RE: [boost] Re: Standard Math Constants?

From: Beman Dawes (beman_at_[hidden])
Date: 2000-07-18 12:40:57

Paul A. Bristow wrote:

 >After all that flurry of disputation
 >
 >Should I use this sort of confusing macro to allow specification, or not?
 >
 >// Do we need to be able to switch exceptions off/on completely?
 >#if _HAS_EXCEPTIONS // Used by Dinkumware/Microsoft Standard Library.
 >  #define _THROW0()	throw ()
 >#else	/* no exceptions */
 >  #define _THROW0()
 >#endif /* _HAS_EXCEPTIONS */
 >
 >and/or
 >
 >#if _HAS_EXCEPTIONS
 >  #if _USES_EXCEPTION_SPECIFICATIONS_WELL   // What should I call this?
 >  #define _THROW0()	throw ()

That's essentially the question in the "Exception specifications in 
smart_ptr.hpp" thread.  I'm leaning toward putting a BOOST_THROW in 
boost/config.hpp, coupled with a dire warning that it (and exception specs 
in general) should never be used without understanding the implications.

Which I will try to get Dave Abrahams to write docs for, based on his 
emails.  We already say "Avoid exception specifications. Rationale: they 
provide no compile-time safety and cause many (if not most) compilers to 
generate poorer code. Do, however, use exceptions to report errors where 
appropriate, and write code that is safe in the face of exceptions." but 
that doesn't go into enough detail, apparently.

--Beman