Reading python io.IOBase class documentation, I'm kind of confused at the expected behavior of operation on a closed file object.
The io.IOBase class doc says: """Note that calling any method (even inquiries) on a closed stream is undefined. Implementations may raise IOError<exceptions.html#exceptions.IOError>in this case.""" But the io.IOBase.close() method document says: """Once the file is closed, any operation on the file (e.g. reading or writing) will raise an IOError <exceptions.html#exceptions.IOError>.""" which unlike the class doc is not conditional about the behavior... Experimentation (see below) show that I get a ValueError in practice (python 3.1) with io.BufferedWriter and io.StringIO objects. So which one is right? Am I reading the wrong documentation? >>> with open( 'dummy', 'wb') as f: ... pass ... >>> f.write( b'' ) Traceback (most recent call last): File "<stdin>", line 1, in <module> ValueError: write to closed file >>> f.writable() Traceback (most recent call last): File "<stdin>", line 1, in <module> ValueError: I/O operation on closed file >>> import io >>> s = io.StringIO() >>> s.close() >>> s.read() Traceback (most recent call last): File "<stdin>", line 1, in <module> ValueError: I/O operation on closed file
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