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<concept id="GUID-79735B25-B4E9-5166-B87A-054080DF9122" xml:lang="en"><title>Patchable

Constants: KDiscoveryDisabledDriveList</title><prolog><metadata><keywords/></metadata></prolog><conbody>

<codeblock id="GUID-11409345-54FC-5483-BED6-6C3AFFC19B91" xml:space="preserve"># define ECOM_PATCHDATA_KDISCOVERYDISABLEDDRIVELIST 0x0

</codeblock>

<table id="GUID-761B3924-D3BE-5568-AEFA-C1D4B4D73AF3">

<tgroup cols="2"><colspec colname="col0"/><colspec colname="col1"/>

<tbody>

<row>

<entry><p>Defined in: </p> </entry>

<entry><p> <filepath>                 .../os/ossrv/lowlevellibsandfws/pluginfw/framework/frame/ecompatchdataconstantv2.cpp</filepath> </p> </entry>

</row>

<row>

<entry><p>Purpose: </p> </entry>

<entry><p>This constant lets device creators specify which drives they do

not want ECom to scan, perhaps because of a platform decision not to support

plugins (or any kind of executable binary) on certain drives e.g. MMC cards.

Note that the Read Only Internal <filepath>Z:</filepath> drive cannot be disabled. </p> <p> <codeph> KDiscoveryDisabledDriveList</codeph> is

a 32-bit integer with each bit representing a drive to disable, e.g. <codeph>0x1</codeph> disables

drive A, <codeph>0x2</codeph> disables drive B etc. Only 25 drives can be

specified (<filepath>Z:</filepath> is not allowed) therefore the 7 most significant

bits are ignored. If you want to disable scanning on drives <filepath>E:</filepath> and <filepath>K:</filepath>,

the patched value is: </p> <codeblock id="GUID-14A08DB9-FFB8-5E1C-8952-9713086A166F" xml:space="preserve">1 &lt;&lt; EDriveE | 1 &lt;&lt; EDriveK = 0x00000410.

</codeblock> <p>See <filepath>f32file.h</filepath> for the enum <codeph>TDriveNumber</codeph>. </p> </entry>

</row>

</tbody>

</tgroup>

</table>

<p>ECom uses a customized scheme to handle patchable constants. Device creators

should follow the scheme described below to set patch values: </p>

<ul>

<li id="GUID-CACEB241-0ADE-5BC1-89E9-D84E68A4A6E7"><p>Each patchable constant

is represented by a macro listed in <filepath>\epoc32\rom\include\ecompatchconstants.hby</filepath>.

The macros in the HBY file are all commented out. </p> </li>

<li id="GUID-C170972B-B993-58F5-98A3-78E92A855ABC"><p>To activate a patch

macro, uncomment the line and change the example value in the line to your

custom value. </p> </li>

</ul>

</conbody></concept>