The InterlockedDecrement function both decrements (decreases 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 InterlockedDecrement(
LPLONG lpAddend // address of the variable to decrement
);
Windows 98, Windows NT 4.0 and later: The return value is the resulting decremented 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.
The functions InterlockedDecrement, InterlockedCompareExchange, InterlockedExchange, InterlockedExchangeAdd, 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 variable pointed to by the lpAddend parameter must be aligned on a 32-bit boundary; otherwise, this function will fail on multiprocessor x86 systems.
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.
Synchronization Overview, Synchronization Functions, InterlockedCompareExchange, InterlockedExchange, InterlockedExchangeAdd, InterlockedIncrement