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 greater than or equal to the 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:

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.
`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_TASK 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_GL_FENCE_SYNC_OBJECT_KHR (if cl_khr_gl_event is enabled) 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_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.
`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, or one of the errors below:

CL_INVALID_VALUE if param_name is not valid, or if size in bytes specified by param_value_size is less than 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.

Specification

OpenCL Specification

Also see

clReleaseEvent, clRetainEvent, clWaitForEvents, cl_khr_gl_event

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