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    Types: TextFile
    Notes: UNIX file
    Names: »wait.2«

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.ig
	@(#)wait.2	2.1	7/1/84
	@(#)Copyright (C) 1983 by National Semiconductor Corp.
..
.TH WAIT 2 
.SH NAME
wait \- wait for process to terminate
.SH SYNOPSIS
.nf
.B wait(status)
.B int *status;
.fi
.PP
.B wait(0)
.SH DESCRIPTION
.I Wait
causes its caller to delay until a signal is received or
one of its child
processes terminates.
If any child has died since the last
.I wait,
return is immediate;
if there are no children, return is immediate with
the error bit set
(resp. with a value of \-1 returned).
The normal return yields the process ID of the terminated child.
In the case of several children, several
.I wait
calls are needed
to learn of all the deaths.
.PP
If
.RI (int) status
is nonzero, the high byte of the word pointed to
receives the low byte of the
argument of
.I exit
when the child terminated.
The low byte
receives the termination status
of the process.
See
.IR signal (2)
for a list of termination statuses (signals);
0 status indicates normal termination.
A special status (0177) is returned for a stopped process
which has not terminated and can be restarted.
See
.IR ptrace (2).
If the 0200 bit of the termination status
is set,
a core image of the process was produced
by the system.
.PP
If the parent process terminates without
waiting on its children,
the initialization process
(process ID = 1)
inherits the children.
.PP
There is another entry
.IR wait3 (2)
which is provides additional options needed by the shell
.IR csh (1)
to do job control.
.SH "SEE ALSO"
wait3(2), exit(2), fork(2), signal(2)
.SH DIAGNOSTICS
Returns
\-1 if there are no children not previously waited for.