HeapReAlloc.md

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Function name : HeapReAlloc

Group: Memory Management - Library: kernel32

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The HeapReAlloc function reallocates a block of memory from a heap. This function enables you to resize a memory block and change other memory block properties. The allocated memory is not movable.

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Code examples:

Using the heap of the calling process to allocate memory blocks

Declaration:

LPVOID HeapReAlloc(
  HANDLE hHeap,   // handle to heap block
  DWORD dwFlags,  // heap reallocation options
  LPVOID lpMem,   // pointer to memory to reallocate
  SIZE_T dwBytes  // number of bytes to reallocate
);  

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FoxPro declaration:

DECLARE INTEGER HeapReAlloc IN kernel32;
	INTEGER hHeap,;
	INTEGER dwFlags,;
	INTEGER lpMem,;
	INTEGER dwBytes  

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Parameters:

hHeap [in] Heap from which the memory will be reallocated. This is a handle returned by the HeapCreate or GetProcessHeap function.

dwFlags [in] Specifies several controllable aspects of heap reallocation.

lpMem [in] Pointer to the block of memory that the function reallocates. This pointer is returned by an earlier call to the HeapAlloc or HeapReAlloc function.

dwBytes [in] New size of the memory block, in bytes. A memory block"s size can be increased or decreased by using this function.

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Return value:

If the function succeeds, the return value is a pointer to the reallocated memory block. Otherwise the return is NULL or an exception generated if you have specified HEAP_GENERATE_EXCEPTIONS in dwFlags.

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Comments:

MSDN: If HeapReAlloc fails, the original memory is not freed, and the original handle and pointer are still valid. To free a block of memory allocated by HeapReAlloc, use the HeapFree function.

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