From QB64 Wiki
The ERR function returns the last QBasic error code number.
- errorNum% = ERR
- If there is no error, the function returns 0
- Can be used in an error handling routine to report the last error code number.
Example: Simulating an error to test a program error handler that looks for a "Subscript out of range" error.
ON ERROR GOTO handler IF x = 0 THEN ERROR 111 'simulate an error code that does not exist x = x + 1 IF x THEN ERROR 9 'simulate array boundary being exceeded END handler: PRINT ERR, _ERRORLINE BEEP IF ERR = 9 THEN PRINT "The program has encountered an error and needs to close! Press a key!" K$ = INPUT$(1) SYSTEM END IF RESUME NEXT 'RESUME can only be used in error handlers