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<!-- ================================ SYNOPSIS -->
<refnamediv id="clCreateFromGLBuffer">
Creates a linked event object.
<refsynopsisdiv xmlns:xlink=""><title></title>
<link xlink:href="abstractDataTypes.html">cl_event</link>
<paramdef><link xlink:href="abstractDataTypes.html">cl_context</link><parameter>context</parameter></paramdef>
<paramdef><link xlink:href="scalarDataTypes.html">cl_int</link><parameter>*errcode_ret</parameter></paramdef>
<!-- ================================ PARAMETERS -->
<refsect1 id="parameters">
<term> <varname> context </varname> </term>
<!-- parameter description --> A valid OpenCL context
created from an OpenGL context or share group, using the
<term> <varname> sync </varname> </term>
<para> <!-- parameter description -->
The name of a sync object of type <constant>EGL_SYNC_FENCE_KHR</constant>
created with respect to EGLDisplay <varname>display</varname>.
<!-- ================================ DESCRIPTION -->
<refsect1 id="description"><title>Description</title>
An event object may be created by linking to an EGL sync object. Completion of such an event
object is equivalent to waiting for completion of the fence command associated with the linked
EGL sync object.
<!-- ================================ NOTES -->
<refsect1 id="notes"><title>Notes</title>
The parameters of an event object linked to
an EGL sync object will return the following values
when queried with
The <constant>CL_EVENT_COMMAND_QUEUE</constant> of
a linked event is NULL, because the event is not
associated with any OpenCL command queue.
The <constant>CL_EVENT_COMMAND_TYPE</constant> of a linked event is
<constant>CL_COMMAND_EGL_FENCE_SYNC_OBJECT_KHR</constant>, indicating that the event is
associated with a EGL sync object, rather than an OpenCL command.
of a linked event is either
<constant>CL_SUBMITTED</constant>, indicating that the
fence command associated with the sync object has
not yet completed, or <constant>CL_COMPLETE</constant>,
indicating that the fence command has completed.
<function>clCreateEventFromEGLSyncKHR</function> performs an implicit
on the returned event
object. Creating a linked event object also
places a reference on the linked EGL sync object.
When the event object is deleted, the reference
will be removed from the EGL sync object.
Events returned from <function>clCreateEventFromEGLSyncKHR</function>
may only be consumed by
<function>clEnqueueAcquire***</function> commands.
Passing such events to any other CL API that enqueues
commands will generate a <errorname>CL_INVALID_EVENT</errorname> error."
Event objects can also be used to reflect the status
of an EGL fence sync object. The sync object
in turn refers to a fence command executing in
an EGL client API command stream. This
provides another method of coordinating sharing
of EGL / EGL client API objects with OpenCL.
Completion of EGL / EGL client API commands may
be determined by placing an EGL fence
command after commands using <function>eglCreateSyncKHR</function>,
creating an event from the resulting EGL
sync object using
and then specifying it in the <varname>event_wait_list</varname>
of a <function>clEnqueueAcquire***</function> command.
This method may be considerably more efficient than
calling operations like <function>glFinish</function>,
and is referred to as <emphasis>explicit synchronization</emphasis>.
The application is
responsible for ensuring the command stream
associated with the EGL fence is flushed to ensure
the CL queue is submitted to the device.
Explicit synchronization is most useful when an EGL
client API context bound to another thread
is accessing the memory objects.
<!-- ================================ ERRORS -->
<refsect1 id="errors"><title>Errors</title>
Returns a valid OpenCL event object and <varname>errcode_ret</varname> is set to
<errorname>CL_SUCCESS</errorname> if the event object is created successfully.
Otherwise, it returns a NULL value with one of the following error values returned
in <varname>errcode_ret</varname>:
<itemizedlist mark="disc">
<errorname>CL_INVALID_CONTEXT</errorname> if <varname>context</varname> is not
a valid context or was not created from a GL context.
<errorname>CL_INVALID_EGL_OBJECT_KHR</errorname> if <varname>sync</varname>
is not a valid EGLSyncKHR handle created with
respect to EGLDisplay <varname>display</varname>.
<errorname>CL_INVALID_EGL_OBJECT_KHR</errorname> if <varname>sync</varname>
is not a valid EGLSyncKHR object of type
<constant>EGL_SYNC_FENCE_KHR</constant> created with
respect to EGLDisplay <varname>display</varname>.
<!-- ================================ EXAMPLE -->
<refsect2 id="example1">
<informaltable frame="none">
<tgroup cols="1" align="left" colsep="0" rowsep="0">
<colspec colname="col1" colnum="1" />
Example goes here - it will be set in "code" type with white space preserved.
<!-- ================================ SPECIFICATION -->
<!-- Set the "uri" attribute in the <olink /> element to the "named destination" for the PDF page
<refsect1 id="specification"><title>Specification</title>
<imagedata fileref="pdficon_small1.gif" format="gif" />
<olink uri="clCreateEventFromEGLSyncKHR">OpenCL Specification</olink>
<!-- ================================ ALSO SEE -->
<refsect1 id="seealso"><title>Also see</title>
<!-- ============================== COPYRIGHT -->
<!-- Content included from -->
<refsect3 id="Copyright"><title></title>
<imagedata fileref="KhronosLogo.jpg" format="jpg" />
<para />
<!-- 4-Nov-2015, API ver 2.1 rev 19; Ext ver 2.1 rev 10; C lang ver 2.0 rev 30 -->