C Specification

To enqueue a marker command which waits for previous commands to complete, call the function

cl_int clEnqueueMarker(
    cl_command_queue command_queue,
    cl_event* event);


  • command_queue is a valid host command-queue.

  • event returns an event object that identifies this particular command. Event objects are unique and can be used to identify this marker command later on. 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.


The marker command waits for all commands previously enqueued in command_queue to complete before it completes. This command returns an event which can be waited on, i.e. this event can be waited on to insure that all previously enqueued commands, queued before this command to command_queue, have completed.

clEnqueueMarker returns CL_​SUCCESS if the function is successfully executed. Otherwise, it returns one of the following errors:

  • CL_​INVALID_​COMMAND_​QUEUE if command_queue is not a valid host command-queue.

  • CL_​INVALID_​VALUE if event is NULL.

  • 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

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 (c) 2014-2020 Khronos Group. This work is licensed under a Creative Commons Attribution 4.0 International License.