modbus_tcp_listen(3) 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);

AUTHORS

The libmodbus documentation was written by St├ęphane Raimbault <m[blue][email protected]m[][1]>