ObjectPascal
IncMillisecond
Function
Increments a TDateTime variable by + or - number of milliseconds DateUtils unit
 function IncMillisecond ( const StartDateTime : TDateTime {; NumberOfMilliSeconds : Integer = 1} ) : TDateTime;
Description
The IncMillisecond function returns a TDateTime value that is NumberOfMilliSeconds greater than the passed StartDateTime value.
 
The year, month, day and hour values are incremented as appropriate.
 
The increment value is optional, being 1 by default.
Notes
There is no DecMillisecond function.

Instead, use IncMillisecond with a negative increment.
Related commands
IncYear Increments a TDateTime variable by a number of years
IncMonth Increments a TDateTime variable by a number of months
IncDay Increments a TDateTime variable by + or - number of days
IncMinute Increments a TDateTime variable by + or - number of minutes
IncSecond Increments a TDateTime variable by + or - number of seconds
 
Example code : A simple example of increment and decrement
var
  myDate : TDateTime;
begin
  // Set up our date to the start of 2006
  myDate := EncodeDateTime(2006, 1, 1, 0, 0, 0, 0);
  WriteLn('myDate = '+DateTimeToStr(myDate));

  // Add 5000 milliseconds to this date
  myDate := IncMillisecond(myDate, 5000);
  WriteLn('myDate + 5000 milliseconds = '+DateTimeToStr(myDate));

  // Subtract 2000 milliseconds from this date
  myDate := IncMillisecond(myDate, -2000);
  WriteLn('myDate -  2000 milliseconds = '+DateTimeToStr(myDate));
end;
Show full unit code
   myDate = 01/01/2006
   myDate = 01/01/2006 00:00:05
   myDate = 01/01/2006 00:00:03