---
name: "clEnqueueUnmapMemObject"
section: "3clc"
platform: "linux"
package: "opencl-1.2-man-doc"
version: "1.0~svn33624-5.1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/clEnqueueUnmapMemObject"
---

# clEnqueueUnmapMemObject(3clc)

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

## NAME

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**(3clc)](/clEnqueueMapBuffer/3clc.md) or [**clEnqueueMapImage**(3clc)](/clEnqueueMapImage/3clc.md) 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**(3clc)](/clEnqueueBarrierWithWaitList/3clc.md) can be used instead.

## NOTES

Reads or writes from the host using the pointer returned by [**clEnqueueMapBuffer**(3clc)](/clEnqueueMapBuffer/3clc.md) or [**clEnqueueMapImage**(3clc)](/clEnqueueMapImage/3clc.md) are considered to be complete.

[**clEnqueueMapBuffer**(3clc)](/clEnqueueMapBuffer/3clc.md) and [**clEnqueueMapImage**(3clc)](/clEnqueueMapImage/3clc.md) increment the mapped count of the memory object. The initial mapped count value of a memory object is zero. Multiple calls to [**clEnqueueMapBuffer**(3clc)](/clEnqueueMapBuffer/3clc.md) or [**clEnqueueMapImage**(3clc)](/clEnqueueMapImage/3clc.md) 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**(3clc)](/clEnqueueMapBuffer/3clc.md) and [**clEnqueueMapImage**(3clc)](/clEnqueueMapImage/3clc.md) 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**(3clc)](/clEnqueueMapBuffer/3clc.md) or [**clEnqueueMapImage**(3clc)](/clEnqueueMapImage/3clc.md) 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**\[1\]

## SEE ALSO

[**clEnqueueMapBuffer**(3clc)](/clEnqueueMapBuffer/3clc.md), [**clEnqueueMapImage**(3clc)](/clEnqueueMapImage/3clc.md)

## AUTHORS

**The Khronos Group**

## COPYRIGHT

Copyright © 2007-2011 The Khronos Group Inc.\
 Permission is hereby granted, free of charge, to any person obtaining a copy of this software and/or associated documentation files (the "Materials"), to deal in the Materials without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Materials, and to permit persons to whom the Materials are furnished to do so, subject to the condition that this copyright notice and permission notice shall be included in all copies or substantial portions of the Materials.

## NOTES

- 1\.

  OpenCL Specification

  page 120, section 5.4.2 - Unmapping Mapped Memory Objects