modbus_new_tcp(3) [debian man page]

MODBUS_NEW_TCP(3)						 Libmodbus Manual						 MODBUS_NEW_TCP(3)

NAME

       modbus_new_tcp - create a libmodbus context for TCP/IPv4

SYNOPSIS

       modbus_t *modbus_new_tcp(const char *ip, int port);

DESCRIPTION

       The modbus_new_tcp() function shall allocate and initialize a modbus_t structure to communicate with a Modbus TCP/IPv4 server.

       The ip argument specifies the IP address of the server to which the client wants etablish a connection.

       The port argument is the TCP port to use. Set the port to MODBUS_TCP_DEFAULT_PORT to use the default one (502). It's convenient to use a
       port number greater than or equal to 1024 because it's not necessary to have administrator privileges.

RETURN VALUE

       The modbus_new_tcp() function shall return a pointer to a modbus_t structure if successful. Otherwise it shall return NULL and set errno to
       one of the values defined below.

ERRORS

       EINVAL
	   An invalid IP address was given.

EXAMPLE

	   modbus_t *ctx;

	   ctx = modbus_new_tcp("127.0.0.1", 1502);
	   if (ctx == NULL) {
	       fprintf(stderr, "Unable to allocate libmodbus context
");
	       return -1;
	   }

	   if (modbus_connect(ctx) == -1) {
	       fprintf(stderr, "Connection failed: %s
", modbus_strerror(errno));
	       modbus_free(ctx);
	       return -1;
	   }

SEE ALSO

       modbus_new_rtu(3) modbus_free(3)

AUTHORS

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

NOTES

	1. stephane.raimbault@gmail.com
	   mailto:stephane.raimbault@gmail.com

libmodbus 3.0.3 						    05/26/2012							 MODBUS_NEW_TCP(3)

Check Out this Related Man Page

MODBUS_TCP_LISTEN(3)						 Libmodbus Manual					      MODBUS_TCP_LISTEN(3)

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
", 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 Stephane Raimbault <stephane.raimbault@gmail.com[1]>

NOTES

	1. stephane.raimbault@gmail.com
	   mailto:stephane.raimbault@gmail.com

libmodbus 3.0.3 						    05/26/2012						      MODBUS_TCP_LISTEN(3)

Linux and UNIX Man Pages

modbus_new_tcp(3) [debian man page]

Check Out this Related Man Page