NetBSD/lib/libpthread/pthread_spin_lock.3

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.\" $NetBSD: pthread_spin_lock.3,v 1.4 2003/07/04 10:19:42 wiz Exp $
.\"
.\" Copyright (c) 2002 The NetBSD Foundation, Inc.
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.Dd January 30, 2003
.Dt PTHREAD_SPIN_LOCK 3
.Os
.Sh NAME
.Nm pthread_spin_lock ,
.Nm pthread_spin_trylock
.Nd acquire a spin lock
.Sh LIBRARY
.Lb libpthread
.Sh SYNOPSIS
.In pthread.h
.Ft int
.Fn pthread_spin_lock "pthread_spinlock_t *lock"
.Ft int
.Fn pthread_spin_trylock "pthread_spinlock_t *lock"
.Sh DESCRIPTION
The
.Fn pthread_spin_lock
function acquires a spin lock on
.Fa lock
provided that
.Fa lock
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is not presently held.
If the lock cannot be
immediately acquired, the calling thread repeatedly retries until it can
acquire the lock.
.Pp
The
.Fn pthread_spin_trylock
function performs the same action, but does not block if the lock
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cannot be immediately obtained (i.e., the lock is held).
.Sh RETURN VALUES
If successful, the
.Fn pthread_spin_lock
and
.Fn pthread_spin_trylock
functions will return zero. Otherwise an error number will be returned
to indicate the error.
.Sh ERRORS
The
.Fn pthread_spin_trylock
function shall fail if:
.Bl -tag -width Er
.It Bq Er EBUSY
The lock could not be acquired because a writer holds the lock or
was blocked on it.
.El
.Pp
The
.Fn pthread_spin_lock
function may fail if:
.Bl -tag -width Er
.It Bq Er EDEADLK
The current thread already owns
.Fa lock
for writing.
.El
.Pp
The
.Fn pthread_spin_lock
and
.Fn pthread_spin_trylock
functions may fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
The value specified by
.Fa lock
is invalid.
.El
.Sh SEE ALSO
.Xr pthread_spin_destroy 3 ,
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.Xr pthread_spin_init 3 ,
.Xr pthread_spin_unlock 3
.Sh STANDARDS
.Fn pthread_spin_lock
and
.Fn pthread_spin_trylock
conform to
.St -p1003.1-2001 .