LOC

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The LOC function returns the status of a serial (COM) port received buffer or the current byte position in an open file.


Syntax

bytes% = LOC(fileOrPortNumber%)


  • fileOrPortNumber% is the number used in the port OPEN AS statement.
  • Returns 0 if the buffer is empty. Any value above 0 indicates the COM port has received data.
  • Use it in conjunction with INPUT$ to get the data bytes received.
  • Can also be used to read the current position in a file routine. See SEEK.


Examples

Example: Reading and writing from a COM port opened in Basic.

OPEN "COM1: 9600,N,8,1,OP0" FOR RANDOM AS #1 LEN = 2048 ' random mode = input and output
  DO: t$ = INKEY$ ' get any transmit keypresses from user
    IF LEN(t$) THEN PRINT #1, t$ ' send keyboard byte to transmit buffer
    bytes% = LOC(1) ' bytes in buffer
    IF bytes% THEN ' check receive buffer for data"
      r$ = INPUT$(bytes%, 1)          ' get bytes in the receive buffer
      PRINT r$; ' print byte strings consecutively to screen"
    END IF
  LOOP UNTIL t$ = CHR$(27) 'escape key exit
CLOSE #


See also



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