c - 返回字符串的内存泄漏

Question

我正在编写一个函数，我在其中操作一个字符串并在一系列 strcpy 和 strcat 之后返回一个 malloc 的字符串:

char * doRequest(char *start, char**headers, char *body)
{
  char * reply;
  char * com;
  int i;

  reply = malloc(512 * sizeof(char));
  if (!reply)
    return SRV_ERR;
  strcpy(reply, "Your request ");
  com = strtok(start, " ");

  strcat(reply, com);
  strcat(reply, " with options: ");

  for (i = 0; headers[i] != NULL; i = i + 2)
  {
    strcat(reply, headers[i]);
    strcat(reply, ", ");
  }
  strcat(reply, "has been received.");
  strcat(reply, "\0");
  return reply;
}

然后我在调用者的代码中释放返回的指针:

  ...

  char * reply = doRequest(command, headers, body);
  int len = strlen(reply);
  printf("Return message: %s\n", doRequest(command, headers, body));
  if(writen(s, reply, len) != len) printf("Write error while replying\n");
  else printf("Request served correctly.\n");
  free(reply);

  ...

我想正确地释放该内存，但 Valgrind 仍然说该内存未释放并因此丢失。那个代码有什么问题？？ 感谢您的帮助!

Answer 1

第二次调用 doRequest() 分配的内存永远不会是 free()d。

我建议替换这一行:

printf("Return message: %s\n", doRequest(command, headers, body));

通过这个:

printf("Return message: '%s'\n", reply);