heapcheckfree

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Header File

alloc.h

Prototype

int heapcheckfree(unsigned int fillvalue);

Description

Checks the free blocks on the heap for a constant value.

Return Value

The return value is less then 0 for an error and greater than 0 for success. The return values and their meaning are as follows:

_BADVALUE	A value other than the fill value was found
_HEAPCORRUPT	Heap has been corrupted
_HEAPEMPTY	No heap
_HEAPOK	Heap is accurate

Portability

	POSIX	ANSI C	ANSI C++	Win32	Win64	OS X
heapcheckfree				+

Example

#include <stdio.h>
#include <alloc.h>
#include <mem.h>

#define NUM_PTRS  10
#define NUM_BYTES 16

int main(void) {
    char *array[NUM_PTRS];
    int i;
    int res;

    for (i = 0; i < NUM_PTRS; i++)
        array[i] = (char *) malloc(NUM_BYTES);

    for (i = 0; i < NUM_PTRS; i += 2)
        free(array[i]);

    if (heapfillfree(1) < 0) {
        printf("Heap corrupted.\n");
        return 1;
    }

    for (i = 1; i < NUM_PTRS; i += 2)
        memset(array[i], 0, NUM_BYTES);

    res = heapcheckfree(1);
    if (res < 0)
        switch (res) {
        case _HEAPCORRUPT:
            printf("Heap corrupted.\n");
            return 1;
        case _BADVALUE:
            printf("Bad value in free space.\n");
            return 1;
        default:
            printf("Unknown error.\n");
            return 1;
        }

    printf("Test successful.\n");
    return 0;
}