#define LENGTH 12
#define ERRCODE_BEGING enum {
#define ERRCODE_END };

#define ERRCODE(errcode, disp, action) errcode,

ERRCODE_BEGING
    ERRCODE(RET_a, "a", "a")         //here cannot recognize RET_a correctly
    ERRCODE(RET_b, "b", "b"#LENGTH)  //here cannot recognize LENGTH correctly
    ERRCODE(RET_c, "c", "c")
ERRCODE_END

#define test ("abc"#LENGTH)

#define obj  "abc"#LENGTH

#define LENGTH 12
#define ERRCODE_BEGING enum {
#define ERRCODE_END };

#define ERRCODE(errcode, disp, action) errcode,

ERRCODE_BEGING
    ERRCODE(RET_a, "a", "a")
    ERRCODE(RET_b, "b", "b"#LENGTH)  //here cannot recognize LENGTH correctly
    ERRCODE(RET_c, "c", "c")         //after the above line, all wrong
    ERRCODE(RET_d, "d", "d")
ERRCODE_END