wait(3) [debian man page]

wait(3) 						     Library Functions Manual							   wait(3)

NAME

       wait - check child process status

SYNTAX

       #include <wait.h>

       int wait_nohang(&wstat);
       int wait_stop(&wstat);
       int wait_stopnohang(&wstat);
       int wait_pid(&wstat,pid);

       int wait_exitcode(wstat);
       int wait_crashed(wstat);
       int wait_stopped(wstat);
       int wait_stopsig(wstat);

       int pid;
       int wstat;

DESCRIPTION

       wait_nohang  looks  for	zombies (child processes that have exited).  If it sees a zombie, it eliminates the zombie, puts the zombie's exit
       status into wstat, and returns the zombie's process ID.	If there are several zombies, wait_nohang picks one.  If there are children but no
       zombies, wait_nohang returns 0.	If there are no children, wait_nohang returns -1, setting errno appropriately.

       wait_stopnohang is similar to wait_nohang, but it also looks for children that have stopped.

       wait_stop is similar to wait_stopnohang, but if there are children it will pause waiting for one of them to stop or exit.

       wait_pid waits for child process pid to exit.  It eliminates any zombie that shows up in the meantime, discarding the exit status.

       wait_stop and wait_pid retry upon error_intr.

STATUS PARSING

       If the child stopped, wait_stopped is nonzero; wait_stopsig is the signal that caused the child to stop.

       If the child exited by crashing, wait_stopped is zero; wait_crashed is nonzero.

       If the child exited normally, wait_stopped is zero; wait_crashed is zero; and wait_exitcode is the child's exit code.

SEE ALSO

       wait(2), error(3)

																	   wait(3)

preap(1)                                                           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 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.

OPTIONS

       The following option is supported:

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

OPERANDS

       The following operand is supported:

       pid      Process ID list.

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 attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE         |      ATTRIBUTE VALUE        |
       +-----------------------------+-----------------------------+
       |Availability                 |SUNWesu (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  will
       not be reaped by the parent process. Otherwise, applying preap may damage the parent process in unpredictable ways.

SunOS 5.10                                                          26 Mar 2001                                                           preap(1)