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InterlockedExchange function

Sets a 32-bit variable to the specified value as an atomic operation.

To operate on a pointer variable, use the InterlockedExchangePointer function.

To operate on a 16-bit variable, use the InterlockedExchange16 function.

To operate on a 64-bit variable, use the InterlockedExchange64 function.

Syntax


LONG __cdecl InterlockedExchange(
  _Inout_  LONG volatile *Target,
  _In_     LONG Value
);

Parameters

Target [in, out]

A pointer to the value to be exchanged. The function sets this variable to Value, and returns its prior value.

Value [in]

The value to be exchanged with the value pointed to by Target.

Return value

The function returns the initial value of the Target parameter.

Remarks

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 _InterlockedExchange.

This function generates a full memory barrier (or fence) to ensure that memory operations are completed in order.

Itanium-based systems:  For performance-critical applications, use InterlockedExchangeAcquire instead.

Note  This function is supported on Windows RT-based systems.

Note  

Requirements

Minimum supported client

Windows XP [desktop apps | Windows Store apps]

Minimum supported server

Windows Server 2003 [desktop apps | Windows Store apps]

Header

WinBase.h (include Windows.h)

Library

Kernel32.lib

DLL

Kernel32.dll

See also

Interlocked Variable Access
InterlockedCompareExchange
InterlockedExchange
InterlockedExchangeAcquire
InterlockedExchangeNoFence
InterlockedExchange8
InterlockedExchange16
InterlockedExchange16Acquire
InterlockedExchange16NoFence
InterlockedExchange64
InterlockedExchangeAcquire64
InterlockedExchangeNoFence64
InterlockedExchangePointer
InterlockedExchangePointerAcquire
InterlockedExchangePointerNoFence
InterlockedExchangeAdd
InterlockedExchangeAddAcquire
InterlockedExchangeAddRelease
InterlockedExchangeAddNoFence
InterlockedExchangeAdd64
InterlockedExchangeAddAcquire64
InterlockedExchangeAddRelease64
InterlockedExchangeAddNoFence64
InterlockedExchangeSubtract
Synchronization Functions

 

 

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