Child class object initialisation - Braced init

In the below code,

struct X
{
  int a;
  int b;
  void *ptr;
};

class Base
{
 public:
  int a;
  int b;
  void *ptr;
};

class Child : public Base
{
public:
  int c;
};

X obj  = { 9, 2, malloc(TWOBYTES), };
Base obj1  = { 3, 4, malloc(TWOBYTES), };
Child obj2  = { 8, 4, malloc(TWOBYTES), 10, }; // Error

obj2 does not get initialised

Question:

Why braced-init syntax does not work for Child class?