Boost C++ Libraries: Ticket #1130: GCC -wundef warnings

andyc@… — Tue, 21 Aug 2007 09:43:18 GMT

I notice that this problem has been discussed previously on <http://lists.boost.org/Archives/boost/2005/10/95850.php> and there's a proposal to do with BoostConfig referenced there: <http://www.crystalclearsoftware.com/cgi-bin/boost_wiki/wiki.pl?BoostConfig>.

I also notice that that's proposing using constructs such as:

Comeau C++ #ifndef BOOST_CXX_COMO #define BOOST_CXX_COMO 0 #endif

I wonder if you could use this instead:

# define BOOST_WORKAROUND(symbol, test) \

((BOOST_COMPILER_DEFINED_ ## symbol) && \

(symbol != 0) && (1 % (( (symbol test) ) + 1)))

and you could then define

#define BOOST_COMPILER_DEFINED_BOOST_MSVC defined(BOOST_MSVC)

for each macro used in a BOOST_WORKAROUND expansion rather than all those #ifndefs. Just a thought. (I also did wonder whether there was some preprocessor magic to save having to define all those by hand but I couldn't come up with any).

Until this problem is resolved in an official boost release, that's what we're intending to do so that we can compile with -Wundef.

-- Andy, BlueArc Engineering

component changed; owner set

René Rivera — Tue, 21 Aug 2007 15:18:27 GMT

owner set to John Maddock
component None → config

status changed

John Maddock — Mon, 10 Sep 2007 09:40:28 GMT

status new → assigned

I'm working on this now, hopefully we'll work something out!

status, milestone changed; resolution set

John Maddock — Sat, 22 Sep 2007 09:27:03 GMT

status assigned → closed
resolution → fixed
milestone To Be Determined → Boost 1.35.0

This is hopefully now fixed with this changeset: http://svn.boost.org/trac/boost/changeset/39473/trunk/boost/detail/workaround.hpp

Note that the logic we've used is the reverse of yours: the danger with your suggested fix is that if you use BOOST_WORKAROUND with a macro about which it knows nothing, then it will always evaluate to false :-(

Regards, John Maddock.