On 8/24/2011 2:15 PM, Larry Evans wrote:
boost/preprocessor/detail/check.hpp in boost version 1.47.0 contains:
# if ~BOOST_PP_CONFIG_FLAGS()& BOOST_PP_CONFIG_MSVC()&& ~BOOST_PP_CONFIG_FLAGS()& BOOST_PP_CONFIG_DMC() # define BOOST_PP_CHECK_D(x, type) BOOST_PP_CHECK_1(BOOST_PP_CAT(BOOST_PP_CHECK_RESULT_, type x)) # define BOOST_PP_CHECK_1(chk) BOOST_PP_CHECK_2(chk) # define BOOST_PP_CHECK_2(res, _) res # elif BOOST_PP_CONFIG_FLAGS()& BOOST_PP_CONFIG_MSVC()
The above shows BOOST_PP_CHECK_2 is called with 1 argument on rhs of BOOST_CHECK_1; yet, the arity is 2, as shown on the next line.
This results in the errors reported here:
http://article.gmane.org/gmane.comp.lib.boost.devel/222795
when that line is changed to:
# define BOOST_PP_CHECK_1(chk) BOOST_PP_CHECK_2(chk,_)
the reported error goes away; however, several other errors occur about too many instead of too few arguments passed to BOOST_PP_CHECK_2.
Is this a BOOST_PP bug? If not; how can the errors reported in:
http://article.gmane.org/gmane.comp.lib.boost.devel/222795
be avoided?
I believe it is allowable because of placeholder expressions, but this may have been because of C99, whereas a preprocessor that does not support C99 may not work. BTW, nothing has changed with BOOST_PP_CHECK with Boost 1.47, as the code has appeared the way it is for a long time. What compiler are you using ? Is there a C99 or a C++0x mode you can turn on in the command line somehow ?