Re: [boost] boost/config/suffix.hpp: spurious BOOST_HAS_THREADS with g++ 3.4

From: Jonathan Wakely (cow_at_[hidden])
Date: 2004-07-03 12:27:11

On Sat, Jun 19, 2004 at 04:53:36PM +0200, Christoph Ludwig wrote:

> Unfortunately, Mark Mitchell postponed yesterday the resolution of
> PR#11953 until gcc 3.4.2.

And 3.4.1 has now been released, which means both 3.4.0 and 3.4.1 have
this problem.

> I think that it's therefore imperative that users of g++ 3.4.x are
> told about this problem and possible workarounds.

I agree.

> Another idea: How about adding a #warning to
> boost/config/compiler/gcc.hpp if:
>  * the compiler version is >= 3.4.0
>  * the platform is linux (maybe other platforms, too? I don't know
>    how they are affected.)
>  * _REENTRANT is defined
>  * the user didn't explicitly define either BOOST_DISABLE_THREADS or
>    BOOST_HAST_THREADS
> 
> This could save boost users upgrading to gcc 3.4.x a lot of time
> chasing linker errors.

Personally I like this idea. I think the inconvenience of a warning is
worth tolerating given the confusion this problem could cause.

The problem is present on non-linux platforms. I first noticed it on
FreeBSD.

The warning could give the URL of the page that explains the problem, to
avoid excessive output from the preprocessor.

jon

-- 
"He who joyfully marches to music in rank and file has already earned my
 contempt.  He has been given a large brain by mistake, since for him the
 spinal cord would fully suffice."
	- Albert Einstein