RWDateTime has the ability to hold sentinel values that are not necessarily dates, but are convenient to use as comparison values within applications. For example, a “future” sentinel provides a value that represents a date larger than the largest RWDateTime. RWDateTime currently provides four internal, pre-defined sentinels and can accommodate up to 128 user-defined sentinels. The RWDateTime sentinels are described in the following sections.

Table 3 summarizes the responses of RWDateTime operations when applied to various sentinels. The sections that follow Table 3 provide more information about the sentinels.