[New - Windows NT]
The InterlockExchangeAdd function performs an atomic addition of an increment value to an addend variable. The function prevents more than one thread from using the same variable simultaneously.
LONG InterlockedExchangeAdd (
| PLONG Addend, | // pointer to the addend |
| LONG Increment | // increment value |
| ); |
Parameters
Addend
Specifies the address of the number that will have the Increment number added to it.
Increment
Specifies the number to be added to the variable pointed to by the Addend parameter.
Return Values
The return value is the initial value of the Addend parameter.
Remarks
The functions InterlockedExchangeAdd, InterlockedCompareExchange, InterlockedDecrement, InterlockedExchange, and InterlockedIncrement provide a simple mechanism for synchronizing access to a variable that is shared by multiple threads. The threads of different processes can use this mechanism if the variable is in shared memory.
The InterlockedExchangeAdd function performs an atomic addition of the Increment value to the Addend value. The result is stored in the address specified by Addend. The initial value of Addend is returned as the function value.
The variables for InterlockedExchangeAdd must be aligned on a 32-bit boundary; otherwise, this function will fail on multiprocessor x86 systems.
See Also
InterlockedCompareExchange, InterlockedDecrement, InterlockedExchange, InterlockedIncrement