UID

title

description

helpviewer_keywords

old-location

tech.root

ms.assetid

ms.date

ms.keywords

req.header

req.include-header

req.target-type

req.target-min-winverclnt

req.target-min-winversvr

req.kmdf-ver

req.umdf-ver

req.ddi-compliance

req.unicode-ansi

req.idl

req.max-support

req.namespace

req.assembly

req.type-library

req.lib

req.dll

req.irql

targetos

req.typenames

req.redist

ms.custom

f1_keywords

dev_langs

topic_type

api_type

api_location

api_name

NF:winnt.InterlockedCompareExchange64

InterlockedCompareExchange64 function (winnt.h)

Performs an atomic compare-and-exchange operation on the specified values. The function compares two specified 64-bit values and exchanges with another 64-bit value based on the outcome of the comparison.

InterlockedCompareExchange64

InterlockedCompareExchange64 function

base.interlockedcompareexchange64

winnt/InterlockedCompareExchange64

base\interlockedcompareexchange64.htm

backup

b0799de3-49f9-4eef-9c14-d145f42ce57b

12/05/2018

InterlockedCompareExchange64, InterlockedCompareExchange64 function, base.interlockedcompareexchange64, winnt/InterlockedCompareExchange64

winnt.h

Windows.h

Windows

Windows Vista [desktop apps \| UWP apps]

Windows Server 2003 [desktop apps \| UWP apps]

Kernel32.lib

Kernel32.dll

Windows

19H1

InterlockedCompareExchange64

winnt/InterlockedCompareExchange64

c++

APIRef

kbSyntax

DllExport

Kernel32.dll

API-MS-Win-Core-Interlocked-l1-1-0.dll

API-MS-Win-Core-Interlocked-l1-2-0.dll

KernelBase.dll

MinKernelBase.dll

InterlockedCompareExchange64

InterlockedCompareExchange64 function

-description

Performs an atomic compare-and-exchange operation on the specified values. The function compares two specified 64-bit values and exchanges with another 64-bit value based on the outcome of the comparison.

-parameters

-param Destination [in, out]

A pointer to the destination value.

-param ExChange [in]

The exchange value.

-param Comperand [in]

The value to compare to Destination.

-returns

The function returns the initial value of the Destination parameter.

-remarks

The function compares the Destination value with the Comparand value. If the Destination value is equal to the Comparand value, the Exchange value is stored in the address specified by Destination. Otherwise, no operation is performed.

The variables for this function must be aligned on a 64-bit boundary; otherwise, this function will behave unpredictably on multiprocessor x86 systems and any non-x86 systems. See _aligned_malloc.

The interlocked functions provide a simple mechanism for synchronizing access to a variable that is shared by multiple threads. This function is atomic with respect to calls to other interlocked functions.

This function is implemented using a compiler intrinsic where possible. For more information, see the WinBase.h header file and _InterlockedCompareExchange64.