InterlockedCompareExchange16 function (winnt.h)

Article
10/13/2021

Performs an atomic compare-and-exchange operation on the specified values. The function compares two specified 16-bit values and exchanges with another 16-bit value based on the outcome of the comparison.

To operate on 32-bit values, use the InterlockedCompareExchange function.

To operate on 64-bit values, use the InterlockedCompareExchange64 function.

To operate on 128-bit values, use the InterlockedCompareExchange128 function.

Syntax

SHORT InterlockedCompareExchange16(
  [in, out] SHORT volatile *Destination,
  [in]      SHORT          ExChange,
  [in]      SHORT          Comperand
);

Parameters

[in, out] Destination

A pointer to the destination value.

[in] ExChange

The exchange value.

[in] Comperand

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 parameters for this function must be aligned on a 16-bit boundary; otherwise, the 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 _InterlockedCompareExchange16.

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

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

Requirements

Requirement	Value
Minimum supported client	Windows 8 [desktop apps only]
Minimum supported server	Windows Server 2012 [desktop apps only]
Target Platform	Windows
Header	winnt.h (include Windows.h)