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59 lines
2.7 KiB
Plaintext
59 lines
2.7 KiB
Plaintext
A [[TIMER]] statement enables, turns off or stops timer event trapping. QBasic only uses the base timer, but '''QB64''' can run many.
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{{PageSyntax}}
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QB
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:::TIMER {ON|STOP|OFF}
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QB64
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:::TIMER(''number%'') {ON|STOP|OFF|FREE}
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{{PageParameters}}
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* ''number'' denotes a specific numbered timer event in '''QB64 only'''. QB64 can run many timer events at once including the base timer.
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* 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.
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* 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.
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* TIMER OFF turns timer event trapping completely off and no subsequent events are remembered.
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* TIMER(n) '''FREE''' clears a specific timer event when it is no longer needed. '''The base TIMER or TIMER(0) cannot be freed!'''
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{{PageDescription}}
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<center>'''QB64 only'''</center>
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* 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.
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* If the TIMER number is omitted or 0, the TIMER used is the base timer.
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* Specific TIMER events can be enabled, suspended, turned off or freed using [[TIMER (statement)|TIMER(n)]] ON, STOP, OFF or FREE.
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<center>'''QB64 Timing Alternatives'''</center>
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* The [[TIMER]] function can be used to find timed intervals down to 1 millisecond(.001) accuracy.
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* The [[_DELAY]] statement can be used to delay program execution for intervals down to milliseconds.
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* [[_LIMIT]] can slow down loops to a specified number of frames per second. This can also alleviate a program's CPU usage.
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{{PageExamples}}
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''Example:'' How to update the time while [[PRINT|printing]] at the same time in a program.
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{{CodeStart}} '' ''
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{{Cl|TIMER}} ON ' enable timer event trapping
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{{Cl|LOCATE}} 4, 2 ' set the starting PRINT position
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{{Cl|ON TIMER(n)|ON TIMER}}(10) {{Cl|GOSUB}} Clock ' set procedure execution repeat time
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{{Cl|DO}} {{Cl|WHILE}} {{Cl|INKEY$}} = "": {{Cl|PRINT}} "A"; : {{Cl|SLEEP}} 6: {{Cl|LOOP}}
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{{Cl|TIMER}} OFF
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{{Cl|SYSTEM}}
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Clock:
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row = {{Cl|CSRLIN}} ' Save current print cursor row.
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col = {{Cl|POS|POS(0)}} ' Save current print cursor column.
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{{Cl|LOCATE}} 2, 37: {{Cl|PRINT}} {{Cl|TIME$}}; ' print current time at top of screen.
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{{Cl|LOCATE}} row, col ' return to last print cursor position
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{{Cl|RETURN}} '' ''
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{{CodeEnd}}
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: NOTE: SLEEP will be interrupted in QBasic.
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{{PageSeeAlso}}
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* [[ON TIMER(n)]], [[TIMER]](function)
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* [[_DELAY]], [[_LIMIT]]
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{{PageNavigation}}
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