ref: c7d9da8f5a41b833946027c802e0e8d7dd014b22
dir: /sys/src/cmd/upas/bayes/msgdb.h/
typedef struct Msgdb Msgdb; Msgdb *mdopen(char*, int); long mdget(Msgdb*, char*); void mdput(Msgdb*, char*, long); void mdenum(Msgdb*); int mdnext(Msgdb*, char**, long*); void mdclose(Msgdb*);