def get_tr1(name):
    """In libstd++ the tr1 namespace needs special care.

    Return either an empty string or tr1::, useful for
    appending to search patterns.

    Args:
        name (str): the name of the declaration

    Returns:
        str: an empty string or "tr1::"
    """
    tr1 = ""
    if "tr1" in name:
        tr1 = "tr1::"
    return tr1