How to read files in a directory on Linux?

Question

I am trying to read files in a given directory on Ubuntu 19.04. I am planning to use directory_iterator in standard library. I am using CLion IDE which uses compiler in the directory "usr/bin/c++". I guess this is g++ compiler and the version of g++ is 8.3 in my system. C++ version I am using is C++17.

I was able to run the code successfully on Visual Studio 2017 on Windows 10. But the code yielded segmentation fault error on Ubuntu while using CLion. The code below is from cppreference page about directory_iterator.

#include <fstream>
#include <iostream>
#include <filesystem>
namespace fs = std::filesystem;

int main()
{
    fs::create_directories("sandbox/a/b");
    std::ofstream("sandbox/file1.txt");
    std::ofstream("sandbox/file2.txt");
    for(auto& p: fs::directory_iterator("sandbox"))
        std::cout << p.path() << '\n';
    fs::remove_all("sandbox");
}

I expected the code to print the files in the given folder but instead I got Segfault.

Process finished with exit code 139 (interrupted by signal 11: SIGSEGV).

What could be the reason behind this issue? Could the problem be related to CMake?

Answer 1

It looks like a bug in gcc 8.3

If you run it, it fail to link. May be in your environement the bug cause a segfault.

But if you update to gcc 9.1: it works fine.

Clang 9 is fine too, but all versions before fail to compile

Edit: As said by Galik if you add the flag -lstdc++fs it seems to work

Source : https://en.cppreference.com/w/cpp/filesystem

Notes

Using this library may require additional compiler/linker options. GNU implementation requires linking with -lstdc++fs and LLVM implementation requires linking with -lc++fs