implementing closure in C (incompleted)

clousre.c

/*
a = 5;
b = 6;
A = lambda(x){
  return A + a;
}

*/

typedef struct closure_A 
{
  int * a;
  int * b;
  void (*call)(void);
  
  } closure_A;

/*
typedef struct closure_B 
{
  int * a_;
  int * b_;
  int * x_;
  void (*call)(void);
  
  } closure_B;
  */


int call_A(void *env, int * x){
  closure_A * clousure_A =  (closure_A*) env;
  
  
  int result = *x + *(clousure_A->b);
  
  return result;
}

int main() {
  
  
  int *a = malloc(sizeof(int));
  *a = 5;
  
  int *b = malloc(sizeof(int));
  *b = 5;
  
  closure_A * clu_A = malloc(sizeof(closure_A));
  clu_A->a = a;
  clu_A->b = b;
  
  clu_A->call = (void (*)(void)) call_A;
  
  int *x = malloc(sizeof(int));
  *x = 5;
  ((int(*)(void*,int*))clu_A->call)(clu_A, x);

  return 0;
}