Re: [boost] Boost public interface macro names

From: Greg Colvin (gcolvin_at_[hidden])
Date: 2000-11-09 13:23:51

From: Beman Dawes <beman_at_[hidden]>
> John Maddock wrote:
> 
>  >Beman,
>  >
>  >>Perhaps I should just work on a core proposal for a new language
>  >>feature.  All of the macro uses we are talking about are needed to get
>  >>__FILE__ and __LINE__.  How about two new special symbols:
>  >>
>  >>namespace boost {
>  >>   static_assert( bool exp, const char * file=__FILE_AT_USE,
>  >>                  int line=__LINE_AT_USE );
>  >>}
>  >>
>  >>The compiler is required to replace these with the appropriate value at
>  >the
>  >>point of a call to static_assert(), rather than at point of declaration.
>  >
>  >If this were going forward as part of the standard I would say yes call 
> in
>  >"static_assert" and place it <cassert>, either as a regular macro, or as 
> a
>  >core language extention (depending how the vendor sees it).
>  >
>  >However, there is a problem with your approach wrt boost:  how does the
>  >static_assert function you've defined above, convert the bool parameter 
> to
>  >a static assertion (as an integral constant expression)?
> 
> I don't know without language support.  It keeps coming back to that; there 
> needs to be better language support for diagnostic tools.
> 
> __FILE_AT_USE and __LINE_AT_USE would allow some better user written tools 
> like various improved runtime asserts, so they wouldn't be be totally 
> useless.  I'm just trying to provoke thought, not actually present a 
> finished solution.

I recall that my proposal for a similar __WHERE__ macro was not well received.

Another related problem is that using the assert macro in inline code can
easily lead to violations of the One Definition Rule.