---
description: "Learn more about: CComAllocator Class"
title: "CComAllocator Class"
ms.date: "11/04/2016"
f1_keywords: ["CComAllocator", "ATLBASE/ATL::CComAllocator", "ATLBASE/ATL::CComAllocator::Allocate", "ATLBASE/ATL::CComAllocator::Free", "ATLBASE/ATL::CComAllocator::Reallocate"]
helpviewer_keywords: ["CComAllocator class"]
ms.assetid: 0cd706fd-0c7b-42d3-9054-febe2966fc8e
---
# CComAllocator Class

This class provides methods for managing memory using COM memory routines.

## Syntax

```
class CComAllocator
```

## Members

### Public Methods

|Name|Description|
|----------|-----------------|
|[CComAllocator::Allocate](#allocate)|Call this static method to allocate memory.|
|[CComAllocator::Free](#free)|Call this static method to free allocated memory.|
|[CComAllocator::Reallocate](#reallocate)|Call this static method to reallocate memory.|

## Remarks

This class is used by [CComHeapPtr](../../atl/reference/ccomheapptr-class.md) to provide the COM memory allocation routines. The counterpart class, [CCRTAllocator](../../atl/reference/ccrtallocator-class.md), provides the same methods using CRT routines.

## Requirements

**Header:** atlbase.h

## <a name="allocate"></a> CComAllocator::Allocate

Call this static function to allocate memory.

```
static void* Allocate(size_t nBytes) throw();
```

### Parameters

*nBytes*<br/>
The number of bytes to allocate.

### Return Value

Returns a void pointer to the allocated space, or NULL if there is insufficient memory available.

### Remarks

Allocates memory. See [CoTaskMemAlloc](/windows/win32/api/combaseapi/nf-combaseapi-cotaskmemalloc) for more details.

## <a name="free"></a> CComAllocator::Free

Call this static function to free allocated memory.

```
static void Free(void* p) throw();
```

### Parameters

*p*<br/>
Pointer to the allocated memory.

### Remarks

Frees the allocated memory. See [CoTaskMemFree](/windows/win32/api/combaseapi/nf-combaseapi-cotaskmemfree) for more details.

## <a name="reallocate"></a> CComAllocator::Reallocate

Call this static function to reallocate memory.

```
static void* Reallocate(void* p, size_t nBytes) throw();
```

### Parameters

*p*<br/>
Pointer to the allocated memory.

*nBytes*<br/>
The number of bytes to reallocate.

### Return Value

Returns a void pointer to the allocated space, or NULL if there is insufficient memory

### Remarks

Resizes the amount of allocated memory. See [CoTaskMemRealloc](/windows/win32/api/combaseapi/nf-combaseapi-cotaskmemrealloc) for more details.

## See also

[CComHeapPtr Class](../../atl/reference/ccomheapptr-class.md)<br/>
[CCRTAllocator Class](../../atl/reference/ccrtallocator-class.md)<br/>
[Class Overview](../../atl/atl-class-overview.md)