The intended use of CLOCK AI-00195/09 1 88-05-23 ra WJ | !standard 09.06 (05) 88-05-23 AI-00195/09 !class ramification 84-03-13 | !status approved by WG9/AJPO 88-02-05 | !status approved by Director, AJPO 88-02-05 | !status approved by WG9/Ada Board 87-12-07 !status approved by Ada Board 87-07-30 !status panel/committee-approved (9-1-3) 87-02-17 (by ballot) !status panel/committee-approved (5-0-0) 86-11-14 (pending letter ballot) !status work-item 86-08-07 !status received 84-03-13 !references AI-00325, AI-00201, 83-00296, 83-00864 !topic The intended use of CLOCK !summary 87-08-20 CLOCK returns a value that reflects the time of day in the external environment. !question 86-12-28 What is the intended function of CLOCK? In particular, must successive calls to CLOCK produce monotonically nondecreasing values? !response 87-06-11 The Standard only requires that CLOCK return values reflecting the behavior of a hardware clock. Successive calls to CLOCK have properties that depend on the execution environment. For example, if the hardware clock is reset by the system operator (to compensate for a change to Daylight Saving Time, power failures, or inaccurate time-keeping), successive calls to CLOCK can fail to produce monotonically nondecreasing values. Similarly, successive calls to CLOCK could exhibit odd behavior if the environment consists of a set of processors each of which provides its own hardware clock. In any case, failure to produce monotonically nondecreasing values would require justification in terms of AI-00325.