3.1.2.1 struct x1f4_trans_type

typedef struct x1f4_trans_type {
    int (*free)(void *, void *), (*link)(void *, void **, unsigned),
	(*mode)(void *, void **, unsigned);
    void *context;
} x1f4_trans_type;

The struct x1f4_trans_type record describes some memory allocation context. It is a regular bs memory allocator construct.

See Memory Allocator Construct.