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-rw-r--r--erts/doc/src/match_spec.xml54
1 files changed, 48 insertions, 6 deletions
diff --git a/erts/doc/src/match_spec.xml b/erts/doc/src/match_spec.xml
index 08dad8cc10..3944f24f84 100644
--- a/erts/doc/src/match_spec.xml
+++ b/erts/doc/src/match_spec.xml
@@ -4,7 +4,7 @@
<chapter>
<header>
<copyright>
- <year>1999</year><year>2013</year>
+ <year>1999</year><year>2016</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
@@ -287,7 +287,7 @@
can <em>not</em> be one of the atoms <c><![CDATA[all]]></c>, <c><![CDATA[new]]></c> or
<c><![CDATA[existing]]></c> (unless, of course, they are registered names).
<c><![CDATA[P2]]></c> can <em>not</em> be <c><![CDATA[cpu_timestamp]]></c> nor
- <c><![CDATA[{tracer,_}]]></c>.
+ <c><![CDATA[tracer]]></c>.
Returns <c><![CDATA[true]]></c> and may only be used in
the <c><![CDATA[MatchBody]]></c> part when tracing.
</p>
@@ -298,7 +298,7 @@
be either a process identifier or a registered name and is given
as the first argument to the match_spec function.
<c><![CDATA[P2]]></c> can <em>not</em> be <c><![CDATA[cpu_timestamp]]></c> nor
- <c><![CDATA[{tracer,_}]]></c>. Returns
+ <c><![CDATA[tracer]]></c>. Returns
<c><![CDATA[true]]></c> and may only be used in the <c><![CDATA[MatchBody]]></c> part
when tracing.
</p>
@@ -308,11 +308,14 @@
disable list is applied first, but effectively all changes
are applied atomically. The trace flags
are the same as for <c><![CDATA[erlang:trace/3]]></c> not including
- <c><![CDATA[cpu_timestamp]]></c> but including <c><![CDATA[{tracer,_}]]></c>. If a
+ <c><![CDATA[cpu_timestamp]]></c> but including <c><![CDATA[tracer]]></c>. If a
tracer is specified in both lists, the tracer in the
enable list takes precedence. If no tracer is specified the
same tracer as the process executing the match spec is
- used. With three parameters to this function the first is
+ used. When using a <seealso marker="erl_tracer">tracer module</seealso>
+ the module has to be loaded before the match specification is executed.
+ If it is not loaded the match will fail.
+ With three parameters to this function the first is
either a process identifier or the registered name of a
process to set trace flags on, the second is the disable
list, and the third is the enable list. Returns
@@ -525,7 +528,7 @@
</section>
<section>
- <title>Examples</title>
+ <title>ETS Examples</title>
<p>Match an argument list of three where the first and third arguments
are equal:</p>
<code type="none"><![CDATA[
@@ -616,5 +619,44 @@
<p>The function <c><![CDATA[ets:test_ms/2]]></c> can be useful for testing
complicated ets matches.</p>
</section>
+ <section>
+ <title>Tracing Examples</title>
+ <p>Only generate trace message if trace control word is set to 1:</p>
+ <code type="none"><![CDATA[
+[{'_',
+ [{'==',{get_tcw},{const, 1}}],
+ []}]
+ ]]></code>
+ <p>Only generate trace message if there is a seq trace token:</p>
+ <code type="none"><![CDATA[
+[{'_',
+ [{'==',{is_seq_trace},{const, 1}}],
+ []}]
+ ]]></code>
+ <p>Remove 'silent' trace flag when first argument is 'verbose'
+ and add it when it is 'silent':</p>
+ <code type="none"><![CDATA[
+[{'$1',
+ [{'==',{hd, '$1'},verbose}],
+ [{trace, [silent],[]}]},
+ {'$1',
+ [{'==',{hd, '$1'},silent}],
+ [{trace, [],[silent]}]}]
+ ]]></code>
+ <p>Add return_trace message if function is of arity 3:</p>
+ <code type="none"><![CDATA[
+[{'$1',
+ [{'==',{length, '$1'},3}],
+ [{return_trace}]},
+ {'_',[],[]}]
+ ]]></code>
+ <p>Only generate trace message if function is of arity 3 and first argument is 'trace':</p>
+ <code type="none"><![CDATA[
+[{['trace','$2','$3'],
+ [],
+ []},
+ {'_',[],[]}]
+ ]]></code>
+ </section>
</chapter>