C Specification

To release OpenCL memory objects that have been created from EGL resources, call the function

// Provided by cl_khr_egl_image
cl_int clEnqueueReleaseEGLObjectsKHR(
    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);
clEnqueueReleaseEGLObjectsKHR is provided by the cl_khr_egl_image extension.

Parameters

  • command_queue is a valid command-queue.

  • 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 were created from EGL resources, within the context associate with command_queue.

  • 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 or 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

The EGL objects are released by the OpenCL context associated with <command_queue>.

OpenCL memory objects created from EGL resources which have been acquired by OpenCL must be released by OpenCL before they may be accessed by EGL or by EGL client APIs. Accessing a EGL resource while its corresponding OpenCL memory object is acquired is in error and will result in undefined behavior, including but not limited to possible OpenCL errors, data corruption, and program termination.

clEnqueueReleaseEGLObjectsKHR returns CL_SUCCESS if the function is executed successfully. If num_objects is 0 and mem_objects is NULL then 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 in the context associated with command_queue.

  • CL_INVALID_EGL_OBJECT_KHR if memory objects in mem_objects have not been created from EGL resources.

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

  • 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_egl_image, 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