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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