Ubuntu Manpage: clEnqueueAcquireGLObjects - Acquire OpenCL memory objects that have been created from

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NAME

       clEnqueueAcquireGLObjects - Acquire OpenCL memory objects that have been created from
       OpenGL objects.

       cl_int clEnqueueAcquireGLObjects(cl_command_queue command_queue, cl_uint num_objects,
                                        const cl_mem *mem_objects,
                                        cl_uint num_events_in_wait_list,
                                        const cl_event *event_wait_list, cl_event *event);

PARAMETERS

command_queue
A valid command-queue. All devices used to create the OpenCL context associated with
command_queue must support acquiring shared CL/GL objects. This constraint is enforced
at context creation time.

num_objects
The number of memory objects to be acquired in mem_objects.

mem_objects
A pointer to a list of CL memory objects that correspond to GL objects.

event_wait_list , num_events_in_wait_list

and Specify events that need to complete before this particular command can be
executed. If event_wait_list is NULL, then this particular command does not wait on
any event to complete. If event_wait_list is NULL, num_events_in_wait_list must be 0.
If event_wait_list is not NULL, the list of events pointed to by event_wait_list must
be valid and num_events_in_wait_list must be greater than 0. The events specified in
event_wait_list act as synchronization points.

event
Returns an event object that identifies this command and can be used to query or queue
a wait for the command to complete. event can be NULL in which case it will not be
possible for the application to query the status of this command or queue a wait for
this command to complete. If the event_wait_list and the event arguments are not NULL,
the event argument should not refer to an element of the event_wait_list array

If the cl_khr_gl_sharing(3clc) extension is supported, if an OpenGL context is bound
to the current thread, then any OpenGL commands which

· affect or access the contents of a memory object listed in the mem_objects list,
and

· were issued on that OpenGL context prior to the call to
clEnqueueAcquireGLObjects.RE

will complete before execution of any OpenCL commands following the
clEnqueueAcquireGLObjects which affect or access any of those memory objects. If a
non-NULL event object is returned, it will report completion only after completion
of such OpenGL commands.

DESCRIPTION

       These objects need to be acquired before they can be used by any OpenCL commands queued to
       a command-queue. The OpenGL objects are acquired by the OpenCL context associated with
       command_queue and can therefore be used by all command-queues associated with the OpenCL
       context.

NOTES

In order to ensure data integrity, the application is responsible for synchronizing access
to shared CL/GL objects by their respective APIs. Failure to provide such synchronization
may result in race conditions and other undefined behavior including non-portability
between implementations.

Prior to calling clEnqueueAcquireGLObjects, the application must ensure that any pending
GL operations which access the objects specified in mem_objects have completed. This may
be accomplished portably by issuing and waiting for completion of a glFinish command on
all GL contexts with pending references to these objects. Implementations may offer more
efficient synchronization methods; for example on some platforms calling glFlush may be
sufficient, or synchronization may be implicit within a thread, or there may be
vendor-specific extensions that enable placing a fence in the GL command stream and
waiting for completion of that fence in the CL command queue. Note that no synchronization
methods other than glFinish are portable between OpenGL implementations at this time.

Similarly, after calling clEnqueueReleaseGLObjects, the application is responsible for
ensuring that any pending OpenCL operations which access the objects specified in
mem_objects have completed prior to executing subsequent GL commands which reference these
objects. This may be accomplished portably by calling clWaitForEvents(3clc) with the event
object returned by clEnqueueReleaseGLObjects, or by calling clFinish(3clc). As above, some
implementations may offer more efficient methods.

The application is responsible for maintaining the proper order of operations if the CL
and GL contexts are in separate threads.

If a GL context is bound to a thread other than the one in which clEnqueueReleaseGLObjects
is called, changes to any of the objects in mem_objects may not be visible to that context
without additional steps being taken by the application. For an OpenGL 3.1 (or later)
context, the requirements are described in Appendix D ("Shared Objects and Multiple
Contexts") of the OpenGL 3.1 Specification. For prior versions of OpenGL, the requirements
are implementation-dependent.

Attempting to access the data store of an OpenGL object after it has been acquired by
OpenCL and before it has been released will result in undefined behavior. Similarly,
attempting to access a shared CL/GL object from OpenCL before it has been acquired by the
OpenCL command queue, or after it has been released, will result in undefined behavior.

If the cl_khr_gl_event(3clc) extension is supported, then the OpenCL implementation will
ensure that any such pending OpenGL operations are complete for an OpenGL context bound to
the same thread as the OpenCL context. This is referred to as implicit synchronization.

ERRORS

       Returns CL_SUCCESS if the function is executed successfully. If num_objects is 0 and
       mem_objects is NULL the function does nothing and returns CL_SUCCESS. Otherwise, it
       returns one of the following errors:

       ·   CL_INVALID_VALUE if num_objects is zero and mem_objects is not a NULL value or if
           num_objects > 0 and mem_objects is NULL.

       ·   CL_INVALID_MEM_OBJECT if memory objects in mem_objects are not valid OpenCL memory
           objects.

       ·   CL_INVALID_COMMAND_QUEUE if command_queue is not a valid command-queue.

       ·   CL_INVALID_CONTEXT if context associated with command_queue was not created from an
           OpenGL context.

       ·   CL_INVALID_GL_OBJECT if memory objects in mem_objects have not been created from a GL
           object(s).

       ·   CL_INVALID_EVENT_WAIT_LIST if event_wait_list is NULL and num_events_in_wait_list > 0,
           or event_wait_list is not NULL and num_events_in_wait_list is 0, or if event objects
           in event_wait_list are not valid events.

       ·   CL_OUT_OF_RESOURCES if there is a failure to allocate resources required by the OpenCL
           implementation on the device.

       ·   CL_OUT_OF_HOST_MEMORY if there is a failure to allocate resources required by the
           OpenCL implementation on the host.

SPECIFICATION

       OpenCL Specification[1]

AUTHORS

       The Khronos Group

COPYRIGHT

       Copyright © 2007-2011 The Khronos Group Inc.
       Permission is hereby granted, free of charge, to any person obtaining a copy of this
       software and/or associated documentation files (the "Materials"), to deal in the Materials
       without restriction, including without limitation the rights to use, copy, modify, merge,
       publish, distribute, sublicense, and/or sell copies of the Materials, and to permit
       persons to whom the Materials are furnished to do so, subject to the condition that this
       copyright notice and permission notice shall be included in all copies or substantial
       portions of the Materials.

NOTES

        1. OpenCL Specification
           page 56, section 9.7.6 - Sharing memory objects that map to GL objects...

NAME

PARAMETERS

DESCRIPTION

NOTES

ERRORS

SPECIFICATION

SEE ALSO

AUTHORS

COPYRIGHT

NOTES