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<task id="GUID-57A909F3-EAEA-5FE2-B620-E21204794497" xml:lang="en"><title>How
to Load the Physical Device Driver and Logical Device Driver: Tutorial</title><shortdesc>When testing using the console, all drivers need to be loaded directly.
This tutorial describes how to load the drivers required for the Serial Communications
Server. </shortdesc><prolog><metadata><keywords/></metadata></prolog><taskbody>
<context><p>Testing of communications software can be done using the Symbian
OS console shell interface rather than a GUI interface. The console shell
interface has advantages when testing since the console allows software to
be tested in isolation. When testing with a GUI interface the testing can
be difficult if other software in the GUI is attempting to access resources.
If the device or the emulator is started with just the console, then only
the kernel and file system are running. The tester can then load the software
required for the test and ensure that no other software is using any resources.
This avoids problems of other software interrupting the CPU or using and releasing
memory or other hardware while a test is running. </p><p>Any test applications
that have not been launched by the GUI should
 explicitly load the correct physical and logical device drivers. In most
cases the bootloader will load the physical device driver. It is safe to load
a
device driver which has already been loaded, since the API will return
<xref href="GUID-D1D25122-F2B8-3C78-8599-84905BFD47B8.dita"><apiname>KErrAlreadyExists</apiname></xref></p> </context>
<steps id="GUID-8D0D239F-51F9-512A-8405-ADD01AE1660B">
<step id="GUID-21876E62-D2A9-510A-BAD2-CB3E4271A02B"><cmd>Identify the names
of the physical and logical device drivers required.</cmd>
<info><p> The names of device drivers change since variations are created
for different platforms: the ecuart and infra-red logical device driver is
usually called <filepath>ECOMM</filepath> while the USB logical device driver
is usually called <filepath>EUSBC</filepath>. For fast infra-red the logical
device driver is usually called <filepath>EFIR</filepath>. For ecuart, infra-red
and USB the physical device driver is usually called <filepath>ECDRV</filepath> on
the emulator. For devices the physical device drivers have a variety of names.
The euart and USB the physical device driver is usually called <filepath>EUART</filepath> or <filepath>EUART</filepath> with
a number for each port from base 1, for example <filepath>EUART1</filepath> and <filepath>EUART2</filepath>.
For infra-red the physical device driver is usually called <filepath>EUART2</filepath>.
For fast infra-red the physical device driver is usually called <filepath>DIFIR</filepath> for
both emulator and devices. </p></info>
</step>
<step id="GUID-AE7AFB08-535A-5195-AF0D-4401390D8518"><cmd>Call <xref href="GUID-C197C9A7-EA05-3F24-9854-542E984C612D.dita#GUID-C197C9A7-EA05-3F24-9854-542E984C612D/GUID-1D773C95-A0DE-38EC-85BA-82162B2DC62E"><apiname>User::LoadPhysicalDevice</apiname></xref> to
load the physical device driver and check the return code.</cmd>
<info>A return code of <codeph>KErrAlreadyExists</codeph> can be ignored. </info>
</step>
<step id="GUID-CE68C060-4A44-5547-9DE6-A81DEAC367B1"><cmd>Call <xref href="GUID-C197C9A7-EA05-3F24-9854-542E984C612D.dita#GUID-C197C9A7-EA05-3F24-9854-542E984C612D/GUID-68D7C877-B611-3FCC-B85D-708501C1B66C"><apiname>User::LoadLogicalDevice</apiname></xref> to
load the logical device driver and check the return code. </cmd>
<info>A return code of <codeph>KErrAlreadyExists</codeph> can be ignored. </info>
</step>
<step id="GUID-E3332825-E22D-5D90-AA89-A6FD20500A9D"><cmd>Start the <xref href="GUID-2FED5145-58E4-5560-8E52-6BD499EECE13.dita">RootServer</xref> by calling <xref href="GUID-CFCBC5A6-FB1F-3DD7-B275-9B9C7389A8A7.dita"><apiname>StartC32()</apiname></xref>.</cmd>
<info> The RootServer loads the Serial Communications Server. </info>
</step>
</steps>
<example><title>Example</title> <codeblock id="GUID-B45CC19A-856B-54C2-84BD-840E72391F20" xml:space="preserve">#if defined (__WINS__)
    #define PDD_NAME _L("ECDRV")
#else
    #define PDD_NAME _L("EUART1")
#endif
#define LDD_NAME _L("ECOMM")
TInt r = User::LoadPhysicalDevice (PDD_NAME);
if (r != KErrNone &amp;&amp; r != KErrAlreadyExists) 
    {
    User::Leave(r);
    }
r = User::LoadLogicalDevice (LDD_NAME);
if (r != KErrNone &amp;&amp; r != KErrAlreadyExists) 
    {
    User::Leave(r);
    }

r = StartC32(); 
User::LeaveIfError(r);</codeblock> </example>
</taskbody><related-links>
<link href="GUID-D90C86C6-B85D-5941-9919-3725A9FFD548.dita"><linktext>Text shell
(eshell)</linktext></link>
</related-links></task>