CODEWITHSUNDEEP
cpointersdynamicmalloc
Pedro T Freidinger
Pedro T Freidinger

Reputation: 48

Do I need to free a pointer which receives a dynamically allocated object from a function?

I am implementing a function that reads a line in C from stdin. Here is the code:

char * stdin_getline(){
  unsigned buffer_size = 100;
  char *string = malloc(buffer_size);
  char *string_temp;
  char temp;
  int i=0;
  while(1) {
    scanf("%c", &temp);
    if (temp == '\n') {break;}
    if (i == buffer_size-1) {
      *(string+buffer_size) = '\0';
      string_temp = malloc(buffer_size);
      strcpy(string_temp, string);
      free(string);
      buffer_size *= 2;
      string = malloc(buffer_size);
      strcpy(string, string_temp);
      free(string_temp);
    }
    *(string+i) = temp;
    i++;
  }
  *(string+i+1) = '\0';
  return string;
}

int main() {
  char *temp_line;
  temp_line = stdin_getline();
  printf("%s\n", temp_line);
  free(temp_line); // Is this line needed?
  return 0;
}

Do I really need to free the temp_line pointer inside the main function?

Upvotes: 0

Views: 145

Answers (1)

Naomi
Naomi

Reputation: 5486

The function call is irrelevant to the question. Everything that was allocated by malloc must be deallocated using free in order to avoid memory leaks.

Upvotes: 2

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