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.Lb libthr 36.Sh SYNOPSIS 37.In pthread.h 38.Ft int 39.Fn pthread_spin_lock "pthread_spinlock_t *lock" 40.Ft int 41.Fn pthread_spin_trylock "pthread_spinlock_t *lock" 42.Ft int 43.Fn pthread_spin_unlock "pthread_spinlock_t *lock" 44.Sh DESCRIPTION 45The 46.Fn pthread_spin_lock 47function will acquire 48.Fa lock 49if it is not currently owned by another thread. 50If the lock cannot be acquired immediately, it will 51spin attempting to acquire the lock (it will not sleep) until 52it becomes available. 53.Pp 54The 55.Fn pthread_spin_trylock 56function is the same as 57.Fn pthread_spin_lock 58except that if it cannot acquire 59.Fa lock 60immediately it will return with an error. 61.Pp 62The 63.Fn pthread_spin_unlock 64function will release 65.Fa lock , 66which must have been previously locked by a call to 67.Fn pthread_spin_lock 68or 69.Fn pthread_spin_trylock . 70.Sh RETURN VALUES 71If successful, all these functions will return zero. 72Otherwise, an error number will be returned to indicate the error. 73.Pp 74None of these functions will return 75.Er EINTR . 76.Sh ERRORS 77The 78.Fn pthread_spin_lock , 79.Fn pthread_spin_trylock 80and 81.Fn pthread_spin_unlock 82functions will fail if: 83.Bl -tag -width Er 84.It Bq Er EINVAL 85The value specified by 86.Fa lock 87is invalid or is not initialized. 88.El 89.Pp 90The 91.Fn pthread_spin_lock 92function may fail if: 93.Bl -tag -width Er 94.It Bq Er EDEADLK 95The calling thread already owns the lock. 96.El 97.Pp 98The 99.Fn pthread_spin_trylock 100function will fail if: 101.Bl -tag -width Er 102.It Bq Er EBUSY 103Another thread currently holds 104.Fa lock . 105.El 106.Pp 107The 108.Fn pthread_spin_unlock 109function may fail if: 110.Bl -tag -width Er 111.It Bq Er EPERM 112The calling thread does not own 113.Fa lock . 114.El 115.Sh SEE ALSO 116.Xr pthread_spin_destroy 3 , 117.Xr pthread_spin_init 3 118.Sh HISTORY 119The 120.Fn pthread_spin_lock , 121.Fn pthread_spin_trylock 122and 123.Fn pthread_spin_unlock 124functions first appeared in 125.Lb libpthread 126in 127.Fx 5.2 , 128and in 129.Lb libthr 130in 131.Fx 5.3 . 132.Sh BUGS 133The implementation of 134.Fn pthread_spin_lock , 135.Fn pthread_spin_trylock 136and 137.Fn pthread_spin_unlock 138is expected to conform to 139.St -p1003.2 . 140