[apple/libc.git] / gen / FreeBSD / usleep.3

.\" Copyright (c) 1986, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)usleep.3	8.1 (Berkeley) 6/4/93
.\" $FreeBSD: src/lib/libc/gen/usleep.3,v 1.18 2002/12/29 00:59:09 mike Exp $
.\"
.Dd February 13, 1998
.Dt USLEEP 3
.Os
.Sh NAME
.Nm usleep
.Nd suspend process execution for an interval measured in microseconds
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In unistd.h
.Ft int
.Fn usleep "useconds_t microseconds"
.Sh DESCRIPTION
The
.Fn usleep
function suspends execution of the calling process until either
.Fa microseconds
microseconds have elapsed or a signal is delivered to the process and its
action is to invoke a signal-catching function or to terminate the
process.
System activity may lengthen the sleep by an indeterminate amount.
.Pp
This function is implemented using
.Xr nanosleep 2
by pausing for
.Fa microseconds
microseconds or until a signal occurs.
Consequently, in this implementation,
sleeping has no effect on the state of process timers,
and there is no special handling for SIGALRM.
.Sh RETURN VALUES
.Rv -std usleep
.Sh ERRORS
The
.Fn usleep
function
will fail if:
.Bl -tag -width Er
.It Bq Er EINTR
A signal was delivered to the process and its
action was to invoke a signal-catching function.
.El
.Sh SEE ALSO
.Xr nanosleep 2 ,
.Xr sleep 3
.Sh HISTORY
The
.Fn usleep
function appeared in
.Bx 4.3 .
Commit	Line	Data
5b2abdfb	1	.\" Copyright (c) 1986, 1991, 1993
e9ce8d39 A	2	.\" The Regents of the University of California. All rights reserved.
	3	.\"
	4	.\" Redistribution and use in source and binary forms, with or without
	5	.\" modification, are permitted provided that the following conditions
	6	.\" are met:
	7	.\" 1. Redistributions of source code must retain the above copyright
	8	.\" notice, this list of conditions and the following disclaimer.
	9	.\" 2. Redistributions in binary form must reproduce the above copyright
	10	.\" notice, this list of conditions and the following disclaimer in the
	11	.\" documentation and/or other materials provided with the distribution.
	12	.\" 3. All advertising materials mentioning features or use of this software
	13	.\" must display the following acknowledgement:
	14	.\" This product includes software developed by the University of
	15	.\" California, Berkeley and its contributors.
	16	.\" 4. Neither the name of the University nor the names of its contributors
	17	.\" may be used to endorse or promote products derived from this software
	18	.\" without specific prior written permission.
	19	.\"
	20	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	21	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	22	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	23	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	24	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	25	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	26	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	27	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	28	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	29	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	30	.\" SUCH DAMAGE.
	31	.\"
5b2abdfb	32	.\" @(#)usleep.3 8.1 (Berkeley) 6/4/93
3d9156a7	33	.\" $FreeBSD: src/lib/libc/gen/usleep.3,v 1.18 2002/12/29 00:59:09 mike Exp $
e9ce8d39	34	.\"
5b2abdfb A	35	.Dd February 13, 1998
5b2abdfb A	36	.Dt USLEEP 3
e9ce8d39 A	37	.Os
e9ce8d39 A	38	.Sh NAME
5b2abdfb A	39	.Nm usleep
5b2abdfb A	40	.Nd suspend process execution for an interval measured in microseconds
e9ce8d39 A	41	.Sh LIBRARY
	42	.Lb libc
	43	.Sh SYNOPSIS
5b2abdfb	44	.In unistd.h
e9ce8d39	45	.Ft int
3d9156a7	46	.Fn usleep "useconds_t microseconds"
e9ce8d39 A	47	.Sh DESCRIPTION
e9ce8d39 A	48	The
5b2abdfb A	49	.Fn usleep
	50	function suspends execution of the calling process until either
	51	.Fa microseconds
	52	microseconds have elapsed or a signal is delivered to the process and its
	53	action is to invoke a signal-catching function or to terminate the
	54	process.
	55	System activity may lengthen the sleep by an indeterminate amount.
	56	.Pp
	57	This function is implemented using
	58	.Xr nanosleep 2
	59	by pausing for
	60	.Fa microseconds
	61	microseconds or until a signal occurs.
	62	Consequently, in this implementation,
	63	sleeping has no effect on the state of process timers,
	64	and there is no special handling for SIGALRM.
e9ce8d39	65	.Sh RETURN VALUES
5b2abdfb	66	.Rv -std usleep
e9ce8d39	67	.Sh ERRORS
5b2abdfb A	68	The
	69	.Fn usleep
	70	function
e9ce8d39 A	71	will fail if:
e9ce8d39 A	72	.Bl -tag -width Er
5b2abdfb A	73	.It Bq Er EINTR
	74	A signal was delivered to the process and its
	75	action was to invoke a signal-catching function.
	76	.El
e9ce8d39	77	.Sh SEE ALSO
5b2abdfb A	78	.Xr nanosleep 2 ,
5b2abdfb A	79	.Xr sleep 3
e9ce8d39 A	80	.Sh HISTORY
e9ce8d39 A	81	The
5b2abdfb A	82	.Fn usleep
	83	function appeared in
	84	.Bx 4.3 .