On 06/21/12 01:33, Joel de Guzman wrote:
On 6/21/2012 10:00 AM, Daniel Larimer wrote:
On Jun 20, 2012, at 9:57 PM, Daniel Larimer wrote:
On Jun 20, 2012, at 7:36 PM, Joel de Guzman wrote:
On 6/20/2012 1:37 PM, Daniel Larimer wrote:
I recently attempted to update to gcc 4.7 and code that compiled with 4.5.3 broke.
It appears that boost::fusion expects boost::fusion::random_access_traversal_tag to implicitly cast to mpl::bool_<false>.
Switching the 3rd argument from mpl::bool_<false> to an extra template arg (that was ignored), seems to fix the compilation errors.
Compiled with std=c++11
Do you have a minimal test case?
#include<boost/fusion/container/vector.hpp> #include<boost/fusion/algorithm.hpp> #include<boost/fusion/include/make_vector.hpp>
struct visitor { template<typename T> void operator()( T t )const{} };
int main() { visitor v; boost::fusion::for_each( boost::fusion::make_vector(5,6.6), v ); return 0; }
I could get things to compile by editing boost/fusion/algorithm/iteration/detail/for_each.hpp and changing the last parameter to Ty. It appears that parameter was ignored anyway and that we didn't care about the type.
template<typename Sequence, typename F, typename Ty> inline void for_each(Sequence& seq, F const& f, Ty) // unsegmented implementation { detail::for_each_dispatch(seq, f, typename traits::category_of<Sequence>::type()); }
No, that is not a proper fix. It just bypasses the problem, which seems to be a gcc 4.7 problem. There is nothing wrong with Fusion code AFAICT. Fusion does not expect boost::fusion::random_access_traversal_tag to be converted to an mpl::bool_<false>. That function (detail::for_each) is called this way:
detail::for_each(seq, f, typename traits::is_segmented<Sequence>::type());
And there is nothing wrong with that code AFAICT.
Sorry, I do not have gcc 4.7 ATM, but at any rate, what errors do you get with the code above. Both VC10 and gcc-4.6 compiles it just fine. The code compiles & runs OK with 4.7 as it was on 20120204 on ubuntu:
make -Wfor_each_rand_access_tag.cpp run install -d `dirname for_each_rand_access_tag.o` /home/evansl/download/gcc/4.7-20120204/install/bin/g++ -c -Wall -Wstrict-overflow -ftemplate-depth-300 -O0 -std=gnu++11 -I/home/evansl/prog_dev/boost-svn/ro/boost_1_49_0 -DTEMPLATE_DEPTH=300 for_each_rand_access_tag.cpp -MMD -o for_each_rand_access_tag.o sed -e 's#^for_each_rand_access_tag.o:#for_each_rand_access_tag.o:#' ./for_each_rand_access_tag.d> ./for_each_rand_access_tag.o.dep #rm ./for_each_rand_access_tag.d /home/evansl/download/gcc/4.7-20120204/install/bin/g++ -L/home/evansl/download/gcc/4.7-20120204/install/lib64 -Wl,-rpath -Wl,/home/evansl/download/gcc/4.7-20120204/install/lib64 -llapack -lblas -lgfortran ./for_each_rand_access_tag.o -o for_each_rand_access_tag.exe ./for_each_rand_access_tag.exe Compilation finished at Thu Jun 21 04:51:54