CGlobalHeap Class

 

The new home for Visual Studio documentation is Visual Studio 2017 Documentation on docs.microsoft.com.

The latest version of this topic can be found at CGlobalHeap Class.

This class implements IAtlMemMgr using the Win32 global heap functions.

System_CAPS_ICON_important.jpg Important

This class and its members cannot be used in applications that execute in the Windows Runtime.

class CGlobalHeap : public IAtlMemMgr

Public Methods

NameDescription
CGlobalHeap::AllocateCall this method to allocate a block of memory.
CGlobalHeap::FreeCall this method to free a block of memory allocated by this memory manager.
CGlobalHeap::GetSizeCall this method to get the allocated size of a memory block allocated by this memory manager.
CGlobalHeap::ReallocateCall this method to reallocate memory allocated by this memory manager.

CGlobalHeap implements memory allocation functions using the Win32 global heap functions.

System_CAPS_ICON_note.jpg Note

The global heap functions are slower than other memory management functions and do not provide as many features. Therefore, new applications should use the heap functions. These are available in the CWin32Heap class. Global functions are still used by DDE and the clipboard functions.

See the example for IAtlMemMgr.

IAtlMemMgr

CGlobalHeap

Header: atlmem.h

Call this method to allocate a block of memory.

virtual __declspec(allocator) void* Allocate(size_t nBytes) throw();

Parameters

nBytes
The requested number of bytes in the new memory block.

Return Value

Returns a pointer to the start of the newly allocated memory block.

Remarks

Call CGlobalHeap::Free or CGlobalHeap::Reallocate to free the memory allocated by this method.

Implemented using GlobalAlloc with a flag parameter of GMEM_FIXED.

Call this method to free a block of memory allocated by this memory manager.

virtual void Free(void* p) throw();

Parameters

p
Pointer to memory previously allocated by this memory manager. NULL is a valid value and does nothing.

Remarks

Implemented using GlobalFree.

Call this method to get the allocated size of a memory block allocated by this memory manager.

virtual size_t GetSize(void* p) throw();

Parameters

p
Pointer to memory previously allocated by this memory manager.

Return Value

Returns the size of the allocated memory block in bytes.

Remarks

Implemented using GlobalSize.

Call this method to reallocate memory allocated by this memory manager.

virtual __declspec(allocator) void* Reallocate(void* p, size_t nBytes) throw();

Parameters

p
Pointer to memory previously allocated by this memory manager.

nBytes
The requested number of bytes in the new memory block.

Return Value

Returns a pointer to the start of the newly allocated memory block.

Remarks

Call CGlobalHeap::Free to free the memory allocated by this method.

Implemented using GlobalReAlloc.

Class Overview
CComHeap Class
CWin32Heap Class
CLocalHeap Class
CCRTHeap Class
IAtlMemMgr Class

Show: