| SIGTIMEDWAIT(2) | System Calls Manual | SIGTIMEDWAIT(2) | 
sigtimedwait, sigwaitinfo,
  sigwait —
#include <signal.h>
int
  
  sigtimedwait(const
    sigset_t * restrict set,
    siginfo_t * restrict
    info, const struct
    timespec * restrict timeout);
int
  
  sigwaitinfo(const
    sigset_t * restrict set,
    siginfo_t * restrict
    info);
int
  
  sigwait(const
    sigset_t * restrict set,
    int * restrict sig);
sigwaitinfo() and sigwait()
  return the first pending signal from the set specified by
  set. Should multiple signals from
  set be pending, the lowest numbered one is returned. The
  selection order between realtime and non-realtime signals is unspecified. If
  there is no signal from set pending at the time of the
  call, the calling thread is suspended until one of the specified signals is
  generated.
sigtimedwait() is exactly equal to
    sigwaitinfo(), except timeout
    specifies the maximum time interval for which the calling thread will be
    suspended. If timeout is zero (tv_sec == tv_nsec ==
    0), sigtimedwait() only checks the currently pending
    signals and returns immediately. If NULL is used for
    timeout, sigtimedwait()
    behaves exactly like sigwaitinfo() in all
  regards.
If several threads are waiting for a given signal, exactly one of them returns from the signal wait when the signal is generated.
Behaviour of these functions is unspecified if any of the signals in set are unblocked at the time these functions are called.
sigtimedwait() or
  sigwaitinfo() info is updated
  with signal information, and the function returns the signal number.
  Otherwise, -1 is returned and the global variable errno
  indicates the error. Upon successful completion of
  sigwait() sig is updated with
  the signal number, and the function returns 0. Otherwise, a non-zero error
  code is returned.
sigwaitinfo() and sigwait()
  always succeed.
sigtimedwait() will fail and the
    info pointer will remain unchanged if:
EAGAIN]sigtimedwait() may also fail if:
EINVAL]This error is only checked if no signal from set is pending and it would be necessary to wait.
sigtimedwait(),
  sigwaitinfo(), and sigwait()
  conform to IEEE Std 1003.1-2001
  (“POSIX.1”).
sigtimedwait(),
  sigwaitinfo(), and sigwait()
  functions appeared in NetBSD 2.0.
| April 2, 2012 | NetBSD 9.4 |