thr_suspend(3C) 					   Standard C Library Functions 					   thr_suspend(3C)

NAME

       thr_suspend, thr_continue - suspend or continue thread execution

SYNOPSIS

       cc -mt [ flag... ] file...[ library... ]
       #include <thread.h>

       int thr_suspend(thread_t target_thread);

       int thr_continue(thread_t target_thread);

DESCRIPTION

       The  thr_suspend() function immediately suspends the execution of the thread specified by target_thread. On successful return from thr_sus-
       pend(), 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, subsequent calls to thr_con-
       tinue() 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 tomu-
       tex_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() functions 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 attributes:

       +-----------------------------+-----------------------------+
       |      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 targeted thread, such as
       mutex locks and condition variables, should be employed instead.

SunOS 5.10							    22 Mar 2002 						   thr_suspend(3C)