libmodbus/MIGRATION

=============================
Migration from the 2.0 series
=============================

modbus_init_listen_tcp() has been renamed to modbus_slave_listen_tcp() and
requires a new argument, the maximal number of connections:

int modbus_slave_init_tcp(modbus_param_t *mb_param, int nb_connection);


New function modbus_slave_accept_tcp() to etablish a new connection (previously
in modbus_init_listen_tcp()):

int modbus_slave_accept_tcp(modbus_param_t *mb_param, int *socket);


modbus_listen() has been renamed to modbus_slave_receive() and requires a new
argument, the socket file descriptor to listen on. If the sockfd is -1, the
internal fd of modbus_param_t is used:

int modbus_slave_receive(modbus_param_t *mb_param, int sockfd,
                         uint8_t *query, int *query_length);


If you use the HEADER_LENGTH_ defines, their values have been incremented by 1
to reflect the PDU and ADU of the Modbus protocol and to reduce the CPU
consumption:
 - HEADER_LENGTH_RTU           0 -> 1
 - HEADER_LENGTH_TCP           6 -> 7

===================================
Migration notes from the 1.2 series
===================================

Init
====

modbus_init_tcp requires a third new argument, the port number.

modbus_init_tcp(modbus_param_t *mb_param, char *ip_address, int port)

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 be root to use this port number.


Pointers of data
================

The coil and input status are now stored in an array of type uint8_t
(in 1.2.X series, array of type int was used).  So now, you need to
pass a pointer of type uint8_t to use read_coil_status(), for example.

The holding and input registers are now stored in an array of type
uint16_t.

These changes reduce the memory consumption.


New functions
=============

report_slave_id

modbus_set_error_handling
modbus_mapping_new
modbus_mapping_free
modbus_init_listen_tcp
modbus_listen
modbus_manage_query

get_slave_query_tcp
set_bits_from_byte
set_bits_from_bytes
get_byte_from_bits

Read modbus.h for more informations.