currentDirectory() {
    var buf = String();
    reserve(buf, 1024);

    while (true) {
        var result = getcwd(Pointer[Int8](&buf[0]), size(buf));
        if (not null?(result))
            break;
        if (errno() != ERANGE)
            error(errorMessage());
        reserve(buf, 2*size(buf));
    }
    
    // 'resize' is not yet available
    // resize(buf, libc.strlen(&buf[0]));
    buf.size = libc.strlen(Pointer[Int8](&buf[0]));
    return move(buf);
}

error: Invalid argument