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);
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.
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.
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 behavior:
clEnqueueWriteBuffer returns CL_SUCCESS if the function is executed successfully. Otherwise, it returns one of the following errors:
clEnqueueCopyBuffer(3clc), clEnqueueReadBuffer(3clc), clEnqueueReadBufferRect(3clc), clEnqueueWriteBufferRect(3clc)
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- OpenCL Specification
|01/14/2021||The Khronos Group|