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Help needed to reconnect a socket to a new endpoint with Boost asio in Windows
by Adolfo Jimenez 06 Mar '11

06 Mar '11

I'm having trouble when in Windows XP, try to connect a socket to an endpoint after being connected to another. This is the situation: a) The boost::asio::ip::tcp::socket is connected to a remote host (say pop.remote1.com) b) The transmission ends, and the socket is closed: socket_.shutdown(boost::asio::ip::tcp::socket::shutdown_both, error); socket_.close(error); Then, when trying to connect to another host (say pop.remote2.com) using the same process that in a), the proccess returns without error, but the socket remains closed. Note that when using pop.remote2.com as the first connection, the things run Ok, and the same problem arises if try to connect to pop.remote1.com after closing. In both situations there are not pending processes in the attached io_service. I tried to open the socket before the reconnection, but the result remains the same. That is, the result is the same if after closing the previous connection with. socket_.shutdown(...); socket_.close(...); is used socket_.open(...); socket_.async_connect( ... ); or just socket_.async_connect( ... ); The questions are: Is that reconnection admissible? Is that the supposed correct process? Thanks in advance.

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Boost.fusion 1.42 / Gcc 4.5: what is this error trying to tell me? (Works with Gcc 4.4)
by Joost Kraaijeveld 06 Mar '11

06 Mar '11

Hi, I have code that compiles OK with Gcc 4.4 but fails with 4.5 and I cannot understand what the error I get from the compiler means. Maybe someone here can give me a suggestion? The error: In file included from /usr/include/boost/fusion/algorithm/query/find.hpp:13:0, from /usr/include/boost/fusion/sequence/intrinsic/has_key.hpp:12, from /usr/include/boost/fusion/sequence/intrinsic.hpp:16, from /usr/include/boost/fusion/sequence.hpp:12, from ../../../library/../include/Danu/DanuModelObjects/User.hpp:11, from ../../../library/../include/Danu/DanuViewObjects/UserViewObject.hpp:12, from ../../../library/../include/Danu/DanuViewObjects/UserDialog.hpp:15, from ../../../library/../include/Danu/DanuModelObjectsFactory/UserCreatorFunction.hpp:10, from ../../../library/DanuModelObjectsFactory/UserCreatorFunction.cpp:7: /usr/include/boost/fusion/iterator/key_of.hpp: In instantiation of 'boost::fusion::result_of::key_of<mpl_::arg<1> >': /usr/include/boost/mpl/aux_/preprocessed/gcc/template_arity.hpp:85:88: instantiated from 'const int boost::mpl::aux::template_arity_impl<boost::is_same<boost::fusion::result_of::key_of<mpl_::arg<1> >, Danu::UserCreator::objectId>, 1>::value' /usr/include/boost/mpl/aux_/preprocessed/gcc/template_arity.hpp:93:261: instantiated from 'const int boost::mpl::aux::template_arity<boost::is_same<boost::fusion::result_of::key_of<mpl_::arg<1> >, Danu::UserCreator::objectId> >::value' /usr/include/boost/mpl/aux_/preprocessed/gcc/template_arity.hpp:98:30: instantiated from 'boost::mpl::aux::template_arity<boost::is_same<boost::fusion::result_of::key_of<mpl_::arg<1> >, Danu::UserCreator::objectId> >' /usr/include/boost/fusion/algorithm/query/detail/find_if.hpp:184:9: instantiated from 'boost::fusion::detail::static_find_if<boost::fusion::basic_iterator<boost::fusion::map_iterator_tag, boost::fusion::map<boost::fusion::pair<Danu::UserCreator::objectId, Danu::ObjectId>, boost::fusion::pair<Danu::UserCreator::userId, int>, boost::fusion::pair<Danu::UserCreator::userName, std::basic_string<char> >, boost::fusion::pair<Danu::UserCreator::password, std::basic_string<char> >, boost::fusion::pair<Danu::UserCreator::firstName, std::basic_string<char> >, boost::fusion::pair<Danu::UserCreator::infix, std::basic_string<char> >, boost::fusion::pair<Danu::UserCreator::lastName, std::basic_string<char> > >::category, const Danu::UserCreator::UserCreationArguments, 0>, boost::fusion::basic_iterator<boost::fusion::map_iterator_tag, boost::fusion::map<boost::fusion::pair<Danu::UserCreator::objectId, Danu::ObjectId>, boost::fusion::pair<Danu::UserCreator::userId, int>, boost::fusion::pair<Danu::UserCreator::userName, std::basic_string<char> >, boost::fusion::pair<Danu::UserCreator::password, std::basic_string<char> >, boost::fusion::pair<Danu::UserCreator::firstName, std::basic_string<char> >, boost::fusion::pair<Danu::UserCreator::infix, std::basic_string<char> >, boost::fusion::pair<Danu::UserCreator::lastName, std::basic_string<char> > >::category, const Danu::UserCreator::UserCreationArguments, 7>, boost::is_same<boost::fusion::result_of::key_of<mpl_::arg<1> >, Danu::UserCreator::objectId> >' /usr/include/boost/fusion/algorithm/query/find.hpp:46:43: instantiated from 'boost::fusion::result_of::find<const Danu::UserCreator::UserCreationArguments, Danu::UserCreator::objectId>' /usr/include/boost/fusion/sequence/intrinsic/at_key.hpp:37:17: instantiated from 'boost::fusion::extension::at_key_impl<boost::fusion::map_tag>::apply<const Danu::UserCreator::UserCreationArguments, Danu::UserCreator::objectId>' /usr/include/boost/fusion/sequence/intrinsic/at_key.hpp:70:9: instantiated from 'boost::fusion::result_of::at_key<const Danu::UserCreator::UserCreationArguments, Danu::UserCreator::objectId>' ../../../library/DanuModelObjectsFactory/UserCreatorFunction.cpp:40:83: instantiated from here /usr/include/boost/fusion/iterator/key_of.hpp:38:9: error: invalid use of incomplete type 'struct boost::fusion::extension::key_of_impl<boost::fusion::non_fusion_tag>' /usr/include/boost/fusion/iterator/key_of.hpp:20:16: error: declaration of 'struct boost::fusion::extension::key_of_impl<boost::fusion::non_fusion_tag>' Snippets of relevant code (hopefully enough): - the first snipped is how I declare the boost::fusion::map - the second is how I use and where the error is (<--!!!!!!!!) ... namespace UserCreator { struct objectId; struct userId; struct userName; typedef boost::fusion::map < boost::fusion::pair< objectId, ObjectId >, boost::fusion::pair< userId, int >, boost::fusion::pair< userName, std::string > > UserArgs; struct UserCreationArguments : public MOCFunctionParameter, public UserArgs ... ... ModelObject* UserCreatorFunction::createObject( const MOCFunctionParameter* aMOCFunctionParameter /* = NULL */) const { ... if ( (arguments = dynamic_cast< UserCreator::UserCreationArguments* >(const_cast<MOCFunctionParameter*>(aMOCFunctionParameter))) ) { ObjectId& objectId = boost::fusion::at_key< UserCreator::objectId >(*arguments); <--!!!!!!!! int& userId = boost::fusion::at_key< UserCreator::userId >(*arguments); std::string& userName = boost::fusion::at_key< UserCreator::userName >(*arguments); ... TIA -- Met vriendelijke groeten, Joost Kraaijeveld Askesis B.V. Molukkenstraat 14 6524NB Nijmegen tel: 024-3888063 / 06-51855277 fax: 024-3608416 web: www.askesis.nl

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Boost.Test with Boost.Thread
by Satish Kaveti 06 Mar '11

06 Mar '11

I am learning to create simple unit tests using Boost.Test. I am getting the following error when I run bjam. C:/DevTools/boost_1_44_0/tools/build/v2/build\feature.jam:138: in feature.feature from module feature error: feature already defined: error: in feature declaration: error: feature "threadapi" : "pthread" "win32" : "propagated" c:\DevTools\boost_1_44_0\libs\thread\build\Jamfile.v2:57: in modules.load from module Jamfile</c:/devtools/boost_1_44_0/libs/thread/build> C:/DevTools/boost_1_44_0/tools/build/v2/build\project.jam:310: in load-jamfile from module project C:/DevTools/boost_1_44_0/tools/build/v2/build\project.jam:62: in project.load from module project C:/DevTools/boost_1_44_0/tools/build/v2/build\project.jam:760: in project.use from module project C:/DevTools/boost_1_44_0/tools/build/v2/build\project.jam:89: in load-used-projects from module project C:/DevTools/boost_1_44_0/tools/build/v2/build\project.jam:73: in load from module project C:/DevTools/boost_1_44_0/tools/build/v2/build\project.jam:115: in load-parent from module project C:/DevTools/boost_1_44_0/tools/build/v2/build\project.jam:458: in initialize from module project C:/DevTools/boost_1_44_0/tools/build/v2/build\project.jam:300: in load-jamfile from module project C:/DevTools/boost_1_44_0/tools/build/v2/build\project.jam:62: in load from module project C:/DevTools/boost_1_44_0/tools/build/v2/build\project.jam:168: in project.find from module project C:/DevTools/boost_1_44_0/tools/build/v2\build-system.jam:569: in load from module build-system C:\DevTools\boost_1_44_0\tools\build\v2/kernel\modules.jam:283: in import from module modules C:\DevTools\boost_1_44_0\tools\build\v2\kernel\bootstrap.jam:142: in boost-build from module C:\DevTools\boost_1_44_0\boost-build.jam:17: in module scope from module My Jamroot file is shown below : ------------------------------------- import os ; import testing ; use-project /blues/system : c:/devtools/boost_1_44_0/libs/system/build ; use-project /blues/thread : c:/devtools/boost_1_44_0/libs/thread/build ; use-project /blues/test : c:/devtools/boost_1_44_0/libs/test/build ; project : : requirements <threading>multi <link>static <include>c:/devtools/boost_1_44_0 <define>_WIN32_WINNT=0x0501 <define>_CRT_SECURE_NO_WARNINGS=1 <define>_SCL_SECURE_NO_WARNINGS=1 ; and my Jamfile is shown below : ------------------------------------- alias unit_test_framework : # Sources /blues/test//boost_unit_test_framework ; explicit unit_test_framework ; run-fail unit_test_example_01.cpp unit_test_framework ; How can I successfully build the unit test ? Thanks.

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[foreach] gcc 4.5 & 4.6 compiler error with BOOST_FOREACH(auto&& ...) loop
by Nathan Ridge 05 Mar '11

05 Mar '11

Hello, The following code fails to compile with gcc 4.5 or 4.6: #include <boost/foreach.hpp> template <typename> void f() { int A[6]; BOOST_FOREACH(auto&& x, A) ; } void g() { f<int>(); } The error is: test.cpp: In function 'void f() [with <template-parameter-1-1> = int]': test.cpp:14:12: instantiated from here test.cpp:6:5: error: invalid initialization of reference of type 'int&&' from expression of type 'int' Interestingly, the error goes away if I make f() a non-template function. It also compiles fine with gcc 4.4. The native range-based for version, however, compiles fine with gcc 4.6 (which is the only version to support it): #include <boost/foreach.hpp> template <typename> void f() { int A[6]; for(auto&& x : A) ; } void g() { f<int>(); } What is going on here? Is this a Boost issue or a gcc issue? Thanks, Nate.

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Re: [Boost-users] Threading a Shared Model with pointers
by pcunite＠fsmail.net 05 Mar '11

05 Mar '11

I explained this wrong. What is really happening is that each thread has a pointer to the object (forget about the vector for the moment) and it uses this as a key many hours later. When it is given serialized access to the "model/database cache", the thread wants to do work using that key, of course now it is no longer valid. This is why using map works, but I did not want to search every time, that is why weak_ptr works. Just wanted to know the best approach for this type of problem. All access to everything is thread safe. Any thoughts now?

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newbie: installation question
by Gunnar Salentin 05 Mar '11

05 Mar '11

Hi folks I just started with boost and have run into the first problem: the example program (see http://www.boost.org/doc/libs/1_46_0/more/getting_started/unix-variants.html) does not run though everything should be in place: The error is 'example.cpp:1:35: error: boost/lambda/lambda.hpp: No such file or directory" yes, I did check my file structure (see attached extract from Terminal). Installation of boost was done via sudo port... Anyone an idea what the issue might be? Thx GS User:~ SUserHG$ ls Desktop Downloads Library Music Public QuantLib-1.0.1.tar.gz example.cpp Documents Install-QuantLib.txt Movies Pictures QuantLib-1.0.1 Sites SUser:~ SUserHG$ cd /opt/local/include/boost/lambda SUser:lambda SUserHG$ ls algorithm.hpp casts.hpp construct.hpp core.hpp exceptions.hpp lambda.hpp numeric.hpp bind.hpp closures.hpp control_structures.hpp detail if.hpp loops.hpp switch.hpp SUser:lambda SUserHG$ cd SUser:~ SUserHG$ c++ -I /opt/local/include/boost example.cpp -o example example.cpp:1:35: error: boost/lambda/lambda.hpp: No such file or directory example.cpp: In function ‘int main()’: example.cpp:8: error: ‘boost’ has not been declared example.cpp:8: error: ‘lambda’ is not a namespace-name example.cpp:8: error: expected namespace-name before ‘;’ token example.cpp:12: error: ‘_1’ was not declared in this scope

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Threading a Shared Model with pointers
by pcunite＠fsmail.net 04 Mar '11

04 Mar '11

Threading a Shared Model with pointers I have a vector of pointers to objects created with new. Multiple threads access this vector in a safe manner with get/set. However, a thread may delete one of the objects, in which case another thread's pointer to the object is no longer valid. How can a method know if the pointer is valid? I have to examples that work and would like your thoughts. Test for pointer validity: 1. Use integers instead of pointers. A hash (std::map) checks to see if the pointer is still valid. Public methods look like get(size_t iKey), etc. Insde the method it does: if((it = mMap.find(iKey)) != mMap.end()) { TMyType * pMyType = it->second; // do something with know good pointer. } 2. Have a vector of shared_ptr. Each thread tries to call lock() on its weak_ptr. If the returned shared_ptr is null we know someone deleted it while we were waiting. Public methods look like get(boost::weak_ptr<TMyType> pMyType), etc. Insde the method it does: boost::shared_ptr<TMyType> pGOOD = pMyType.lock(); if (pGOOD == NULL) { // null, bad pointer do something return; } 3. Test for null on plain raw pointers? Is this possible? Public methods look like get(TMyType * pMyType), etc. Option 1 and 2 actually seem to work well. I don't know how they will scale. What is the best approach? Is there a portable version 3?

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[general] mingw.org site was hacked
by Jim Bell 04 Mar '11

04 Mar '11

Of interest to MinGW users: It seems that the mingw.org site was hacked a couple days ago: <http://sourceforge.net/mailarchive/message.php?msg_id=27147169>

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Boost Concepts with iterators and ranges
by Robert Ramey 04 Mar '11

04 Mar '11

I've been experimenting with Boost Concepts in conjunction with Boost Range and by implication boost iterators. I have a few questions from the documentation: a) I see BOOST_CONCEPT_USAGE described in some detail in the section Creating Concept Checking Classes. But in the section titled "Reference" I only find in the subsection "macros" BOOST_CONCEPT_ASSERT and BOOST_CONCEPT_REQUIRES. Is BOOST_CONCEPT_USAGE meant to be used? b) "Deprecated Concept Checking Classes" "For each of the concepts documented here, the library includes an identical concept checking class whose name ends in "Concept" For example, in addition to RandomAccessIterator, the library defines a RandomAccessIteratorConcept class template." It sounds like this means that I shouldn't expect to find "WritableIteratorConcept" but in fact in "interator_concepts.hpp" find just that. I'm assuming that's an oversight. c) except for the above, the Range library uses things like ForwardTraversal and ForwardTraversalConcept the iterators library uses ForwardTraversal only. d) the iterators concepts are in the root namespace boost_concepts while the range concepts are in the root namespace boost. e) boost/range/concepts.hpp includes the file boost/iterator/iterator_concepts.hpp All this makes it very hard to keep all this straight in one's head. Is there any possibility that all this could be made simpler to follow by some combination of documentation improvements and/or namespace coordination? Robert Ramey

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[program_options] escaping literal hash symbol for parse_config_file
by Rhys Ulerich 04 Mar '11

04 Mar '11

Hi all, With boost::program_options::parse_config_file, is there any way to escape a literal hash symbol ('#')? I want to set std::string-based option 'foo' to contain the var 'bar#baz', but the sensible-seeming foo=bar\#baz fails in that 'foo' only contains 'bar'. Other variants on quoting and escaping also fail. The source for common_config_file_iterator::get() in config_file.cpp seems to indicate this isn't possible. Can anyone confirm or deny that? Thanks, Rhys

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