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Warning C26101

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Failing to use interlocked operation properly for variable 'var'.

Windows APIs offer various interlocked operations. Annotation _Interlocked_ specifies that a variable should only be accessed through an interlocked operation. Warning C26101 is issued when a variable access isn't consistent with the _Interlocked_ annotation.

Example

The following example generates warning C26101 because there's a violation of the _Interlocked_ contract.

CRITICAL_SECTION cs;
typedef struct _DATA
{
    _Interlocked_ LONG data;
} DATA;

void Safe(DATA* p)
{
    InterlockedIncrement(&p->data); // OK
}

void Unsafe(DATA* p)
{
    p->data += 1; // Warning C26101
    EnterCriticalSection(&cs);
    LeaveCriticalSection(&cs);
}