mirror of
https://github.com/QB64Official/qb64.git
synced 2024-07-16 18:55:13 +00:00
35 lines
1.2 KiB
Markdown
35 lines
1.2 KiB
Markdown
The [LOC](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](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$](INPUT$) to get the data bytes received.
|
|
* Can also be used to read the current position in a file routine. See [SEEK](SEEK).
|
|
|
|
## Example(s)
|
|
|
|
Reading and writing from a COM port opened in Basic.
|
|
|
|
```vb
|
|
|
|
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
|
|
|
|
* [PRINT](PRINT), [OPEN COM](OPEN-COM), [PRINT (file statement)](PRINT-(file-statement))
|
|
* [SEEK](SEEK)
|