modbus_mapping_new(3) [debian man page]

MODBUS_MAPPING_NEW(3)						 Libmodbus Manual					     MODBUS_MAPPING_NEW(3)

NAME

       modbus_mapping_new - allocate four arrays of bits and registers

SYNOPSIS

       modbus_mapping_t modbus_mapping_new(int nb_bits, int nb_input_bits, int nb_registers, int nb_input_registers);*

DESCRIPTION

       The modbus_mapping_new() function shall allocate four arrays to store bits, input bits, registers and inputs registers. The pointers are
       stored in modbus_mapping_t structure. All values of the arrays are initialized to zero.

       If it isn't necessary to allocate an array for a specific type of data, you can pass the zero value in argument, the associated pointer
       will be NULL.

       This function is convenient to handle requests in a Modbus server/slave.

RETURN VALUE

       The modbus_mapping_new() function shall return the new allocated structure if successful. Otherwise it shall return NULL and set errno.

ERRORS

       ENOMEM
	   Not enough memory

EXAMPLE

	   /* The fist value of each array is accessible from the 0 address. */
	   mb_mapping = modbus_mapping_new(BITS_ADDRESS + BITS_NB,
					   INPUT_BITS_ADDRESS + INPUT_BITS_NB,
					   REGISTERS_ADDRESS + REGISTERS_NB,
					   INPUT_REGISTERS_ADDRESS + INPUT_REGISTERS_NB);
	   if (mb_mapping == NULL) {
	       fprintf(stderr, "Failed to allocate the mapping: %s
",
		       modbus_strerror(errno));
	       modbus_free(ctx);
	       return -1;
	   }

SEE ALSO

       modbus_mapping_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_MAPPING_NEW(3)

MODBUS_NEW_TCP_PI(3)						 Libmodbus Manual					      MODBUS_NEW_TCP_PI(3)

NAME

       modbus_new_tcp_pi - create a libmodbus context for TCP Protocol Independent

SYNOPSIS

       modbus_t *modbus_new_tcp_pi(const char *node, const char *service);

DESCRIPTION

       The modbus_new_tcp_pi() function shall allocate and initialize a modbus_t structure to communicate with a Modbus TCP IPv4 or Ipv6 server.

       The node argument specifies the host name or IP address of the host to connect to, eg. 192.168.0.5 , ::1 or server.com.

       The service argument is the service name/port number to connect to. To use the default Modbus port use the string "502". On many Unix
       systems, 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_pi() 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
	   The node string is empty or has been truncated. The service string is empty or has been truncated.

EXAMPLE

	   modbus_t *ctx;

	   ctx = modbus_new_tcp_pi("::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_tcp(3) 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_PI(3)