Provides a way to check whether there was any "modification" during execution of a body of code.
with-modification-check-macro macro-name modification-place &body body
A place as defined in Common Lisp which can receive a fixnum.
with-modification-check-macro, 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.
with-modification-check-macro defines a lexical macro (by macrolet) with the name macro-name which takes no arguments, and is used to check whether there was any change since entering the body.
modification-place 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.
modification-place does not need to be one of the places defined for low level atomic operations.
LispWorks User Guide and Reference Manual - 13 Feb 2015