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

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