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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 to establish a connection. A NULL value can	be used	to
       listen any addresses in server mode.

       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 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.

       ENOMEM
	   Out of memory. Possibly, the	application hits its memory limit
	   and/or whole	system is running out of memory.

EXAMPLE
	   modbus_t *ctx;

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

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

SEE ALSO
       modbus_tcp_listen(3) modbus_free(3)

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

libmodbus v3.1.6		  03/01/2021		     MODBUS_NEW_TCP(3)

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

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