Function

OSIncrementAtomic

32-bit increment operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.

Declaration

SInt32 OSIncrementAtomic(volatile SInt32 *address);

Parameters

address

The 4-byte aligned address of the value to update atomically.

Return Value

The value before the increment.

Discussion

The OSIncrementAtomic function increments the value at the specified address by one and returns the original value.

This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device.