...
| Code Block |
|---|
|
#include <stdlib.h>
struct node {
struct node *next;
};
void func(struct node *head) {
for (struct node *p = head; p != NULL; p = p->next) {
free(p);
}
} |
Compliant Solution
Kernighan and Ritchie also show the correct solution. To correct this error, a reference to p->next is stored in q before freeing p.
| Code Block |
|---|
|
#include <stdlib.h>
struct node {
struct node *next;
};
void func(struct node *head) {
struct node *q;
for (struct node *p = head; p != NULL; p = q) {
q = p->next;
free(p);
}
head = NULL;}
} |
Noncompliant Code Example
...
| Code Block |
|---|
|
#include <stdlib.h>
#include <string.h>
enum { BUFFERSIZE = 32 };
int main(int argc, const char *argv[]) {
char *buff;
buff = (char *)malloc(BUFFERSIZE);
if (!buff) {
/* Handle error condition */
}
/* ... */
free(buff);
if (argc /* ... */
> 1) {
strncpy(buff, argv[1], BUFFERSIZE - 1);
}
return 0;
}
|
Compliant Solution
In this compliant solution do not free the memory until it is no longer required:
| Code Block |
|---|
|
#include <stdlib.h>
#include <string.h>
enum { BUFFERSIZE = 32 };
int main(int argc, const char *argv[]) {
char *buff;
buff = (char *)malloc(BUFFERSIZE);
if (!buff) {
/* Handle error condition */
}
/* ... */if (argc > 1){
strncpy(buff, argv[1], BUFFERSIZE - 1);
/* ... */}
free(buff);
return 0;
}
|
Noncompliant Code Example
...
| Code Block |
|---|
|
void gdClipSetAdd(gdImagePtr im,gdClipRectanglePtr rect) {
gdClipRectanglePtr more;
if (im->clip == 0) {
...
}
if (im->clip->count == im->clip->max) {
more = gdRealloc (im->clip->list,(im->clip->max + 8) *
sizeof (gdClipRectangle));
if (more == 0) return; //if /* If the realloc fails, then we have not lost the
im->clip->list value. */
if (more == 0) return;
im->clip->max += 8;
}
im->clip->list[im->clip->count] = (*rect);
im->clip->count++;
|
...
