I asked this question to boost-bugs, but I was told not to expect a response from that email address and instead ask here.

#define BOOST_FILESYSTEM_VERSION 3
#define BOOST_FILESYSTEM_NO_DEPRECATED
#include "boost/filesystem.hpp"

namespace fs = ::boost::filesystem;

// return the filenames of all files that have the specified extension
// in the specified directory and all subdirectories
void get_all(const fs::path& root, const string& ext, vector<fs::path>&ret)
{
    if(!fs::exists(root) || !fs::is_directory(root)) return;

    fs::recursive_directory_iterator it(root);
    fs::recursive_directory_iterator endit;

    while(it != endit)
    {
        if(fs::is_regular_file(*it) && it->path().extension() == ext) ret.push_back(it->path().filename());

        ++it;
    }
}

This code is used as part of the CXX file, which is built with an appropriate CMakeLists file using CMake 3.5.1 to produce a corresponding .xcodeproj file. CXX and CMakeLists files are attached.

However, the main problem that I'm facing is that attempting to build the project using an ALL_BUILD scheme in Xcode 7.0.1 leads to a series of errors pointing to the #include statements of the header files in the Boost folder (which is located in the same folder as the CXX and CMakeLists files).

For instance, it starts off saying that "'boost/filesystem/config.hpp' file not found" in response to the following line of boost/filesystem.hpp:

#  include <boost/filesystem/config.hpp>

Such errors could be resolved if I were to modify the syntax of the #include statements to follow a different format:

#  include "./filesystem/config.hpp"

i.e., replacing the <> with "" and using relative paths to find the other required header files.