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    10 <!DOCTYPE concept

    11   PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">

    12 <concept id="GUID-D5984540-A411-52ED-B435-94C67F34ADD5" xml:lang="en"><title>How

    13 to Enable Tracing</title><prolog><metadata><keywords/></metadata></prolog><conbody>

    14 <p>Enabling a trace means that the trace adds trace packets to the output.

    15 A disabled trace adds no trace packets to the output. There are two options

    16 to enable tracing in the source code or component, depending on the tracing

    17 requirement. </p>

    18 <section><title>Enabling traces during build-time</title> <p>To enable tracing

    19 at build-time, the Instrumentor has to include the <codeph>#define SYMBIAN_TRACE_ENABLE</codeph> flag

    20 in the relevant source code (file) of the project. If it is not included,

    21 all traces will be excluded at the build time and it will not be possible

    22 for a Trace Collector to gather any trace information regardless of the filter

    23 settings in trace configuration tool. </p> <p>If the requirement is to enable

    24 tracing in all the files in an executable, the Instrumentor can achieve this

    25 by adding <codeph>MACRO           SYMBIAN_TRACE_ENABLE</codeph> to the MMP

    26 file of the project. </p> </section>

    27 <section><title>Enabling traces during run-time</title> <p>To enable tracing

    28 at run-time, the Instrumentor has to have enabled traces at the build-time.

    29 That is, if the traces are enabled at build-time, the Trace Collector can

    30 enable or disable any traces at run-time. But if the traces for a particular

    31 component are disabled at build-time, the Trace Collector cannot enable them

    32 at run-time. </p><p><b>Considerations</b></p><p>Before enabling trace points,

    33 the Trace Collector has to consider the  following two options of outputting

    34 traces:</p><ul>

    35 <li><p><b>Outputting all traces from a component or a set of components:</b> After

    36 the traces have been enabled at build time by the Instrumentor, the Trace

    37 Collector will be able to generate the trace packets when the instrumented

    38 component is executed, provided the trace configuration tool is configured

    39 to filter in all of these traces. </p></li>

    40 <li><p><b>Outputting some of the traces (subset) from one or more components:</b> The

    41 Trace Collector can achieve this by enabling or disabling the predefined primary

    42 and secondary filter combination used within the instrumented component. </p><p>The

    43 Trace Collector is able to turn on any combination of filters for a component,

    44 according to the scenarios presented in the Relationship between primary and

    45 secondary filters section in <xref href="GUID-715D065D-4FF7-55D0-882E-3B37F36369C4.dita#GUID-715D065D-4FF7-55D0-882E-3B37F36369C4/GUID-A7E551D1-DED5-5BC7-A19F-523B65B2AE00">Key

    46 concepts and terms</xref>. </p></li>

    47 </ul> </section>

    48 </conbody><related-links>

    49 <link href="GUID-AFB1F350-C5D3-5495-AE20-1AA6888B6FB1.dita"><linktext>How to insert

    50 trace points in a component</linktext></link>

    51 </related-links></concept>