'\" te
.\" Copyright (c) 2006, Sun Microsystems, Inc. All Rights Reserved.
.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License").  You may not use this file except in compliance with the License.
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.TH ATOMIC_CAS 9F "Jan 16, 2006"
.SH NAME
atomic_cas, atomic_cas_8, atomic_cas_uchar, atomic_cas_16, atomic_cas_ushort,
atomic_cas_32, atomic_cas_uint, atomic_cas_ulong, atomic_cas_64, atomic_cas_ptr
\- atomic compare and swap operations
.SH SYNOPSIS
.LP
.nf
#include <sys/atomic.h>

\fBuint8_t\fR \fBatomic_cas_8\fR(\fBvolatile uint8_t *\fR\fItarget\fR, \fBuint8_t\fR \fIcmp\fR, \fBuint8_t\fR
     \fInewval\fR);
.fi

.LP
.nf
\fBuchar_t\fR \fBatomic_cas_uchar\fR(\fBvolatile uchar_t *\fR\fItarget\fR, \fBuchar_t\fR \fIcmp\fR, \fBuchar_t\fR
     \fInewval\fR);
.fi

.LP
.nf
\fBuint16_t\fR \fBatomic_cas_16\fR(\fBvolatile uint16_t *\fR\fItarget\fR, \fBuint16_t\fR \fIcmp\fR, \fBuint16_t\fR
     \fInewval\fR);
.fi

.LP
.nf
\fBushort_t\fR \fBatomic_cas_ushort\fR(\fBvolatile ushort_t *\fR\fItarget\fR, \fBushort_t\fR \fIcmp\fR,
     \fBushort_t\fR \fInewval\fR);
.fi

.LP
.nf
\fBuint32_t\fR \fBatomic_cas_32\fR(\fBvolatile uint32_t *\fR\fItarget\fR, \fBuint32_t\fR \fIcmp\fR, \fBuint32_t\fR
     \fInewval\fR);
.fi

.LP
.nf
\fBuint_t\fR \fBatomic_cas_uint\fR(\fBvolatile uint_t *\fR\fItarget\fR, \fBuint_t\fR \fIcmp\fR, \fBuint_t\fR \fInewval\fR);
.fi

.LP
.nf
\fBulong_t\fR \fBatomic_cas_ulong\fR(\fBvolatile ulong_t *\fR\fItarget\fR, \fBulong_t\fR \fIcmp\fR, \fBulong_t\fR
     \fInewval\fR);
.fi

.LP
.nf
\fBuint64_t\fR \fBatomic_cas_64\fR(\fBvolatile uint64_t *\fR\fItarget\fR, \fBuint64_t\fR \fIcmp\fR, \fBuint64_t\fR
     \fInewval\fR);
.fi

.LP
.nf
\fBvoid *\fR\fBatomic_cas_ptr\fR(\fBvolatile void *\fR\fItarget\fR, \fBvoid *\fR\fIcmp\fR, \fBvoid *\fR\fInewval\fR);
.fi

.SH DESCRIPTION
.sp
.LP
These functions enable a compare and swap operation to occur atomically. The
value stored in \fItarget\fR is compared with \fIcmp\fR. If these values are
equal, the value stored in \fItarget\fR is replaced with \fInewval\fR. The old
value stored in \fItarget\fR is returned by the function whether or not the
replacement occurred.
.SH RETURN VALUES
.sp
.LP
These functions return the old of *\fItarget\fR.
.SH ERRORS
.sp
.LP
No errors are defined.
.SH CONTEXT
.sp
.LP
These functions can be called from user, interrupt, or kernel context.
.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	Committed
.TE

.SH SEE ALSO
.sp
.LP
\fBatomic_add\fR(9F), \fBatomic_and\fR(9F), \fBatomic_bits\fR(9F),
\fBatomic_dec\fR(9F), \fBatomic_inc\fR(9F), \fBatomic_or\fR(9F),
\fBatomic_swap\fR(9F), \fBmembar_ops\fR(9F), \fBattributes\fR(5),
\fBatomic_ops\fR(3C)