MODBUS_TCP_LISTEN

NAME

modbus_tcp_listen − create and listen a TCP Modbus socket

SYNOPSIS

int modbus_tcp_listen(modbus_t *ctx, int nb_connection);

DESCRIPTION

The modbus_tcp_listen() function shall create a socket and listen for nb_connection incoming connections.

RETURN VALUE

The modbus_tcp_listen() function shall return a new socket if successful. Otherwise it shall return −1 and set errno.

EXAMPLE

For a detailed example, see source file bandwith−server−many−up.c provided in tests directory.

...

ctx = modbus_new_tcp("127.0.0.1", 502);
if (modbus_connect(ctx) == −1) {
fprintf(stderr, "Connection failed: %s\n", modbus_strerror(errno));
modbus_free(ctx);
return −1;
}

/* Handle until 10 established connections */
server_socket = modbus_tcp_listen(ctx, 10);

/* Clear the reference set of socket */
FD_ZERO(&refset);

/* Add the server socket */
FD_SET(server_socket, &refset);

if (select(server_socket + 1, &refset, NULL, NULL, NULL) == −1) {
}

...

close(server_socket);
modbus_free(ctx);

SEE ALSO

modbus_tcp_accept(3) modbus_tcp_pi_accept(3) modbus_tcp_pi_listen(3)

AUTHORS

The libmodbus documentation was written by Stéphane Raimbault <stephane.raimbault@gmail.com [1] >

NOTES

mailto:stephane DOT raimbault AT gmail DOT com