glUnmapBuffer - OpenGL 4 Reference Pages

## Name

glUnmapBuffer, glUnmapNamedBuffer — release the mapping of a buffer object's data store into the client's address space

## C Specification

`GLboolean glUnmapBuffer(` | GLenum target`)`;

`GLboolean glUnmapNamedBuffer(` | GLuint buffer`)`;

## Parameters

`target`

  Specifies the target to which the buffer object is bound for `glUnmapBuffer`, which must be one of the buffer binding targets in the following table:

  Buffer Binding Target | Purpose
  --- | ---
  `GL_ARRAY_BUFFER` | Vertex attributes
  `GL_ATOMIC_COUNTER_BUFFER` | Atomic counter storage
  `GL_COPY_READ_BUFFER` | Buffer copy source
  `GL_COPY_WRITE_BUFFER` | Buffer copy destination
  `GL_DISPATCH_INDIRECT_BUFFER` | Indirect compute dispatch commands
  `GL_DRAW_INDIRECT_BUFFER` | Indirect command arguments
  `GL_ELEMENT_ARRAY_BUFFER` | Vertex array indices
  `GL_PIXEL_PACK_BUFFER` | Pixel read target
  `GL_PIXEL_UNPACK_BUFFER` | Texture data source
  `GL_QUERY_BUFFER` | Query result buffer
  `GL_SHADER_STORAGE_BUFFER` | Read-write storage for shaders
  `GL_TEXTURE_BUFFER` | Texture data buffer
  `GL_TRANSFORM_FEEDBACK_BUFFER` | Transform feedback buffer
  `GL_UNIFORM_BUFFER` | Uniform block storage

`buffer`

  Specifies the name of the buffer object for `glUnmapNamedBuffer`.

## Description

`glUnmapBuffer` and `glUnmapNamedBuffer` unmap (release) any mapping of a specified buffer object into the client's address space (see glMapBufferRange and glMapBuffer).

If a mapping is not unmapped before the corresponding buffer object's data store is used by the GL, an error will be generated by any GL command that attempts to dereference the buffer object's data store, unless the buffer was successfully mapped with `GL_MAP_PERSISTENT_BIT` (see glMapBufferRange). When a data store is unmapped, the mapped pointer becomes invalid.

`glUnmapBuffer` returns `GL_TRUE` unless the data store contents have become corrupt during the time the data store was mapped. This can occur for system-specific reasons that affect the availability of graphics memory, such as screen mode changes. In such situations, `GL_FALSE` is returned and the data store contents are undefined. An application must detect this rare condition and reinitialize the data store.

A buffer object's mapped data store is automatically unmapped when the buffer object is deleted or its data store is recreated with glBufferData).

## Notes

If an error is generated, `glUnmapBuffer` returns `GL_FALSE`.

The `GL_ATOMIC_COUNTER_BUFFER` target is accepted only if the GL version is 4.2 or greater.

The `GL_DISPATCH_INDIRECT_BUFFER` and `GL_SHADER_STORAGE_BUFFER` targets are available only if the GL version is 4.3 or greater.

The `GL_QUERY_BUFFER` target is available only if the GL version is 4.4 or greater.

## Errors

`GL_INVALID_ENUM` is generated by `glUnmapBuffer` if `target` is not one of the buffer binding targets listed above.

`GL_INVALID_OPERATION` is generated by `glUnmapBuffer` if zero is bound to `target`.

`GL_INVALID_OPERATION` is generated by `glUnmapNamedBuffer` if `buffer` is not the name of an existing buffer object.

`GL_INVALID_OPERATION` is generated if the buffer object is not in a mapped state.

## Associated Gets

glGetBufferParameter with argument `GL_BUFFER_MAPPED`.

## Version Support

| OpenGL Version
--- | ---
Function / Feature Name | 2.0 | 2.1 | 3.0 | 3.1 | 3.2 | 3.3 | 4.0 | 4.1 | 4.2 | 4.3 | 4.4 | 4.5
`glUnmapBuffer` | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔
`glUnmapNamedBuffer` | - | - | - | - | - | - | - | - | - | - | - | ✔

## See Also

glBufferData, glDeleteBuffers, glMapBuffer, glMapBufferRange

## Copyright

Copyright © 2005 Addison-Wesley. Copyright © 2010-2014 Khronos Group. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. http://opencontent.org/openpub/.