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Subject: Re: I/O - exception handling
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Randy Brukardt wrote:

> While I don't think any implementor would plan to raise an exception
> from Is_Open, certainly the standard allows Use_Error or Device_Error
> and of course Storage_Error and Program_Error (if there are elaboration
> problems). In practice, I think it's safe to ignore that possibility.

Totally agree with respect to Is_Open. However, there are cases where 
exceptions on Close are not only possible but likely in some situations. 
  For example it is perfectly legal in Ada to close Standard_Output and 
other standard files.  There was even an AI a while back making it clear 
that it is legal to do so, and what it means if the implementation does 
support it.  But implementations (notice, not compilers, this is a 
target OS or environment issue) may not allow some files to be closed, 
and you will get Use_Error.