freebsd-skq/lib/libc/sys/nanosleep.2
1998-05-03 22:50:14 +00:00

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.\" $Id: nanosleep.2,v 1.4 1997/09/29 19:11:21 wosch Exp $
.\" $OpenBSD: nanosleep.2,v 1.1 1997/04/20 20:56:20 tholo Exp $
.\" $NetBSD: nanosleep.2,v 1.1 1997/04/17 18:12:02 jtc Exp $
.\"
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.\" @(#)sleep.3 8.1 (Berkeley) 6/4/93
.\"
.Dd April 17, 1997
.Dt NANOSLEEP 2
.Os
.Sh NAME
.Nm nanosleep ,
.Nm signanosleep
.Sh SYNOPSIS
.Fd #include <time.h>
.Ft int
.Fn nanosleep "const struct timespec *rqtp" "struct timespec *rmtp"
.Pp
.Fd #include <signal.h>
.Fd #include <time.h>
.Ft int
.Fn signanosleep "const struct timespec *rqtp" "struct timespec *rmtp" "sigset_t *mask"
.Sh DESCRIPTION
.Fn Nanosleep
causes the process to sleep for the specified time. An unmasked signal will
cause it to terminate the sleep early, regardless of the
.Dv SA_RESTART
value on the interrupting signal.
.Pp
The
.Fn signanosleep
function temporarily (and atomically) sets the signal mask of the process
for the duration of the system call so that specific signals can be
nominated to cause an early termination of the sleep.
.Sh RETURN VALUE
If the
.Fn nanosleep
function returns because the requested time has elapsed, the value
returned will be zero.
.Pp
If the
.Fn nanosleep
function returns due to the delivery of a signal, the value returned
will be the -1, and the global variable
.Va errno
will be set to indicate the interruption.
If
.Fa rmtp
is
.Pf non- Dv NULL ,
the timespec structure it references is updated to contain the
unslept amount (the request time minus the time actually slept).
.Sh ERRORS
If any of the following conditions occur, the
.Nm
function shall return -1 and set
.Va errno
to the corresponding value.
.Bl -tag -width Er
.It Bq Er EFAULT
Either
.Fa rqtp
or
.Fa rmtp
points to memory that is not a valid part of the process
address space.
.It Bq Er EINTR
.Nm
was interrupted by the delivery of a signal.
.It Bq Er EINVAL
.Fa rqtp
specified a nanosecond value less than zero
or greater than or equal to 1000 million.
.It Bq Er ENOSYS
.Nm
is not supported by this implementation.
.El
.Sh SEE ALSO
.Xr sigsuspend 2 ,
.Xr sleep 3
.Sh STANDARDS
The
.Fn nanosleep
function conforms to
.St -p1003.1b-93 .
.Pp
The
.Fn signanosleep
function is an extension that first appeared in
.Fx 3.0