1.\" Copyright (c) 2004 Michael Telahun Makonnen 2.\" 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.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.\" 27.Dd January 22, 2004 28.Dt PTHREAD_SPIN_LOCK 3 29.Os 30.Sh NAME 31.Nm pthread_spin_lock , pthread_spin_trylock , pthread_spin_unlock 32.Nd "lock or unlock a spin lock" 33.Sh LIBRARY 34.Lb libpthread 35.Sh SYNOPSIS 36.In pthread.h 37.Ft int 38.Fn pthread_spin_lock "pthread_spinlock_t *lock" 39.Ft int 40.Fn pthread_spin_trylock "pthread_spinlock_t *lock" 41.Ft int 42.Fn pthread_spin_unlock "pthread_spinlock_t *lock" 43.Sh DESCRIPTION 44The 45.Fn pthread_spin_lock 46function will acquire 47.Fa lock 48if it is not currently owned by another thread. 49If the lock cannot be acquired immediately, it will 50spin attempting to acquire the lock (it will not sleep) until 51it becomes available. 52.Pp 53The 54.Fn pthread_spin_trylock 55function is the same as 56.Fn pthread_spin_lock 57except that if it cannot acquire 58.Fa lock 59immediately it will return with an error. 60.Pp 61The 62.Fn pthread_spin_unlock 63function will release 64.Fa lock , 65which must have been previously locked by a call to 66.Fn pthread_spin_lock 67or 68.Fn pthread_spin_trylock . 69.Sh RETURN VALUES 70If successful, all these functions will return zero. 71Otherwise, an error number will be returned to indicate the error. 72.Pp 73None of these functions will return 74.Er EINTR . 75.Sh ERRORS 76The 77.Fn pthread_spin_lock , 78.Fn pthread_spin_trylock 79and 80.Fn pthread_spin_unlock 81functions will fail if: 82.Bl -tag -width Er 83.It Bq Er EINVAL 84The value specified by 85.Fa lock 86is invalid or is not initialized. 87.El 88.Pp 89The 90.Fn pthread_spin_lock 91function may fail if: 92.Bl -tag -width Er 93.It Bq Er EDEADLK 94The calling thread already owns the lock. 95.El 96.Pp 97The 98.Fn pthread_spin_trylock 99function will fail if: 100.Bl -tag -width Er 101.It Bq Er EBUSY 102Another thread currently holds 103.Fa lock . 104.El 105.Pp 106The 107.Fn pthread_spin_unlock 108function may fail if: 109.Bl -tag -width Er 110.It Bq Er EPERM 111The calling thread does not own 112.Fa lock . 113.El 114.Sh SEE ALSO 115.Xr pthread_spin_destroy 3 , 116.Xr pthread_spin_init 3 117.Sh HISTORY 118The 119.Fn pthread_spin_lock , 120.Fn pthread_spin_trylock 121and 122.Fn pthread_spin_unlock 123functions first appeared in 124.Lb libkse 125in 126.Fx 5.2 , 127and in 128.Lb libthr 129in 130.Fx 5.3 . 131.Sh BUGS 132The implementation of 133.Fn pthread_spin_lock , 134.Fn pthread_spin_trylock 135and 136.Fn pthread_spin_unlock 137is expected to conform to 138.St -p1003.2 . 139