Re: [boost] Current Guidance on Compiler Warnings?

Subject: Re: [boost] Current Guidance on Compiler Warnings?
From: Robert Ramey (ramey_at_[hidden])
Date: 2018-11-24 19:17:44

On 11/24/18 7:52 AM, Peter Dimov via Boost wrote:
> Daniela Engert wrote:

> Making it an error would be a useful first step towards making it work 
> correctly. :-)
> 
> (It's perfectly possible to compare a value in [INT_MIN, INT_MAX] with a 
> value in [0, UINT_MAX], it's just that the standard says op< needs to do 
> the wrong thing.)

I appologize in advance for perhaps hijacking the thread, but I can't 
restrain myself from the opportunity  to plug the most recent addition 
to the boost libaries - safe_numerics.

C/C++ "arithmetic" is not really arithmetic.  That is, results of the 
arithmetic operations are not guaranteed to map to their counterparts in 
the arithmetic of integers.  The C/C++ rules for promoting operands to 
the same type can and do introduce errors.  Then the application of 
operations defined in terms to unbounded integers to the bounded 
integers we use in our programs can and do return incorrect results. 
Warnings like the above can definitely help, but can't guarantee that 
the problem does not occur.  It is not possible to prove that these 
problems cannot occur by visual inspection.  We're living a lie.

So I invite all parties who write programs which much function as 
written to take a look a the boost safe numerics library.  I think 
you'll find it interesting.

Robert Ramey