Provides a way to check whether there was any "modification" during execution of a body of code.
A place as defined in Common Lisp which can receive a fixnum.
, together with the macro with-modification-change, provides a way for a body of code to execute and check whether there was any "modification" during this execution, where modification is execution of some other piece of code.
defines a lexical macro (by macrolet) with the name
which takes no arguments, and is used to check if there was any change since entering the body.
must be initialized to a fixnum. It must not be modified by any code except with-modification-change.
See Aids for implementing modification checks for the full description and an example.
does not need to be one of the places defined for low level atomic operations.
LispWorks User Guide and Reference Manual - 22 Dec 2009