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<concept id="GUID-2022F702-9899-5798-8932-D70119C7177D" xml:lang="en"><title>Setting

Up A Log Engine Client </title><shortdesc>This tutorial describes how to set up a Log Engine client. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

<section id="GUID-4EAACF43-7B17-522C-A617-96C15971EBCA"><title>Introduction</title> <p>If

you are certain that you are coding for a platform with logging functionality

you create a custom class with some such name as <xref href="GUID-3016DE27-6C94-3119-B174-831B67B09B27.dita"><apiname>CMyLogEngine</apiname></xref>.

It should have members of the classes <xref href="GUID-51C67545-12BA-326D-BD8F-662B24C68ED2.dita"><apiname>CLogClient</apiname></xref>, <xref href="GUID-3A3E6F09-0F78-38E1-95F5-00C743F41073.dita"><apiname>CLogViewEvent</apiname></xref>, <xref href="GUID-F40F9556-F223-36A5-9812-6EF6FF3F5156.dita"><apiname>CLogViewRecent</apiname></xref> and <xref href="GUID-99144BA6-F79A-3D3C-B1D3-272B3723C42C.dita"><apiname>CLogFilter</apiname></xref> and an observer of some kind. The functions of your

custom class will use the functionality of these classes by calls to the member

objects. </p> <p>If you are not certain that your platform will provide logging

functionality you must use a log wrapper framework. Write a custom class to

use the log wrapper functionality with some such name as <codeph>myLogWrapper</codeph>.

It should have two members which own <xref href="GUID-146D719E-BDD6-3F20-80B1-EDE09081A6EA.dita"><apiname>CLogWrapper</apiname></xref> and <xref href="GUID-51C67545-12BA-326D-BD8F-662B24C68ED2.dita"><apiname>CLogClient</apiname></xref> objects.

In the constructor function of <codeph>myLogWrapper</codeph> call the <xref href="GUID-51862DAE-2285-352F-B66E-B2544638E30E.dita"><apiname>ClientAvailable()</apiname></xref> function

of <xref href="GUID-146D719E-BDD6-3F20-80B1-EDE09081A6EA.dita"><apiname>CLogWrapper</apiname></xref> to determine whether logging functionality

is present. If so, construct the <xref href="GUID-51C67545-12BA-326D-BD8F-662B24C68ED2.dita"><apiname>CLogClient</apiname></xref> member: if

not, leave. The effect of this is that calls to the log client functionality

of <codeph>myLogWrapper</codeph> will access an actual log client if the functionality

is available. However, if the functionality is not available calls to the

log client functionality will either have no effect or else leave as in this

example code. </p> </section>

<section id="GUID-00974547-A3DC-442C-B50C-1C8E7180B8A4"><title>Procedure</title> <ol id="GUID-F8F83C3B-A722-5C79-B286-F48F51019524">

<li id="GUID-7F2D3FBF-E541-530D-9A56-3C49A1D006E2"><p>Create a custom class <xref href="GUID-3016DE27-6C94-3119-B174-831B67B09B27.dita"><apiname>CMyLogEngine</apiname></xref>  </p> </li>

<li id="GUID-DFCDEC1F-3B62-5A65-97DB-E63DC68BFEED"><p>Declare the members <xref href="GUID-51C67545-12BA-326D-BD8F-662B24C68ED2.dita"><apiname>CLogClient</apiname></xref>, <xref href="GUID-3A3E6F09-0F78-38E1-95F5-00C743F41073.dita"><apiname>CLogViewEvent</apiname></xref>, <xref href="GUID-F40F9556-F223-36A5-9812-6EF6FF3F5156.dita"><apiname>CLogViewRecent</apiname></xref> and <xref href="GUID-99144BA6-F79A-3D3C-B1D3-272B3723C42C.dita"><apiname>CLogFilter</apiname></xref> in the header

file of the client application </p> </li>

<li id="GUID-3471D668-8369-5458-B436-FD8344988065"><p>Declare <xref href="GUID-BD2669C7-AE36-3AA8-AAAE-A2F01A319369.dita"><apiname>ConstrucL()</apiname></xref> function

in the header file of the client application </p> </li>

<li id="GUID-5B55236A-F7C8-54FB-B0E9-D3CAC99ADDF0"><p>Implement <xref href="GUID-C8E0575D-5A7F-3D00-9BE5-AD8D6DBCF2F7.dita"><apiname>ConstructL()</apiname></xref> function </p> <ol id="GUID-B6FFC684-372C-5FC3-9035-B7A0FF4B884E">

<li id="GUID-8FAB2EEA-79D9-5572-B2F2-15057B860366"><p>Establish a connection

to the Log Engine </p> <p><codeblock id="GUID-CDFA500C-FB18-5713-B4F9-7D355D107122" xml:space="preserve">    iLogClient = CLogClient::NewL(iFs);</codeblock> </p> </li>

<li id="GUID-E8DFFAD0-506E-5752-B51D-52153AEADD37"><p>get the log events using <codeph>CLogViewEvent</codeph>  </p> <p><codeblock id="GUID-55F3DE8A-FAC5-5C9F-8931-55CA7838A8F2" xml:space="preserve">iLogViewEvent = CLogViewEvent::NewL(*iLogClient);</codeblock> </p> </li>

<li id="GUID-7CF80109-CA54-549F-A46D-3C950DAC1711"><p>get the log of recent

events using <xref href="GUID-F40F9556-F223-36A5-9812-6EF6FF3F5156.dita"><apiname>CLogViewRecent</apiname></xref>  </p> <p><codeblock id="GUID-3406E92A-432B-57E6-B6A2-3D63C4EC0B72" xml:space="preserve">iLogViewRecent = CLogViewRecent::NewL(*iLogClient);</codeblock> </p> </li>

<li id="GUID-F9DB43F5-F69D-50D1-B287-EFC85DA9828E"><p>add a log filter using <xref href="GUID-99144BA6-F79A-3D3C-B1D3-272B3723C42C.dita"><apiname>CLogFilter</apiname></xref>  </p> <p><codeblock id="GUID-F90E0B70-AC53-54B9-93B4-26B33A919B33" xml:space="preserve">iLogFilter = CLogFilter::NewL();</codeblock> </p> </li>

</ol> </li>

</ol> </section>

<section id="GUID-BE0D8C52-2FCA-45F2-9BEF-42D5F8CCD4F9"><title>Result</title> <p>The

client applications can use the log events to be displayed to the user or

for other used as a data for further processing. </p> </section>

<example id="GUID-22EAC40F-881C-5AC0-B919-016E502CC7E6"><title>Log engine

client example</title> <p>Example code for a Log Engine client on a platform

with logging functionality </p> <codeblock id="GUID-2C393B78-BAA0-5893-9A6A-9DC9D76749B6" xml:space="preserve">void CMyLogEngine::ConstructL()

    {

    // Establish connection to log engine

    iLogClient = CLogClient::NewL(iFs);

    // Log view and view for recent events with standard priority

    iLogViewEvent = CLogViewEvent::NewL(*iLogClient);

    iLogViewRecent = CLogViewRecent::NewL(*iLogClient);

    // Filter for events

    iLogFilter = CLogFilter::NewL();

</codeblock> <p>Example code for a Log Engine client using a wrapper framework </p> <codeblock id="GUID-A409E255-3B0B-51C9-9633-010608E07122" xml:space="preserve">void CMyLogWrapper::ConstructL(RFs&amp; aFs)

     {

     // create the CLogWrapper to forward requests to.

     iLogWrapper = CLogWrapper::NewL(aFs);

     if (iLogWrapper->ClientAvailable())

         {

         iLogClient = static_cast<CLogClient*>(&iLogWrapper->Log());

         }

     else

         {

         User::Leave(KErrNotSupported);

         }

     }

</codeblock> <p>You can now use <codeph>myLogWrapper</codeph> as if it was

a log client. </p> </example>

</conbody><related-links>

<link href="GUID-E4A950EA-5671-5755-B3EF-5D6B90E19AE6.dita"><linktext>Maintaining

Log Events</linktext></link>

<link href="GUID-BE65B3A7-04E8-5406-B46A-09E2608E0F1F.dita"><linktext>Requesting

Log Engine Notifications</linktext></link>

<link href="GUID-55ECBCF5-FC29-5A4A-A3C6-1CB1C0D562CE.dita"><linktext>Displaying

Log Events</linktext></link>

<link href="GUID-BCB0E50F-B22E-5964-BB68-BEE1870D9C79.dita"><linktext>Configuring

Log Engine </linktext></link>