InterlockedIncrement

The InterlockedIncrement function both increments (increases by one) the value of the specified 32-bit variable and checks the resulting value. The function prevents more than one thread from using the same variable simultaneously.

LONG InterlockedIncrement(
  LPLONG lpAddend   // pointer to the variable to increment
);
 

Parameters

lpAddend
Pointer to the LONG variable to increment.

Return Values

Windows 98, Windows NT 4.0 and later: The return value is the resulting incremented value.

Windows 95, Windows NT 3.51 and earlier: If the result of the operation is zero, the return value is zero. If the result of the operation is less than zero, the return value is negative, but it is not necessarily equal to the result. If the result of the operation is greater than zero, the return value is positive, but it is not necessarily equal to the result.

Remarks

The functions InterlockedIncrement, InterlockedCompareExchange, InterlockedDecrement, InterlockedExchange, and InterlockedExchangeAdd 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 variable pointed to by the lpAddend parameter must be aligned on a 32-bit boundary; otherwise, this function will fail on multiprocessor x86 systems.

QuickInfo

  Windows NT: Requires version 3.1 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Requires version 1.0 or later.
  Header: Declared in winbase.h.
  Import Library: Use kernel32.lib.

See Also

Synchronization Overview, Synchronization Functions, InterlockedCompareExchange, InterlockedDecrement, InterlockedExchange, InterlockedExchangeAdd