clSetUserEventStatus clSetUserEventStatus
clSetUserEventStatus
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clSetUserEventStatus Sets the execution status of a user event object.

##

cl_int `clSetUserEventStatus` cl_event event cl_int execution_status

## Parameters

`event`

  A user event object created using clCreateUserEvent.

`execution_status`

  Specifies the new execution status to be set and can be `CL_COMPLETE` or a negative integer value to indicate an error. A negative integer value causes all enqueued commands that wait on this user event to be terminated. `clSetUserEventStatus` can only be called once to change the execution status of `event`.

## Notes

Enqueued commands that specify user events in the `event_wait_list` argument of `clEnqueue***` commands must ensure that the status of these user events being waited on are set using `clSetUserEventStatus` before any OpenCL APIs that release OpenCL objects except for event objects are called; otherwise the behavior is undefined.

## Errors

Returns CL_SUCCESS if the function was executed successfully. Otherwise, it returns one of the following errors

- CL_INVALID_EVENT if `event` is not a valid user event.
- CL_INVALID_VALUE if the `execution_status` is not `CL_COMPLETE` or a negative integer value.
- CL_INVALID_OPERATION if the `execution_status` for `event` has already been changed by a previous call to `clSetUserEventStatus`.
- 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.

## Example

For example, the following code sequence will result in undefined behavior of clReleaseMemObject.

ev1 = clCreateUserEvent(ctx, NULL); clEnqueueWriteBuffer(cq, buf1, CL_FALSE, ..., 1, &ev1, NULL; clEnqueueWriteBuffer(cq, buf2, CL_FALSE,...); clReleaseMemObject(buf2); clSetUserEventStatus(ev1, CL_COMPLETE);

The following code sequence, however, works correctly.

ev1 = clCreateUserEvent(ctx, NULL); clEnqueueWriteBuffer(cq, buf1, CL_FALSE, ..., 1, &ev1, NULL; clEnqueueWriteBuffer(cq, buf2, CL_FALSE,...); clSetUserEventStatus(ev1, CL_COMPLETE); clReleaseMemObject(buf2);

## Specification

OpenCL Specification

## Also see

clCreateUserEvent

##