SOCKREAD integer-variable, variable

Reads a value from an open TCP socket into variable.
The first parameter must be an integer variable containing the socket handle returned by CONNECT.

The semantics match INPUT:

The call is blocking: it waits until there is enough data to parse a valid value for the destination type.
variable may be string, integer, or real.
If the incoming data does not form a valid number when an integer or real is expected, the destination is set to 0.
Unlike INPUT, there is no echo (data comes from the socket, not the keyboard).

Note: Press CTRL+ESC at any time to cancel waiting for socket input.; Without an error handler, the program terminates.; With an ON ERROR handler, control passes there instead.

Examples

Read a text line

CONNECT S, "93.184.216.34", 80
REM Ask the server for a line, then read it
SOCKWRITE S, "HEAD / HTTP/1.0" + CHR$(13) + CHR$(10) + CHR$(13) + CHR$(10)
SOCKREAD S, LINE$
PRINT LINE$
SOCKCLOSE S

Read a number

CONNECT S, "192.0.2.10", 1234
REM Peer will send an integer in ASCII, e.g. 42 followed by newline
SOCKREAD S, N
IF N = 0 THEN
    PRINT "Invalid or zero value received"
ELSE
    PRINT "Got: "; N
ENDIF

Handle cancellation and errors

ON ERROR PROCnet_err
 
CONNECT S, "203.0.113.5", 7000
IF S >= 0 THEN
    PRINT "Waiting for data (CTRL+ESC to cancel)..."
    SOCKREAD S, DATA$
    PRINT "Received: "; DATA$
    SOCKCLOSE S
ENDIF
END
 
DEF PROCnet_err
    PRINT "Socket error: "; ERR$
    ON ERROR PROCnet_err
ENDPROC

Notes

Treat the socket as a byte stream; if you need to read multiple fields on one line, call SOCKREAD multiple times or define a simple protocol (for example, one value per line).
After SOCKCLOSE, the handle is invalid for further SOCKREAD/SOCKWRITE.
Use DNS$ to resolve hostnames to IP strings for CONNECT.

See also:
CONNECT · SOCKWRITE · SOCKCLOSE · INPUT