# PR_MemUnmap

Unmap a memory region that is backed by a memory-mapped file.

## Syntax

```{code}
#include <prio.h>

PRStatus PR_MemUnmap(
  void *addr,
  PRUint32 len);
```

### Parameters

The function has the following parameters:

`addr`

: The starting address of the memory region to be unmapped.

`len`

: The length, in bytes, of the memory region.

### Returns

The function returns one of the following values:

- If the memory region is successfully unmapped, `PR_SUCCESS`.
- If the memory region is not successfully unmapped, `PR_FAILURE`.
  The error code can be retrieved via {ref}`PR_GetError`.

## Description

{ref}`PR_MemUnmap` removes the file mapping for the memory region
(`addr`, `addr + len`). The parameter `addr` is the return value
of an earlier call to {ref}`PR_MemMap`.