[boost] threads and gcc and BSD

From: John Maddock (john_maddock_at_[hidden])
Date: 2003-01-23 07:28:45

I think I may be the one who broke a lot of the OpenBSD regression tests by
defining BOOST_HAS_PTHREADS in the OpenBSD platform configuration.  IMO this
is correct (OpenBSD supports pthreads right?), but it causes a problem:
currently the gcc config unconditionally defines BOOST_HAS_THREADS,
basically because we didn't know what else to do (gcc on *BSD doesn't define
anything when you build with -pthread - basically defining -pthread affects
only the linker, so we can't detect when to turn on threading support).
This in turn is breaking a lot of libraries: mainly those that depend upon
smart pointers, which do internal thread synchronisation, and therefore need
the -pthread option in order to link correctly.

What should we do about this?

Option 1:
~~~~~~

would putting:

        flags gcc CFLAGS <threading>single : -DBOOST_DISABLE_THREADS ;

fix the problem?

Option 2:
~~~~~~

Add

        flags gcc CFLAGS <threading>multi : -pthread -D_REENTRANT ;

to the toolset, and stop defining BOOST_HAS_THREADS unconditionally for gcc.
This one may have all sorts of unexpected side effects on other platforms
though - even though philosophically it does seem the right thing to do.

Option 3:
~~~~~~

Make -pthread the default build option in the gcc toolset for *BSD platforms

~~~~~~~~~~~

Any other ideas?

John Maddock
http://ourworld.compuserve.com/homepages/john_maddock/index.htm