Re: [Boost-users] BOOST_CHECK_CLOSE with integral types

From: Will Bryant (will_at_[hidden])
Date: 2005-09-23 20:28:53

Gennadiy Rozental wrote:

>I chose to divide percent tolerance by 100 (multiplication would lead to 
>overflow issues). BOOST_CHECK_CLOSE doesn't really fit for integral type 
>closeness check. You could use BOOST_CHECK_SMALL instead.
>
>  
>
Would it not be useful to provide a specialisation of the comparison 
template for integral types?  The current semantics aren't useful IMHO - 
they just give undocumented false test passes - so even a naive 
implementation which risked overflow would be an improvement.

But we can actually prevent overflow - just check if |a-b| is >= the 
maximum value for the integer type / 100, if not use 100*|a-b|/a, if so 
use something like |a-b|/(a/100).

Will

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Will Bryant
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