How to skip/disregard files with names that use wide characters using std::filesystem?

Question

I am iterating through a large set of nested directories searching for files of some extension, say ".foo" using code like the following:

namespace fs = std::filesystem;

int main(int argc, char* argv[])
{
    std::ios_base::sync_with_stdio(false);
    for (const auto& entry : fs::recursive_directory_iterator("<some directory>")) {
        if (entry.path().extension() == ".foo") {
            std::cout << entry.path().string() << std::endl;
        }
    }
}

however the above throws on files with names that use unicode/wide characters. I know I can fix the problem in the little program above by using wstring everywhere i.e. std::wcout << entry.path().wstring() << std::endl; but what I actually need to do in my real program is skip such files. Right now I am catching the exception in the body of the for-loop and doing nothing in that case but am wondering if there is a more direct approach.

In Windows/Visual Studio the specific exception being thrown is

No mapping for the Unicode character exists in the target multi-byte code page.

How do I test for such filenames using standard C++?

Answer 1

Unicode characters have values > 0x7f, so you could do something like this:

bool is_wide = false;
for (auto ch : entry.path().wstring())
{
    if (ch > 0x7f)
    {
        is_wide = true;
        break;
    }
}

if (!is_wide)
    std::cout << entry.path().string() << std::endl;