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THR_WAKE(2)		       System Calls Manual		     THR_WAKE(2)

NAME
     thr_wake -- wake up the suspended thread

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <sys/thr.h>

     int
     thr_wake(long id);

DESCRIPTION
     This  function is intended for implementing threading.  Normal applications
     should  use  pthread_cond_timedwait(3)  together  with  pthread_cond_broad-
     cast(3)  for  typical  safe suspension with cooperation of the thread being
     suspended, or pthread_suspend_np(3) and pthread_resume_np(3) in  some  spe-
     cific situations, instead.

     Passing  the  thread  identifier of the calling thread (see thr_self(2)) to
     thr_wake() sets a thread's flag  to  cause  the  next  signal-interruptible
     sleep  of	that thread in the kernel to fail immediately with the EINTR er-
     ror.  The flag is cleared by an interruptible sleep attempt or by a call to
     thr_suspend(2).  This is used by the system threading library to  implement
     cancellation.

     If  id  is not equal to the current thread identifier, the specified thread
     is woken up if suspended by the thr_suspend(2) system call.  If the  thread
     is  not  suspended at the time of the thr_wake call, the wake is remembered
     and the next attempt of the thread to  suspend  itself  with  the	thr_sus-
     pend(2)  results in immediate return with success.  Only one wake is remem-
     bered.

RETURN VALUES
     The thr_wake() function returns the value 0 if  successful;  otherwise  the
     value  -1	is returned and the global variable errno is set to indicate the
     error.

ERRORS
     The thr_wake() operation returns these errors:

     [ESRCH]		The specified thread was not found or does not belong to
			the process of the calling thread.

SEE ALSO
     ps(1),   thr_self(2),   thr_suspend(2),   pthread_cancel(3),    pthread_re-
     sume_np(3), pthread_suspend_np(3)

STANDARDS
     The  thr_suspend() system call is non-standard and is used by 1:1 Threading
     Library (libthr, -lthr)  to  implement  IEEE  Std	1003.1-2001  ("POSIX.1")
     pthread(3) functionality.

HISTORY
     The thr_suspend() system call first appeared in FreeBSD 5.2.

FreeBSD ports 15.quarterly	   May 5, 2020			     THR_WAKE(2)

Want to link to this manual page? Use this URL:
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