_heapchk

Runs consistency checks on the heap.

int_heapchk(void);

For additional compatibility information, see Compatibility in the Introduction.

Libraries

Return Value

_heapchk returns one of the following integer manifest constants defined in MALLOC.H:

_HEAPBADBEGIN

Initial header information is bad or cannot be found

_HEAPBADNODE

Bad node has been found or heap is damaged

_HEAPBADPTR

Pointer into heap is not valid

_HEAPEMPTY

Heap has not been initialized

_HEAPOK

Heap appears to be consistent

In addition, if an error occurs, _heapchk sets errno to ENOSYS.

Remarks

The _heapchk function helps debug heap-related problems by checking for minimal consistency of the heap.

Example

/* HEAPCHK.C: This program checks the heap for
 * consistency and prints an appropriate message.
 */

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

void main( void )
{
   int  heapstatus;
   char *buffer;

   /* Allocate and deallocate some memory */
   if( (buffer = (char *)malloc( 100 )) != NULL )
      free( buffer );

   /* Check heap status */
   heapstatus = _heapchk();
   switch( heapstatus )
   {
   case _HEAPOK:
      printf(" OK - heap is fine\n" );
      break;
   case _HEAPEMPTY:
      printf(" OK - heap is empty\n" );
      break;
   case _HEAPBADBEGIN:
      printf( "ERROR - bad start of heap\n" );
      break;
   case _HEAPBADNODE:
      printf( "ERROR - bad node in heap\n" );
      break;
   }
}

Output

OK - heap is fine

Memory Allocation Routines

See Also   _heapadd, _heapmin, _heapset, _heapwalk