extern int pthread_sigmask (int, const sigset_t *, sigset_t *);
extern int sigismember (const sigset_t *, int);
extern int setpgrp (int, int);
extern int sigaction (int, const struct sigaction *, struct sigaction *);
extern int alarm (int);
extern int pthread_sigmask (int, const sigset_t *, sigset_t *);
extern int sigismember (const sigset_t *, int);
extern int setpgrp (int, int);
extern int sigaction (int, const struct sigaction *, struct sigaction *);
extern int alarm (int);