clEnqueueUnmapMemObject
clEnqueueUnmapMemObject
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clEnqueueUnmapMemObject Enqueues a command to unmap a previously mapped region of a memory object.

##

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

## Parameters

`command_queue`

  Must be a valid command-queue.

`memobj`

  A valid memory object. The OpenCL context associated with `command_queue` and `memobj` must be the same.

`mapped_ptr`

  The host address returned by a previous call to clEnqueueMapBuffer or clEnqueueMapImage for `memobj`.

`event_wait_list ,` `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 copy 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. clEnqueueBarrierWithWaitList can be used instead.

## Notes

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 a 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.

## Errors

`clEnqueueUnmapMemObject` 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_MEM_OBJECT if `memobj` is not a valid memory object.
- CL_INVALID_VALUE if `mapped_ptr` is not a valid pointer returned by clEnqueueMapBuffer or clEnqueueMapImage for `memobj`.
- CL_INVALID_EVENT_WAIT_LIST if `event_wait_list` is NULL and `num_events_in_wait_list` > 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_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.
- CL_INVALID_CONTEXT if the 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.

## Specification

OpenCL Specification

## Also see

clEnqueueMapBuffer, clEnqueueMapImage

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