Writing Code

Below is the entire project. You can just copy/paste it into the main.tbs file -- it will be opened and "in front of you" when you create your tcp_echo project.

The only line that will probably need changing is the net_ip="" line. Choose a suitable IP address for your device and set it here. Obviously, the address you choose should be unoccupied -- you can verify this by pinging this IP and making sure nobody responds.

We don't want to go into a lengthy explanation here... just a few comments on how this works:

•The sock_on_sock_data_arrival event handler takes whatever is received by the TCP socket and sends it back.

•The sock_on_sock_event event handler is not actually necessary for the echo application. We added this because we wanted to have this proverbial "HELLO WORLD" somewhere. The string is sent whenever a TCP connection is established.

Notice how small your first Tibbo BASIC program is! This is the power of Tibbo BASIC -- you accomplish complex things in just several lines of code.

include "global.tbh"

sub on_sys_init()

sys.halt

net.ip="192.168.1.222"

sock.rxbuffrq(1)

sock.txbuffrq(1)

sys.buffalloc

sock.protocol=PL_SOCK_PROTOCOL_TCP

sock.localportlist="1000"

sock.inconmode=PL_SOCK_INCONMODE_ANY_IP_ANY_PORT

sock.reconmode=PL_SOCK_RECONMODE_3

end sub

sub on_sock_data_arrival()

dim s as string

s=sock.getdata(sock.txfree)

sock.setdata(s)

sock.send

end sub

sub on_sock_event(newstate as enum pl_sock_state,newstatesimple as enum pl_sock_state_simple)

if newstatesimple=PL_SSTS_EST then

sock.setdata("HELLO WORLD!")

sock.send

end if

end sub