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Non-compliant Code Example 2

This example attempts to resize the string referenced by buf to make enough room to append the string line. However, once in the function append(), there is no way to determine how buf was allocated. When realloc() is called on buf, since buf does not point to dynamic memory, an error may occur.demonstrates an error that can occur when memory is freed in different functions. First, an array of number integers is dynamically allocated. That array, referred to by list, and its size, number, are then passed to func2. If the number of elements in the array is greater than the value MIN_SIZE_ALLOWED, the array is processed. Otherwise, it is assumed an error has occurred, list is freed, and the function returns. If the error occurs in func2 the dynamic memory referred to by list will be freed twice: once in func2 and again at the end of func1.

 

#define MIN_SIZE_ALLOWED 10

void func2(int *list, size_t list_size) {
  if (size < MIN_SIZE_ALLOWED) {
     /* Error Condition */

void handle_error (char *buf) {
    printf("%s is not correct!\n",buf);
    free(buflist);
    return;
  } 

void func(char * str1, char * str2) {



   /* Process list */
}

int func1 (size_t number) {
  int *list = malloc (number * sizeof(int));
  if (list == NULL) {
    /* Handle Allocation Error */
  }
  func2(list,number);

  /* Process list */

  free(list);
}

  

Compliant Solution 2

/* NOTE: buf must point to dynamically allocated memory */
void append(char \*buf, size_t count, size_t size) {
  char *line = " <- THIS IS A LINE";
  size_t line_len = strlen(line);
  if ((count + line_len) > size)
  buf = realloc(buf,count+line_len);
  strncat(buf,line);
}

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