tempfile.py 文件源码

def mktemp(suffix="", prefix=template, dir=None):
    """User-callable function to return a unique temporary file name.  The
    file is not created.

    Arguments are as for mkstemp, except that the 'text' argument is
    not accepted.

    This function is unsafe and should not be used.  The file name
    refers to a file that did not exist at some point, but by the time
    you get around to creating it, someone else may have beaten you to
    the punch.
    """

##    from warnings import warn as _warn
##    _warn("mktemp is a potential security risk to your program",
##          RuntimeWarning, stacklevel=2)

    if dir is None:
        dir = gettempdir()

    names = _get_candidate_names()
    for seq in range(TMP_MAX):
        name = next(names)
        file = _os.path.join(dir, prefix + name + suffix)
        if not _exists(file):
            return file

    raise IOError(_errno.EEXIST, "No usable temporary filename found")