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<concept id="GUID-8BEE0411-C6E9-5840-BE22-EC271A4D97DD" xml:lang="en"><title>OpenWF
Composition Engine Component Overview</title><shortdesc>The OpenWF Composition (OpenWF-C) Engine component consists of
a reference implementation of the OpenWF-C Interface. Device creators can
replace the Symbian platform implementation with their own. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
<p><b>Target audience</b>: Device creators. </p>
<p>The Symbian reference implementation is a pure software implementation
that is based on the Khronos sample OpenWF-C implementation, which was developed
by Ardites. The Symbian implementation has not been optimized for speed or
memory usage. Device creators can use all or part of the reference implementation
when they create their own implementations or they can replace it completely. </p>
<p>An OpenWF-C implementation must implement the public APIs defined by the <xref href="GUID-3B9AC7E9-3133-505F-9C1E-EB4BB4969838.dita">OpenWF-C interface</xref>.
An OpenWF-C implementation can also implement extension functions. Clients
obtain extension functions by using <xref href="GUID-9887B071-1DA4-3882-B9C7-A229C29A05C3.dita"><apiname>eglGetProcAddress()</apiname></xref>. </p>
<p> <xref href="GUID-9887B071-1DA4-3882-B9C7-A229C29A05C3.dita"><apiname>eglGetProcAddress()</apiname></xref> uses the first exported OpenWF-C
function to fill in a table of pointers to the OpenWF-C extension functions.
The OpenWF-C implementation must therefore export at ordinal position one
a function that provides pointers to all of the implemented extension functions. </p>
<p>In order to be able to claim that an OpenWF-C implementation conforms to
the Khronos standard, it must pass the relevant conformance tests. The OpenWF-C
conformance tests have been ported to Symbian and are available through the
Khronos website to those who have an appropriate license. However, you may
need to adapt the conformance test's porting layer further to make it work
with your implementation. </p>
</conbody><related-links>
<link href="GUID-8FE41C9A-8171-58A2-A808-17B81E79B11F.dita"><linktext>OpenWF Composition</linktext>
</link>
</related-links></concept>