Atomically exchange a place value with a new value, returning the old value.
system
atomic-exchange place new-value => old-value
| place⇩ | 
One of the specific set of places defined for low level atomic operations. | 
| new-value⇩ | 
An object. | 
| old-value⇩ | 
An object. | 
The macro atomic-exchange exchanges the value in place with new-value, returning old-value. The operation is guaranteed to be atomic.
place must be one of the places described in 19.13.1 Low level atomic operations, or expand to one of them.
LispWorks® User Guide and Reference Manual - 01 Dec 2021 19:31:02