled_running_procs/3</c></seealso></tag>
+      <item>Optional</item>
+      <tag><seealso marker="#Module:trace_running_procs/5">
+        <c>Module:trace_running_procs/5</c></seealso></tag>
+      <item>Optional</item>
+      <tag><seealso marker="#Module:enabled_send/3">
+        <c>Module:enabled_send/3</c></seealso></tag>
+      <item>Optional</item>
+      <tag><seealso marker="#Module:trace_send/5">
+        <c>Module:trace_send/5</c></seealso></tag>
+      <item>Optional</item>
    </taglist>
-
   </section>
 
   <funcs>
     <func>
       <name>Module:enabled(TraceTag, TracerState, Tracee) -> Result</name>
-      <fsummary>Check if a trace event should be generated.</fsummary>
+      <fsummary>Check if a trace event is to be generated.</fsummary>
       <type>
-        <v>TraceTag = <seealso marker="#type-trace_tag">trace_tag()</seealso> | trace_status</v>
+        <v>TraceTag = <seealso marker="#type-trace_tag">
+          trace_tag()</seealso> | trace_status</v>
         <v>TracerState = term()</v>
         <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
-        <v>Result =  trace | discard | remove</v>
+        <v>Result = trace | discard | remove</v>
       </type>
       <desc>
-        <p>This callback will be called whenever a tracepoint is triggered. It
-        allows the tracer to decide whether a trace should be generated or not.
-        This check is made as early as possible in order to limit the amount of
-        overhead associated with tracing. If <c>trace</c> is returned the
-        necessary trace data will be created and the trace call-back of the tracer
-        will be called. If <c>discard</c> is returned, this trace call
-        will be discarded and no call to trace will be done.
-        </p>
-        <p><c>trace_status</c> is a special type of <c>TraceTag</c> which is used
-        to check if the tracer should still be active. It is called in multiple
-        scenarios, but most significantly it is used when tracing is started
-        using this tracer. If <c>remove</c> is returned when the <c>trace_status</c>
-        is checked, the tracer will be removed from the tracee.</p>
-        <p>This function may be called multiple times per tracepoint, so it
-        is important that it is both fast and side effect free.</p>
+        <p>This callback is called whenever a tracepoint is triggered. It
+          allows the tracer to decide whether a trace is to be generated or not.
+          This check is made as early as possible to limit the amount of
+          overhead associated with tracing. If <c>trace</c> is returned, the
+          necessary trace data is created and the trace callback of the tracer
+          is called. If <c>discard</c> is returned, this trace call is
+          discarded and no call to trace is done.</p>
+        <p><c>trace_status</c> is a special type of <c>TraceTag</c>, which is
+          used to check if the tracer is still to be active. It is called in
+          multiple scenarios, but most significantly it is used when tracing
+          is started using this tracer. If <c>remove</c> is returned when the
+          <c>trace_status</c> is checked, the tracer is removed from the
+          tracee.</p>
+        <p>This function can be called multiple times per tracepoint, so it
+          is important that it is both fast and without side effects.</p>
       </desc>
     </func>
 
     <func>
-        <name>Module:enabled_call(TraceTag, TracerState, Tracee) -> Result</name>
-        <fsummary>Check if a trace event should be generated.</fsummary>
-        <type>
-            <v>TraceTag = <seealso marker="#type-trace_tag_call">trace_tag_call()</seealso></v>
-            <v>TracerState = term()</v>
-            <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
-            <v>Result = trace | discard | remove</v>
-        </type>
-        <desc>
-            <p>This callback will be called whenever a tracepoint with trace flag
-                <seealso marker="erlang#trace-3"><c>call | return_to</c></seealso>
-                is triggered.</p>
-            <p>If <c>enabled_call/3</c> is not defined <c>enabled/3</c> will be called instead.</p>
-        </desc>
+      <name>Module:enabled_call(TraceTag, TracerState, Tracee) -> Result</name>
+      <fsummary>Check if a trace event is to be generated.</fsummary>
+      <type>
+        <v>TraceTag = <seealso marker="#type-trace_tag_call">
+          trace_tag_call()</seealso></v>
+        <v>TracerState = term()</v>
+        <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
+        <v>Result = trace | discard | remove</v>
+      </type>
+      <desc>
+        <p>This callback is called whenever a tracepoint with trace flag
+          <seealso marker="erlang#trace-3"><c>call | return_to</c></seealso>
+          is triggered.</p>
+        <p>If <c>enabled_call/3</c> is undefined,
+          <seealso marker="#Module:enabled/3"><c>Module:enabled/3</c></seealso>
+          is called instead.</p>
+      </desc>
     </func>
 
     <func>
-        <name>Module:enabled_garbage_collection(TraceTag, TracerState, Tracee) -> Result</name>
-        <fsummary>Check if a trace event should be generated.</fsummary>
-        <type>
-            <v>TraceTag = <seealso marker="#type-trace_tag_gc">trace_tag_gc()</seealso></v>
-            <v>TracerState = term()</v>
-            <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
-            <v>Result = trace | discard | remove</v>
-        </type>
-        <desc>
-            <p>This callback will be called whenever a tracepoint with trace flag
-                <seealso marker="erlang#trace-3"><c>garbage_collection</c></seealso>
-                is triggered.</p>
-            <p>If <c>enabled_garbage_collection/3</c> is not defined <c>enabled/3</c> will be called instead.</p>
-        </desc>
+      <name>Module:enabled_garbage_collection(TraceTag, TracerState, Tracee) -> Result</name>
+      <fsummary>Check if a trace event is to be generated.</fsummary>
+      <type>
+        <v>TraceTag = <seealso marker="#type-trace_tag_gc">
+          trace_tag_garbage_collection()</seealso></v>
+        <v>TracerState = term()</v>
+        <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
+        <v>Result = trace | discard | remove</v>
+      </type>
+      <desc>
+        <p>This callback is called whenever a tracepoint with trace flag
+          <seealso marker="erlang#trace-3"><c>garbage_collection</c></seealso>
+          is triggered.</p>
+        <p>If <c>enabled_garbage_collection/3</c> is undefined,
+          <seealso marker="#Module:enabled/3"><c>Module:enabled/3</c></seealso>
+          is called instead.</p>
+      </desc>
     </func>
 
     <func>
-        <name>Module:enabled_ports(TraceTag, TracerState, Tracee) -> Result</name>
-        <fsummary>Check if a trace event should be generated.</fsummary>
-        <type>
-            <v>TraceTag = <seealso marker="#type-trace_tag_ports">trace_tag_ports()</seealso></v>
-            <v>TracerState = term()</v>
-            <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
-            <v>Result = trace | discard | remove</v>
-        </type>
-        <desc>
-            <p>This callback will be called whenever a tracepoint with trace flag
-                <seealso marker="erlang#trace-3"><c>ports</c></seealso>
-                is triggered.</p>
-            <p>If <c>enabled_ports/3</c> is not defined <c>enabled/3</c> will be called instead.</p>
-        </desc>
+      <name>Module:enabled_ports(TraceTag, TracerState, Tracee) -> Result</name>
+      <fsummary>Check if a trace event is to be generated.</fsummary>
+      <type>
+        <v>TraceTag = <seealso marker="#type-trace_tag_ports">
+          trace_tag_ports()</seealso></v>
+        <v>TracerState = term()</v>
+        <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
+        <v>Result = trace | discard | remove</v>
+      </type>
+      <desc>
+        <p>This callback is called whenever a tracepoint with trace flag
+          <seealso marker="erlang#trace-3"><c>ports</c></seealso>
+          is triggered.</p>
+        <p>If <c>enabled_ports/3</c> is undefined,
+          <seealso marker="#Module:enabled/3"><c>Module:enabled/3</c></seealso>
+          is called instead.</p>
+      </desc>
     </func>
 
     <func>
-        <name>Module:enabled_procs(TraceTag, TracerState, Tracee) -> Result</name>
-        <fsummary>Check if a trace event should be generated.</fsummary>
-        <type>
-            <v>TraceTag = <seealso marker="#type-trace_tag_procs">trace_tag_procs()</seealso></v>
-            <v>TracerState = term()</v>
-            <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
-            <v>Result = trace | discard | remove</v>
-        </type>
-        <desc>
-            <p>This callback will be called whenever a tracepoint with trace flag
-                <seealso marker="erlang#trace-3"><c>procs</c></seealso>
-                is triggered.</p>
-            <p>If <c>enabled_procs/3</c> is not defined <c>enabled/3</c> will be called instead.</p>
-        </desc>
+      <name>Module:enabled_procs(TraceTag, TracerState, Tracee) -> Result</name>
+      <fsummary>Check if a trace event is to be generated.</fsummary>
+      <type>
+        <v>TraceTag = <seealso marker="#type-trace_tag_procs">
+          trace_tag_procs()</seealso></v>
+        <v>TracerState = term()</v>
+        <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
+        <v>Result = trace | discard | remove</v>
+      </type>
+      <desc>
+        <p>This callback is called whenever a tracepoint with trace flag
+          <seealso marker="erlang#trace-3"><c>procs</c></seealso>
+          is triggered.</p>
+        <p>If <c>enabled_procs/3</c> is undefined,
+          <seealso marker="#Module:enabled/3"><c>Module:enabled/3</c></seealso>
+          is called instead.</p>
+      </desc>
     </func>
 
     <func>
-        <name>Module:enabled_receive(TraceTag, TracerState, Tracee) -> Result</name>
-        <fsummary>Check if a trace event should be generated.</fsummary>
-        <type>
-            <v>TraceTag = <seealso marker="#type-trace_tag_receive">trace_tag_receive()</seealso></v>
-            <v>TracerState = term()</v>
-            <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
-            <v>Result = trace | discard | remove</v>
-        </type>
-        <desc>
-            <p>This callback will be called whenever a tracepoint with trace flag
-                <seealso marker="erlang#trace-3"><c>'receive'</c></seealso>
-                is triggered.</p>
-            <p>If <c>enabled_receive/3</c> is not defined <c>enabled/3</c> will be called instead.</p>
-        </desc>
+      <name>Module:enabled_receive(TraceTag, TracerState, Tracee) -> Result
+      </name>
+      <fsummary>Check if a trace event is to be generated.</fsummary>
+      <type>
+        <v>TraceTag = <seealso marker="#type-trace_tag_receive">
+          trace_tag_receive()</seealso></v>
+        <v>TracerState = term()</v>
+        <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
+        <v>Result = trace | discard | remove</v>
+      </type>
+      <desc>
+        <p>This callback is called whenever a tracepoint with trace flag
+          <seealso marker="erlang#trace-3"><c>'receive'</c></seealso>
+          is triggered.</p>
+        <p>If <c>enabled_receive/3</c> is undefined,
+          <seealso marker="#Module:enabled/3"><c>Module:enabled/3</c></seealso>
+          is called instead.</p>
+      </desc>
     </func>
 
     <func>
-        <name>Module:enabled_running_ports(TraceTag, TracerState, Tracee) -> Result</name>
-        <fsummary>Check if a trace event should be generated.</fsummary>
-        <type>
-            <v>TraceTag = <seealso marker="#type-trace_tag_running_ports">trace_tag_running_ports()</seealso></v>
-            <v>TracerState = term()</v>
-            <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
-            <v>Result = trace | discard | remove</v>
-        </type>
-        <desc>
-            <p>This callback will be called whenever a tracepoint with trace flag
-                <seealso marker="erlang#trace-3"><c>running_ports</c></seealso>
-                is triggered.</p>
-            <p>If <c>enabled_running_ports/3</c> is not defined <c>enabled/3</c> will be called instead.</p>
-        </desc>
+      <name>Module:enabled_running_ports(TraceTag, TracerState, Tracee) ->
+        Result</name>
+      <fsummary>Check if a trace event is to be generated.</fsummary>
+      <type>
+        <v>TraceTag = <seealso marker="#type-trace_tag_running_ports">
+          trace_tag_running_ports()</seealso></v>
+        <v>TracerState = term()</v>
+        <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
+        <v>Result = trace | discard | remove</v>
+      </type>
+      <desc>
+        <p>This callback is called whenever a tracepoint with trace flag
+          <seealso marker="erlang#trace-3"><c>running_ports</c></seealso>
+          is triggered.</p>
+        <p>If <c>enabled_running_ports/3</c> is undefined,
+          <seealso marker="#Module:enabled/3"><c>Module:enabled/3</c></seealso>
+          is called instead.</p>
+      </desc>
     </func>
 
     <func>
-        <name>Module:enabled_running_procs(TraceTag, TracerState, Tracee) -> Result</name>
-        <fsummary>Check if a trace event should be generated.</fsummary>
-        <type>
-            <v>TraceTag = <seealso marker="#type-trace_tag_running_procs">trace_tag_running_procs()</seealso></v>
-            <v>TracerState = term()</v>
-            <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
-            <v>Result = trace | discard | remove</v>
-        </type>
-        <desc>
-            <p>This callback will be called whenever a tracepoint with trace flag
-                <seealso marker="erlang#trace-3"><c>running_procs | running</c></seealso>
-                is triggered.</p>
-            <p>If <c>enabled_running_procs/3</c> is not defined <c>enabled/3</c> will be called instead.</p>
-        </desc>
+      <name>Module:enabled_running_procs(TraceTag, TracerState, Tracee) ->
+        Result</name>
+      <fsummary>Check if a trace event is to be generated.</fsummary>
+      <type>
+        <v>TraceTag = <seealso marker="#type-trace_tag_running_procs">
+          trace_tag_running_procs()</seealso></v>
+        <v>TracerState = term()</v>
+        <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
+        <v>Result = trace | discard | remove</v>
+      </type>
+      <desc>
+        <p>This callback is called whenever a tracepoint with trace flag
+          <seealso marker="erlang#trace-3">
+          <c>running_procs | running</c></seealso>
+          is triggered.</p>
+        <p>If <c>enabled_running_procs/3</c> is undefined,
+          <seealso marker="#Module:enabled/3"><c>Module:enabled/3</c></seealso>
+          is called instead.</p>
+      </desc>
     </func>
 
     <func>
-        <name>Module:enabled_send(TraceTag, TracerState, Tracee) -> Result</name>
-        <fsummary>Check if a trace event should be generated.</fsummary>
-        <type>
-            <v>TraceTag = <seealso marker="#type-trace_tag_send">trace_tag_send()</seealso></v>
-            <v>TracerState = term()</v>
-            <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
-            <v>Result = trace | discard | remove</v>
-        </type>
-        <desc>
-            <p>This callback will be called whenever a tracepoint with trace flag
-                <seealso marker="erlang#trace-3"><c>send</c></seealso>
-                is triggered.</p>
-            <p>If <c>enabled_send/3</c> is not defined <c>enabled/3</c> will be called instead.</p>
-        </desc>
+      <name>Module:enabled_send(TraceTag, TracerState, Tracee) -> Result</name>
+      <fsummary>Check if a trace event is to be generated.</fsummary>
+      <type>
+        <v>TraceTag = <seealso marker="#type-trace_tag_send">
+          trace_tag_send()</seealso></v>
+        <v>TracerState = term()</v>
+        <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
+        <v>Result = trace | discard | remove</v>
+      </type>
+      <desc>
+        <p>This callback is called whenever a tracepoint with trace flag
+          <seealso marker="erlang#trace-3"><c>send</c></seealso>
+          is triggered.</p>
+        <p>If <c>enabled_send/3</c> is undefined,
+          <seealso marker="#Module:enabled/3"><c>Module:enabled/3</c></seealso>
+          is called instead.</p>
+      </desc>
     </func>
 
     <func>
-      <name>Module:trace(TraceTag, TracerState, Tracee, TraceTerm, Opts) -> Result</name>
-      <fsummary>Check if a trace event should be generated.</fsummary>
+      <name>Module:trace(TraceTag, TracerState, Tracee, TraceTerm,
+        Opts) -> Result</name>
+      <fsummary>Check if a trace event is to be generated.</fsummary>
       <type>
-        <v>TraceTag = <seealso marker="#type-trace_tag">trace_tag()</seealso></v>
+        <v>TraceTag = <seealso marker="#type-trace_tag">
+          trace_tag()</seealso></v>
         <v>TracerState = term()</v>
         <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
-        <v>FirstTraceTerm = term()</v>
+        <v>TraceTerm = term()</v>
         <v>Opts = <seealso marker="#type-trace_opts">trace_opts()</seealso></v>
-        <v>Result =  ok</v>
+        <v>Result = ok</v>
       </type>
       <desc>
-        <p>This callback will be called when a tracepoint is triggered and
-        the <seealso marker="#Module:enabled/3">Module:enabled/3</seealso>
-        callback returned <c>trace</c>. In it any side effects needed by
-        the tracer should be done. The tracepoint payload is located in
-        the <c>TraceTerm</c>. The content of the TraceTerm depends on which
-        <c>TraceTag</c> has been triggered.
-        The <c>TraceTerm</c> corresponds to the
-        fourth element in the trace tuples described in
-        <seealso marker="erlang#trace_3_trace_messages">erlang:trace/3</seealso>.
-        If the trace tuple has five elements, the fifth element will be sent as
-        the <c>extra</c> value in the <c>Opts</c> maps.</p>
+        <p>This callback is called when a tracepoint is triggered and the
+          <seealso marker="#Module:enabled/3"><c>Module:enabled/3</c></seealso>
+          callback returned <c>trace</c>. In it any side effects needed by
+          the tracer are to be done. The tracepoint payload is located in
+          the <c>TraceTerm</c>. The content of the <c>TraceTerm</c>
+          depends on which <c>TraceTag</c> is triggered.
+          <c>TraceTerm</c> corresponds to the
+          fourth element in the trace tuples described in
+          <seealso marker="erlang#trace_3_trace_messages">
+          <c>erlang:trace/3</c></seealso>.</p>
+        <p>If the trace tuple has five elements, the fifth element
+          will be sent as the <c>extra</c> value in the <c>Opts</c> maps.</p>
       </desc>
     </func>
+
     <func>
-      <name name="trace">Module:trace(seq_trace, TracerState, Label, SeqTraceInfo, Opts) -> Result</name>
-      <fsummary>Check if a sequence trace event should be generated.</fsummary>
+      <name name="trace">Module:trace(seq_trace, TracerState, Label,
+        SeqTraceInfo, Opts) -> Result</name>
+      <fsummary>Check if a sequence trace event is to be generated.</fsummary>
       <type>
         <v>TracerState = term()</v>
         <v>Label = term()</v>
         <v>SeqTraceInfo = term()</v>
         <v>Opts = <seealso marker="#type-trace_opts">trace_opts()</seealso></v>
-        <v>Result =  ok</v>
+        <v>Result = ok</v>
       </type>
       <desc>
-        <p>The <c>TraceTag</c> <c>seq_trace</c> is handled a little bit
-        differently. There is not <c>Tracee</c> for seq_trace, instead the
-        <c>Label</c> associated with the seq_trace event is given.
-        For more info on what <c>Label</c> and <c>SeqTraceInfo</c> can be
-        see the <seealso marker="kernel:seq_trace">seq_trace</seealso> manual.</p>
+        <p>The <c>TraceTag</c> <c>seq_trace</c> is handled slightly
+          differently. There is no <c>Tracee</c> for <c>seq_trace</c>, instead
+          the <c>Label</c> associated with the <c>seq_trace</c> event is
+          specified.</p>
+        <p>For more information on what <c>Label</c> and <c>SeqTraceInfo</c>
+          can be, see <seealso marker="kernel:seq_trace">
+          <c>kernel:seq_trace</c></seealso>.</p>
       </desc>
     </func>
 
     <func>
-        <name>Module:trace_call(TraceTag, TracerState, Tracee, TraceTerm, Opts) -> Result</name>
-        <fsummary>Check if a trace event should be generated.</fsummary>
-        <type>
-            <v>TraceTag = <seealso marker="#type-trace_tag_call">trace_tag_call()</seealso></v>
-            <v>TracerState = term()</v>
-            <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
-            <v>FirstTraceTerm = term()</v>
-            <v>Opts = <seealso marker="#type-trace_opts">trace_opts()</seealso></v>
-            <v>Result = ok</v>
-        </type>
-        <desc>
-            <p>This callback will be called when a tracepoint is triggered and
-                the <seealso marker="#Module:enabled_call/3">Module:enabled_call/3</seealso>
-                callback returned <c>trace</c>.</p>
-            <p>If <c>trace_call/5</c> is not defined <c>trace/5</c> will be called instead.</p>
-        </desc>
+      <name>Module:trace_call(TraceTag, TracerState, Tracee, TraceTerm,
+          Opts) -> Result</name>
+      <fsummary>Check if a trace event is to be generated.</fsummary>
+      <type>
+        <v>TraceTag = <seealso marker="#type-trace_tag_call">
+          trace_tag_call()</seealso></v>
+        <v>TracerState = term()</v>
+        <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
+        <v>TraceTerm = term()</v>
+        <v>Opts = <seealso marker="#type-trace_opts">trace_opts()</seealso></v>
+        <v>Result = ok</v>
+      </type>
+      <desc>
+        <p>This callback is called when a tracepoint is triggered and the
+          <seealso marker="#Module:enabled_call/3">
+          <c>Module:enabled_call/3</c></seealso>
+          callback returned <c>trace</c>.</p>
+        <p>If <c>trace_call/5</c> is undefined,
+          <seealso marker="#Module:trace/5"><c>Module:trace/5</c></seealso>
+          is called instead.</p>
+      </desc>
     </func>
 
     <func>
-        <name>Module:trace_garbage_collection(TraceTag, TracerState, Tracee, TraceTerm, Opts) -> Result</name>
-        <fsummary>Check if a trace event should be generated.</fsummary>
-        <type>
-            <v>TraceTag = <seealso marker="#type-trace_tag_gc">trace_tag_gc()</seealso></v>
-            <v>TracerState = term()</v>
-            <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
-            <v>FirstTraceTerm = term()</v>
-            <v>Opts = <seealso marker="#type-trace_opts">trace_opts()</seealso></v>
-            <v>Result =  ok</v>
-        </type>
-        <desc>
-            <p>This callback will be called when a tracepoint is triggered and
-                the <seealso marker="#Module:enabled_garbage_collection/3">Module:enabled_garbage_collection/3</seealso>
-                callback returned <c>trace</c>.</p>
-            <p>If <c>trace_garbage_collection/5</c> is not defined <c>trace/5</c> will be called instead.</p>
-        </desc>
+      <name>Module:trace_garbage_collection(TraceTag, TracerState, Tracee,
+        TraceTerm, Opts) -> Result</name>
+      <fsummary>Check if a trace event is to be generated.</fsummary>
+      <type>
+        <v>TraceTag = <seealso marker="#type-trace_tag_gc">
+          trace_tag_gc()</seealso></v>
+        <v>TracerState = term()</v>
+        <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
+        <v>TraceTerm = term()</v>
+        <v>Opts = <seealso marker="#type-trace_opts">trace_opts()</seealso></v>
+        <v>Result = ok</v>
+      </type>
+      <desc>
+        <p>This callback is called when a tracepoint is triggered and the
+          <seealso marker="#Module:enabled_garbage_collection/3">
+          <c>Module:enabled_garbage_collection/3</c></seealso>
+          callback returned <c>trace</c>.</p>
+        <p>If <c>trace_garbage_collection/5</c> is undefined,
+          <seealso marker="#Module:trace/5"><c>Module:trace/5</c></seealso>
+          is called instead.</p>
+      </desc>
     </func>
 
     <func>
-        <name>Module:trace_ports(TraceTag, TracerState, Tracee, TraceTerm, Opts) -> Result</name>
-        <fsummary>Check if a trace event should be generated.</fsummary>
-        <type>
-            <v>TraceTag = <seealso marker="#type-trace_tag_ports">trace_tag()</seealso></v>
-            <v>TracerState = term()</v>
-            <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
-            <v>FirstTraceTerm = term()</v>
-            <v>Opts = <seealso marker="#type-trace_opts">trace_opts()</seealso></v>
-            <v>Result = ok</v>
-        </type>
-        <desc>
-            <p>This callback will be called when a tracepoint is triggered and
-                the <seealso marker="#Module:enabled_ports/3">Module:enabled_ports/3</seealso>
-                callback returned <c>trace</c>.</p>
-            <p>If <c>trace_ports/5</c> is not defined <c>trace/5</c> will be called instead.</p>
-        </desc>
+      <name>Module:trace_ports(TraceTag, TracerState, Tracee, TraceTerm,
+        Opts) -> Result</name>
+      <fsummary>Check if a trace event is to be generated.</fsummary>
+      <type>
+        <v>TraceTag = <seealso marker="#type-trace_tag_ports">
+          trace_tag()</seealso></v>
+        <v>TracerState = term()</v>
+        <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
+        <v>TraceTerm = term()</v>
+        <v>Opts = <seealso marker="#type-trace_opts">trace_opts()</seealso></v>
+        <v>Result = ok</v>
+      </type>
+      <desc>
+        <p>This callback is called when a tracepoint is triggered and the
+          <seealso marker="#Module:enabled_ports/3">
+          <c>Module:enabled_ports/3</c></seealso>
+          callback returned <c>trace</c>.</p>
+        <p>If <c>trace_ports/5</c> is undefined,
+          <seealso marker="#Module:trace/5"><c>Module:trace/5</c></seealso>
+          is called instead.</p>
+      </desc>
     </func>
 
     <func>
-        <name>Module:trace_procs(TraceTag, TracerState, Tracee, TraceTerm, Opts) -> Result</name>
-        <fsummary>Check if a trace event should be generated.</fsummary>
-        <type>
-            <v>TraceTag = <seealso marker="#type-trace_tag_procs">trace_tag()</seealso></v>
-            <v>TracerState = term()</v>
-            <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
-            <v>FirstTraceTerm = term()</v>
-            <v>Opts = <seealso marker="#type-trace_opts">trace_opts()</seealso></v>
-            <v>Result = ok</v>
-        </type>
-        <desc>
-            <p>This callback will be called when a tracepoint is triggered and
-                the <seealso marker="#Module:enabled_procs/3">Module:enabled_procs/3</seealso>
-                callback returned <c>trace</c>.</p>
-            <p>If <c>trace_procs/5</c> is not defined <c>trace/5</c> will be called instead.</p>
-        </desc>
+      <name>Module:trace_procs(TraceTag, TracerState, Tracee, TraceTerm,
+        Opts) -> Result</name>
+      <fsummary>Check if a trace event is to be generated.</fsummary>
+      <type>
+        <v>TraceTag = <seealso marker="#type-trace_tag_procs">
+          trace_tag()</seealso></v>
+        <v>TracerState = term()</v>
+        <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
+        <v>TraceTerm = term()</v>
+        <v>Opts = <seealso marker="#type-trace_opts">trace_opts()</seealso></v>
+        <v>Result = ok</v>
+      </type>
+      <desc>
+        <p>This callback is called when a tracepoint is triggered and the
+          <seealso marker="#Module:enabled_procs/3">
+          <c>Module:enabled_procs/3</c></seealso>
+          callback returned <c>trace</c>.</p>
+        <p>If <c>trace_procs/5</c> is undefined,
+          <seealso marker="#Module:trace/5"><c>Module:trace/5</c></seealso>
+          is called instead.</p>
+      </desc>
     </func>
 
     <func>
-        <name>Module:trace_receive(TraceTag, TracerState, Tracee, TraceTerm, Opts) -> Result</name>
-        <fsummary>Check if a trace event should be generated.</fsummary>
-        <type>
-            <v>TraceTag = <seealso marker="#type-trace_tag_receive">trace_tag_receive()</seealso></v>
-            <v>TracerState = term()</v>
-            <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
-            <v>FirstTraceTerm = term()</v>
-            <v>Opts = <seealso marker="#type-trace_opts">trace_opts()</seealso></v>
-            <v>Result =  ok</v>
-        </type>
-        <desc>
-            <p>This callback will be called when a tracepoint is triggered and
-                the <seealso marker="#Module:enabled_receive/3">Module:enabled_receive/3</seealso>
-                callback returned <c>trace</c>.</p>
-            <p>If <c>trace_receive/5</c> is not defined <c>trace/5</c> will be called instead.</p>
-        </desc>
+      <name>Module:trace_receive(TraceTag, TracerState, Tracee, TraceTerm,
+        Opts) -> Result</name>
+      <fsummary>Check if a trace event is to be generated.</fsummary>
+      <type>
+        <v>TraceTag = <seealso marker="#type-trace_tag_receive">
+          trace_tag_receive()</seealso></v>
+        <v>TracerState = term()</v>
+        <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
+        <v>TraceTerm = term()</v>
+        <v>Opts = <seealso marker="#type-trace_opts">trace_opts()</seealso></v>
+        <v>Result = ok</v>
+      </type>
+      <desc>
+        <p>This callback is called when a tracepoint is triggered and the
+          <seealso marker="#Module:enabled_receive/3">
+          <c>Module:enabled_receive/3</c></seealso>
+          callback returned <c>trace</c>.</p>
+        <p>If <c>trace_receive/5</c> is undefined,
+          <seealso marker="#Module:trace/5"><c>Module:trace/5</c></seealso>
+          is called instead.</p>
+      </desc>
     </func>
 
     <func>
-        <name>Module:trace_running_ports(TraceTag, TracerState, Tracee, TraceTerm, Opts) -> Result</name>
-        <fsummary>Check if a trace event should be generated.</fsummary>
-        <type>
-            <v>TraceTag = <seealso marker="#type-trace_tag_running_ports">trace_tag_running_ports()</seealso></v>
-            <v>TracerState = term()</v>
-            <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
-            <v>FirstTraceTerm = term()</v>
-            <v>Opts = <seealso marker="#type-trace_opts">trace_opts()</seealso></v>
-            <v>Result = ok</v>
-        </type>
-        <desc>
-            <p>This callback will be called when a tracepoint is triggered and
-                the <seealso marker="#Module:enabled_running_ports/3">Module:enabled_running_ports/3</seealso>
-                callback returned <c>trace</c>.</p>
-            <p>If <c>trace_running_ports/5</c> is not defined <c>trace/5</c> will be called instead.</p>
-        </desc>
+      <name>Module:trace_running_ports(TraceTag, TracerState, Tracee,
+        TraceTerm, Opts) -> Result</name>
+      <fsummary>Check if a trace event is to be generated.</fsummary>
+      <type>
+        <v>TraceTag = <seealso marker="#type-trace_tag_running_ports">
+          trace_tag_running_ports()</seealso></v>
+        <v>TracerState = term()</v>
+        <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
+        <v>TraceTerm = term()</v>
+        <v>Opts = <seealso marker="#type-trace_opts">trace_opts()</seealso></v>
+        <v>Result = ok</v>
+      </type>
+      <desc>
+        <p>This callback is called when a tracepoint is triggered and the
+          <seealso marker="#Module:enabled_running_ports/3">
+          <c>Module:enabled_running_ports/3</c></seealso>
+          callback returned <c>trace</c>.</p>
+        <p>If <c>trace_running_ports/5</c> is undefined,
+          <seealso marker="#Module:trace/5"><c>Module:trace/5</c></seealso>
+          is called instead.</p>
+      </desc>
     </func>
 
     <func>
-        <name>Module:trace_running_procs(TraceTag, TracerState, Tracee, TraceTerm, Opts) -> Result</name>
-        <fsummary>Check if a trace event should be generated.</fsummary>
-        <type>
-            <v>TraceTag = <seealso marker="#type-trace_tag_running_procs">trace_tag_running_procs()</seealso></v>
-            <v>TracerState = term()</v>
-            <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
-            <v>FirstTraceTerm = term()</v>
-            <v>Opts = <seealso marker="#type-trace_opts">trace_opts()</seealso></v>
-            <v>Result = ok</v>
-        </type>
-        <desc>
-            <p>This callback will be called when a tracepoint is triggered and
-                the <seealso marker="#Module:enabled_running_procs/3">Module:enabled_running_procs/3</seealso>
-                callback returned <c>trace</c>.</p>
-            <p>If <c>trace_running_procs/5</c> is not defined <c>trace/5</c> will be called instead.</p>
-        </desc>
+      <name>Module:trace_running_procs(TraceTag, TracerState, Tracee,
+        TraceTerm, Opts) -> Result</name>
+      <fsummary>Check if a trace event is to be generated.</fsummary>
+      <type>
+        <v>TraceTag = <seealso marker="#type-trace_tag_running_procs">
+          trace_tag_running_procs()</seealso></v>
+        <v>TracerState = term()</v>
+        <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
+        <v>TraceTerm = term()</v>
+        <v>Opts = <seealso marker="#type-trace_opts">trace_opts()</seealso></v>
+        <v>Result = ok</v>
+      </type>
+      <desc>
+        <p>This callback is called when a tracepoint is triggered and the
+          <seealso marker="#Module:enabled_running_procs/3">
+          <c>Module:enabled_running_procs/3</c></seealso>
+          callback returned <c>trace</c>.</p>
+        <p>If <c>trace_running_procs/5</c> is undefined,
+          <seealso marker="#Module:trace/5"><c>Module:trace/5</c></seealso>
+          is called instead.</p>
+      </desc>
     </func>
 
     <func>
-        <name>Module:trace_send(TraceTag, TracerState, Tracee, TraceTerm, Opts) -> Result</name>
-        <fsummary>Check if a trace event should be generated.</fsummary>
-        <type>
-            <v>TraceTag = <seealso marker="#type-trace_tag_send">trace_tag_send()</seealso></v>
-            <v>TracerState = term()</v>
-            <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
-            <v>FirstTraceTerm = term()</v>
-            <v>Opts = <seealso marker="#type-trace_opts">trace_opts()</seealso></v>
-            <v>Result =  ok</v>
-        </type>
-        <desc>
-            <p>This callback will be called when a tracepoint is triggered and
-                the <seealso marker="#Module:enabled_send/3">Module:enabled_send/3</seealso>
-                callback returned <c>trace</c>.</p>
-            <p>If <c>trace_send/5</c> is not defined <c>trace/5</c> will be called instead.</p>
-        </desc>
+      <name>Module:trace_send(TraceTag, TracerState, Tracee, TraceTerm,
+        Opts) -> Result</name>
+      <fsummary>Check if a trace event is to be generated.</fsummary>
+      <type>
+        <v>TraceTag = <seealso marker="#type-trace_tag_send">
+          trace_tag_send()</seealso></v>
+        <v>TracerState = term()</v>
+        <v>Tracee = <seealso marker="#type-tracee">tracee()</seealso></v>
+        <v>TraceTerm = term()</v>
+        <v>Opts = <seealso marker="#type-trace_opts">trace_opts()</seealso></v>
+        <v>Result = ok</v>
+      </type>
+      <desc>
+        <p>This callback is called when a tracepoint is triggered and the
+          <seealso marker="#Module:enabled_send/3">
+          <c>Module:enabled_send/3</c></seealso>
+          callback returned <c>trace</c>.</p>
+        <p>If <c>trace_send/5</c> is undefined,
+          <seealso marker="#Module:trace/5"><c>Module:trace/5</c></seealso>
+          is called instead.</p>
+      </desc>
     </func>
-
   </funcs>
+
   <section>
     <marker id="example"></marker>
-    <title>Erl Tracer Module example</title>
-    <p>In the example below a tracer module with a nif backend sends a message
-    for each <c>send</c> trace tag containing only the sender and receiver.
-    Using this tracer module, a much more lightweight message tracer is
-    used that only records who sent messages to who.</p>
-    <p>Here is an example session using it on Linux.</p>
+    <title>Erl Tracer Module Example</title>
+    <p>In this example, a tracer module with a NIF back end sends a
+      message for each <c>send</c> trace tag containing only the sender and
+      receiver. Using this tracer module, a much more lightweight message
+      tracer is used, which only records who sent messages to who.</p>
+
+    <p>The following is an example session using it on Linux:</p>
+
     <pre>
 $ gcc -I erts-8.0/include/ -fPIC -shared -o erl_msg_tracer.so erl_msg_tracer.c
 $ erl
@@ -533,9 +663,10 @@ ok
 {trace,#Port&lt;0.490&gt;,&lt;0.4.0&gt;}
 {ok,&lt;0.40.0&gt;}
 {trace,&lt;0.41.0&gt;,&lt;0.27.0&gt;}
-5&gt;
-    </pre>
-    <p>erl_msg_tracer.erl</p>
+5&gt;</pre>
+
+    <p><c>erl_msg_tracer.erl</c>:</p>
+
     <pre>
 -module(erl_msg_tracer).
 
@@ -547,10 +678,11 @@ load() ->
 enabled(_, _, _) ->
     error.
 
-trace(_, _, _,_, _) ->
-    error.
-    </pre>
-    <p>erl_msg_tracer.c</p>
+trace(_, _, _, _, _) ->
+    error.</pre>
+
+    <p><c>erl_msg_tracer.c</c>:</p>
+
     <pre>
 #include "erl_nif.h"
 
@@ -641,7 +773,6 @@ static ERL_NIF_TERM trace(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
     }
 
     return enif_make_atom(env, "ok");
-}
-    </pre>
+}</pre>
   </section>
 </erlref>