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How boost::tupe avoid compilor error of get member function?
by simon Ye 08 May '09

08 May '09

Hi, all. boost::tuple provide a member template function get to gain a element of tuple, As following: #include "boost\tuple\tuple.hpp" using namespace boost; template<typename T> class TA{public: template<typename T1, typename T2> void testfun(T1 e1, T2 e2) { tuple<T1, T2> t1(e1, e2); //T1 _e1 = t1.template get<0>(); //works *T1 _e1 = t1.get<0>(); //works for boost::tuple* /* However, according c++98, t1.get<0>() seems to should be encounter a compilor error. *I want to known how boost::tuple avoid this compile error.* */ } }; int main() { int i=10; float f=10.5f; TA<char> obj; obj.testfun(i, f); return 0; } The above sample pass the compilation of gcc3.4.2 and gcc 4.2.4. *According to boost::tuple, I implement a new tuple by myself. as following: * (In fact, the following code is mostly extracted from boost::tuple. ) namespace testNS{ template<int N, class T> struct element { private: typedef typename T::tail_type Next; public: typedef typename element<N-1, Next>::type type; }; template<class T> struct element<0,T> { typedef typename T::head_type type; }; struct null_type{}; template<typename HT, typename TT> struct cons { typedef HT head_type; typedef TT tail_type; template <int N> typename element<N, cons<HT, TT> >::type *get()* { typedef typename element<N, cons<HT, TT> >::type RetType; return RetType(); } }; template<typename HT> struct cons<HT, null_type> { typedef HT head_type; typedef null_type tail_type; typedef cons<HT, null_type> self_type; //get(BOOST_EXPLICIT_TEMPLATE_NON_TYPE(int, N)) template <int N> typename element<N, self_type>::type *get()* { typedef typename element<N, cons<HT,null_type> >::type RetType; return RetType(); //return boost::tuples::get<N>(*this); } }; template <class T0, class T1, class T2> struct map_tuple_to_cons { typedef cons<T0, typename map_tuple_to_cons<T1, T2, null_type>::type > type; }; // The empty tuple is a null_type template <> struct map_tuple_to_cons<null_type, null_type, null_type> { typedef null_type type; }; template<typename T0, typename T1, typename T2=null_type> class Tuple; template<typename T0, typename T1, typename T2> class Tuple: public map_tuple_to_cons<T0, T1, T2>::type { public: typedef T0 E0T; typedef T1 E1T; typedef T2 E2T; Tuple(const E0T& e0, const E1T& e1) { } }; }//endof testNS using namespace testNS; template<typename T> class TA{public: template<typename T1, typename T2> void testfun(T1 e1, T2 e2) { Tuple<T1, T2> t1(e1, e2); //T1 _e1 = t1.template get<0>(); //works * T1 _e1 = t1.get<0>(); //encounter compilor error /* the gcc3.4.2 error message: syntax error before `;' token the gcc4.2.4 error message: error: expected primary-expression before ')' token error: invalid operands of types '<unresolved overloaded function type>' and 'int' to binary 'operator<' */* } }; int main() { int i=10; float f=10.5f; TA<char> obj; obj.testfun(i, f); return 0; } By the way, how can i get contact with boost::tuple author.? -- miss you!

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Fwd: banded symmetricmatrix
by Hicham Mouline 08 May '09

08 May '09

Sending this to boost users as well as ublas's list seems a bit dry... Rds, --------------- Hello, Is there a template to store a matrix that is both band diagonal and symmetric? Is there a compact storage for it that is even more optimal than just banded's and symmetric's ? Regards,

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[Date time] warning C4244
by Seweryn Habdank-Wojewódzki 08 May '09

08 May '09

Dears, I have a lot of warnings: boost/date_time/microsec_time_clock.hpp(103) : warning C4244: 'argument' : conversion from 'int' to 'unsigned short', possible loss of data Best regards, -- |\/\/| Seweryn Habdank-Wojewódzki \/\/ Professionalism in programming - www.accu.org ---------------------------------------------------- Zobacz extremalne skoki (base jumping) i jazdę na krechę - kliknij: http://klik.wp.pl/?adr=http%3A%2F%2Fcorto.www.wp.pl%2Fas%2Fe4.html&sid=720

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Re: [Boost-users] CMake Problems with boost 1.39
by Tan, Tom (Shanghai) 08 May '09

08 May '09

>> - The generated boost.test libs have an additional "-s" to the file >> names, ex. libboost_unit_test_framework-vc90-mt-1_39-s.lib, instead of >> libboost_unit_test_framework-vc90-mt-1_39.lib. This will cause a linking >> error while using boost.test. this does noto happen to the bjamed >> results. >> >.-s means that the library links to the static C++ runtime. The issue is, -s is appended to the end of the file name to all .lib files, even for those statically linked files that already have 's' in the middle. Ex. libboost_unit_test_framework-vc90-mt-s-1_39-s.lib, rather than libboost_unit_test_framework-vc90-mt-s-1_39.lib

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Re: [Boost-users] CMake Problems with boost 1.39
by Tan, Tom (Shanghai) 08 May '09

08 May '09

>> - The generated boost.test libs have an additional "-s" to the file >> names, ex. libboost_unit_test_framework-vc90-mt-1_39-s.lib, instead of >> libboost_unit_test_framework-vc90-mt-1_39.lib. This will cause a linking >> error while using boost.test. this does noto happen to the bjamed >> results. >> >.-s means that the library links to the static C++ runtime. The issue is, -s is appended to the end of the file name to all .lib files, even for those statically linked files that already have 's' in the middle. Ex. libboost_unit_test_framework-vc90-mt-s-1_39-s.lib, rather than libboost_unit_test_framework-vc90-mt-s-1_39.lib

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Why is _internal_weak_this public in enable_shared_from_this?
by Joseph Garvin 07 May '09

07 May '09

I can see why you might want to make it protected and have it friend the shared_ptr template (because it does the initialization of _internal_weak_this I think), but I don't see any obvious reason for it to be public. Can anyone explain? You can see the relevant code here: http://www.boost.org/doc/libs/1_38_0/boost/enable_shared_from_this.hpp

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[Boost] Boost 1.39: libdir installation path problem
by Marco Guazzone 07 May '09

07 May '09

Hi, I'm installing Boost 1.39 on Fedora 10 64bit (gcc 4.3.2) with the following command: $ ./bootstrip.sh --prefix=/home/marco/sys $ ./bjam install The installation process showed a lot of error like this: --- [error_snip] --- common.copy /lib/libboost_math_tr1f-gcc43-mt-1_39.so.1.39.0 cp: cannot create regular file `/lib/libboost_math_tr1f-gcc43-mt-1_39.so.1.39.0': Permission denied cp "bin.v2/libs/math/build/gcc-4.3.2/release/threading-multi/libboost_math_tr1f-gcc43-mt-1_39.so.1.39.0" "/lib/libboost_math_tr1f-gcc43-mt-1_39.so.1.39.0" ...failed common.copy /lib/libboost_math_tr1f-gcc43-mt-1_39.so.1.39.0... --- [/error_snip] --- In effect it seems that the script "boostrap.sh" did not correctly write the "libdir" configuration in the JAM project config file (at least as expected from what is said in the "boostraip.sh --help" message, which claims that "libdir" defaults to "EPREFIX/lib" which in turns defaults to "PREFIX/lib"). Here below is the generated "project-config.jam" file: --- [snip] --- # Boost.Build Configuration # Automatically generated by bootstrap.sh import option ; import feature ; # Compiler configuration. This definition will be used unless # you already have defined some toolsets in your user-config.jam # file. if ! gcc in [ feature.values <toolset> ] { using gcc ; } project : default-build <toolset>gcc ; # Python configuration using python : 2.5 : /usr ; # List of --with-<library> and --without-<library> # options. If left empty, all libraries will be built. # Options specified on the command line completely # override this variable. libraries = ; # These settings are equivivalent to corresponding command-line # options. option.set prefix : /home/marco/Sys ; option.set exec-prefix : /home/marco/Sys ; option.set libdir : /lib ; option.set includedir : /home/marco/Sys/include ; --- [/snip] --- To solve, I have to explicitly force the lib path with "--libdir=/home/marco/Sys/lib". Ciao, -- Marco

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BGL - graph_viz
by liquid 07 May '09

07 May '09

How to use label_writer (graph_viz) with bundled properties? Regards liquid

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[bind] performance implications?
by Dominique Devienne 07 May '09

07 May '09

Probably a silly question, but has anyone performed benchmarks on using a std::for_each(begin, end, bind(&C::f, _1)); compared to the hand written loop? Under the debugger I see bind adds a 4 or 5 stack frames between the for_each frame and the C::f frame, so I'm wondering if there is any overhead in these? I could bench it for myself on my everyday compiler for my one task, but surely this was considered and is documented somewhere, much more extensively I'll ever can, no? Some boost libraries discuss performance, but I didn't such a section in the Boost.Bind doco. Thanks for pointers or insights, --DD

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multi_array warning with vs2005
by Hicham Mouline 07 May '09

07 May '09

Hello, I get these warnings : c:\program files\boost\boost_1_39_0\boost\multi_array.hpp(477) : warning C4996: 'std::uninitialized_fill_n': Function call with parameters that may be unsafe - this call relies on the caller to check that the passed values are correct. To disable this warning, use -D_SCL_SECURE_NO_WARNINGS. See documentation on how to use Visual C++ 'Checked Iterators' c:\program files\boost\boost_1_38_0\boost\multi_array\extent_gen.hpp(49) : warning C4996: 'std::copy': Function call with parameters that may be unsafe - this call relies on the caller to check that the passed values are correct. To disable this warning, use -D_SCL_SECURE_NO_WARNINGS. See documentation on how to use Visual C++ 'Checked Iterators' 1>c:\program files\boost\boost_1_38_0\boost\multi_array\multi_array_ref.hpp(374) : warning C4996: 'std::transform': Function call with parameters that may be unsafe - this call relies on the caller to check that the passed values are correct. To disable this warning, use -D_SCL_SECURE_NO_WARNINGS. See documentation on how to use Visual C++ 'Checked Iterators' 1>c:\program files\boost\boost_1_38_0\boost\multi_array\multi_array_ref.hpp(380) : warning C4996: 'std::transform': Function call with parameters that may be unsafe - this call relies on the caller to check that the passed values are correct. To disable this warning, use -D_SCL_SECURE_NO_WARNINGS. See documentation on how to use Visual C++ 'Checked Iterators' Ditto for boost_1_38_0 Am I supposed to disable the warning explicitly in my user code? Or should the warning disable be pushed/pop in boost multi_array? Rds,

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