Syntax

#include <umalloc.h>
int _uheapchk(Heap_t heap);

• uheapchk checks the heap you specify for minimal consistency by checking all allocated and freed objects on the heap.

  _uheapchk works just like _heapchk, except that you specify the heap to check; _heapchk always checks the default heap.

  Note: Using the _uheapchk, _uheapset, and _uheap_walk functions (and their equivalents for the default heap) may add overhead to each object allocated from the heap.

• uheapchk returns one of the following values, defined in both <umalloc.h> and <malloc.h>:

• HEAPBADBEGIN
  The heap specifed is not valid. It may have been closed or destroyed.
  _HEAPBADNODE
  A memory node is corrupted, or the heap is damaged.
  _HEAPEMPTY
  The heap has not been initialized.
  _HEAPOK
  The heap appears to be consistent.

This example creates a heap and performs memory operations on it. It then calls _uheapchk to validate the heap.

#include <stdlib.h>#include <stdio.h>
#include <umalloc.h>

int main(void)
{
   Heap_t  myheap;
   char    *ptr;
   int     rc;

   /* Use default heap as user heap */
   myheap = _udefault(NULL);

   if (NULL == (ptr = _ucalloc(myheap, 100, 1))) {
      puts("Cannot allocate memory from user heap.");
      exit(EXIT_FAILURE);
   }
   *(ptr - 1) = 'x';     /* overwrite storage that was not allocated */

   if (_HEAPOK != (rc = _uheapchk(myheap))) {
      switch(rc) {
         case _HEAPEMPTY:
            puts("The heap has not been initialized.");
            break;
         case _HEAPBADNODE:
            puts("A memory node is corrupted or the heap is damaged.");
            break;
         case _HEAPBADBEGIN:
            puts("The heap specified is not valid.");
            break;
      }
      exit(rc);
   }
   free(ptr);
   return 0;

   /****************************************************************************
      The output should be similar to :

      A memory node is corrupted or the heap is damaged.
   ****************************************************************************/
}

• heapchk
  
• heapmin
  
• uheapset
  
• uheap_walk
  
• Managing Memory" in the VisualAge C++ Programming Guide
  
• Debugging Your Heaps" in the VisualAge C++ Programming Guide

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