How do I include the experimental/filesystem C++ header in Simulink Real-Time custom code?

When compiling custom C++ code for use in Simulink Real-Time R2022a, I receive a compiler error:

fatal error: experimental/filesystem: No such file or directory

on the include statement for the "experimental/filesystem" header. The "Language Standard" option in the configuration parameters is set to "C++11", which should have this library as part of its standard library.

Why can't I include "experimental/filesystem", and how can I use its functionality in my C++ code?

Answer 1

[MathWorks Support Team]

The standard library and headers available to the Simulink Real-Time compiler are determined by the Real-Time Operating System, which compiles and runs the custom code and model. Since R2020b, this is QNX Neutrino.

This is not affected by the "Language Standard" option in the configuration parameters, which only affects code generated from Simulink, not compiler options.

The "experimental/filesystem" library was renamed to just "filesystem" in the C++17 standard, so the following include statement works:

#include <filesystem>

Alternatively, you can use the Boost filesystem library with the following include statement:

#include <boost/filesystem.hpp>

The C++ filesystem library was directly based on the Boost filesystem library, so similar functionality is present. For more information on the C++ filesystem library and its history, refer to the following external links:

• https://en.cppreference.com/w/cpp/experimental/fs.html
• https://en.cppreference.com/w/cpp/filesystem.html