clGetEventInfo.adoc

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clGetEventInfo

Returns information about the event object.

cl_int clGetEventInfo(cl_event event,
                      cl_event_info param_name,
                      size_t param_value_size,
                      void *param_value,
                      size_t *param_value_size_ret)

Parameters

event

Specifies the event object being queried.

param_value

A pointer to memory where the appropriate result being queried is returned. If param_value is NULL, it is ignored.

param_value_size

Specifies the size in bytes of memory pointed to by param_value. This size must be ≥ size of the return type as described in the table below.

param_value_size_ret

Returns the actual size in bytes of data copied to param_value. If param_value_size_ret is NULL, it is ignored.

param_name

Specifies the information to query. The list of supported param_name types and the information returned in param_value by clGetEventInfo is described in the table below (Table 5.22):

cl_event_info	Return Type	Information returned in param_value
CL_EVENT_COMMAND_QUEUE	cl_command_queue	Return the command-queue associated with event. For user event objects, a NULL value is returned. If the cl_khr_gl_sharing extension is enabled, the command queue of a linked event NULL, because the event is not associated with any OpenCL command queue. If the cl_khr_egl_event extension is enabled, the CL_EVENT_COMMAND_QUEUE of a linked event is NULL, because the event is not associated with any OpenCL command queue.
CL_EVENT_CONTEXT	cl_context	Return the context associated with event.
CL_EVENT_COMMAND_TYPE	cl_command_type	Return the command associated with event. Can be one of the following values: CL_COMMAND_NDRANGE_KERNEL CL_COMMAND_NATIVE_KERNEL CL_COMMAND_READ_BUFFER CL_COMMAND_WRITE_BUFFER CL_COMMAND_COPY_BUFFER CL_COMMAND_READ_IMAGE CL_COMMAND_WRITE_IMAGE CL_COMMAND_COPY_IMAGE CL_COMMAND_COPY_BUFFER_TO_IMAGE CL_COMMAND_COPY_IMAGE_TO_BUFFER CL_COMMAND_MAP_BUFFER CL_COMMAND_MAP_IMAGE CL_COMMAND_UNMAP_MEM_OBJECT CL_COMMAND_MARKER CL_COMMAND_ACQUIRE_GL_OBJECTS CL_COMMAND_RELEASE_GL_OBJECTS CL_COMMAND_READ_BUFFER_RECT CL_COMMAND_WRITE_BUFFER_RECT CL_COMMAND_COPY_BUFFER_RECT CL_COMMAND_USER CL_COMMAND_BARRIER CL_COMMAND_MIGRATE_MEM_OBJECTS CL_COMMAND_FILL_BUFFER CL_COMMAND_FILL_IMAGE CL_COMMAND_SVM_FREE CL_COMMAND_SVM_MEMCPY CL_COMMAND_SVM_MEMFILL CL_COMMAND_SVM_MAP CL_COMMAND_SVM_UNMAP CL_COMMAND_GL_FENCE_SYNC_OBJECT_KHR (if cl_khr_gl_event is enabled, indicating that the event is associated with a GL sync object, rather than an OpenCL command) CL_COMMAND_ACQUIRE_D3D10_OBJECTS_KHR (if cl_khr_d3d10_sharing is enabled) CL_COMMAND_RELEASE_D3D10_OBJECTS_KHR (if cl_khr_d3d10_sharing is enabled) CL_COMMAND_ACQUIRE_DX9_MEDIA_SURFACES_KHR (if cl_khr_dx9_media_sharing is enabled) CL_COMMAND_RELEASE_DX9_MEDIA_SURFACES_KHR (if cl_khr_dx9_media_sharing is enabled) CL_COMMAND_ACQUIRE_D3D11_OBJECTS_KHR (if cl_khr_d3d11_sharing is enabled) CL_COMMAND_RELEASE_D3D11_OBJECTS_KHR (if cl_khr_d3d11_sharing is enabled) CL_COMMAND_EGL_FENCE_SYNC_OBJECT_KHR (if cl_khr_egl_event is enabled)
CL_EVENT_COMMAND_ EXECUTION_STATUS	cl_int	Return the execution status of the command identified by event. The valid values are: CL_QUEUED (command has been enqueued in the command-queue), CL_SUBMITTED (enqueued command has been submitted by the host to the device associated with the command-queue), CL_RUNNING (device is currently executing this command), CL_COMPLETE (the command has completed), or Error code given by a negative integer value. (command was abnormally terminated – this may be caused by a bad memory access etc.) These error codes come from the same set of error codes that are returned from the platform or runtime API calls as return values or errcode_ret values. The error code values are negative, and event state values are positive. The event state values are ordered from the largest value (CL_QUEUED) for the first or initial state to the smallest value (CL_COMPLETE or negative integer value) for the last or complete state. The value of CL_COMPLETE and CL_SUCCESS are the same. If the cl_khr_gl_event extension is enabled, the status of a linked event is either CL_SUBMITTED, indicating that the fence command associated with the sync object has not yet completed, or CL_COMPLETE, indicating that the fence command has completed. If the cl_khr_egl_event extension is enabled, the status of a linked event is either CL_SUBMITTED, indicating that the fence command associated with the sync object has not yet completed, or CL_COMPLETE, indicating that the fence command has completed.
CL_EVENT_REFERENCE_COUNT	cl_uint	Return the event reference count. The reference count returned should be considered immediately stale. It is unsuitable for general use in applications. This feature is provided for identifying memory leaks.

Notes

Using clGetEventInfo to determine if a command identified by event has finished execution (i.e. CL_EVENT_COMMAND_EXECUTION_STATUS returns CL_COMPLETE) is not a synchronization point. There are no guarantees that the memory objects being modified by command associated with event will be visible to other enqueued commands.

Errors

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

• CL_INVALID_VALUE if param_name is not valid, or if size in bytes specified by param_value_size is < size of return type as described in the table above and param_value is not NULL.

• CL_INVALID_VALUE if information to query given in param_name cannot be queried for event.

• CL_INVALID_EVENT if event is not a valid event object.

• 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.

Also see

enums, clReleaseEvent, clRetainEvent, clWaitForEvents, cl_khr_gl_event

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