How to use STD::filesystem::recursive_directory_iterator with relative path?

Question

I’m trying to use the recursive_directory_iterator in filesystem, but I’m getting an error message. My main.cpp file is in “A/main.cpp” file, but I want to access a bunch of .txt files in “B/“. Both A & B folders are located in the same level directory. So, I’m assuming the relative path to B from A is : “./B/“ or “../B/“

Here’s my code:

#include <iostream>
#include <experimental/filesystem>

using namespace std;

int main()
{
 //Absolute path works

    for (auto& file : std::filesystem::recursive_directory_iterator("/Users/Tonny/Desktop/Project/B/"))
    {
        cout<< “Through absolute path: “ << file.path() << endl;
    }
//Relative path doesn’t work
    for (auto& file : std::filesystem::recursive_directory_iterator("../B/"))
    {
        cout << “Through relative path: “ << file.path() << endl;
    }
}

However, I’m getting the following error When trying both:

libc++abi.dylib: terminating with uncaught exception of type std::__1::__fs::filesystem::filesystem_error: filesystem error: in recursive_directory_iterator: No such file or directory [../B]

Here's my compiler version:

gcc --version

Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/4.2.1
Apple clang version 11.0.3 (clang-1103.0.32.62)
Target: x86_64-apple-darwin19.6.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

Answer 1

set the current path first. the system assumes the currently set path when the param to recursive_directory_iterator(...) is empty or a relative path.

std::filesystem::current_path("/Users/Tonny/Desktop/Project/B/");  //set cur path first

for (auto& file : std::filesystem::recursive_directory_iterator("../B/"))
{
    cout << “Through relative path: “ << file.path() << endl;
}

alternative:

if you don't want messing up the current_path(), atleast track your target path and then concat relative paths to that path-string.

#include <iostream>
#include <experimental/filesystem>

using namespace std;
namespace fs = std::experimental::filesystem;

int main()
{
    
    std::string targetPath = "/Users/Tonny/Desktop/Project/B/";

    
     //Absolute path
    for (auto& file : fs:recursive_directory_iterator(targetPath))
    {
        cout<< “Through absolute path: “ << file.path() << endl;
    }
    
    //Relative path
    for (auto& file : fs::recursive_directory_iterator(targetPath + "../B/"))
    {
        cout << “Through relative path: “ << file.path() << endl;
    }
}