[Boost-users] System library, error_category

Subject: [Boost-users] System library, error_category
From: John Dlugosz (JDlugosz_at_[hidden])
Date: 2010-09-28 17:45:32

I've derived a class from error_category to categorize errors associated with my class.  Elsewhere, I want to test to see if an error code I've gotten (from an exception) is one of those, or not.  A line like
          if (X.code().category != mycategory) ...
should do the trick.  'mycategory' is the same object used to create error codes in my class: a single instance of the derived error_category class.

However, this gives ambiguities in matching the operator.

This makes it quite unfriendly to use.  I have to cast the right-hand-side to the base class reference, for example.

If I reversed the arguments, the list of possible matches the compiler mentioned did not even include the one I wanted.

As this is a TR2 candidate, I think such rough edges should be examined and avoided.

--John

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