InterlockedCompare64Exchange128

InterlockedCompare64Exchange128 performs an atomic compare-and-exchange operation on the specified values. The function compares the 64-bit values and exchanges with the 128-bit value based on the comparison outcome.

Syntax

Copy

LONG64 InterlockedCompare64Exchange128(
    [in, out]  LONG64 volatile  *Destination,
    [in]       LONG64            ExchangeHigh,
    [in]       LONG64            ExchangeLow,
    [in]       LONG64            Comparand
);

Parameters

[in, out] Destination

A pointer to the destination value.

[in] ExchangeHigh

The high-order part of the exchange value.

[in] ExchangeLow

The low-order part of the exchange value.

[in] Comparand

The value to compare to Destination.

Return Value

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 variable pointed to by the Destination parameter must be aligned on a 128-bit boundary.

The interlocked functions provide a simple mechanism for synchronizing access to a variable shared by multiple threads. This function is atomic concerning 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 _InterlockedCompare64Exchange128.

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

Requirements

Minimum supported version	Header
wRTOS 1.0 SDK	windows.h