Boost :

From: David Abrahams (dave_at_[hidden])
Date: 2003-12-11 09:55:33

> This issue is coming up so often we need to provide a better error message
> scheme, when users see:
>
> #error : Thread support is unavailable!
>
> They assume it's a bug in the library rather than a compile time problem on
> their part.
>
> whenever BOOST_HAS_THREADS is undefined and issues the appropriate messages

Looks good to me, except that it should be called something like
boost/thread/check_options.hpp, and you should be able to include it
unconditionally - *it* should do the checking.

```--
Dave Abrahams
Boost Consulting
www.boost-consulting.com
```