We don't know how its mistress works maybe we don't want to know
#if defined(Identity_CHECK)
/** This goes in each structure which will be checked. */
#define Identity \
unsigned long Identity_verifier;
#define Identity_set(pointer) \
(pointer)->Identity_verifier = Identity_MAGIC
#define Identity_check(pointer) \
(__extension__ ({ \
__typeof__(pointer) Identity_ptr = (pointer); \
Assert_true(Identity_ptr->Identity_verifier == Identity_MAGIC); \
Identity_ptr; \
}))
#define Identity_ncheck(pointer) \
(__extension__ ({ \
__typeof__(pointer) Identity_ptr = (pointer); \
Assert_true(!Identity_ptr || Identity_ptr->Identity_verifier == Identity_MAGIC); \
Identity_ptr; \
}))
#else
#define Identity
#define Identity_set(pointer)
#define Identity_check(pointer) \
(__extension__ ({ \
(pointer); \
}))
#define Identity_ncheck(pointer) Identity_check(pointer)
#endif