C Specification

To set the execution status of a user event object, call the function

// Provided by CL_VERSION_1_1
cl_int clSetUserEventStatus(
    cl_event event,
    cl_int execution_status);
clSetUserEventStatus is missing before version 1.1.

Parameters

  • event is 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.

Description

If there are enqueued commands with user events in the event_wait_list argument of clEnqueue* commands, the user 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.

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);

clSetUserEventStatus 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 object.

  • 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.

See Also

CL_VERSION_1_1, cl_event, cl_int

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 2014-2024 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0