heapchk.md

description	title	ms.date	api_name	api_location	api_type	topic_type	f1_keywords	helpviewer_keywords	ms.assetid
Learn more about: _heapchk	_heapchk	4/2/2020	_heapchk _o__heapchk	msvcrt.dll msvcr80.dll msvcr90.dll msvcr100.dll msvcr100_clr0400.dll msvcr110.dll msvcr110_clr0400.dll msvcr120.dll msvcr120_clr0400.dll ucrtbase.dll api-ms-win-crt-heap-l1-1-0.dll	DLLExport	apiref	_heapchk heapchk	debugging [CRT], heap-related problems consistency checking of heaps heapchk function heaps, checking consistency _heapchk function	859619a5-1e35-4f02-9e09-11d9fa266ec0

_heapchk

Runs consistency checks on the heap.

Syntax

int _heapchk( void );

Return value

_heapchk returns one of the following integer manifest constants defined in Malloc.h.

Return value	Condition
_HEAPBADBEGIN	Initial header information is bad or can't be found.
_HEAPBADNODE	Bad node has been found or heap is damaged.
_HEAPBADPTR	Pointer into heap isn't valid.
_HEAPEMPTY	Heap hasn't 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. If the operating system doesn't support _heapchk(for example, Windows 98), the function returns _HEAPOK and sets errno to ENOSYS.

By default, this function's global state is scoped to the application. To change this behavior, see Global state in the CRT.

Requirements

Routine	Required header	Optional header
_heapchk	<malloc.h>	<errno.h>

For more compatibility information, see Compatibility.

Example

// crt_heapchk.c
// This program checks the heap for
// consistency and prints an appropriate message.

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

int 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;
   }
}

OK - heap is fine

See also

Memory allocation
_heapadd
_heapmin
_heapset
_heapwalk