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  Argument
 
    pointer_variable    Pointer of any type, pointing to variable
                        previously allocated on heap
 
  Description
 
    The Dispose procedure deallocates a dynamic variable, returning it
    to the heap. An assignment statement or call to the New procedure
    must have previously set the pointer_variable argument to a
    location of a dynamic variable in the heap.
 
    The pointer can be of any type.
 
    After the call to Dispose, the pointer is undefined. The area that
    the pointer pointed to is no longer valid. Dispose does not affect
    other heap memory.
 
    Dispose is similar to the FreeMem procedure, which deallocates an
    area in memory of a specified size in bytes. Use Dispose to free a
    variable allocated by New. Use FreeMem to free memory allocated by
    GetMem.
 
    QuickPascal uses a free list to manage areas returned to the heap
    by Dispose and FreeMem. The free list is a list of pointers that
    grows downward (toward 0) from the top of the heap segment.
    FreePtr, defined in the System unit, points to the free list.
    Deallocated areas below the current top of the heap are pointed to
    by pointers kept in the free list. GetMem and New allocate from the
    free list before taking any new memory from the heap.
 
    Use caution when mixing methods for deallocating variables. Dynamic
    allocation and deallocation are usually done with the related pairs
    of procedures New/Dispose and GetMem/FreeMem. The Mark and Release
    procedures allow freeing of large areas of the heap at one time.
    Release clears the entire free list when called.
 
    If pointer_variable does not point to a dynamic variable in the
    heap, the HeapError function provided at startup causes a run-time
    error. It is possible to replace the default HeapError function
    with a custom function.