SOCKFLUSH integer-variable

Blocks until any pending outbound data for the given TCP socket has been flushed from the BASIC send buffer to the TCP stack. Use after SOCKWRITE when you need to ensure queued bytes have been handed off before proceeding (e.g. before closing the socket).

Note: This waits for the local send buffer to empty; it does not wait for peer acknowledgements.

How to use it

integer-variable must contain a socket handle returned by CONNECT or SOCKACCEPT.
The statement yields like SOCKREAD: your program pauses and resumes automatically when the condition is met.
Typical use is SOCKWRITE → SOCKFLUSH → SOCKCLOSE.

Note: Press CTRL+ESC at any time to cancel waiting.; Without an error handler, the program terminates on errors; with ON ERROR, control passes to your handler.

Examples

Send a line, flush, then close

server = SOCKLISTEN(NETINFO$("ip"), 2000, 5)
client = SOCKACCEPT(server)
IF client >= 0 THEN
    SOCKWRITE client, "HELLORLD!" + CHR$(13) + CHR$(10)
    SOCKFLUSH client
    SOCKCLOSE client
END IF
SOCKCLOSE server

Ensure data is flushed before reusing variables

CONNECT s, "93.184.216.34", 80
SOCKWRITE s, "HEAD / HTTP/1.0" + CHR$(13) + CHR$(10) + CHR$(13) + CHR$(10)
SOCKFLUSH s
SOCKCLOSE s

Notes

If the socket has no pending data, SOCKFLUSH returns immediately.
If the connection is no longer valid (e.g. already closed), SOCKFLUSH returns without waiting.
Use SOCKSTATUS to query whether a socket is connected.

See also: SOCKWRITE · SOCKREAD · SOCKCLOSE · CONNECT · SOCKACCEPT · SOCKLISTEN