_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