TIMER (statement) - QB64Official/qb64 GitHub Wiki

A TIMER statement enables, turns off or stops timer event trapping. QBasic only uses the base timer, but QB64 can run many.

Syntax

QB

TIMER {ON|STOP|OFF}

QB64

TIMER(number%) {ON|STOP|OFF|FREE}

Parameter(s)

  • number denotes a specific numbered timer event in QB64 only. QB64 can run many timer events at once including the base timer.
  • TIMER ON enables event trapping of an ON TIMER (n) statement. While enabled, a check is made after every code statement to see if the specified time has elapsed and the ON TIMER GOSUB (or SUB in QB64) procedure is executed.
  • TIMER STOP disables timer event trapping. When an event occurs while stopped, it is remembered. If timer events are turned back on later, any remembered events are immediately executed.
  • TIMER OFF turns timer event trapping completely off and no subsequent events are remembered.
  • TIMER(n) FREE clears a specific timer event when it is no longer needed. The base TIMER or TIMER(0) cannot be freed!

Description

QB64 only

  • Get a TIMER number from _FREETIMER ONLY except when the base timer(no number or 0) is used. Use specific variables or an array to hold each event number value for later reference.
  • If the TIMER number is omitted or 0, the TIMER used is the base timer.
  • Specific TIMER events can be enabled, suspended, turned off or freed using TIMER (statement) ON, STOP, OFF or FREE.
  • TIMER(n) FREE clears a specific timer event when it is no longer needed. The base TIMER or TIMER(0) cannot be freed!

QB64 Timing Alternatives

  • The TIMER function can be used to find timed intervals down to 1 millisecond(.001) accuracy.
  • The _DELAY statement can be used to delay program execution for intervals down to milliseconds.
  • _LIMIT can slow down loops to a specified number of frames per second. This can also alleviate a program's CPU usage.

Example(s)

How to update the time while PRINT at the same time in a program.


TIMER ON ' enable timer event trapping
LOCATE 4, 2 ' set the starting PRINT position
ON TIMER(10) GOSUB Clock ' set procedure execution repeat time
DO WHILE INKEY$ = "": PRINT "A"; : SLEEP 6: LOOP
TIMER OFF
SYSTEM

Clock:
  row = CSRLIN ' Save current print cursor row.
  col = POS(0) ' Save current print cursor column.
  LOCATE 2, 37: PRINT TIME$; ' print current time at top of screen.
  LOCATE row, col ' return to last print cursor position 
RETURN

NOTE: SLEEP will be interrupted in QBasic.

See Also