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 via the wait(3C),
waitid(2), or waitpid(3C) system call. In the normal course of system
operation, zombies may occur, but are typically short-lived. This may
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 may 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 represents a defunct process.
preap will attempt 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.
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
See attributes(5) for descriptions of the following attributes:
tab() allbox; cw(2.750000i)| cw(2.750000i) lw(2.750000i)|
lw(2.750000i). ATTRIBUTE TYPEATTRIBUTE VALUE AvailabilitySUNWesu
proc(1), init(1M), waitid(2), wait(3C), waitpid(3C), proc(4),
preap should be applied sparingly and only in situations in which the
administrator or developer has confirmed that defunct processes will
not be reaped by the parent process. Otherwise, applying preap may dam-
age the parent process in unpredictable ways.
SunOS 5.10 26 Mar 2001 preap(1)