April 2008 - Boost-users - lists.preview.boost.org

[Signals] Connecting to signals with bind and member functions
by Grant Patterson 26 Apr '08

26 Apr '08

Hi Folks, I'm just getting started with Boost signals (actually moving from sigc++ signals) and I'm having trouble with something that seems rather simple: #include <boost/bind.hpp> #include <boost/signals/slot.hpp> #include "dlg.hh" // includes <boost/signal.hpp> Dlg::Dlg() { boost::signal<void()> login; login.connect(boost::bind(&Dlg::Foo, this)); } void Dlg::Foo() { // stuff } In fact, I've found an example in LyX's source http://tinyurl.com/68secc that seems to do exactly what I'm doing. I get: .../boost-1.33.1/include/boost-1_33_1/boost/bind.hpp: In function 'void boost::visit_each(V&, const boost::_bi::value<T>&, int) [with V = boost::signals::detail::bound_objects_visitor, T = Dlg*]': .../boost-1.33.1/include/boost-1_33_1/boost/bind.hpp:239: instantiated from 'void boost::_bi::list1<A1>::accept(V&) const [with V = boost::signals::detail::bound_objects_visitor, A1 = boost::_bi::value<Dlg*>]' .../boost-1.33.1/include/boost-1_33_1/boost/bind/bind_template.hpp:150: instantiated from 'void boost::_bi::bind_t<R, F, L>::accept(V&) const [with V = boost::signals::detail::bound_objects_visitor, R = void, F = boost::_mfi::mf0<void, Dlg>, L = boost::_bi::list1<boost::_bi::value<Dlg*> >]' .../boost-1.33.1/include/boost-1_33_1/boost/bind.hpp:1213: instantiated from 'void boost::visit_each(V&, const boost::_bi::bind_t<R, F, L>&, int) [with V = boost::signals::detail::bound_objects_visitor, R = void, F = boost::_mfi::mf0<void, Dlg>, L = boost::_bi::list1<boost::_bi::value<Dlg*> >]' .../boost-1.33.1/include/boost-1_33_1/boost/visit_each.hpp:25: instantiated from 'void boost::visit_each(Visitor&, const T&) [with Visitor = boost::signals::detail::bound_objects_visitor, T = boost::_bi::bind_t<void, boost::_mfi::mf0<void, Dlg>, boost::_bi::list1<boost::_bi::value<Dlg*> > >]' .../boost-1.33.1/include/boost-1_33_1/boost/signals/slot.hpp:121: instantiated from 'boost::slot<SlotFunction>::slot(const F&) [with F = boost::_bi::bind_t<void, boost::_mfi::mf0<void, Dlg>, boost::_bi::list1<boost::_bi::value<Dlg*> > >, SlotFunction = boost::function<void ()(), std::allocator<void> >]' .../source_tree/dlg.cc:92: instantiated from here .../boost-1.33.1/include/boost-1_33_1/boost/bind.hpp:1208: error: no matching function for call to 'visit_each(boost::signals::detail::bound_objects_visitor&, Dlg* const&, int)' Any idea what might be causing this? Thanks! grant

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Newbie question - matrix class
by Sajjad 26 Apr '08

26 Apr '08

Hello I have just installed boost library and i want to use the matrix and vector operations that are provided within the library computer graphics programming instead of creating matrix and vector classes by myself. Is there any function available with in the libbbost that linearize the 2D array so that i can use them directly to OpenGL. And i am also having trouble to create a Makefile for that to link to libboost. i attached a sample Makefile Could anyone provide me hint which library to put in the LDFLAGS so that i can use all the functionalities of libboost? Thanks in advance Regards Sajjad ***************************Makefile***************************************' CC = g++ CFLAGS = LD = cc LDFLAGS = -lGL -lglut -lGLEW PROG = volumizer SRCS = SiGaussianElimination.cpp volMain.cpp SiVector4.cpp SiVector3.cpp SiWriter.cpp SiMath.cpp SiMatrix4.cpp SiMatrix3.cpp SiClock.cpp SiDisplay.cpp SiEventHandler.cpp SiGLUtil.cpp SiAffine.cpp OBJS = $(SRCS:.cpp=.o) all: $(PROG) $(PROG): $(OBJS) $(CC) -o $@ $(OBJS) $(LDFLAGS) %.o: %.cpp $(CC) $(CFLAGS) -c $< clean: rm -f $(PROGS) *.o *~ # rule for building dependency lists, and writing them to a file # named ".depend". depend: $(RM) .depend makedepend -f- -- $(CFLAGS) -- $(SRCS) > .depend # now add a line to include the dependency list. include .depend # DO NOT DELETE

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[function] template deduction issues
by Robert Dailey 25 Apr '08

25 Apr '08

Say I have a function as follows: *template< typename t_packet > void Subscribe( boost::function<void (t_packet const&)> func ) { // gSignal is a boost::signal somewhere. Assume valid. gSignal.connect( func ); }* And in some other function, I invoke Subscribe() as follows: * void MyCallback( WalkPacket const& p ) { } void MainTest() { Subscribe( &MyCallback ); }* The code above will actually not compile, since the template parameter t_packet cannot be deduced. Is there a way I can make the template deduction work?

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uBLAS vs IntelMKL/AMD/SunPerf
by Hicham Mouline 25 Apr '08

25 Apr '08

hello, i am writing BLAS L3 code that i wish to be optimal on 3 CPU kinds (Intel core2, AMD k8/k10, SPARCIV+/T1/T2). There are IntelMKL, AMD perf and SUN perf library that are supposedly optimized for the respective processor. They probably (haven't looked yet) have different interfaces. Then there is uBLAS. Is uBLAS configurable to forward calls to the 3rd party lib, or should i just study these libs, and introduce myself an indirection layer? Any thoughts appreciated, rds,

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[operator] Can't figure out syntax
by Peter 25 Apr '08

25 Apr '08

Assuming I have a class like the following: template <typename T> struct point : boost::additive<point<T>, T> { T x_; T y_; explicit point(T x=0, T y=0) : x_(x), y_(y) { } operator += (T offset) { x_ += offset; y_ += offset; } operator -= (T offset) { x_ -= offset; y_ -= offset; } } Now I want to change the addition and subtraction operators to allow for different types using the following template class point ... template <typename U> operator += (U offset) { x_ += offset; y_ += offset; } template <typename U> operator -= (T offset) { x_ -= offset; y_ -= offset; } ... I cannot figure out how to write the proper syntax for the boost::additive class, so that it generates the proper additional operators for all type combinations. Is that possible, at all? Thanks, Peter

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shared_ptr Initial Assignment
by Lex Fridman 25 Apr '08

25 Apr '08

Hi, Say I have a class definition: class Foo() {...}; And an instance of that class: Foo fooInstance; I would like to create a shared_ptr pointing to this instance of Foo. Most documentation recommends the following way to do it: shared_ptr<Foo> bla(new Foo(fooInstance)); But can I also do this: shared_ptr<Foo> bla; bla = shared_ptr<Foo>(new Foo(fooInstance)); Are there any problems with the second (or the first) method? Thanks, Lex

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[MultiIndex] re-indexing on load
by Mark Westcott 25 Apr '08

25 Apr '08

Hi, Loading a multi_index_container from an archive seems to be involving a re-index of that archive. I'm setting breakpoints on my key extract functions, and they're getting called when i load the container from the archive. I would have thought that the serialization would mimic the copy constructor in this respect, and not do any re-indexing? This is causing me significant performance problems at the moment. Is there any workaround? Thanks, Mark

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[serialization] binary woes...
by Robert Bielik 25 Apr '08

25 Apr '08

Just broke into a cold sweat... the binary i/o archives... are they byte order dependent? TIA /R

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[filesystem] basic_path question
by Robert Dailey 25 Apr '08

25 Apr '08

Hi, I create the following object: boost::filesystem::path mypath( "SomeFolder/OnWindows/SubFolder" ); In Microsoft Windows, the standard slash direction is "\", so when I run the above in the debugger, I notice m_path is still using forward slashes ("/"). I would have expected the slashes to be normalized. Am I misunderstanding something? How can I construct a path object like above and have it normalize the slashes? Thanks.

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Re: [Boost-users] boost vs libboost naming problem with bjamcompilefor vc90
by atshoom＠apple.lu 25 Apr '08

25 Apr '08

Hi, i'm a newbie on VC++2008 express and boost and I can't make my example program to work. Same linking prob of this thread with '1>LINK : fatal error LNK1104: cannot open file 'libboost_regex-vc90-mt-gd-1_35.lib' i've run bjam with the link=static argument and now I have the 'libboost_regex-vc90-mt-gd-1_35.lib' file in my stage\lib directory but the linking problem is always the same. anyhint ? PS: i have not understood how to do the following because I am a little bit lost in VC++2008 express >> add BOOST_REGEX_DYN_LIB to the list of project defines for your VC >> project. Thank you for any help/suggestions that could help me. John Maddock wrote: Rene Rivera wrote: > John Maddock wrote: >> Phelps Williams wrote: >>>> During compilation of this project I receive link errors: >>>> LINK : fatal error LNK1104: cannot open file >>>> 'libboost_regex-vc90-mt-gd-1 _35.lib' >> >> You'll need to build with bjam link=static, *or* add >> BOOST_REGEX_DYN_LIB to the list of project defines for your VC >> project. And yes, I know we need to fix this before release!

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