---
title: unmap
framework: kernel
role: pseudoSymbol
path: kernel/iomedia/1813719-unmap
---

# unmap

## Declaration

```occ
virtual IOReturn unmap(
 IOService *client, 
 IOStorageExtent *extents, 
 UInt32extentsCount, 
 UInt32 options = 0); 
```

## Parameters

- `client`: Client requesting the operation.
- `extents`: List of extents. See IOStorageExtent. It is legal for the callee to overwrite the contents of this buffer in order to satisfy the request.
- `extentsCount`: Number of extents.

## Return Value

Return Value Returns the status of the operation.

## Overview

Overview Delete unused data from the storage object at the specified byte offsets, synchronously.

## See Also

### Miscellaneous

- [copyPhysicalExtent](kernel/iomedia/1813424-copyphysicalextent.md)
- [getAttributes](kernel/iomedia/1813444-getattributes.md)
- [getBase](kernel/iomedia/1813468-getbase.md)
- [getContent](kernel/iomedia/1813495-getcontent.md)
- [getContentHint](kernel/iomedia/1813522-getcontenthint.md)
- [getPreferredBlockSize](kernel/iomedia/1813553-getpreferredblocksize.md)
- [getSize](kernel/iomedia/1813585-getsize.md)
- [handleClose](kernel/iomedia/1813614-handleclose.md)
- [handleIsOpen](kernel/iomedia/1813630-handleisopen.md)
- [handleOpen](kernel/iomedia/1813647-handleopen.md)
- [init](kernel/iomedia/1813657-init.md)
- [isEjectable](kernel/iomedia/1813664-isejectable.md)
- [isFormatted](kernel/iomedia/1813670-isformatted.md)
- [isWhole](kernel/iomedia/1813677-iswhole.md)
- [isWritable](kernel/iomedia/1813683-iswritable.md)
- [lockPhysicalExtents](kernel/iomedia/1813689-lockphysicalextents.md)
- [read](kernel/iomedia/1813696-read.md)
- [synchronizeCache](kernel/iomedia/1813702-synchronizecache.md)
- [unlockPhysicalExtents](kernel/iomedia/1813710-unlockphysicalextents.md)
- [write](kernel/iomedia/1813725-write.md)