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       clEnqueueWriteBuffer - Enqueue commands to write to a buffer object from host memory.

       cl_int clEnqueueWriteBuffer(cl_command_queue command_queue, cl_mem buffer,
                                   cl_bool blocking_write, size_t offset, size_t size,
                                   const void *ptr, cl_uint num_events_in_wait_list,
                                   const cl_event *event_wait_list, cl_event *event);


           Refers to the command-queue in which the write command will be queued.  command_queue
           and buffer must be created with the same OpenCL context.

           Refers to a valid buffer object.

           Indicates if the write operations are blocking or nonblocking.

           If blocking_write is CL_TRUE, the OpenCL implementation copies the data referred to by
           ptr and enqueues the write operation in the command-queue. The memory pointed to by
           ptr can be reused by the application after the clEnqueueWriteBuffer call returns.

           If blocking_write is CL_FALSE, the OpenCL implementation will use ptr to perform a
           nonblocking write. As the write is non-blocking the implementation can return
           immediately. The memory pointed to by ptr cannot be reused by the application after
           the call returns. The event argument returns an event object which can be used to
           query the execution status of the write command. When the write command has completed,
           the memory pointed to by ptr can then be reused by the application.

           The offset in bytes in the buffer object to write to.

           The size in bytes of data being written.

           The pointer to buffer in host memory where data is to be written from.

         event_wait_list ,   num_events_in_wait_list
           event_wait_list and num_events_in_wait_list specify events that need to complete
           before this particular command can be executed. If event_wait_list is NULL, then this
           particular command does not wait on any event to complete. If event_wait_list is NULL,
           num_events_in_wait_list must be 0. If event_wait_list is not NULL, the list of events
           pointed to by event_wait_list must be valid and num_events_in_wait_list must be
           greater than 0. The events specified in event_wait_list act as synchronization points.
           The context associated with events in event_wait_list and command_queue must be the
           same. The memory associated with event_wait_list can be reused or freed after the
           function returns.

           Returns an event object that identifies this particular write command and can be used
           to query or queue a wait for this particular command to complete.  event can be NULL
           in which case it will not be possible for the application to query the status of this
           command or queue a wait for this command to complete.


       Calling clEnqueueWriteBuffer to update the latest bits in a region of the buffer object
       with the ptr argument value set to host_ptr + offset, where host_ptr is a pointer to the
       memory region specified when the buffer object being written is created with
       CL_MEM_USE_HOST_PTR, must meet the following requirements in order to avoid undefined

       ·    The host memory region given by (host_ptr + offset, cb) contains the latest bits when
           the enqueued write command begins execution.

       ·    The buffer object or memory objects created from this buffer object are not mapped.

       ·    The buffer object or memory objects created from this buffer object are not used by
           any command-queue until the read command has finished execution.


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

       ·   CL_INVALID_COMMAND_QUEUE if command_queue is not a valid command-queue.

       ·   CL_INVALID_CONTEXT if the context associated with command_queue and buffer are not the
           same or if the context associated with command_queue and events in event_wait_list are
           not the same.

       ·   CL_INVALID_MEM_OBJECT if buffer is not a valid buffer object.

       ·   CL_INVALID_VALUE if the region being written specified by (offset, size) is out of
           bounds or if ptr is a NULL value or if size is 0.

       ·   CL_INVALID_EVENT_WAIT_LIST if event_wait_list is NULL and num_events_in_wait_list
           greater than 0, or event_wait_list is not NULL and num_events_in_wait_list is 0, or if
           event objects in event_wait_list are not valid events.

       ·   CL_MISALIGNED_SUB_BUFFER_OFFSET if buffer is a sub-buffer object and offset specified
           when the sub-buffer object is created is not aligned to CL_DEVICE_MEM_BASE_ADDR_ALIGN
           value for device associated with queue.

       ·   CL_EXEC_STATUS_ERROR_FOR_EVENTS_IN_WAIT_LIST if the read and write operations are
           blocking and the execution status of any of the events in event_wait_list is a
           negative integer value.

       ·   CL_MEM_OBJECT_ALLOCATION_FAILURE if there is a failure to allocate memory for data
           store associated with buffer.

       ·   CL_INVALID_OPERATION if clEnqueueWriteBuffer(3clc) is called on buffer which has been
           created with CL_MEM_HOST_READ_ONLY or CL_MEM_HOST_NO_ACCESS.

       ·   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.


       OpenCL Specification[1]


       clEnqueueCopyBuffer(3clc), clEnqueueReadBuffer(3clc), clEnqueueReadBufferRect(3clc),


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        1. OpenCL Specification
           page 72, section 5.2.2 - Reading, Writing, Copying Buffer Objects