correct version of --> Allow "" and NULL on TCP host and service (=> IP=INADDR_ANY, and port=0)
/*
* Copyright (c) 2001-2003,2016 Mario de Sousa (msousa@fe.up.pt)
*
* This file is part of the Modbus library for Beremiz and matiec.
*
* This Modbus library is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
* General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this Modbus library. If not, see <http://www.gnu.org/licenses/>.
*
* This code is made available on the understanding that it will not be
* used in safety-critical situations without a full and competent review.
*/
Modbus Protocol Libraries
=========================
This directory contains the libararies that implement the modbus protocol
stack.
This protocol has been implemented as a two layer stack. Layer two includes
the mb_master and the mb_slave protocols. Layer one is composed of
the mb_rtu, mb_ascii and mb_tcp protocols.
Layer1 protocols all implement the same interface, defined in mb_layer1.h
Layer2 protocols implement different interfaces, defined in mb_master.h
and mb_slave.h
Which layer1 protocol that will be used by the program will depend on which
layer1 protocol implementation is linked to the final binary/executable.
It is not possible to define during run-time which layer1 protocol is to
be used. Each compiled program can only support a single layer1 protocol.
Users of these libraries should only use functions defined in the layer2
protocol header files (i.e. mb_master.h and mb_slave.h)
If writing a program that will simultaneously be a master and a slave,
then only use the mb_slave_and_master.h header file!
In this case, do not forget to link the final binary to both the
master and slave protocol implementations (as well as the chosen
layer1 protocol implementation).
------------------------------------------
| | |
layer 2 | mb_master.h | mb_slave.h |
| mb_master.c | mb_slave.c |
| | |
|----------------------------------------|
| mb_layer1.h |
Layer 1 | | | |
| mb_rtu.c | mb_ascii.c | mb_tcp.c |
| | | |
------------------------------------------