Union

Similar to structure, union declaration can be
  1. Union names form a separate namespace
    struct UNION {
      member1type member1;
      member2type member2;
    };
    
    usage in declarations and definitions requires keyword union in C (recommended to C++ too)
    union UNION u;
    
  2. typedef can be used to shorten declarations and definitions
    typedef union UNION Union;
    Union u;
    
  3. typedef and union declarations can be combined into one construct
    typedef union UNION {
      member1type member1;
      member2type member2;
    } Union;
    
  4. Typically, inner union declaration needs no name
    typedef union {
      member1type member1;
      member2type member2;
    } Union;
    
Index