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Decrements (decreases by one) the value of the specified 64-bit variable as an atomic operation.
To operate on 32-bit values, use the InterlockedDecrement function.
Syntax
LONG64 InterlockedDecrement64(
[in, out] LONG64 volatile *Addend
);
Parameters
[in, out] Addend
A pointer to the variable to be decremented.
Return value
The function returns the resulting decremented value.
Remarks
The variable pointed to by the Addend parameter must be aligned on a 64-bit boundary; otherwise, this 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 _InterlockedDecrement64.
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 InterlockedDecrementAcquire64 or InterlockedDecrementRelease64 instead.
Note This function is supported on Windows RT-based systems.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows Vista [desktop apps | UWP apps] |
| Minimum supported server | Windows Server 2003 [desktop apps | UWP apps] |
| Target Platform | Windows |
| Header | winnt.h (include Windows.h) |