====== Writing EEROS Applications for cb20 Board ======
Back to [[getting_started:install:use_with_cb20|]].

You will use C++ to develop your EEROS applications. For this you need at least some knowledge of the basic language features. A good starting point might be [[https://www.cplusplus.com/doc/tutorial/]]. Minimal help can also be found under [[tools:cplusplus|]].

What do you want to do next?

  * [[getting_started:write_app:use_on_cb20#Say Hello with EEROS|]]
  * [[getting_started:write_app:use_on_cb20#Use Existing Project|]]

===== Say Hello with EEROS =====

  - Create a project directory and change into it with <code>
$ mkdir hello
$ cd hello 
</code>
  - Create a text file "main.cpp" and copy the following code into it <code cpp>
#include <iostream>
#include <eeros/logger/Logger.hpp>
#include <eeros/logger/StreamLogWriter.hpp>
 
int main() {
  using namespace eeros::logger;
 
  Logger::setDefaultStreamLogger(std::cout);
  Logger log = Logger::getLogger();
 
  log.info() << "Hello, EEROS";

  return 0;
}
</code>
  - Create a text file "CMakeLists.txt" and copy the following text into it: <code cpp>
cmake_minimum_required(VERSION 3.10)
project(helloworld)

set(CMAKE_CXX_STANDARD 14)
find_package(EEROS REQUIRED)

add_executable(helloworld main.cpp)
target_link_libraries(helloworld PRIVATE EEROS::eeros)
</code> 
  - Create a build directory and change into it with <code>
$ mkdir build-armhf
$ cd build-armhf 
</code>
  - Source the script for the SDK which has been installed in [[getting_started:install:use_on_bbb#Install_SDK_on_the_Host|Install SDK on the Host]] with <code>
$ . ~/ost-devel/tdx-xmayland/5.1.0/environment-setup-armv7at2hf-neon-tdx-linux-gnueabi
</code> This step has to be done only once. However, you have to repeat it as soon as you open another shell.
  - Build the project with <code>
$ cmake ..
$ make
</code>
  - Make changes to "main.cpp", save them and rebuild with <code>
$ make
</code> In order to be able to write your own EEROS programs, you could use any text editor. However, we recommend to use an integrated development environment, see [[getting_started:kdevelop|]].

Continue with [[getting_started:deploy:deploy_cb20|]].

===== Use Existing Project =====
As an example we use the [[getting_started:tutorials:oneaxis|]] demo program.
  - Clone the code for the project and change into the directory <code>
$ git clone https://github.com/eeros-project/simple-motor-control.git
$ cd simple-motor-control
</code>
  - Create a build directory, change into it and checkout a stable version with <code>
$ mkdir build-armhf
$ cd build-armhf 
$ git checkout v1.0.0
</code>
  - Source the script for the SDK which has been installed in [[getting_started:install:use_on_bbb#Install_SDK_on_the_Host|Install SDK on the Host]] with <code>
$ . ~/ost-devel/tdx-xmayland/5.1.0/environment-setup-armv7at2hf-neon-tdx-linux-gnueabi
</code> This step has to be done only once. However, you have to repeat it as soon as you open another shell.  - Build the project with <code>
$ cmake -DUSE_FLINK=TRUE ..
$ make
</code>

Continue with [[getting_started:deploy:deploy_cb20|]].