InterlockedOr function (winnt.h)

Article
10/13/2021

Performs an atomic OR operation on the specified LONG values. The function prevents more than one thread from using the same variable simultaneously.

Syntax

LONG InterlockedOr(
  [in, out] LONG volatile *Destination,
  [in]      LONG          Value
);

Parameters

[in, out] Destination

A pointer to the first operand. This value will be replaced with the result of the operation.

[in] Value

The second operand.

Return value

The function returns the original value of the Destination 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.

For the Intel Itanium-based systems and x64 architectures, this function is implemented using the compiler intrinsic. For the x86 architecture, use the _InterlockedOr compiler intrinsic directly.

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 InterlockedOrAcquire or InterlockedOrRelease instead.

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

Requirements

Requirement	Value
Target Platform	Windows
Header	winnt.h (include Windows.h)