Re: [jamboost] [BBv1] (newbie) how to enable multithreading under Cygwin?

From: John Maddock (john_at_[hidden])
Date: 2005-08-30 11:40:02

> Environment:
> * Cygwin 1.5.7
> * GCC 3.2
>
> I've got a very simple (testing-based) Jamfile that works fine, and
> I'd like to run one of the tests with multithreading options:
>
> bjam "-sTOOLS=GCC" "-sBUILD=<threading>multi" test_basic
>
> This invocation succeeds, but I can see in my code that
> BOOST_HAS_THREADS is *not* defined. I've tried also
>
> bjam "-sTOOLS=GCC" "-sBUILD=<threading>multi <define>BOOST_HAS_THREADS"
> test_basic
>
> with a similar effect: BOOST_HAS_THREADS is later undef'd, I
> guess by some Boost.Config header.
>
> My last attempt involved expicitly plugging the <threading>multi
> requierement
> in the test rule itself inside the Jamfile, same result.
>
> So, what need I have to do in order to enable multithreading support
> under the
> aforementioned platform? I guess I'm missing something very obvious, and
> feel
> kinda stupid :(

With Boost-1.33.0 and the latest cygwin (gcc-4.4.4) then if I build the 
config_info test case (under libs/config/test) then I see the 
BOOST_HAS_THREADS *is* getting defined.

It would only be explicitly undef'ed if gcc and/or libstdc++3 had been built 
single-threaded, in which case there is no way to build thread safe 
programs, you need to look into boost/config/compiler/gcc.hpp and 
boost/config/stdlib/libstdcpp3.hpp to see why it's getting undef'ed in your 
case, but before you do that, do a:

g++ -v

and make sure it says:

Thread model: posix

HTH, John.