_LIMIT - mkilgore/QB64pe GitHub Wiki

The _LIMIT statement sets the loop repeat rate of a program to so many per second, relinquishing spare CPU cycles to other applications.

_LIMIT framesPerSecond!

• The framesPerSecond! SINGLE parameter value adjusts the loops per second of a program loop. Do not use negative values.
• The loop code is executed before the loop is delayed. Loop cycles below once per second may delay program _EXITs.
• _LIMIT measures its interval from the previous time that it was called and minor adjustments are automatically made to ensure that the number of times a loop is repeated is correct overall.
• Loop cycle rates of 1000 or less can significantly reduce CPU usage in programs.
• Do not use it to limit a loop to less than once every 60 seconds(.0167) or an ILLEGAL FUNCTION CALL error will occur.
• Do not use _LIMIT as a timing delay outside of loops. Use _DELAY instead.
• Use _LIMIT to slow down old QBasic program loops that run too fast and use too much CPU.

Example: Limits loop execution to 30 frames per second and limits the program's CPU usage.

 '' ''
PRINT "To Quit press ESC key!"
DO
   _LIMIT 30
   PRINT CHR$(26);
   IF...THEN INKEY$ = CHR$(27) THEN EXIT DO '' ''
LOOP 

To Quit press ESC key!
→→→→→→→→→→→→→→→→→→→→

Note: In the above example, _LIMIT has to be within the loop.

• _DELAY
• TIMER, ON TIMER(n)
• SLEEP