Re: URGENT: Pascal Clock - Gpc

3 Jun 2000


      I see what the problem is: I'm using GNU Pascal as opposed to DEC VAX 
Pascal (where clock is a global function defined below).
Does anyone know a way to mimic this "clock" in GNU Pascal?  (I apologize 
for my lack of Pascal knowledge!)
e.g. y := clock/1000-y1
Source:http://www.openvms.digital.com/wizard/group3/335.HTML
Ask the Wizard Questions
PASCAL Language: PASCAL CLOCK
The Question is:
What is the granularity of the CLOCK command in VAX
      PASCAL, also, what units does it measure?
The Answer is:
According to the DEC Pascal Language Reference Manual:
"  8.21 CLOCK Function
          The CLOCK function returns an integer value indicating the
         amount of central processor time (in milliseconds) used by
         the current process. This function does not have a parame-
         ter list. The result of CLOCK includes the amount of central
         processor time allocated to all previously executed images."
That being the case, the value is most likely taken from the system
        clock which is incremented at 10ms intervals - hence the granularity
        will be 10ms. A simple program seems to support this:
PROGRAM CheckClock(OUTPUT);
      VAR LastTime,NextTime : INTEGER;
BEGIN
        LastTime:=CLOCK;
        REPEAT
          NextTime:=CLOCK;
        UNTIL LastTime <> NextTime;
        WriteLn('LastTime = ',LastTime,' NextTime = ',NextTime);
      END.
      $ run checkclock
      LastTime =    3495890 NextTime =    3495900
Note however that the granularity may vary in future as OpenVMS is 
capable
        of expressing times to an accuracy of 100ns.
- - - - - - - - - - - - -
Raymond Wang
Department of Electrical Engineering
Stanford University
www.stanford.edu/~rayw