Standard C Library Functions                      thrsuspend(3C)



NAME
     thrsuspend, thrcontinue - suspend or continue thread  exe-
     cution

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

     int thrsuspend(threadt targetthread);


     int thrcontinue(threadt targetthread);


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


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


     A suspended thread will not be  awakened  by  any  mechanism
     other than a call to thrcontinue().  Signals and the effect
     of calls tomutexunlock(3C),  rwunlock(3C),  semapost(3C),
     condsignal(3C), and condbroadcast(3C) remain pending until
     the execution of the thread is resumed by thrcontinue().

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

ERORS
     The thrsuspend() and thrcontinue() functions will fail if:

     ESRCH     The targetthread cannot be found in  the  current
               process.


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







SunOS 5.11          Last change: 22 Mar 2002                    1






Standard C Library Functions                      thrsuspend(3C)



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     MT-Level                     MT-Safe                     
    


SEE ALSO
     thrcreate(3C), thrjoin(3C), attributes(5), standards(5)

WARNINGS
     The thrsuspend() 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 thrcontinue() is applied, regardless of
     any   calls    to    mutexunlock(),    condsignal(),    or
     condbroadcast()  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 thrsuspend() and  thrcontinue()  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