.\" $NetBSD: pthread_suspend_np.3,v 1.2 2003/11/12 11:58:34 wiz Exp $ .\" .\" Copyright (c) 2003 The NetBSD Foundation, Inc. .\" All rights reserved. .\" .\" This code is derived from software contributed to The NetBSD Foundation .\" by Christos Zoulas. .\" .\" 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 NetBSD .\" Foundation, Inc. and its contributors. .\" 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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. .\" .Dd November 12, 2003 .Dt PTHREAD_SUSPEND_NP 3 .Os .Sh NAME .Nm pthread_suspend_np , .Nm pthread_resume_np .Nd suspend/resume the given thread .Sh LIBRARY .Lb libpthread .Sh SYNOPSIS .In pthread.h .Ft int .Fn pthread_suspend_np "pthread_t thread" .Ft int .Fn pthread_resume_np "pthread_t thread" .Sh DESCRIPTION The .Fn pthread_suspend_np function suspends the .Ar thread given as argument. If .Ar thread is the currently running thread as returned by .Xr pthread_self 3 , the function fails and returns .Er EDEADLK . Otherwise, it removes the named thread from the running queue, and adds it to the suspended queue. The .Ar thread will remain blocked until .Fn pthread_resume_np is called on it. .Pp .Fn pthread_resume_np resumes the .Ar thread given as argument, if it was suspended. .Sh RETURN VALUES The .Fn pthread_suspend_np function returns 0 on success and an error number indicating the reason for the failure. The .Fn pthread_resume_np function always returns 0. .Sh ERRORS .Fn pthread_suspend_np shall fail if: .Bl -tag -width Er .It Bq Er EDEADLK The thread requested to suspend was the currently running thread. .El .Pp .Fn pthread_resume_np never fails. .Sh NOTES Some .Fn pthread_suspend_np implementations may allow suspending the current thread. This is dangerous, because the semantics of the function would then require the scheduler to schedule another thread, causing a thread context switch. Since that context switch can happen in a signal handler by someone calling .Fn pthread_suspend_np in a signal handler, this is currently not allowed. .Pp In .Fn pthread_resume_np we don't check if the .Ar thread argument is not already suspended. Some implementations might return an error condition if .Fn pthread_resume_np is called on a non-suspended thread. .Sh SEE ALSO .Xr pthread_attr_setcreatesuspend_np 3 , .Xr pthread_self 3