text: /*! Signals */
  #pragma once
  
  #include <types/signal.h>
  
  /*! interface to threads */
  
  int sys__sigqueue ( pid_t pid, int signo, sigval_t sigval );
  int sys__pthread_sigmask ( int how, sigset_t *set, sigset_t *oset );
  int sys__sigaction ( int sig, sigaction_t *act, sigaction_t *oact );
  int sys__sigwaitinfo ( sigset_t *set, siginfo_t *info );