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linking with libboost_graph not enough, but libboost_regex required?
by Oliver Kullmann 04 Sep '11

04 Sep '11

Hello, we have some legacy code, which after a change of system no longer runs: The new system is Boost 1.44.0 under Linux (Suse 11.4 for the record), but compiling with gcc version 4.1.2. > uname -a Linux csnereid 2.6.37.1-1.2-desktop #1 SMP PREEMPT 2011-02-21 10:34:10 +0100 i686 i686 i386 GNU/Linux We have a simple application which reads a graph-file and performs a simple computation. It links to libboost_graph. Apparently that draws in the libboost_regex, but that used to work: On the older installation (Suse 10.0 for the record) we had for the application > ldd Application libboost_graph.so.1.44.0 => /home/csoliver/SAT-Algorithmen/OKplatform/ExternalSources/Installations/Boost/4.1.2/1_44_0/lib/libboost_graph.so.1.44.0 (0x00002aaaaabc2000) libboost_regex.so.1.44.0 => /home/csoliver/SAT-Algorithmen/OKplatform/ExternalSources/Installations/Boost/4.1.2/1_44_0/lib/libboost_regex.so.1.44.0 (0x00002aaaab6f5000) and we see that at that time, also with Boost 1.44.0, linking was established to the local Boost installation, the same for libboost_graph and libboost_regex. However, now this implicit addition of the regex-link-library (which is managed by the Graph-library itself, not visible to the user --- I can't find the boost-regex-library anywhere mentioned in the Boost-Graph-documentation) does not work anymore --- if there is a system-wide Boost installation, it uses that, and otherwise it breaks: libboost_graph.so.1.44.0 => /home/csoliver/OKplatform/ExternalSources/Installations/Boost/4.1.2/1_44_0/lib/libboost_graph.so.1.44.0 (0x00007f8170fbe000) libboost_regex.so.1.44.0 => /usr/lib64/libboost_regex.so.1.44.0 (0x00007f81701c1000) libboost_graph.so.1.44.0 => /compsci/saturn/staff/csoliver/OKplatform/ExternalSources/Installations/Boost/4.1.2/1_44_0/lib/libboost_graph.so.1.44.0 (0xb7774000) libboost_regex.so.1.44.0 => not found I guess linking explicitly to libboost_regex would solve the problem, but that's under the circumstances not so easy to do, and furthermore something seems wrong here, and I would like to know what (it shouldn't be needed to link to libboost_regex, or, if so, then it should be documented). Thanks for your consideration! Oliver

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boost::zip_iterator does not work with std::istreambuf_iterator
by Krzysztof Żelechowski 04 Sep '11

04 Sep '11

1. boost::zip_iterator requires a readable iterator. 2. std::istreambuf_iterator is a readable iterator. 3. boost::zip_iterator cannot dereference std::istream_iterator because std::istreambuf_iterator returns by value while boost::zip_iterator returns by reference; the exact error message is invalid initialization of non-const reference of type ‘char&’ from an rvalue of type ‘std::istreambuf_iterator<char, std::char_traits<char> >::char_type’ Contradiction? Am I missing anything? Chris

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boost serialization help
by ohad barta 04 Sep '11

04 Sep '11

Hi My name is Ohad, and I work for the Technion institution, Israel. We are currently working on a research that involves programming in C++, and for that project we are using the serialization module of Boost. I'm not sure if this is the place to ask for help with boost. If not, Could you please direct me to the right address? my problems: 1) does the following supposed to work? : I have a : class saving helper{ boost::archive::binary_archive* ar; } and: class Y { X* first vector <Y*> second } and I try to save Y with the saving helper: for each level of Y object I initialize a saving helper, directly call a function that does *ar & * first (the function name isnt serialize\save) for each Y* on the next level I create a new saving helper object with a new pointer, initiallized the same: saving_helper::saving_helper(saving_helper* to_copy){ this->ar = to_copy->ar;} and continue saving the very same object (another level) with the new saving helper (the load is standard - via a regualr load function) I know that this is not the standard way to use boost, but I dont have much choice. 2) When trying to use the above method with text archive, I always get a streaming error, but If I use a binary archive than the streaming error vanished and instead I start to read the file from its middle (i.e. read the forth number instead of the first, reading the fifth bumber instead the second,etc). increasing the file length by adding to it 3 redundent numbers solved those two problems, and yet Im looking for a more stable solution, so help will be apprecialted. 3) boost tracking: where should I put the BOOST_CLASS_TRACKING macro? I currently use: boost 1.47.0 visual studio 2010 OS windows 7 Thanks in advance Ohad

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Subclassing "position_iterator"
by Alexander Feldman 04 Sep '11

04 Sep '11

Hi, I have the following question. I want to subclass/implement a new position_iterator that recognizes lines such as: #line 11 "electrical.lcl" and updates accordingly its location. My question is how to do that in the most elegant manner. Shall I copy/paste "position_iterator.hpp" and hack the increment() method? Would you, guys, use a Qi parser to recognize these lines? Maybe there is a better way... Thanks, -- Alex

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Asio example 5 sagmentation fault
by Alessandro Candini 04 Sep '11

04 Sep '11

I'm really interested in exemple 5 of boost asio: http://www.boost.org/doc/libs/1_47_0/doc/html/boost_asio/tutorial/tuttimer5… I've tried it with boost-1.47.0. I can compile without warnings using: g++ -Wall -pedantic -lboost_thread -lboost_system -o timer5 timer5.cpp but when I launch the executable it gives me a Segmentation fault. Commenting the code I found that the segmentation fault raise at the 3rd line of main: boost::thread t(boost::bind(&boost::asio::io_service::run, &io)); I'm trying on the following machine: Linux office-007 2.6.38-11-generic #48-Ubuntu SMP Fri Jul 29 19:02:55 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux Can anyone help me? -- Alessandro Candini MEEO S.r.l. Via Saragat 9 I-44122 Ferrara, Italy Tel: +39 0532 1861501 Fax: +39 0532 1861637 http://www.meeo.it ======================================== "ATTENZIONE:le informazioni contenute in questo messaggio sono da considerarsi confidenziali ed il loro utilizzo è riservato unicamente al destinatario sopra indicato. Chi dovesse ricevere questo messaggio per errore è tenuto ad informare il mittente ed a rimuoverlo definitivamente da ogni supporto elettronico o cartaceo." "WARNING:This message contains confidential and/or proprietary information which may be subject to privilege or immunity and which is intended for use of its addressee only. Should you receive this message in error, you are kindly requested to inform the sender and to definitively remove it from any paper or electronic format."

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[test] Does boost.test support mock objects?
by Jonathon 04 Sep '11

04 Sep '11

Hi, One facility that I really love about Google test is their mock object framework. It facilitates the development of tests/stub objects. Note that this is also delivered in easy mock and mockpp. Does anyone know if Boost.Test offers such a thing? I've looked through the documentation and I couldn't find anything. Thanks, J

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broken link in "New Iterator Concepts"
by Krzysztof Żelechowski 03 Sep '11

03 Sep '11

<URL: http://www.boost.org/ doc/libs/1_47_0/libs/iterator/doc/new-iter-concepts.html > or const T& once issue 200 is resolved <URL: http://anubis.dkuug.dk/JTC1/SC22/WG21/docs/lwg-active.html#200 > Not Found Issue 200 can be found instead at <URL: http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#200 > I suspect there are more broken links there but I cannot produce a report because the page is invalid, and indeed, so are all pages under doc/libs/1_47_0/libs/iterator/: … href="/favicon.ico" type="image/ico"><link rel="stylesheet" type="text/css" h… (unclosed link element in XHTML mode) Please fix, Chris

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outdated information in "New Iterator Concepts"
by Krzysztof Żelechowski 03 Sep '11

03 Sep '11

<URL: http://www.boost.org/ doc/libs/1_47_0/libs/iterator/doc/new-iter-concepts.html#motivation > "once issue 299 is resolved" However, issue 299 *is* resolved: <URL: http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#299 > Please update, Chris

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[range] What's the best way to initialize a new container from a range?
by Martin B. 03 Sep '11

03 Sep '11

Hi! Say I have a range R and I want to construct a new container from the range R. Will I always have to repeat the expression yielding the range, or is there a shorter way? Example: std::vector<int> numbers( boost::irange(7, 42).begin(), boost::irange(7, 42).end() ); Note that it's just an example. Is it possible to create a container C from a range expression R in one step? Any helper function for this? cheers, Martin

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[type_traits] deduce argument type of member function with function_traits
by alfC 03 Sep '11

03 Sep '11

Is function_traits the right way to extract the argument type of a member function? In the following example I want to make the last line work. This will be part of larger question, on how to deduce the argument type of operator() for function objects in which operator() is not overloaded. #include <typeinfo> #include <iostream> #include <boost/type_traits/function_traits.hpp> #include <boost/type_traits/remove_pointer.hpp> using namespace std; double dsquare(double l){ return l*l; } int isquare(int l){ return l*l; } struct csquare_impl{ int do(char c) const{ return 'c'; } }; csquare_impl csquare; template<class F> void test(F f){ typename boost::function_traits<typename boost::remove_pointer<F>::type>::arg1_type test_var; cout << typeid(test_var).name() << endl; } int main(){ test(dsquare); // ok, prints "d"(double) test(isquare); // ok, prints "i"(int) test(csquare_impl::do); // not ok, want to print "c"(char) return 0; } Thanks, Alfredo

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