exists doesn't clear no_such_file_or_directory type of error codes

[Alex Weiss <alexweiss86@…>]

Windows 10, MSVC 19.13.26128.

exists() fails when it successfully determines that a file doesn't exist (i.e. it sets the error code to ERROR_FILE_NOT_FOUND or throws in the throwing version). According to the reference and the tutorial example, that should not happen.

Code example:

        boost::filesystem::path p("c:\\filethatdoesntexist");
	boost::system::error_code ec;
	bool doesExist = boost::filesystem::exists(p, ec);
	if (ec == boost::system::errc::no_such_file_or_directory) {
		std::cout << "shouldn't happen!\n";
	}

Note that for existing files, exists() works as expected.