Method of passing data from actual parameters to formal parameters when the procedure is called, which is defined in the parameter interface of a procedure. In pass by value, a local data object is created as a copy of the actual parameter and the procedure receives the value of the actual parameter at calling time. Changed formal parameters are only passed to the actual parameter if the procedure was concluded without errors - that is, whenever the last statement is reached or there is an exit using RETURN (or EXIT or CHECK). Refer also to pass by reference.