ID Number: Q38327
5.10 6.00 6.00a 6.00ax | 5.10 6.00 6.00a
MS-DOS | OS/2
Summary:
In Microsoft C versions 5.1, 6.0, 6.0a, and 6.0ax, the HeapWalk
routines are provided as an aid in debugging heap-related problems in
programs. In large-, huge-, and compact-memory models _heapwalk() will
map onto the function _fheapwalk(). In small- and medium-memory
models, it maps onto function _nheapwalk(). The _fheapwalk() function
does not check or examine the near heap in the default data segment,
while _nheapwalk() examines only the near heap.
Because _fheapwalk() does not check the near heap, you should not
assume that the HeapWalk routine will always reflect information about
all your pointers when you are using compact-, large- and huge-memory
models. This is because in these models, calloc() and malloc() will
draw upon the far heap until it is exhausted, then turn to the near
heap. In this case, it is possible to have valid pointers but
_fheapwalk() will not acknowledge them. Starting in C 6.0 calloc() and
malloc() do not allocate from the near heap when the far heap is
exhausted.
For this reason, you should not assume that _fheapwalk() will provide
information about all your pointers, or you should use both
_fheapwalk() and _nheapwalk() to check both the near heap and the far
heap.
Additional reference words: 5.10 6.00 6.00a 6.00ax