# Passing and Returning Bounds

The pointer checker is not supported on macOS* systems.

When you pass a pointer to a function, the pointer checker also passes the bounds information associated with the pointer. The feature uses the following methods to pass and return arguments:

- If you pass a pointer on the stack, the pointer is in a memory location, so the pointer checker stores the bounds information when you compile your enabled module. The bounds information is stored in the bounds table entry associated with the address of the pointer.

- If you pass a pointer on a register, the compiler uses a location in thread local storage to pass the bounds. There is one such location associated with each register in which a pointer can be passed. This same location is used to return the bounds when a pointer is returned by a function.

Parent topic: Using the Pointer Checker