Re: [boost] [bind][tr1] patch for more compliant placeholders

From: Peter Dimov (pdimov_at_[hidden])
Date: 2007-05-10 06:59:10

Daniel Walker wrote:
> On 5/9/07, Daniel Walker <daniel.j.walker_at_[hidden]> wrote:
>> On 5/9/07, Peter Dimov <pdimov_at_[hidden]> wrote:
>>>
>>> Other comments:
>>>
>>> BOOST_WORKAROUND(BOOST_GCC, <= 0x0400) is always true when the
>>> compiler isn't GCC since BOOST_GCC is not defined.
>>
>> Oops! Good catch. Thanks!
>
> Double oops. I take that back. I just remembered I actually tested
> this last week on msvc, and it worked. If the first argument to
> BOOST_WORKAROUND is undefined the condition won't be met. There's
> documentation in boost/detail/workaround.hpp.

Cool, I'd forgotten about this. :-)

There's an additional reason to check with defined() first, though: using an 
undefined symbol with BOOST_WORKAROUND generates a warning with -Wundef, and 
there are people who use this flag. This doesn't really apply here 
since -Wundef is a GCC option and the symbol will be defined, but I still 
consider it a good practice to qualify any use of BOOST_WORKAROUND with the 
appropriate defined().

Not triggering -Wundef is another feature that we don't test.