Re: [boost] Supressing warnings

From: Paul A Bristow (pbristow_at_[hidden])
Date: 2006-06-30 05:43:17

|  -----Original Message-----
|  From: boost-bounces_at_[hidden] 
|  [mailto:boost-bounces_at_[hidden]] On Behalf Of Yuval Ronen
|  Sent: 29 June 2006 20:55
|  To: boost_at_[hidden]
|  Subject: Re: [boost] Supressing warnings
|  
|  Paul A Bristow wrote:
|  > IMO Boost-worthy code should be able to be compiled in 
|  strict mode, for MSVC
|  > level 4, without producing a blizzard of warnings.
|  > 
|  > Including a list of warnings that the authors of the 
|  library consider
|  > unhelpful, and in some cases, unfixable (specifically the warning
|  > "conditional expression is constant. ")
|  > 
|  > by using, for example
|  > 
|  > #ifdef _MSC_VER
|  > #  pragma warning(disable: 4127) // conditional expression 
|  is constant. 
|  > #endif
|  
|  This warning is not so bad, IMO. It tells you that you are trying 
|  evaluate a compile-time constant in run-time, and that's wasting CPU 
|  cycles. The runtime 'if' can be substituted by a compile-time 
|  specialization.

<snip>

If I now write (a VERY common example)

   if(std::numeric_limits<T>::has_infinity)
      return std::numeric_limits<T>::infinity();

It IS I believe a C++ language fault, that has_infinity doesn't work like a
macro constant,

described by Bjarne Stroustrup as "an embarassment",

(a TODO for C++0X but reference to which escapes me at present).

What in this type of case are you suggesting that I write for the time
being?

And since it is VERY common, it had better be short ;-)  MACROs just about
allowed!

Thanks

Paul

PS If I write

if(true) ...

I'm not sure why I need a warning about it :-)

---
Paul A Bristow
Prizet Farmhouse, Kendal, Cumbria UK LA8 8AB
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pbristow_at_[hidden]