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[Python-Dev] IO module precisions and exception hierarchy

Michael Foord fuzzyman at voidspace.org.uk
Mon Sep 28 12:03:35 CEST 2009 
Greg Ewing wrote:
> Michael Foord wrote:
>
>> Some of the error messages are truly awful though as things stand, 
>> especially for someone new to Python. Try to read from a file handle 
>> opened in read mode for example: IOError: [Errno 9] Bad file descriptor
>
> Subdividing the IOError exception won't help with
> that, because all you have to go on when deciding
> which exception to raise is the error code returned
> by the OS. If the same error code results from a
> bunch of different things, there's not much Python
> can do to sort them out.
>

Well, the file type knows what mode it is opened in so catching these 
errors is really not difficult at all.

Michael


> The error messages produced for the various error
> codes could perhaps be improved, but that's an
> orthogonal issue.
>


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