typedef void process_callback_fn(void *cst, pid_t pid, int status);
typedef void process_entry_fn(void *cst);
typedef void signal_notify_fn(void *cst, int signum);
typedef void process_callback_fn(void *cst, pid_t pid, int status);
typedef void process_entry_fn(void *cst);
typedef void signal_notify_fn(void *cst, int signum);
void *est, void *cbst, string_t desc);
extern void request_signal_notification(int signum, signal_notify_fn *notify,
void *est, void *cbst, string_t desc);
extern void request_signal_notification(int signum, signal_notify_fn *notify,