static file_t* _cast_file(const oe_fd_t* file_)
{
    file_t* file = (file_t*)file_;

    if (file == NULL || file->magic != MAGIC)
        return NULL;

    return file;
}
static file_t* _cast_file(const oe_fd_t* file_)
{
    file_t* file = (file_t*)file_;

    if (file == NULL || file->magic != MAGIC)
        return NULL;

    return file;
}