C语言安全之数组长度与指针实例解析

void func(size_t s) {
 int vla[s];
 /*...*/
}
/*...*/
func(size);
/*...*/

enum {MAX_ARRAY = 1024};
void func(size_t s) {
 if(s < MAX_ARRAY && s != 0) {
  int vla[s];
  /*...*/
 } else {
  //错误处理
 }
}
/*...*/
func(size);
/*...*/

enum {WORKSPACE_SIZE = 256};
void func(const int src[], size_t len) {
 int dest[WORKSPACE_SIZE];
 if(len > WORKSPACE_SIZE) {
  //错误处理
 }
 memcpy(dest, src, sizeof(int) * len);
 /*...*/
}

struct numbers {
 short num1;
 short num2;
 /*...*/
 short num9;
};
int sum_numbers(const struct numbers *numb) {
 int total = 0;
 const int *numb_ptr;
 for(numb_ptr = &numb->num1; numb_ptr <= &numb->num9; numb_ptr++) {
  total += *(numb_ptr);
 }
 return total;
}
int main(void) {
 struct numbers my_numbers = {1,2,3,4,5,6,7,8,9};
 sum_numbers(&my_numbers);
 return 0;
}

struct numbers {
 short num1;
 short num2;
 /*...*/
 short num9;
};
int sum_numbers(const short *numb, size_t dim) {
 int total = 0;
 const int *numb_ptr;
 for(numb_ptr = numb; numb_ptr < numb + dim; numb_ptr++) {
  total += *(numb_ptr);
 }
 return total;
}
int main(void) {
 short my_numbers[9] = {1,2,3,4,5,6,7,8,9};
 sum_numbers(my_numbers, sizeof(my_numbers) / sizeof(my_numbers[0]));
 return 0;
}