InterlockedExchangePointer function

Atomically exchanges a pair of addresses.

Syntax

PVOID InterlockedExchangePointer(
  PVOID volatile *Target,
  PVOID          Value
);

Parameters

Target

A pointer to the address to exchange. The function sets the address pointed to by the Target parameter (*Target) to the address that is the value of the Value parameter, and returns the prior value of the Target parameter.

Value

The address to be exchanged with the address pointed to by the Target parameter (*Target).

Return Value

The function returns the initial address pointed to by the Target parameter.

Remarks

This function copies the address passed as the second parameter to the first and returns the original address of the first.

On a 64-bit system, the parameters are 64 bits and the Target parameter must be aligned on 64-bit boundaries; otherwise, the function will behave unpredictably. On a 32-bit system, the parameters are 32 bits and the Target parameter must be aligned on 32-bit boundaries.

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 _InterlockedExchangePointer.

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 InterlockedExchangePointerAcquire instead.

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

Requirements

   
Minimum supported client Windows XP [desktop apps | UWP apps]
Minimum supported server Windows Server 2003 [desktop apps | UWP apps]
Target Platform Windows
Header winnt.h (include Windows.h)

See Also

Interlocked Variable Access

InterlockedCompareExchange

InterlockedExchange

InterlockedExchange16

InterlockedExchange16Acquire

InterlockedExchange16NoFence

InterlockedExchange64

InterlockedExchange8

InterlockedExchangeAcquire

InterlockedExchangeAcquire64

InterlockedExchangeAdd

InterlockedExchangeNoFence

InterlockedExchangeNoFence64

InterlockedExchangePointerAcquire

InterlockedExchangePointerNoFence

InterlockedExchangeSubtract

Synchronization Functions