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Important This document may not represent best practices for current development, links to downloads and other resources may no longer be valid. Current recommended version can be found here.


Sets a hook that enables calling of the specified function before each memory block is allocated.

AFX_ALLOC_HOOK AfxSetAllocHook( 
   AFX_ALLOC_HOOK pfnAllocHook  


Specifies the name of the function to call. See the Remarks for the prototype of an allocation function.

Nonzero if you want to permit the allocation; otherwise 0.

The Microsoft Foundation Class Library debug-memory allocator can call a user-defined hook function to allow the user to monitor a memory allocation and to control whether the allocation is permitted. Allocation hook functions are prototyped as follows:

BOOL AFXAPI AllocHook( size_t nSize, BOOL bObject, LONG lRequestNumber );


The size of the proposed memory allocation.


TRUE if the allocation is for a CObject-derived object; otherwise FALSE.


The memory allocation's sequence number.

Note that the AFXAPI calling convention implies that the callee must remove the parameters from the stack.

Header: afx.h

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