INPUT TIMEOUT
Let t be a numeric expression.
`INPUT TIMEOUT t : variable, variable , …
INPUT TIMEOUT t ,PROMPT Format_String : variable , variable , …
` If no input reply is given within t seconds, an exception of extype 8401 is raised.
Example

    100 LET prompt$="If no reply is given within 3 seconds, it is assumed that 1 is entered."
    110 WHEN EXCEPTION IN
    120    INPUT TIMEOUT 3 ,PROMPT prompt$:n
    130 USE
    140    SELECT CASE EXTYPE
    150    CASE 8401
    160       LET n=1
    170    CASE 8103
    180       LET prompt$="Re-input"
    190       RETRY
    200    CASE ELSE
    210       EXIT HANDLER
    220    END SELECT
    230 END WHEN
    240 PRINT n
    250 END