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OpenSolaris 2009.06 - man page for preap (opensolaris section 1)

preap(1)				  User Commands 				 preap(1)

       preap - force a defunct process to be reaped by its parent

       preap [-F] pid...

       A defunct (or zombie) process is one whose exit status has yet to be reaped by its parent.
       The exit status is reaped by way of the wait(3C), waitid(2), or waitpid(3C)  system  call.
       In  the	normal	course	of  system operation, zombies can occur, but are typically short-
       lived. This can happen if a parent exits without having reaped the exit status of some  or
       all  of	its children. In that case, those children are reparented to PID 1. See init(1M),
       which periodically reaps such processes.

       An irresponsible parent process can not exit for a very long time and thus  leave  zombies
       on  the	system.  Since	the  operating system destroys nearly all components of a process
       before it becomes defunct, such defunct processes do not normally impact system operation.
       However, they do consume a small amount of system memory.

       preap forces the parent of the process specified by pid to waitid(3C) for pid, if pid rep-
       resents a defunct process.

       preap attempts to prevent the administrator from unwisely reaping a  child  process  which
       might soon be reaped by the parent, if:

	   o	  The process is a child of init(1M).

	   o	  The  parent  process	is  stopped  and might wait on the child when it is again
		  allowed to run.

	   o	  The process has been defunct for less than one minute.

       The following option is supported:

       -F    Forces the parent to reap the child, overriding safety checks.

       The following operand is supported:

       pid    Process ID list.

       Caution should be exercised when using the -F flag. Imposing two controlling processes  on
       one  victim  process  can lead to chaos. Safety is assured only if the primary controlling
       process, typically a debugger, has stopped the victim process and the primary  controlling
       process is doing nothing at the moment of application of the proc tool in question.

       The following exit values are returned by preap, which prints the exit status of each tar-
       get process reaped:

       0	   Successfully operation.

       non-zero    Failure, such as no such process, permission denied, or invalid option.

       See attributes(5) for descriptions of the following attributes:

       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       |Availability		     |SUNWesu (32-bit)		   |
       |			     |SUNWesxu (64-bit) 	   |

       proc(1), init(1M), waitid(2), wait(3C), waitpid(3C), proc(4), attributes(5)

       preap should be applied sparingly and only in situations in  which  the	administrator  or
       developer  has confirmed that defunct processes are not reaped by the parent process. Oth-
       erwise, applying preap can damage the parent process in unpredictable ways.

SunOS 5.11				   19 Jun 2006					 preap(1)

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