modbus-cpp

This is a C++ wrapper around libmodbus, a library to communicate with Modbus devices. It brings you the benefit of automatic resource management due to RAII and convenient error handling due to exceptions. It is a header-only library, has zero performance overhead, and does not require installation.

The library implements only a subset of libmodbus interface (actually, only the functions that I needed for my projects). If you want more -- feel free to add them and create a pull request!

Code example

#include <modbus/Modbus.hpp>
#include <iostream>

int main(int, char **)
{
    try
    {
        modbus::Context modbus = modbus::new_tcp("192.168.0.100");
        modbus::Connection connection {modbus};

        std::array<std::uint16_t, 3> data;
        connection.read_registers(0x123, data.size(), data.data());
        connection.write_register(0x456, 0x42ff);
    }
    catch (std::system_error const& e)
    {
        std::cerr << "Error: " << e.message() << std::endl;
    }

    return 0;
}

Dependencies

Besides the C++ standard library, modbus-cpp depends on Boost Exception. Although this dependency is not strictly necessary, I find it nice to have function and line info in exceptions, therefore I use BOOST_THROW_EXCEPTION(). Now Boost recommends to use Boost LEAF, so I may switch to that. I also like the idea to give the user a choice (by adding a configuration option/macro) to use only the standard C++ library.

If you want to run library tests, you will also need to install GoogleTest.

Using

1. Install Boost Exception. On Ubuntu and Debian Linux, the command is:

   sudo apt install libboost-exception-dev

2. Copy include/modbus where your compiler can see it.
3. Add #include <modbus/Modbus.hpp> in your program.
4. Don't forget to link to libmodbus.
5. Enjoy!

Tests

The library is equipped with some tests. First, install GoogleTest:

sudo apt install googletest

To build and run the tests, do

sudo apt install googletest
cd modbus-cpp
mkdir build
cd build
cmake ..
make
make test