155 lines
4.2 KiB
Groff
155 lines
4.2 KiB
Groff
.\" $NetBSD: sigtimedwait.2,v 1.8 2012/04/02 22:06:47 agc Exp $
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.\"
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.\" Copyright (c) 2003 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to The NetBSD Foundation
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.\" by Jaromir Dolecek.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd April 2, 2012
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.Dt SIGTIMEDWAIT 2
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.Os
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.Sh NAME
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.Nm sigtimedwait ,
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.Nm sigwaitinfo ,
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.Nm sigwait
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.Nd wait for queued signals
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In signal.h
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.Ft int
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.Fn sigtimedwait "const sigset_t * restrict set" "siginfo_t * restrict info" "const struct timespec * restrict timeout"
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.Ft int
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.Fn sigwaitinfo "const sigset_t * restrict set" "siginfo_t * restrict info"
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.Ft int
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.Fn sigwait "const sigset_t * restrict set" "int * restrict sig"
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.Sh DESCRIPTION
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.Fn sigwaitinfo
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and
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.Fn sigwait
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return the first pending signal from the set specified by
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.Fa set .
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Should multiple signals from
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.Fa set
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be pending, the lowest numbered one is returned.
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The selection order between realtime and non-realtime signals is unspecified.
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If there is no signal from
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.Ar set
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pending at the time of the call, the calling thread
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is suspended until one of the specified signals is generated.
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.Pp
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.Fn sigtimedwait
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is exactly equal to
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.Fn sigwaitinfo ,
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except
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.Fa timeout
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specifies the maximum time interval for which the calling thread will
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be suspended.
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If
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.Fa timeout
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is zero (tv_sec == tv_nsec == 0),
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.Fn sigtimedwait
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only checks the currently pending signals and returns immediately.
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If
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.Dv NULL
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is used for
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.Fa timeout ,
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.Fn sigtimedwait
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behaves exactly like
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.Fn sigwaitinfo
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in all regards.
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.Pp
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If several threads are waiting for a given signal, exactly one of them
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returns from the signal wait when the signal is generated.
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.Pp
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Behaviour of these functions is unspecified if any of the signals in
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.Fa set
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are unblocked at the time these functions are called.
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.Sh RETURN VALUES
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Upon successful completion of
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.Fn sigtimedwait
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or
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.Fn sigwaitinfo
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.Fa info
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is updated with signal information, and the function returns the signal number.
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Otherwise, \-1 is returned and the global variable
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.Va errno
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indicates the error.
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Upon successful completion of
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.Fn sigwait
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.Fa sig
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is updated with the signal number, and the function returns 0.
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Otherwise, a non-zero error code is returned.
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.Sh ERRORS
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.Fn sigwaitinfo
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and
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.Fn sigwait
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always succeed.
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.Pp
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.Fn sigtimedwait
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will fail and the
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.Fa info
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pointer will remain unchanged if:
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.Bl -tag -width Er
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.It Bq Er EAGAIN
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No signal specified in
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.Fa set
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was generated in the specified
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.Fa timeout .
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.El
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.Pp
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.Fn sigtimedwait
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may also fail if:
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.Bl -tag -width Er
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.It Bq Er EINVAL
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The specified
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.Fa timeout
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was invalid.
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.El
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.Pp
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This error is only checked if no signal from
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.Fa set
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is pending and it would be necessary to wait.
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.Sh SEE ALSO
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.Xr sigaction 2 ,
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.Xr sigprocmask 2 ,
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.Xr signal 7
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.Sh STANDARDS
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The functions
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.Fn sigtimedwait ,
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.Fn sigwaitinfo ,
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and
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.Fn sigwait
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conform to
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.St -p1003.1-2001 .
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.Sh HISTORY
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The
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.Fn sigtimedwait ,
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.Fn sigwaitinfo ,
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and
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.Fn sigwait
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functions appeared in
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.Nx 2.0 .
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