[boost] Re: Next revision of boost::thread & OS error code.

From: Martin Brown (martin_w_brown_at_[hidden])
Date: 2003-01-10 05:30:53

Hi,

Regarding the OS error code / exception type debate; I
may have missed something here, so apologies if I
have.   Speaking as a user of your wonderful
libraries:

1. I need all the data available - the error may be
happening on a computer in Japan and the data may be
filtered through many layers of sales and support.   

2. The user needs a localised error message.

3. Most errors are for the user to deal with.   Many
problems are simply due to configuration (e.g.
permissions) or interaction with other software (e.g.
virus scanners).   Auto-recovery is often only
possible to a limited extent.

4. Exception object types are useful for
auto-recovery, but are less important when generating
a message for a user.

(1) implies that the error reporting system cannot
destroy any information (e.g. representing many error
codes in a single exception object with no way to get
at the original code).

(2) & (3) imply that OS error codes must be available
for generating a message using the OS facilities.   It
is pointless having a boost set of error codes, as
this would require boost writing and maintaining
localised error messages.   

(4) implies that I still want exception types so I can
recover when possible, but there must be a way of
getting the OS error code.

I hope this is useful,

Martin Brown

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