readme.txt

一个堆栈管理器的源码

                 Introduction to the Replacement Heap Manager
                 --------------------------------------------


    The enclosed software is a library of heap management routines
    compatible with MSC 5.1.  It consists of the basic heap manager,
    which is fully compatible with the original, but provides superior
    performance, the extended capability package, which provides user
    programs with control over the behavior of the heap, and the heap
    debugging package, which adds error checking routines to the basic
    heap operations.

    The replacement heap library manages the heap in such a way as to
    limit the fragmentation of the heap, and, with the global free list,
    optimize the speed of heap operations.  It also offers the following
    benefits:

        - automatic recovery of space wasted in the default data segment

        - rational handling of zero-length entries and NULL pointers

        - precise control over the interface with the DOS memory manager

        - consistent treatment of "far" and "huge" heap entries


    The extended capabilities of the replacement heap manager include:

        - relocation of heap entries for garbage collection and heap
          compaction

        - shrinking the heap, and releasing excess memory back to DOS
          to maximize the space for spawned programs

        - user control over the behavior of the heap manager offers
          LIFO, first-fit, and best-fit algorithms

        - detailed reports on the state of the heap for analysis of
          heap usage and behavior

        - extended versions of standard functions for "huge" heap entries
          (_hexpand, _hmsize, and hrealloc).

        - direct access to the heap control data structures

        - heap manager accepts non-DOS memory as a resource


    The replacement heap manager is less vulnerable to corruption than
    the original.  It also provides the following tools for identifying
    heap-related problems:

        - distinctive heap pointers reduce possibility of heap corruption

        - user controlled safety margins on every allocation

        - detailed consistency checks, including heap-control-block
          reciprocity and safety margin integrity

        - debugging versions of heap functions check heap integrity
          and report errors.

        - tracing versions of heap functions report heap transactions
          including parameters and return values.

        - read-only heap entries may be monitored for unanticipated changes


    Further information is avaiable in the file heapinfo.txt which
    contains a detailed description of the operation of the replacement
    heap manager, and the file heap.man which contains a reference manual
    for the heap management functions.

    
    FAIR WARNING:  This version of the heap manager has no known bugs, and
                   and passes a battery of tests designed to exercise it.
                   However, it has not been around very long, so the
                   possibility exists that there are residual bugs still
                   in existence.