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Compiler craziness on boost::result_of ? Please help
by John M. Dlugosz 13 Apr '12

13 Apr '12

I'm using Visual Studio 10, and Boost 1.49. The following complete CPP file compiles without error: ===== #include <boost/test/unit_test.hpp> #include "boost/thread/future.hpp" #include <boost/utility/result_of.hpp> #include <functional> using boost::unique_future; template <typename F> unique_future<typename boost::result_of< F() >::type> foo (F&& f) { typedef typename boost::result_of< F() >::type RetType; unique_future<RetType> future_result; return std::move(future_result); } template <typename F, typename A1> unique_future<typename boost::result_of< F(A1) >::type> foo (F&& f, A1&& a1) { return std::move(foo (std::tr1::bind(f,a1))); } class C {}; class D : public C { public: void mf() const { } // virtual void toxic() { } }; void mainfunc() { D* p; foo (&D::mf, p); } ===== But, if you un-comment the definition of toxic, then it will not compile, giving instead: 1>E:\boost_1_49\boost/utility/result_of.hpp(82): error C2825: 'F': must be a class or namespace when followed by '::' 1> E:\boost_1_49\boost/utility/result_of.hpp(90) : see reference to class template instantiation 'boost::detail::result_of_nested_result<F,FArgs>' being compiled 1> with 1> [ 1> F=void (__thiscall D::* &)(void) const, 1> FArgs=void (__thiscall D::* &(D *&))(void) const 1> ] 1> E:\boost_1_49\boost/utility/detail/result_of_iterate.hpp(33) : see reference to class template instantiation 'boost::detail::tr1_result_of_impl<F,FArgs,HasResultType>' being compiled 1> with 1> [ 1> F=void (__thiscall D::* &)(void) const, 1> FArgs=void (__thiscall D::* &(D *&))(void) const, 1> HasResultType=false 1> ] 1> E:\boost_1_49\boost/utility/detail/result_of_iterate.hpp(75) : see reference to class template instantiation 'boost::tr1_result_of<F>' being compiled 1> with 1> [ 1> F=void (__thiscall D::* &(D *&))(void) const 1> ] 1> threadpoolTest.cpp(39) : see reference to class template instantiation 'boost::result_of<F>' being compiled 1> with 1> [ 1> F=void (__thiscall D::* &(D *&))(void) const 1> ] 1>E:\boost_1_49\boost/utility/result_of.hpp(82): error C2516: 'F' : is not a legal base class 1> E:\boost_1_49\boost/utility/result_of.hpp(90) : see declaration of 'F' 1>E:\boost_1_49\boost/utility/result_of.hpp(82): error C2143: syntax error : missing ',' before '::' 1>E:\boost_1_49\boost/utility/result_of.hpp(82): error C2903: 'result' : symbol is neither a class template nor a function template 1>E:\boost_1_49\boost/utility/result_of.hpp(82): error C2039: 'result' : is not a member of '`global namespace'' 1>E:\boost_1_49\boost/utility/result_of.hpp(82): error C2504: 'result' : base class undefined 1>E:\boost_1_49\boost/utility/result_of.hpp(82): error C2143: syntax error : missing ',' before '<' 1>threadpoolTest.cpp(39): error C2893: Failed to specialize function template 'boost::unique_future<boost::result_of<F(T0)>::type> foo(F &&,A1 &&)' 1> With the following template arguments: 1> 'void (__thiscall D::* &)(void) const' 1> 'D *&' 1>threadpoolTest.cpp(39): error C2780: 'boost::unique_future<boost::result_of<F(void)>::type> foo(F &&)' : expects 1 arguments - 2 provided 1> threadpoolTest.cpp(10) : see declaration of 'foo' 1> 1>Build FAILED. Note that both the presence of a virtual function and a base class in necessary. if toxic is present but C is not, then it still works.

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boost::result_of template
by John M. Dlugosz 13 Apr '12

13 Apr '12

Consider these functions: template <typename F> unique_future<typename boost::result_of< F() >::type> foo (F&& f) { ⋯ template <typename F, typename A1> unique_future<typename boost::result_of< F(A1) >::type> foo (F&& f, A1&& a1) { return foo (std::tr1::bind(f,a1)); } I can call foo(&bar,5) to mean the same thing as foo(bind(&bar,5)), OK. But I cannot call foo(&C::mf, pc) to mean the same as foo(bind(&C::mf,pc)) when the binding in question is pc->mf(). That is, bind treats a member function automatically as a function whose first argument is 'this', but boost::result_of does not have the same trick. How can I express the result type of the second form of foo shown above? —John

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Problem with 'future' on compiler without move semantics
by John M. Dlugosz 13 Apr '12

13 Apr '12

In my earlier note, I figured it should just work. But it's not. I think it might be different on Boost 1.47? Can anyone give me a VERY QUICK answer on how to return a unique_future on a compiler without && using Boost 1.47? Thanks! —John In file included from /Volumes/VSee_Source/svnTree/Trunk/stable/Testing/UnitTests/Tools/threadpoolTest.cpp:2: ⋯: error: calling a private constructor of class 'boost::unique_future<int>' return future_result; // built-in mover via implicit conversions ^ /⋯lTest.cpp:61:30: note: in instantiation of function template specialization 'vst::async<int (*)()>' requested here vst::unique_future<int> fi= vst::async (&calculate_the_answer_to_life_the_universe_and_everything); ^ /opt/local/include/boost/thread/future.hpp:619:9: note: implicitly declared private here unique_future(unique_future & rhs);// = delete; ^

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Patch required to build Boost.Locale 1.49 with ICU support
by Peter Klotz 13 Apr '12

13 Apr '12

Hello I followed ICU 49.1 build instructions and have set compiler define U_USING_ICU_NAMESPACE to 0 in order to avoid polluting the global namespace. Doing so requires the attached patch to make Boost.Locale compile with MSVC2010 SP1. Regards, Peter.

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Minimal vector initialization
by Henrik Vallgren 13 Apr '12

13 Apr '12

I'm proposing a small boost library: struct minimal_init {}; template <typename T> struct minimal_constructible : public T { minimal_constructible() : T(minimal_init()) {} }; The purpose of this is to enable vectors of simple structs (containing only POD members) to have resize calling a do-nothing constructor. Let's say that I have a loop that I'd like to calculate in parallel: struct Dummy { Dummy(int a_=0) : a(a_) {} Dummy(const minimal_init &) {} // Without a v-table, this shouldn't need to touch any part of the created object? int a; }; void foo() { #define N 100 std::vector<minimal_constructible<Dummy> > data; data.resize(N); #pragma omp parallel for for (size_t i=0;i<N;++i) data[i].a=i; } Using reserve+push_back is unlikely to create a properly sorted vector. Ideally, we'd add a resize member to std::vector that takes a template T2 that is different from T, just like emplace_back does, but that won't happen soon. I'll probably want to add a few things to make minimal_constructible<T> behave more like a T, but I really liked the idea of a five line boost library ;) Good idea, or not? Thanks in advance, Henrik

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disabling automatic thread-local storage cleanup in boost::thread
by Sarah Tappon 13 Apr '12

13 Apr '12

I would like to use boost::thread (static library) in a DLL project that also includes some managed C++. Thus I am attempting to disable the automatic TLS cleanup, since the TLS callbacks it uses are not compatible with managed code. I have found references to two methods of doing this: 1) Define tss_cleanup_implemented() to prevent the automatic cleanup code from being linked in: http://lists.boost.org/Archives/boost/2007/11/130440.php 2) Build the thread library without tss_pe.cpp: http://boost.2283326.n4.nabble.com/Using-new-threads-link-issues-td2637128.… My questions are: 1) Are these two methods functionally equivalent? 2) How exactly does defining tss_cleanup_implemented prevent the cleanup code from being linked in? Is the idea that if a definition exists locally the linker won't go looking for one in the library and thus won't link the cleanup code either? When I define extern "C" void tss_cleanup_implemented(void){} within my project in the global namespace, I get linker errors about multiply defined symbols (LNK2005, LNK1169) -- are there other linker settings I need to change in order for it to work? I'm using Visual Studio 2008. Finally, I just want to confirm that once I've disabled the automatic cleanup, I only need to call on_thread_exit() from threads launched through the native API that use boost::thread functionality like thread_specific_ptr. If the application only launches threads through boost, I just need to call on_process_enter/exit in main. Correct? Thanks, Sarah

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Several novice questions concerning threading
by Master 12 Apr '12

12 Apr '12

Hello all . i am a newbie to the boost community . i recently started learning about threads in boost . now there are some questions i would like to ask : 1.where can i find examples showing practical uses of boost::thread features? 2.how can i get all threads ID issued by me in my app? 3.how can i iterate through running threads in my app ? 4.is there any kind of means to get all the running threads using boost library? if it does whats the calss? if it doesnt how can i do that? 5.can i resume a thread after pausing it ? ( how can i pause a thread? ) 6. how can i share a variable between two or more threads , suppose i have a loop , i want two threads to simultaneously iterate through it , if thread1 counted to 3, thread2 continues it from 4 and so on . ? i already tried ------ > what is wrong with my sample app ? > #include <iostream> > #include <boost/thread.hpp> > using namespace std; > using namespace boost; > > mutex bmutex; > int i=0; > int sum=0; > void IteratorFunc(int threadid) > { > for ( ; i<25 ; i++) > { > lock_guard<mutex> locker(bmutex); > > cout<<"\t"<<threadid<<"\t"<<this_thread::get_id()<<"\t"<<i<<"\n"; > sum+=i; > } > } > > int main() > { > //boost::posix_time::ptime start = > boost::posix_time::microsec_clock::local_time(); > > thread thrd(IteratorFunc,1); > thread thrd2(IteratorFunc,2); > > cout<<sum; > thrd.join(); > thrd2.join(); > } > Thank you in advance

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[BLL] Problem with print vector elements.
by mik 12 Apr '12

12 Apr '12

Hi, I'm trying to use thew BLL for the first time and I've the following program: class Date { public: Date(long d): _lDate(d) {} long getDate() const { return _lDate; } [...] private: long _lDate; }; std::ostream& operator<<(std::ostream &s, const Date &x) { [...] } struct C { C(long d): date(d) {} Date date; }; int main() { const C c(46000); std::cout << boost::bind(&C::date, boost::lambda::_1)(c) << std::endl; std::vector<C> cont(1, C(46000)); std::for_each(cont.begin(), cont.end(), std::cout << boost::bind(&C::date, boost::lambda::_1)); return 0; } The first std::cout is ok. But for the second one nested int the for_each I get this message error: error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'boost::_bi::bind_t<R,F,L>' (or there is no acceptable conversion) with [ R=const Date &, F=boost::_mfi::dm<Date,C>, L=boost::_bi::list1<boost::arg<1>> ] C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\INCLUDE\ostream(653): could be 'std::basic_ostream<_Elem,_Traits> &std::operator <<<char,std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,const char *)' [found using argument-dependent lookup] with [ _Elem=char, _Traits=std::char_traits<char> ] Can you help me? Thank you, Mirko **

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boost arm compilation
by Bisegni Claudio 12 Apr '12

12 Apr '12

Hi all, i have some problem compiling boost on arm. i can compile package individually but when i use "install" i go segmentation fault after a some times. So i have compiled by every library and i have installed by handle all file. after that compiling my code with boost i got this error: /usr/local/include/boost/cstdint.hpp:104: error: '::int_least8_t' has not been declared /usr/local/include/boost/cstdint.hpp:105: error: '::int_fast8_t' has not been declared /usr/local/include/boost/cstdint.hpp:106: error: '::uint8_t' has not been declared /usr/local/include/boost/cstdint.hpp:107: error: '::uint_least8_t' has not been declared /usr/local/include/boost/cstdint.hpp:108: error: '::uint_fast8_t' has not been declared /usr/local/include/boost/cstdint.hpp:111: error: '::int_least16_t' has not been declared /usr/local/include/boost/cstdint.hpp:112: error: '::int_fast16_t' has not been declared /usr/local/include/boost/cstdint.hpp:113: error: '::uint16_t' has not been declared /usr/local/include/boost/cstdint.hpp:114: error: '::uint_least16_t' has not been declared /usr/local/include/boost/cstdint.hpp:115: error: '::uint_fast16_t' has not been declared /usr/local/include/boost/cstdint.hpp:118: error: '::int_least32_t' has not been declared /usr/local/include/boost/cstdint.hpp:119: error: '::int_fast32_t' has not been declared /usr/local/include/boost/cstdint.hpp:120: error: '::uint32_t' has not been declared /usr/local/include/boost/cstdint.hpp:121: error: '::uint_least32_t' has not been declared /usr/local/include/boost/cstdint.hpp:122: error: '::uint_fast32_t' has not been declared /usr/local/include/boost/cstdint.hpp:127: error: '::int_least64_t' has not been declared /usr/local/include/boost/cstdint.hpp:128: error: '::int_fast64_t' has not been declared /usr/local/include/boost/cstdint.hpp:129: error: '::uint64_t' has not been declared /usr/local/include/boost/cstdint.hpp:130: error: '::uint_least64_t' has not been declared /usr/local/include/boost/cstdint.hpp:131: error: '::uint_fast64_t' has not been declared /usr/local/include/boost/cstdint.hpp:135: error: '::intmax_t' has not been declared /usr/local/include/boost/cstdint.hpp:136: error: '::uintmax_t' has not been declared someone has some idea on how resolve this issue? thank in advanced

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Prim's algorithm with custom weights?
by John asdf 11 Apr '12

11 Apr '12

I feel like I explain the problem well with my question on stackoverflow but it's not getting much response. http://stackoverflow.com/questions/10098437/c-boost-prims-algorithm-with-cu… If anyone can help I would greatly appreciate it.

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