Manual Pages for UNIX Operating System command usage for man thr_suspend

Standard C Library Functions                      thr_suspend(3C)



NAME
     thr_suspend, thr_continue - suspend or continue thread  exe-
     cution

SYNOPSIS
     cc -mt [ flag... ] file...[ library... ]
     #include 

     int thr_suspend(thread_t target_thread);


     int thr_continue(thread_t target_thread);


DESCRIPTION
     The thr_suspend() function immediately suspends  the  execu-
     tion of the thread specified by target_thread. On successful
     return from thr_suspend(), the suspended thread is no longer
     executing.  Once  a thread is suspended, subsequent calls to
     thr_suspend() have no effect.


     The thr_continue()  function  resumes  the  execution  of  a
     suspended thread. Once a suspended thread is continued, sub-
     sequent calls to thr_continue() have no effect.


     A suspended thread will not be  awakened  by  any  mechanism
     other than a call to thr_continue().  Signals and the effect
     of calls tomutex_unlock(3C),  rw_unlock(3C),  sema_post(3C),
     cond_signal(3C), and cond_broadcast(3C) remain pending until
     the execution of the thread is resumed by thr_continue().

RETURN VALUES
     If successful, the thr_suspend()  and  thr_continue()  func-
     tions  return  0. Otherwise, a non-zero value is returned to
     indicate the error.

ERRORS
     The thr_suspend() and thr_continue() functions will fail if:

     ESRCH     The target_thread cannot be found in  the  current
               process.


ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:







SunOS 5.11          Last change: 22 Mar 2002                    1






Standard C Library Functions                      thr_suspend(3C)



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|


SEE ALSO
     thr_create(3C), thr_join(3C), attributes(5), standards(5)

WARNINGS
     The thr_suspend() function is  extremely  difficult  to  use
     safely because it suspends the target thread with no concern
     for the target thread's state. The target  thread  could  be
     holding locks, waiting for a lock, or waiting on a condition
     variable when it is unconditionally  suspended.  The  thread
     will  not run until thr_continue() is applied, regardless of
     any   calls    to    mutex_unlock(),    cond_signal(),    or
     cond_broadcast()  by other threads. Its existence on a sleep
     queue can interfere with the waking up of other threads that
     are on the same sleep queue.


     The thr_suspend() and  thr_continue()  functions  should  be
     avoided. Mechanisms that involve the cooperation of the tar-
     geted thread, such as mutex locks and  condition  variables,
     should be employed instead.




























SunOS 5.11          Last change: 22 Mar 2002                    2