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.Dd January 22, 2004 26.Dt PTHREAD_SPIN_LOCK 3 27.Os 28.Sh NAME 29.Nm pthread_spin_lock , pthread_spin_trylock , pthread_spin_unlock 30.Nd "lock or unlock a spin lock" 31.Sh LIBRARY 32.Lb libpthread 33.Sh SYNOPSIS 34.In pthread.h 35.Ft int 36.Fn pthread_spin_lock "pthread_spinlock_t *lock" 37.Ft int 38.Fn pthread_spin_trylock "pthread_spinlock_t *lock" 39.Ft int 40.Fn pthread_spin_unlock "pthread_spinlock_t *lock" 41.Sh DESCRIPTION 42The 43.Fn pthread_spin_lock 44function will acquire 45.Fa lock 46if it is not currently owned by another thread. 47If the lock cannot be acquired immediately, it will 48spin attempting to acquire the lock (it will not sleep) until 49it becomes available. 50.Pp 51The 52.Fn pthread_spin_trylock 53function is the same as 54.Fn pthread_spin_lock 55except that if it cannot acquire 56.Fa lock 57immediately it will return with an error. 58.Pp 59The 60.Fn pthread_spin_unlock 61function will release 62.Fa lock , 63which must have been previously locked by a call to 64.Fn pthread_spin_lock 65or 66.Fn pthread_spin_trylock . 67.Sh RETURN VALUES 68If successful, all these functions will return zero. 69Otherwise, an error number will be returned to indicate the error. 70.Pp 71None of these functions will return 72.Er EINTR . 73.Sh ERRORS 74The 75.Fn pthread_spin_lock , 76.Fn pthread_spin_trylock 77and 78.Fn pthread_spin_unlock 79functions will fail if: 80.Bl -tag -width Er 81.It Bq Er EINVAL 82The value specified by 83.Fa lock 84is invalid or is not initialized. 85.El 86.Pp 87The 88.Fn pthread_spin_lock 89function may fail if: 90.Bl -tag -width Er 91.It Bq Er EDEADLK 92The calling thread already owns the lock. 93.El 94.Pp 95The 96.Fn pthread_spin_trylock 97function will fail if: 98.Bl -tag -width Er 99.It Bq Er EBUSY 100Another thread currently holds 101.Fa lock . 102.El 103.Pp 104The 105.Fn pthread_spin_unlock 106function may fail if: 107.Bl -tag -width Er 108.It Bq Er EPERM 109The calling thread does not own 110.Fa lock . 111.El 112.Sh SEE ALSO 113.Xr pthread_spin_destroy 3 , 114.Xr pthread_spin_init 3 115.Sh HISTORY 116The 117.Fn pthread_spin_lock , 118.Fn pthread_spin_trylock 119and 120.Fn pthread_spin_unlock 121functions first appeared in 122.Lb libkse 123in 124.Fx 5.2 , 125and in 126.Lb libthr 127in 128.Fx 5.3 . 129.Sh BUGS 130The implementation of 131.Fn pthread_spin_lock , 132.Fn pthread_spin_trylock 133and 134.Fn pthread_spin_unlock 135is expected to conform to 136.St -p1003.2 . 137