heapchk.md

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_heapchk | Microsoft Docs		11/04/2016			cpp-standard-libraries		article	_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	_heapchk heapchk	C++	debugging [CRT], heap-related problems consistency checking of heaps heapchk function heaps, checking consistency _heapchk function	859619a5-1e35-4f02-9e09-11d9fa266ec0	13	corob-msft	corob	ghogen

_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.

_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. If the operating system does not support _heapchk(for example, Windows 98), the function returns _HEAPOK and sets errno to ENOSYS.

Requirements

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

For more compatibility information, see Compatibility in the Introduction.

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