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MODBUS_TCP_LISTEN(3)	       libmodbus Manual		  MODBUS_TCP_LISTEN(3)

NAME
       modbus_tcp_listen - create and listen a TCP Modbus socket (IPv4)

SYNOPSIS
       int modbus_tcp_listen(modbus_t *ctx, int	nb_connection);

DESCRIPTION
       The modbus_tcp_listen() function	shall create a socket and listen to
       maximum nb_connection incoming connections on the specified IP address.
       The context _ctx	_must be allocated and initialized with
       modbus_new_tcp(3) before	to set the IP address to listen, if IP address
       is set to NULL, any addresses will be listen.

RETURN VALUE
       The function shall return a new socket if successful. Otherwise it
       shall return -1 and set errno.

EXAMPLE
       For detailed examples, see source files in tests	directory:

       o   unit-test-server.c, simple but handle only one connection

       o   bandwidth-server-many-up.c, handles several connections at once

	   ...

	   /* To listen	any addresses on port 502 */
	   ctx = modbus_new_tcp(NULL, 502);

	   /* 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_new_tcp(3) modbus_tcp_accept(3) modbus_tcp_pi_listen(3)

AUTHORS
       The libmodbus documentation was written by StA(C)phane Raimbault
       <stephane.raimbault@gmail.com>

libmodbus v3.1.4		  04/29/2017		  MODBUS_TCP_LISTEN(3)

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | EXAMPLE | SEE ALSO | AUTHORS

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