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

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

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

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

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

requirement. </p>

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

traces:</p><ul>

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

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

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

component is executed, provided the trace configuration tool is configured

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

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

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

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

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

according to the scenarios presented in the Relationship between primary and

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

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

</ul> </section>

</conbody><related-links>

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

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