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InterlockedDecrement function (winnt.h)

Decrements (decreases by one) the value of the specified 32-bit variable as an atomic operation.

To operate on 64-bit values, use the InterlockedDecrement64 function.

Syntax

LONG InterlockedDecrement(
  [in, out] LONG 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 32-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 _InterlockedDecrement.

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 InterlockedDecrementAcquire or InterlockedDecrementRelease instead.

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

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

Interlocked Variable Access

InterlockedDecrement16

InterlockedDecrement16Acquire

InterlockedDecrement16NoFence

InterlockedDecrement16Release

InterlockedDecrement64

InterlockedDecrementAcquire

InterlockedDecrementAcquire64

InterlockedDecrementNoFence

InterlockedDecrementNoFence64

InterlockedDecrementRelease

InterlockedDecrementRelease64

InterlockedIncrement

Synchronization Functions


Additional resources