Re: [boost] suggestion on assertion macros

Subject: Re: [boost] suggestion on assertion macros
From: Peter Dimov (pdimov_at_[hidden])
Date: 2010-03-12 16:11:55

Steven Watanabe:

> AMDG
>
> Roland Bock wrote:
>> Stewart, Robert wrote:
>>> C4800 seems ridiculous.  Writing code using int as a Boolean is common 
>>> to C code. Why would VC 9 inflict useless noise when compiling such 
>>> code?  Besides, if the variable is int, and it is needed in a Boolean 
>>> context, what else would the developer do?  I've seen use of the 
>>> conditional operator to avoid that warning.  I suspect that produces 
>>> worse code than what is done when "forcing value to bool 'true' or 
>>> 'false'."
>>>
>> I agree. Still, I hope that static_cast is allowed to remove C4800
>
> Nope.
>
> .\scratch.cpp(20) : warning C4800: 'int' : forcing value to bool 'true' or 
> 'false' (performance warning)

C4800 is avoided with expr? true: false. In this case, sizeof( expr? 0: 0 ) 
will also work, as we don't care about the value.