Syntax

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

• uheapmin returns all unused memory blocks from the heap you specify to the operating system.

  _uheapmin works just like _heapmin, except that you specify the heap to use; _heapmin always uses the default heap. A debug version of this function, _debug_uheapmin, is also provided.

  To return the memory, _uheapmin calls the release_fn you supplied when you created the heap with _ucreate. If you did not supply a release_fn, _uheapmin has no effect and simply returns 0.

If successful, _uheapmin returns 0. A nonzero return value indicates failure. Passing _uheapmin a heap that is not valid has undefined results.

The following example creates a heap and then allocates and frees a large block of memory from it. It then calls _uheapmin to return free blocks of memory to the system.

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

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

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

   /* Allocate a large object */
   if (NULL == (ptr = _umalloc(myheap, 60000))) {
      puts("Cannot allocate memory from user heap.");
      exit(EXIT_FAILURE);
   }
   memset(ptr, 'x', 60000);
   free(ptr);

   /* _uheapmin will attempt to return the freed object to the system */
   if (0 != _uheapmin(myheap)) {
      puts("_uheapmin failed.");
      exit(EXIT_FAILURE);
   }
   return 0;
}

• heapmin
  
• ucreate
  
• Differentiating between Memory Management Functions
  
• Managing Memory" in the VisualAge C++ Programming Guide
  
• Debugging Your Heaps" in the VisualAge C++ Programming Guide

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