[boost] MSVC++ warnings in boost headers (mem_fn.hpp)

From: Pavel Kuznetsov (pavel_at_[hidden])
Date: 2003-09-30 07:54:53

It seems that boost code is written to avoid compilers warnings. Though
some warnings do slip into MSVC++ builds when boost headers are included.
Most (all?) of these are the warnings which are turned of by default. In
particular sometimes I can see C4668 warnings shown:

  boost\boost\mem_fn.hpp(296) : warning C4668:
    '__MWERKS__' is not defined as a preprocessor macro,
    replacing with '0' for '#if/#elif'

Where boost\boost\mem_fn.hpp(296) is:

  #if !BOOST_WORKAROUND(BOOST_MSVC, <= 1300) && 
      !BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003))

Where BOOST_WORKAROUND is:

  #  define BOOST_WORKAROUND(symbol, test)                \
          ((symbol != 0) && (1 % (( (symbol test) ) + 1)))

It seems that in some places authors are aware of the problem stated.
E.g.: boost\boost\intrusive_ptr.hpp(124):

  #if defined(__SUNPRO_CC) && BOOST_WORKAROUND(__SUNPRO_CC, <= 0x530)

(Of course it is possible that in fact __SUNPRO_CC can be defined to 0 and
it is that case what is tested here...)

So I see two ways to eliminate the warning in question: either suppress it
with corresponding #pragmas, or rewrite BOOST_WORKAROUND so that it would
test whether 'symbol' is defined before comparing it to 0.

I could submit the patches for either of these. Which one do you prefer?
Or maybe I miss something and some other third way should be taken?

--
Pavel