stdcxx-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Martin Sebor <se...@roguewave.com>
Subject Re: svn commit: r668225 - /stdcxx/branches/4.3.x/etc/config/src/VA_LIST_FUNC_MACRO.cpp
Date Mon, 23 Jun 2008 21:50:23 GMT
Eric Lemings wrote:
>  
> 
>> -----Original Message-----
>> From: Martin Sebor [mailto:sebor@roguewave.com] 
>> Sent: Monday, June 23, 2008 2:10 PM
>> To: dev@stdcxx.apache.org
>> Subject: Re: svn commit: r668225 - 
>> /stdcxx/branches/4.3.x/etc/config/src/VA_LIST_FUNC_MACRO.cpp
>>
>> elemings@apache.org wrote:
>>> Author: elemings
>>> Date: Mon Jun 16 09:31:03 2008
>>> New Revision: 668225
>>>
>>> URL: http://svn.apache.org/viewvc?rev=668225&view=rev
>>> Log:
>>> 2008-06-16  Eric Lemings <eric.lemings@roguewave.com>
>>>
>>> 	STDCXX-958
>>> 	* etc/config/src/VA_LIST_FUNC_MACRO.cpp: Initial version of
>>> 	configuration check for va-list function macros.
>> Out of curiosity, what do you expect to use this for? (FWIW,
>> I've often wished variadic macros were supported in C++
>> compilers but I could never come up with a workaround for
>> their absence, making them essentially unusable as a general
>> purpose feature.)
> 
> The most obvious use would be in RWTest printf-like functions.
> 
> I'm not sure how well variadic function macros mesh with variadic
> templates but, if they do, I could take advantage of the feature
> in tuples.

My point was that I couldn't find a way to use a feature
that depends on variadic macros on platforms where they
are not supported. In other words, I can't picture what
the #else branch below would look like:

   #ifndef _RWSTD_NO_VARIADIC_MACROS
   #  define RW_ASSERT(expr, ...) \
             rw_assert (expr, 0, __LINE__, __VA_LIST__)
   #else
   #  define RW_ASSERT(expr, ???) ...
   #endif

Martin

> 
> In any case, I figured we'll need the config test sooner or later.
> 
>> If we do come up with a use for the feature, I'd like to
>> suggest renaming the config test VARIADIC_MACRO.cpp.
> 
> Fine by me.  :)
> 
> Brad.


Mime
View raw message