Sets the execution status of a user event object.
cl_int clSetUserEventStatus(cl_event event, cl_int execution_status);
event
A user event object created using clCreateUserEvent(3clc).
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.
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.
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.
For example, the following code sequence will result in undefined behavior of clReleaseMemObject(3clc).
| ev1 = clCreateUserEvent(ctx, NULL); clEnqueueWriteBuffer(cq, buf1, CL_FALSE, ..., 1, &ev1, NULL; clEnqueueWriteBuffer(cq, buf2, CL_FALSE,...); clReleaseMemObject(buf2); clSetUserEventStatus(ev1, CL_COMPLETE); |
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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); |
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clCreateUserEvent(3clc)
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OpenCL Specification
page 178, section 5.9 - Event Objects