121 lines
3.5 KiB
Groff
121 lines
3.5 KiB
Groff
.\" $NetBSD: pthread_suspend_np.3,v 1.5 2010/07/09 09:18:45 jruoho Exp $
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.\"
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.\" Copyright (c) 2003, 2010 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 Christos Zoulas.
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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 July 9, 2010
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.Dt PTHREAD_SUSPEND_NP 3
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.Os
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.Sh NAME
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.Nm pthread_suspend_np ,
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.Nm pthread_resume_np
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.Nd suspend/resume the given thread
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.Sh LIBRARY
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.Lb libpthread
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.Sh SYNOPSIS
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.In pthread.h
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.Ft int
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.Fn pthread_suspend_np "pthread_t thread"
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.Ft int
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.Fn pthread_resume_np "pthread_t thread"
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.Sh DESCRIPTION
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The
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.Fn pthread_suspend_np
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function suspends the
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.Fa thread
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given as argument.
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If
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.Fa thread
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is the currently running thread as returned by
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.Xr pthread_self 3 ,
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the function fails and returns
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.Er EDEADLK .
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Otherwise, it removes the named thread from the running queue, and
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adds it to the suspended queue.
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The
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.Fa thread
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will remain blocked until
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.Fn pthread_resume_np
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is called on it.
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In other words,
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.Fn pthread_resume_np
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resumes the
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.Fa thread
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given as argument, if it was suspended.
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.Sh RETURN VALUES
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Both functions return 0 on success and an error number indicating the
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reason for the failure.
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.Sh COMPATIBILITY
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These functions are non-standard extensions.
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.Sh ERRORS
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The
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.Fn pthread_suspend_np
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function may fail if:
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.Bl -tag -width Er
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.It Bq Er EDEADLK
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The thread requested to suspend was the currently running thread.
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.It Bq Er ESRCH
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The supplied
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.Fa thread
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was invalid.
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.El
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.Pp
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The
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.Fn pthread_resume_np
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function may fail if:
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.Bl -tag -width Er
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.It Bq Er ESRCH
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The supplied
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.Fa thread
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was invalid.
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.El
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.Sh NOTES
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Some
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.Fn pthread_suspend_np
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implementations may allow suspending the current thread.
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This is dangerous, because the semantics of the function would then
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require the scheduler to schedule another thread, causing a thread
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context switch.
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Since that context switch can happen in a signal handler by someone
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calling
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.Fn pthread_suspend_np
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in a signal handler, this is currently not allowed.
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.Pp
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In
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.Fn pthread_resume_np
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the
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.Nx
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implementation does not check if the
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.Fa thread
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argument is not already suspended.
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Some implementations might return an error condition if
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.Fn pthread_resume_np
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is called on a non-suspended thread.
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.Sh SEE ALSO
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.Xr pthread_attr_setcreatesuspend_np 3 ,
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.Xr pthread_self 3
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