A '''TIMER''' statement enables, turns off or stops timer event trapping. QBasic only uses the base timer, but '''QB64''' can run many.
QB {{PageSyntax}}
:::TIMER {ON|STOP|OFF}
QB64 {{PageSyntax}}
:::TIMER(''number%'') {ON|STOP|OFF|FREE}
{{Parameters}}
* ''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.
<center>'''QB64 only'''</center>
* 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)|TIMER(n)]] 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!'''
<center>'''QB64 Timing Alternatives'''</center>
* 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:'' How to update the time while [[PRINT|printing]] at the same time in a program.
{{CodeStart}}
TIMER ON ' enable timer event trapping
LOCATE 4, 2 ' set the starting PRINT position
{{Cl|ON TIMER(n)|ON TIMER}}(10) GOSUB Clock ' set procedure execution repeat time
DO WHILE INKEY$ = "": PRINT "A"; : SLEEP 6: LOOP
TIMER OFF
{{Cl|SYSTEM}}
Clock:
row = {{Cl|CSRLIN}} ' Save current print cursor row.
col = {{Cl|POS|POS(0)}} ' Save current print cursor column.
LOCATE 2, 37: PRINT {{Cl|TIME$}}; ' print current time at top of screen.
LOCATE row, col ' return to last print cursor position