From QB64.org wiki
The $CHECKING metacommand turns C++ event checking ON or OFF.
- The Metacommand does not require a comment or REM before it. There is no space after the colon.
- The OFF action turns event checking off and should only be used when running stable, errorless code.
- The default $CHECKING:ON action is only required when checking has been turned OFF previously.
- When $CHECKING:OFF is used, all error code and the reporting code is removed from the EXE program.
- Warning: Turning OFF error checking could create a General Protection Fault (or segfault). Use only with 100% stable sections of code.
- After every QB64 command is translated to C++, the compiler adds special code sections to check for ON TIMER (n) events and errors that may have occured in the last function call. Disabling error checking with the $CHECKING:OFF directive prevents the compiler from adding the extra code sections.
- Setting $CHECKING:OFF is only designed for 100% stable, errorless sections of code, where every CPU cycle saved counts, such as in a software 3D texture mapper, for example.