activation record

activation record

[‚ak·tə′vā·shən ′rek·ərd] (computer science) A variable part of a program module, such as data and control information, that may vary with different instances of execution.

activation record

(compiler)(Or "data frame", "stack frame") A data structurecontaining the variables belonging to one particular scope(e.g. a procedure body), as well as links to other activationrecords.

Activation records are usually created (on the stack) onentry to a block and destroyed on exit. If a procedure orfunction may be returned as a result, stored in a variable andused in an outer scope then its activation record must bestored in a heap so that its variables still exist when itis used. Variables in the current scope are accessed viathe frame pointer which points to the current activationrecord. Variables in an outer scope are accessed by followingchains of links between activation records. There are twokinds of link - the static link and the dynamic link.