SDK >= 2021.6

The SDK compiler was set to C 17

With the SDK version 2021.6 the language standard C 17 has been set in the compiler options (-std=c 17). The firmware itself is also compiled with this option set. Besides some general C issues related to this C 17 standard, the following issue is related to PLCnext: C 17 introduces the data type std::byte which is unfortunately not compatible with Arp::byte. Therefore, if the namespaces std and Arp are both active the compilation, this results in an error. In this case existing C sources have to be adjusted so that they explicitly use Arp::byte (e.g. by adding using byte = Arp::byte;).

Known for firmware on ALL PLCnext devices

[cmake]: [ 71%] Building CXX object CMakeFiles/FileStreamExample.dir/src/FileStreamExampleComponent.cpp.o
[cmake]: /home/myworkpcuser/Downloads/CppExamples/Examples/FileStreamExample/src/FileStreamExampleComponent.cpp: In member function 'void FileStreamExample::FileStreamExampleComponent::WriteToFile(Arp::String)':
[cmake]: /home/myworkpcuser/Downloads/CppExamples/Examples/FileStreamExample/src/FileStreamExampleComponent.cpp:85:19: error: reference to 'byte' is ambiguous
[cmake]:    85 |     stream.Write((byte*) str.CStr(), str.Length(), 0, str.Length());

can be fixed With:

stream.Write((Arp::byte*) str.CStr(), str.Length(), 0, str.Length());
stream.Read((Arp::byte*) str.CStr(), stream.GetLength(), 0,    stream.GetLength());