Use the heap-specific versions to allocate and free memory from a user-created heap that you specify. (You can also explicitly use the run-time heap if you want.) Their names are prefixed by _u (for "user heaps"), for example, _umalloc, and they are defined in <umalloc.h>.
The functions provided are:
Notice there is no heap-specific version of realloc or free. Because they both always check what heap the memory was allocated from, you can always use the regular versions regardless of what heap the memory came from.
For more information about creating your own heaps and using the heap-specific memory management functions, see "Managing Memory with Multiple Heaps" in the VisualAge C++ Programming Guide.