Method and apparatus for identifying and correcting date calculation errors caused by truncated year values

摘要

A standardized test environment assists identifying problematic instances of instructions in computer programs that produce erroneous results caused by dates having years expressed in a truncated form. A standardized production environment takes corrective action for specified instances of instructions by modifying one or more values such that the instructions achieve correct results. In one embodiment of a test environment, a computer system collects diagnostic information for instances of subtraction operations that produce negative results. In one embodiment of a production environment, a computer system intercepts execution of a computer program at specified locations and takes corrective action according to information obtained from a table of control information.