To enqueue a command to unmap a previously mapped region of a memory object, call the function
cl_int clEnqueueUnmapMemObject( cl_command_queue command_queue, cl_mem memobj, void* mapped_ptr, cl_uint num_events_in_wait_list, const cl_event* event_wait_list, cl_event* event);
command_queue must be a valid host command-queue.
memobj is a valid memory (buffer or image) object. The OpenCL context associated with command_queue and memobj must be the same.
mapped_ptr is the host address returned by a previous call to clEnqueueMapBuffer, or clEnqueueMapImage for memobj.
event_wait_list and num_events_in_wait_list specify events that need to complete before clEnqueueUnmapMemObject can be executed. If event_wait_list is
NULL, then clEnqueueUnmapMemObject 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.
event returns an event object that identifies this particular command and can be used to query or queue a wait for this particular command to complete. event can be
NULLin 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. clEnqueueBarrierWithWaitList can be used instead. If the event_wait_list and the event arguments are not
NULL, the event argument should not refer to an element of the event_wait_list array.
Reads or writes from the host using the pointer returned by clEnqueueMapBuffer or clEnqueueMapImage are considered to be complete.
clEnqueueMapBuffer and clEnqueueMapImage increment the mapped count of the memory object. The initial mapped count value of the memory object is zero. Multiple calls to clEnqueueMapBuffer, or clEnqueueMapImage on the same memory object will increment this mapped count by appropriate number of calls. clEnqueueUnmapMemObject decrements the mapped count of the memory object.
clEnqueueMapBuffer, and clEnqueueMapImage act as synchronization points for a region of the buffer object being mapped.
CL_SUCCESS if the function is executed
Otherwise, it returns one of the following errors:
CL_INVALID_COMMAND_QUEUEif command_queue is not a valid host command-queue.
CL_INVALID_MEM_OBJECTif memobj is not a valid memory object or is a pipe object.
CL_INVALID_VALUEif mapped_ptr is not a valid pointer returned by clEnqueueMapBuffer or clEnqueueMapImage for memobj.
CL_INVALID_EVENT_WAIT_LISTif event_wait_list is
NULLand num_events_in_wait_list > 0, or if event_wait_list is not
NULLand num_events_in_wait_list is 0, or if event objects in event_wait_list are not valid events.
CL_OUT_OF_RESOURCESif there is a failure to allocate resources required by the OpenCL implementation on the device.
CL_OUT_OF_HOST_MEMORYif there is a failure to allocate resources required by the OpenCL implementation on the host.
CL_INVALID_CONTEXTif context associated with command_queue and memobj are not the same or if the context associated with command_queue and events in event_wait_list are not the same.
For more information, see the OpenCL Specification
This page is extracted from the OpenCL Specification. Fixes and changes should be made to the Specification, not directly.
Copyright (c) 2014-2020 Khronos Group. This work is licensed under a Creative Commons Attribution 4.0 International License.