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tuple and enums
by Tom Matelich 29 Aug '02

29 Aug '02

It appears that an enum cannot be default constructed in the way that tuple does, cons() : head(), tail() {} Any idea on how to get around this (besides using an int in the tuple)? Thanks, Tom <sample_code> #include <boost/tuple/tuple.hpp> #include <string> enum Foo { Willis, Arnold }; void test() { boost::tuple<Foo, std::string> a; } </sample_code> </error compiler="gcc version 2.96 20000731 (Mandrake Linux 8.2)"> /usr/local/eddynet/opt/include/boost/tuple/detail/tuple_basic.hpp: In method `boost::tuples::cons<HT, TT>::cons () [with HT = Foo, TT = boost::tuples::cons<string, boost::tuples::null_type>]': /usr/local/eddynet/opt/include/boost/tuple/detail/tuple_basic.hpp:454: instantiated from `boost::tuples::tuple<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9>::tuple () [with T0 = Foo, T1 = string, T2 = boost::tuples::null_type, T3 = boost::tuples::null_type, T4 = boost::tuples::null_type, T5 = boost::tuples::null_type, T6 = boost::tuples::null_type, T7 = boost::tuples::null_type, T8 = boost::tuples::null_type, T9 = boost::tuples::null_type]' tuple_enum_test.cpp:8: instantiated from here /usr/local/eddynet/opt/include/boost/tuple/detail/tuple_basic.hpp:263: cannot convert `int' to `Foo' in assignment </error> ----------------------------------------------------------------------- DISCLAIMER: Information contained in this message and/or attachment(s) may contain confidential information of Zetec, Inc. If you have received this transmission in error, please notify the sender by return email. -----------------------------------------------------------------------

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shared_ptr const problem
by Olaf Petzold 28 Aug '02

28 Aug '02

Hi, now I have a new problem - const correctness. ---8<--- #include <iostream> #include <algorithm> #include <iterator> #include <vector> #include <boost/shared_ptr.hpp> class Doc { public: virtual ~Doc() { } public: const std::vector<double>& foo() const { return m_foo; } protected: std::vector<double>& foo() { return m_foo; } private: std::vector<double> m_foo; }; using namespace std; int main() { boost::shared_ptr<Doc> lp_doc( new Doc ); std::copy(lp_doc->foo().begin(), lp_doc->foo().end(), std::ostream_iterator<double>(cout, " ") ); cout << endl; } --->8--- `std::vector<double, std::allocator<double> >& Doc::foo()' is protected I hoped std::copy takes the const foo() member function. Thanks olaf

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iterator_adaptors on mipspro 7.3.1.3m
by marcinzalewski 28 Aug '02

28 Aug '02

Hi, I am trying to use iterator adaptors on mipspro and am unsuccessfull as for now. I was wandering if any of you has experience with boost and mipspro. Here are some examples of errors I am getting: ----------- cc-1132 CC: ERROR File = ../../boost_1_28_0/boost/iterator.hpp, Line = 54 The namespace "std" has no member "ptrdiff_t". template <class Category, class T, class Distance = std::ptrdiff_t, ^ or cc-3307 CC: ERROR File = ../../boost_1_28_0/boost/type_traits/array_traits.hpp, Line = 24 Invalid partial specialization--class "boost::is_array<<error-type>>" is already fully specialized. template <typename T, std::size_t N> struct is_array<T[N]> ----------- Please, let me know if you did this before. :) -m ^

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[BGL] undirectedS self-loop add_edge assertion
by Chris Russell 27 Aug '02

27 Aug '02

Just a quick mention: A call to add_edge with u == v causes an assertion if Directed == undirectedS. adjacency_list.hpp line 843: assert( u != v ); // don't allow self-loops ^- boost_1_28_0 Avoiding the assertion is easy enough but this is inconsistent w/section 14.1.1 p.220 of the BGL book: "... Also if u and v are descriptors for the same vertex (creating self loop) and the graph is undirected, then the edge will not be created and the flag will be false." Am having tons of fun - the BGL and the book are super. Thanks! - Chris

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lambda library usage
by khuroth 27 Aug '02

27 Aug '02

I have a View class that has some widgets, and a Controller class that controls the view, so the View class has a GetController() member function that returns a reference to its controller. When the View's constructor is called, GetController() would return a bad ref, but it would return a valid reference by the time a button is clicked... so what I'm trying to do is, inside the View constructor: my_button.on_click = bind( (_1 ->* &A::GetController).DoSomething(), this ); but that obviously doesn't work... I'm even having trouble just saving the first part: my_button.on_click = bind<Controller&>(_1 ->* &A::GetController, this); also doesn't work... I tried defining the on_click member of the button as a boost::function<void> or a boost::function0<void> in the first example, and a boost::function<Controller&> or boost::function0<Controller&> in the second snip... I get immense compiler errors, so I'm not sure where I messed up. What am I doing wrong?

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shared_ptr swap problems
by Olaf Petzold 27 Aug '02

27 Aug '02

Hello, I've trouble with the follwong snippet: #include <iostream> #include <boost/shared_ptr.hpp> struct A { A(const char* n) : name(n) { } const char* name; }; struct B : public A { B(const char* n) : A(n) { std::cout << "construct " << name << std::endl; } ~B() { std::cout << "destruct " << name << std::endl; } }; struct BaseC { virtual void set(const boost::shared_ptr<A>& ptr) = 0; }; struct C : public BaseC { C() : b( new B("C::b") ) { } void set(const boost::shared_ptr<A>& ptr) { b.swap( boost::shared_static_cast<B>( ptr ) ); // L21 } void print() { std::cout << b->name << std::endl; } boost::shared_ptr<B> b; }; using namespace std; int main() { boost::shared_ptr<A> b( new B("b") ); C c; c.print(); c.set( b ); c.print(); } t.cc: In member function `virtual void C::set(const boost::shared_ptr<A>&)': t.cc:21: no matching function for call to `boost::shared_ptr<B>::swap(boost::shared_ptr<B>)' /usr/include/boost/shared_ptr.hpp:234: candidates are: void boost::shared_ptr<T>::swap(boost::shared_ptr<T>&) [with T = B] I did try boost::shared_polymorphic_cast to get a std::bad_cast exception - but it doesn't compile too. How can get it working? Thanks Olaf

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RE: [Boost-Users] How can checkout the files in Attic (hidden) fr om the cvs server?
by Jim.Hyslop 27 Aug '02

27 Aug '02

> I'm using WinCvs to checkout the current version of boost from the > cvs server. However, I found that I can not checkout some of the > libs which are put in the Attic, though I can browse them through my > internet browser. Anyone knows how to check these files out? (for > example, the mpl lib) Any files in the Attic are either obsolete, or have been added only on a branch and have not been merged to the trunk yet. Unless you are having a specific problem that requires a file from the Attic, then don't worry about what's up there (I suspect that's probably why it's called the "Attic" - out of sight, out of mind ;-) -- Jim

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How can checkout the files in Attic (hidden) from the cvs server?
by li_lirong 27 Aug '02

27 Aug '02

I'm using WinCvs to checkout the current version of boost from the cvs server. However, I found that I can not checkout some of the libs which are put in the Attic, though I can browse them through my internet browser. Anyone knows how to check these files out? (for example, the mpl lib) Thanks in advance, Lirong

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boost::any and operator ==
by billrobertson42 27 Aug '02

27 Aug '02

How do I compare two boost::any values for equality? How to I compare two containers of boost::any's for equality? Why doesn't boost::any define this operator? There has to be a reason. Thanks!

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What's your wish list?
by Kevin S. Van Horn 26 Aug '02

26 Aug '02

I'm teaching a graduate class on generic programming this semester, and I'm looking for some solid, meaningful projects for my students. If there are extensions to existing Boost libraries that you would like, or some new C++ library that you would like written, please contact me. -- Kevin S. Van Horn kevin.vanhorn(a)ndsu.nodak.edu

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