modbus_tcp_listen man page

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

1.

stephane.raimbault@gmail.com

mailto:stephane.raimbault@gmail.com

Info

04/02/2014 libmodbus 3.0.6 Libmodbus Manual