InterlockedExchange function (winnt.h)
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 InterlockedExchange(
[in, out] LONG volatile *Target,
[in] LONG Value
);
Parameters
[in, out] Target
A pointer to the value to be exchanged. The function sets this variable to Value, and returns its prior value.
[in] Value
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.
Requirements
| Requirement | Value |
|---|---|
| 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) |
| Library | Kernel32.lib |
| DLL | Kernel32.dll |
See also
">InterlockedExchangeAddAcquire64
InterlockedExchangeAddNoFence64
<a href="/previous-versions/windows/desktop/legacy/ms683605(v=vs.85)".InterlockedExchangeAddRelease
InterlockedExchangeAddRelease64
InterlockedExchangePointerAcquire