---
title: unmap
framework: kernel
role: pseudoSymbol
path: kernel/iopartitionscheme/1810548-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/iopartitionscheme/1810278-copyphysicalextent.md)
- [handleClose](kernel/iopartitionscheme/1810310-handleclose.md)
- [handleIsOpen](kernel/iopartitionscheme/1810337-handleisopen.md)
- [handleOpen](kernel/iopartitionscheme/1810366-handleopen.md)
- [lockPhysicalExtents](kernel/iopartitionscheme/1810387-lockphysicalextents.md)
- [read](kernel/iopartitionscheme/1810409-read.md)
- [synchronizeCache](kernel/iopartitionscheme/1810446-synchronizecache.md)
- [unlockPhysicalExtents](kernel/iopartitionscheme/1810496-unlockphysicalextents.md)
- [write](kernel/iopartitionscheme/1810601-write.md)