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Synopsis:
    #include <malloc.h>
    int  _heapchk( void );
    int _bheapchk( __segment seg );
    int _fheapchk( void );
    int _nheapchk( void );

Description:
    The _heapchk functions along with  _heapset and  _heapwalk are provided
    for debugging heap related problems in programs.

    The _heapchk functions perform a consistency check on the unallocated
    memory space or "heap".  The consistency check determines whether all
    the heap entries are valid.  Each function checks a particular heap, as
    listed below:

    Function     Heap Checked

_heapchk
    Depends on data model of the program

_bheapchk
    Based heap specified by seg value;  _NULLSEG specifies all based heaps

_fheapchk
    Far heap (outside the default data segment)

_nheapchk
    Near heap (inside the default data segment)

    In a small data memory model, the _heapchk function is equivalent to the
     _nheapchk function; in a large data memory model, the _heapchk function
    is equivalent to the  _fheapchk function.

Returns:
    All four functions return one of the following manifest constants which
    are defined in <malloc.h>.

    Constant     Meaning

_HEAPOK
    The heap appears to be consistent.

_HEAPEMPTY
    The heap is empty.

_HEAPBADBEGIN
    The heap has been damaged.

_HEAPBADNODE
    The heap contains a bad node, or is damaged.


Example:
    #include <stdio.h>
    #include <malloc.h>

    void main()
      {
        char *buffer;

        buffer = (char *)malloc( 80 );
        malloc( 1024 );
        free( buffer );
        switch( _heapchk() ) {
        case _HEAPOK:
          printf( "OK - heap is good\n" );
          break;
        case _HEAPEMPTY:
          printf( "OK - heap is empty\n" );
          break;
        case _HEAPBADBEGIN:
          printf( "ERROR - heap is damaged\n" );
          break;
        case _HEAPBADNODE:
          printf( "ERROR - bad node in heap\n" );
          break;
        }
      }

Classification:
    WATCOM

Systems:
     _heapchk - All

    _fheapchk - DOS/16, Windows, QNX/16, OS/2 1.x(all)
    _nheapchk - DOS, Windows, Win386, Win32, QNX, OS/2 1.x, OS/2 1.x(MT),
    OS/2-32
    _bheapchk - DOS/16, Windows, QNX/16, OS/2 1.x(all)

See Also:
    _heapenable, _heapgrow, _heapmin, _heapset, _heapshrink, _heapwalk