mailbox.py 文件源码

def _create_carefully(path):
    """Create a file if it doesn't exist and open for reading and writing."""
    fd = os.open(path, os.O_CREAT | os.O_EXCL | os.O_RDWR, 0666)
    try:
        return open(path, 'rb+')
    finally:
        os.close(fd)