Flip the back buffer to screen and wait for next frame. This call is not needed when there is a _DRAW() or _UPDATE() callback defined, as the flip is performed automatically. But when using a custom main loop, a call to FLIP is normally needed:
::_:: CLS() FOR I=1,100 DO A=I/50 - T() X=64+COS(A)*I Y=64+SIN(A)*I CIRCFILL(X,Y,1,8+(I/4)%8) END FLIP()GOTO _
If your program does not call FLIP before a frame is up, and a _DRAW() callback is not in progress, the current contents of the back buffer are copied to screen.
(temporarily copied from manual - to be edited)
5 Feb 2023