April 2007 - Boost-users - lists.preview.boost.org

[-s- lib versions][vc80] new user Q: what's the difference between lib*vc80-mt-1_33_1.lib and lib*vc80-mt-s-1_33_1.lib
by John McMahon 30 Apr '07

30 Apr '07

Hi I'm a new boost user. I downloaded the pre-built Visual Studio 2005/vc80 version of boost from http://www.boost-consulting.com/products/free and read the instructions at http://www.boost.org/more/getting_started.html , specifically the section on library runtimes. I have a question; In the context of vc80, and for components which have libraries, what's the difference between -s- and non-s static libs, e.g. for 'thread' -rw-r--r-- 1 John None 516994 Mar 25 2006 libboost_thread-vc80-mt-1_33_1.lib -rw-r--r-- 1 John None 845330 Mar 25 2006 libboost_thread-vc80-mt-s-1_33_1.lib thanks in advance John McMahon

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[filesystem] Can't create absolute paths from strings on windows
by Ken Klose 29 Apr '07

29 Apr '07

cout << "init path " << initial_path().string() << endl; cout << "init path exists " << exists(initial_path()) << endl; prints: init path C:/Documents and Settings/me/workspace/3.2/DciApiTest init path exists 1 But if I try to construct the same path from a string: I get: path init_path2(initial_path().string(), no_check); // I've also tried 'native' checker cout << "init path 2 " << init_path2.string() << endl; cout << "init path 2 exists " << exists(init_path2) << endl; I get: init path 2 C:Documents and Settings/ken.klose/workspace/3.2/DciApiTest init path 2 exists 0 The / after the : gets lost and therefore the file isn't found. Thanks in advance! BTW: Using MinGW.

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iostreams and compression
by Aljaz 29 Apr '07

29 Apr '07

Hello I've been trying to figure out another way to compress data from/to std::stringstream. Here is the source how I do it now: std::stringstream decompressed; decompressed << "somestring....."; std::stringstream compressed; { boost::iostreams::filtering_streambuf<boost::iostreams::input> out; out.push(boost::iostreams::zlib_compressor()); out.push(decompressed); boost::iostreams::copy(out, compressed); } Is there any way around this? I want to avoid boost::iostreams::copy because it takes 40% of this source execution time. How can I compress data directly to stringstream (to compressed in this example) without copying it? Thank you very much for help Regards Aljaz

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Re: [Boost-users] [thread] Segfault constructing a thread
by Ken Klose 28 Apr '07

28 Apr '07

Peter, Thank you very much. Your suggestions have fixed it. Ken "Peter Dimov" <pdimov(a)mmltd.net> wrote in message news:<008b01c789b2$21b0fe20$6607a8c0@pdimov2>... > Ken Klose wrote: > > I've got a singleton object that is trying to run its operator() > > method in a separate thread, but I'm getting a segfault when I > > construct the thread object: > > > > PublishedListener::PublishedListener(string directory) > > { > > _thread = new thread(*this); // segfault here > > } > > This line makes a copy of *this. It's very likely that this isn't what you > want. Use ref(*this) to store a reference, and consider disabling the copy > constructor and the assignment operator of the class.

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Re: [Boost-users] [thread] Segfault constructing a thread
by Ken Klose 28 Apr '07

28 Apr '07

Thanks for replying! The operator()() method is just a stub at the moment: void PublishedListener::operator()() { this->run(); } void PublishedListener::run() { cout << "Hooray! My thread is running" << endl; } I tried stepping through the construction of the thread and it looks like the problem is occurring somewhere in the construction of the function0<void>. As a test I changed the constructor to this: PublishedListener::PublishedListener(string directory) { cout << "1" << endl; function0<void> runnable(*this); cout << "2" << endl; _thread = new thread(runnable); cout << "3" << endl; } And I get the problem between 1 and 2. Thanks, Ken PS - I see Peter Dimov suggested I use ref. I'm going to try that now and reply to his post. "Digvijoy Chatterjee" <digvijoy.c(a)gmail.com> wrote in message news:<2f7228250704271831y58640424ld32d3cfe0c1bbc50(a)mail.gmail.com>... > On 4/27/07, Ken Klose <ken.klose(a)future-skies.com> wrote: > > > > I've got a singleton object that is trying to run its operator() method in > > a > > separate thread, but I'm getting a segfault when I construct the thread > > object: > > > > PublishedListener::PublishedListener(string directory) > > { > > _thread = new thread(*this); // segfault here > > } > > > > PublishedListener.h: > > class PublishedListener > > { > > public: > > static PublishedListener &getInstance(); > > void run(); > > void operator()(); > > boost::filesystem::path getItemDirectory(); > > virtual ~PublishedListener(); > > private: > > PublishedListener(std::string directory); > > static PublishedListener *_instance; > > boost::thread *_thread; > > boost::filesystem::path *itemDirectory; > > }; > > > > Thanks in advance! > > > Are you sure the implementation of operator()() isnt seg faulting, the > thread should be able to invoke it properly and i dont see any reason for > the thread instantiation to segfault.. > HTH > Digz >

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[Serialization] Multiple BOOST_CLASS_EXPORT
by Sohail Somani 28 Apr '07

28 Apr '07

Hi, Is there any danger in having multiple BOOST_CLASS_EXPORTs within a shared library or executable? I have a template child class that is always serialized by base class pointer and to keep myself sane I figure I can just blindly add BOOST_CLASS_EXPORT(ChildClass<T>); at the end of the .cpp file that uses it. Thanks, Sohail

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[boost] [math toolkit] Review Ends
by Matthias Schabel 28 Apr '07

28 Apr '07

The review period for the proposed Math Toolkit by John Maddock and Paul Bristow is now over. I will be assembling responses and put together a synopsis over then next few days. Thanks to everyone who participated and submitted reviews. Matthias

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very simple shared_ptr and copy constructor question
by Robert Marion 28 Apr '07

28 Apr '07

So, I've been using std::auto_ptr for some time, and have always been careful to either create a copy constructor or make it private (same for assignment). But now that I am becoming a boost::shared_ptr convert, I think that is no longer necessary. Is that so? Thanks, Robert

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[thread] Segfault constructing a thread
by Ken Klose 28 Apr '07

28 Apr '07

I've got a singleton object that is trying to run its operator() method in a separate thread, but I'm getting a segfault when I construct the thread object: PublishedListener::PublishedListener(string directory) { _thread = new thread(*this); // segfault here } PublishedListener.h: class PublishedListener { public: static PublishedListener &getInstance(); void run(); void operator()(); boost::filesystem::path getItemDirectory(); virtual ~PublishedListener(); private: PublishedListener(std::string directory); static PublishedListener *_instance; boost::thread *_thread; boost::filesystem::path *itemDirectory; }; Thanks in advance!

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Question on Boost::statechart library orthogonal regions
by Serena Fritsch 28 Apr '07

28 Apr '07

Hi All, Apologies if there are multiple psoting of this message. I want to use the boost::statechart library. However i encountered a small problem with using the orthogonal regions. In the statechart tutorial, every class declaration is put into one file, however i would like to put each class declaration into separate files. An example ( boost specific headers are omitted for readability reasons, also .cpp files which contain only test functions): A.h #include "Machine.h" class C; class B; class A: public sc::simple_state< A, Machine, mpl::list< C, B > > {}; C.h #include "A.H" class C: public sc::simple_state<C, A::orthogonal <0> > {}; B.h #include "A.H" class B: public sc::simple_state<B, A::orthogonal <1> > {}; Machine.h class A; class B; class Machine : public sc::state_machine<Machine, A> {}; Makefile CXX = g++-3.4 CFLAG = -c -g -w -O0 OBJECTS = Main.o A.o B.o C.o Machine.o all: $(OBJECTS) $(CXX) $(OBJECTS) -o $@ Main.o: Main.cpp $(CXX) $(CFLAG) $< A.o: A.cpp A.h $(CXX) $(CFLAG) $< B.o: B.cpp B.h $(CXX) $(CFLAG) $< C.o : C.cpp C.h $(CXX) $(CFLAG) $< Machine.o: Machine.cpp Machine.h $(CXX) $(CFLAG) $< clean: rm -f *.o a.out .PHONY: clean .PHONY: all Compiling this program fails, containing the following error messages (we only list an excerpt here): /usr/include/boost/statechart/simple_state.hpp: In static member function `static void boost::statechart::simple_state<MostDerived, Context, InnerInitial, historyMode>::deep_construct_inner_impl_non_empty::deep_construct_inner_impl(const boost::intrusive_ptr<T>&, typename Context::inner_context_type::outermost_context_base_type&) [with InnerList = boost::mpl::list1<B>, MostDerived = A, Context = Machine, InnerInitial = boost::mpl::list<C, B, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, boost::statechart::history_mode historyMode = has_no_history]': When putting all class declarations into one file, it works perfectly. So my question now is, is it possible to modularise the different state declarations into external files? Thanks very much for any insights on this Cheers Serena

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