IMallocSpy:IUnknown

Article
06/30/2006

This interface is a debugging interface that allows application developers to monitor (spy on) memory allocation, detect memory leaks, and simulate memory failure in calls to IMalloc methods.

**Caution **The IMallocSpy interface is intended only for use in debugging application code under development. Do not ship this interface to retail customers of your application because it causes severe performance degradation and could conflict with user-installed software to produce unpredictable results.

When to Implement

Implement this interface to debug memory allocation during application development.

When to Use

When an implementation of IMallocSpy is registered with the CoRegisterMallocSpy function, COM calls the pair of IMallocSpy methods around the corresponding IMalloc method. You would not make direct calls to IMallocSpy methods. The call to the pre-method through the return from the corresponding post-method is guaranteed to be thread-safe in multithreaded operations.

Methods

The following table shows the methods for this interface in the order that the compiler calls the methods. Like all COM interfaces, this interface inherits the methods for the IUnknown interface.

IUnknown method	Description
QueryInterface	Returns pointers to supported interfaces.
AddRef	Increments reference count.
Release	Decrements reference count.

IMallocSpy method	Description
PreAlloc	Called before invoking IMalloc::Alloc, and may extend or modify the allocation to store debug information.
PostAlloc	Called after invoking IMalloc::Alloc.
PreFree	Called before invoking IMalloc::Free.
PostFree	Called after invoking IMalloc::Free.
PreRealloc	Called before invoking IMalloc::Realloc.
PostRealloc	Called after invoking IMalloc::Realloc.
PreGetSize	Called before invoking IMalloc::GetSize.
PostGetSize	Called after invoking IMalloc::GetSize.
PreDidAlloc	Called before invoking IMalloc::DidAlloc.
PostDidAlloc	Called after invoking IMalloc::DidAlloc.
PreHeapMinimize	Called before invoking IMalloc::HeapMinimize.
PostHeapMinimize	Called after invoking IMalloc::HeapMinimize.

Remarks

To determine whether the platform supports this interface, see Determining Supported COM APIs.

Requirements

OS Versions: Windows CE 3.0 and later.
Header: Objidl.h, Objidl.idl.
Link Library: Ole32.lib

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