From QB64 Wiki
- OFF can be used to turn off the display of soft-key assignments at the bottom of the screen using KEY.
- OFF can also be used to disable an event trapping in the following statements: KEY(n), COM(n), PEN, PLAY, STRIG(n), TIMER, UEVENT. The trap can be turned back ON, but does not retain any events since OFF was used.
- $CHECKING:OFF is used to disable c++ error trapping, make sure that your code is flawless before using this metacommand, can cause a General Protection Fault if there are errors in the code.