unsigned int fun1 ( void );
unsigned int fun2 ( void );

int main ( void )
{
  unsigned int a1 = 0U;
  unsigned int a2 = 0U;
  unsigned int a3 = 0U;

  a1 = fun1 ( );
  a2 = fun2 ( );
  a3 = a1 + a2;

  return ( 0 );
}

unsigned int fun1 ( void )
{
  unsigned int x = 0U;

#define BLOCKDEF1 2U  //遵循1

  x = x + BLOCKDEF1;

#undef BLOCKDEF1      //遵循2

  return x;
}

unsigned int fun2 ( void )
{
  unsigned int x = 0U;

#define BLOCKDEF2 2U  //遵循3

  x = x + BLOCKDEF2;

#undef BLOCKDEF2      //遵循4

  return x;
}