Manual Pages for UNIX Operating System command usage for man preap

User Commands                                            preap(1)



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

SYNOPSIS
     preap [-F] pid...


DESCRIPTION
     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 operat-
     ing 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 represents 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.

OPTIONS
     The following option is supported:

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


OPERANDS




SunOS 5.11          Last change: 19 Jun 2006                    1






User Commands                                            preap(1)



     The following operand is supported:

     pid    Process ID list.


USAGE
     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 pro-
     cess and the primary controlling process is doing nothing at
     the moment of application of the proc tool in question.

EXIT STATUS
     The following exit  values  are  returned  by  preap,  which
     prints the exit status of each target process reaped:

     0           Successfully operation.


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


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



     ____________________________________________________________
   |        ATTRIBUTE TYPE       |        ATTRIBUTE VALUE      |
   | ____________________________|_____________________________|_
   |  Availability               |  system/extended-system-    |
   |                             |  utilities (32-bit)         |
   |                             | SUNWesxu (64-bit)           |
   |_____________________________|_____________________________|


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

WARNINGS
     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          Last change: 19 Jun 2006                    2