[unix-history] / usr / man / man2 / wait.2

.TH WAIT 2 
.SH NAME
wait \- wait for process to terminate
.SH SYNOPSIS
.B wait(status)
.br
.B int *status;
.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.
.SH "SEE ALSO"
exit(2), fork(2), signal(2)
.SH DIAGNOSTICS
Returns
\-1 if there are no children not previously waited for.
.SH "ASSEMBLER (PDP-11)"
(wait = 7.)
.br
.B sys  wait
.br
(process ID in r0)
.br
(status in r1)
.PP
The high byte of the status is
the low byte of r0 in the child at termination.
Commit	Line	Data
e6817382 BJ	1	.TH WAIT 2
	2	.SH NAME
	3	wait \- wait for process to terminate
	4	.SH SYNOPSIS
	5	.B wait(status)
	6	.br
	7	.B int *status;
	8	.PP
	9	.B wait(0)
	10	.SH DESCRIPTION
	11	.I Wait
	12	causes its caller to delay until a signal is received or
	13	one of its child
	14	processes terminates.
	15	If any child has died since the last
	16	.I wait,
	17	return is immediate;
	18	if there are no children, return is immediate with
	19	the error bit set
	20	(resp. with a value of \-1 returned).
	21	The normal return yields the process ID of the terminated child.
	22	In the case of several children several
	23	.I wait
	24	calls are needed
	25	to learn of all the deaths.
	26	.PP
	27	If
	28	.RI (int) status
	29	is nonzero, the high byte of the word pointed to
	30	receives the low byte of the
	31	argument of
	32	.I exit
	33	when the child terminated.
	34	The low byte
	35	receives the termination status
	36	of the process.
	37	See
	38	.IR signal (2)
	39	for a list of termination statuses (signals);
	40	0 status indicates normal termination.
	41	A special status (0177) is returned for a stopped process
	42	which has not terminated and can be restarted.
	43	See
	44	.IR ptrace (2).
	45	If the 0200 bit of the termination status
	46	is set,
	47	a core image of the process was produced
	48	by the system.
	49	.PP
	50	If the parent process terminates without
	51	waiting on its children,
	52	the initialization process
	53	(process ID = 1)
	54	inherits the children.
	55	.SH "SEE ALSO"
	56	exit(2), fork(2), signal(2)
	57	.SH DIAGNOSTICS
	58	Returns
	59	\-1 if there are no children not previously waited for.
	60	.SH "ASSEMBLER (PDP-11)"
	61	(wait = 7.)
	62	.br
	63	.B sys wait
	64	.br
65	(process ID in r0)
66	.br
67	(status in r1)
68	.PP
69	The high byte of the status is
70	the low byte of r0 in the child at termination.