Error and I/O Functions

Error functions give information about the latest error that occurred. This information is useful in an error handling routine established by ON ERROR.

Operator	Meaning	Example	Result
ERRL	Test for error line	ERRL(100)	0
ERRLN	Line number	ERRLN	10
ERRM$	Error Message	ERRM$	"ERROR 31 IN "...
ERRN	Error Number	ERRN	31

I/O functions complement the regular I/O statements by providing additional information about I/O operations, devices, and paths.

Operator	Meaning	Example	Result
KBD$	ON KBD, keyboard buffer	KBD$	"A"
KNOBX	ON KNOB, x movement	KNOBX	217
KNOBY	ON KNOB, y movement	KNOBY	-45
PPOLL	Parallel poll on IEEE-488	PPOLL(7)	8
READIO	Read hardware register	READIO(9,0)	7
SC	Select Code in I/O path	SC(@Io)	10
SPOLL	Serial poll on IEEE-488	SPOLL(701)	0
STATUS	Read interface register	STATUS(CRT,1)	1