The function get-process-private-property
gets the value associated with indicator in the private properties of the process process. If there is no such property, the value default is returned.
get-process-private-property
can be used to read the values of private properties from another process.
process-private-property
remove-process-private-property
pushnew-to-process-private-property
remove-from-process-private-property
LispWorks User Guide and Reference Manual - 13 Feb 2015