Syntax

#include <umalloc.h>
int _ustats(Heap_t heap, _HEAPSTATS *hpinfo);

• ustats gets information about the heap you specify and stores it in the hpinfo structure you pass to it.

  The _HEAPSTATS structure type is defined in <umalloc.h>. The members it contains and the information that _ustats stores in each is as follows: compact break=fit.

• provided
  How much memory the heap holds (excluding memory used for overhead for the heap)
  _used
  How much memory is currently allocated from the heap
  _shared
  Whether the memory is shared (_shared is 1) or not (_shared is 0)
  _maxfree
  The size of the largest contiguous piece of memory available on the heap

If successful, _ustats returns 0. A nonzero return code indicates failure. Passing _ustats a heap that is not valid results in undefined behavior.

This example creates a heap and allocates memory from it. It then calls _ustats to print out information about the heap.

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

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

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

   if (NULL == (ptr = _umalloc(myheap, 100))) {
      puts("Cannot allocate memory from user heap.");
      exit(EXIT_FAILURE);
   }
   if (0 != _ustats(myheap, &myheap_stat)) {
      puts("_ustats failed.");
      exit(EXIT_FAILURE);
   }
   printf ("_provided: %u\n", myheap_stat._provided);
   printf ("_used    : %u\n", myheap_stat._used);
   printf ("_shared  : %u\n", myheap_stat._shared);
   printf ("_max_free: %u\n", myheap_stat._max_free);
   free(ptr);
   return 0;
   /****************************************************************************
      The output should be similar to :

      _provided: 65264
      _used    : 14304
      _shared  : 0
      _max_free: 50960
   ****************************************************************************/
}

• mheap
  
• ucreate
  
• Managing Memory" in the VisualAge C++ Programming Guide

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