C Specification

To acquire OpenCL memory objects that have been created from OpenGL objects, call the function

// Provided by cl_khr_gl_sharing
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);
clEnqueueAcquireGLObjects is provided by the cl_khr_gl_sharing extension.

Parameters

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

  • num_objects is the number of memory objects to be acquired in mem_objects.

  • mem_objects is a pointer to a list of OpenCL memory objects that correspond to OpenGL objects.

  • event_wait_list and num_events_in_wait_list 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 wait for this command to complete. If event is NULL or the enqueue is unsuccessful, no event will be created and therefore it will not be possible to query the status of this command or to wait for this command to complete. If event_wait_list and event are not NULL, event must not refer to an element of the event_wait_list array.

Description

If an OpenGL context is bound to the current thread, then any OpenGL commands which

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

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

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.

These objects need to be acquired before they can be used by any OpenCL commands queued to a command-queue or the behaviour is undefined. 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.

clEnqueueAcquireGLObjects 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 an OpenGL 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.

See Also

cl_command_queue, cl_event, cl_khr_gl_sharing, cl_mem, cl_uint

Document Notes

For more information, see the OpenCL Specification

This page is extracted from the OpenCL Specification. Fixes and changes should be made to the Specification, not directly.

Copyright

Copyright 2014-2025 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0