August 2010 - Boost-users - lists.preview.boost.org

[MPL] has_xxx always returns false!
by Eric 27 Aug '10

27 Aug '10

This code: BOOST_MPL_HAS_XXX_TRAIT_DEF(normal); template<class T, bool HasNormal> class getVertexHasNormal { public: static void getNormal(T &tv) {} }; template<class T> class getVertexHasNormal<T, true> // true case { public: static void getNormal(T &tv) { // do something } }; template<class VT> class A : public base { void doit(v) /* override */ { VT tv; getVertexHasNormal<VT, has_normal<VT>::value >::getNormal(tv); } } if I understand correctly, this code is suppose to do call a different "getNormal" method if the method "normal" exists (or not) in the template parameter class. Basically mimicking the infamous "__if_exists" macro on the Microsoft c++ compiler.... right? but, has_normal<VT> always return false (visual studio 2008) so we don't get the right expected behavior! Feel free to educate me.... thanks in advance. eric

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[Serialization] Is this example legal usage of the serialization library
by Elizabeta 26 Aug '10

26 Aug '10

Hi, Is it ok to serialize/deserialize in the object I get when dereference a pointer ? void f() { B* bObj=new B(); /// save { std::ofstream ofs("C:\\hh.txt"); boost::archive::xml_oarchive oa(ofs); oa & make_nvp("bObj",*bObj); } //// Load { std::ifstream ifs("C:\\hh.txt"); boost::archive::xml_iarchive ia(ifs); ia & make_nvp("bObj",*bObj); } } My second question : Is it ok to serialize/deserialize in *this ? Thanks

3 3

[serialization] problem with custom archive type
by Kenneth Riddile 26 Aug '10

26 Aug '10

I have a custom input archive type that has worked fine when statically linked to the serialization library. I'm now must use serialization as a DLL and the code no longer compiles. This is under MSVC9 with BOOST_ALL_DYN_LINK defined. This code works fine on Linux/GCC with serialization built as a shared library...so the problem appears specific to Windows/MSVC. Here is a boiled down version of the code that exhibits the problem: // HEADER CONTENTS #include <boost/archive/xml_iarchive.hpp> class CustomArchive : public boost::archive::xml_iarchive_impl<CustomArchive> , public boost::archive::detail::shared_ptr_helper { public: CustomArchive( std::istream& is, int foo ) : boost::archive::xml_iarchive_impl<CustomArchive>( is, 0 ) , m_foo( foo ) { } int GetFoo() const { return m_foo; } template<class T> void load( T& t ) { boost::archive::xml_iarchive_impl<CustomArchive>::load( t ); } private: friend class boost::archive::xml_iarchive_impl<CustomArchive>; friend class boost::archive::basic_xml_iarchive<CustomArchive>; friend class boost::archive::load_access; int m_foo; }; // CPP CONTENTS #include <CustomArchive.hpp> #include <boost/archive/impl/basic_xml_iarchive.ipp> #include <boost/archive/impl/xml_iarchive_impl.ipp> #include <boost/archive/impl/archive_serializer_map.ipp> namespace boost { namespace archive { template class basic_xml_iarchive<CustomArchive>; template class xml_iarchive_impl<CustomArchive>; template class detail::archive_serializer_map<CustomArchive>; } } BOOST_SERIALIZATION_REGISTER_ARCHIVE( CustomArchive ) and here are the errors: 1>C:\Boost\include\boost/archive/impl/basic_xml_iarchive.ipp(41) : error C2491: 'boost::archive::basic_xml_iarchive<Archive>::load_start' : definition of dllimport function not allowed 1>C:\Boost\include\boost/archive/impl/basic_xml_iarchive.ipp(77) : error C2491: 'boost::archive::basic_xml_iarchive<Archive>::load_end' : definition of dllimport function not allowed 1>C:\Boost\include\boost/archive/impl/basic_xml_iarchive.ipp(83) : error C2491: 'boost::archive::basic_xml_iarchive<Archive>::load_override' : definition of dllimport function not allowed 1>C:\Boost\include\boost/archive/impl/basic_xml_iarchive.ipp(89) : error C2491: 'boost::archive::basic_xml_iarchive<Archive>::load_override' : definition of dllimport function not allowed 1>C:\Boost\include\boost/archive/impl/basic_xml_iarchive.ipp(95) : error C2491: 'boost::archive::basic_xml_iarchive<Archive>::load_override' : definition of dllimport function not allowed 1>C:\Boost\include\boost/archive/impl/basic_xml_iarchive.ipp(101) : error C2491: 'boost::archive::basic_xml_iarchive<Archive>::load_override' : definition of dllimport function not allowed 1>C:\Boost\include\boost/archive/impl/basic_xml_iarchive.ipp(108) : error C2491: 'boost::archive::basic_xml_iarchive<Archive>::basic_xml_iarchive' : definition of dllimport function not allowed 1>C:\Boost\include\boost/archive/impl/basic_xml_iarchive.ipp(111) : error C2491: 'boost::archive::basic_xml_iarchive<Archive>::~basic_xml_iarchive' : definition of dllimport function not allowed 1>Warning: This header is deprecated. Please use: boost/spirit/include/classic_rule.hpp 1>C:\Boost\include\boost/archive/impl/xml_iarchive_impl.ipp(83) : error C2491: 'boost::archive::xml_iarchive_impl<Archive>::load' : definition of dllimport function not allowed 1>C:\Boost\include\boost/archive/impl/xml_iarchive_impl.ipp(114) : error C2491: 'boost::archive::xml_iarchive_impl<Archive>::load' : definition of dllimport function not allowed 1>C:\Boost\include\boost/archive/impl/xml_iarchive_impl.ipp(127) : error C2491: 'boost::archive::xml_iarchive_impl<Archive>::load' : definition of dllimport function not allowed 1>C:\Boost\include\boost/archive/impl/xml_iarchive_impl.ipp(140) : error C2491: 'boost::archive::xml_iarchive_impl<Archive>::load' : definition of dllimport function not allowed 1>C:\Boost\include\boost/archive/impl/xml_iarchive_impl.ipp(153) : error C2491: 'boost::archive::xml_iarchive_impl<Archive>::load_override' : definition of dllimport function not allowed 1>C:\Boost\include\boost/archive/impl/xml_iarchive_impl.ipp(162) : error C2491: 'boost::archive::xml_iarchive_impl<Archive>::init' : definition of dllimport function not allowed 1>C:\Boost\include\boost/archive/impl/xml_iarchive_impl.ipp(189) : error C2491: 'boost::archive::xml_iarchive_impl<Archive>::xml_iarchive_impl' : definition of dllimport function not allowed 1>C:\Boost\include\boost/archive/impl/xml_iarchive_impl.ipp(202) : error C2491: 'boost::archive::xml_iarchive_impl<Archive>::~xml_iarchive_impl' : definition of dllimport function not allowed 1>C:\Boost\include\boost/archive/impl/archive_serializer_map.ipp(45) : error C2491: 'boost::archive::detail::archive_serializer_map<Archive>::insert' : definition of dllimport function not allowed 1>C:\Boost\include\boost/archive/impl/archive_serializer_map.ipp(57) : error C2491: 'boost::archive::detail::archive_serializer_map<Archive>::erase' : definition of dllimport function not allowed 1>C:\Boost\include\boost/archive/impl/archive_serializer_map.ipp(67) : error C2491: 'boost::archive::detail::archive_serializer_map<Archive>::find' : definition of dllimport function not allowed

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[interprocess] Checking for existence Named Mutex
by Brian Davis 26 Aug '10

26 Aug '10

How do I check for the existence of a named resource in using boost interprocess without wrapping a open_only in a try catch block and waiting for the exception? Also are there calls for launching a process such as std::system that are nonblocking in Windows using the _spawnlp and friends calls?

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Boost's additional test compilers - test results available?
by Jon Payne 26 Aug '10

26 Aug '10

Hi all, In the boost release notes (I was looked at 1.44) there is a section listing the "additional test compilers" - I use Borland/Codegear C++ 2010. Presumably this means the tests are run on those compilers? If so, are the results available anywhere? Thanks, Jon

1 0

Bost.thread: how to force Pthreads-w32 usage with MingW (x-compile)?
by Joost Kraaijeveld 26 Aug '10

26 Aug '10

Hi, I have x-compiled Boost using Pthreads-w32, using threading=multi,single threadapi=pthread. But when I x-compile my application Boost uses the win32 headers. I have looked at the thread sources but I cannot find out if it just should work or that I should use some macros. Can anyone help me with this? TIA -- 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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X-compile: undefined reference to `boost::this_thread::interruptible_wait using Boost 1.42
by Joost Kraaijeveld 26 Aug '10

26 Aug '10

Hi, I am cross compiling an application from Linux to Windows using Boost 1.42. Doing that I get an undefined reference error when linking one of my own dll's to my own application: /bin/bash ../../libtool --tag=CXX --mode=link i586-mingw32msvc-g++ -pipe -Wall -Wextra -Wundef -Wshadow -Wconversion -I/home/jkr/mingw/boost/include -g -O2 -Wl,--enable-runtime-pseudo-reloc,--enable-auto-import -no-undefined -L/home/jkr/mingw/boost/lib -o ORBRegistration.exe ORBRegistration-Main.o ../../../library/DagdaORB/libdagdaorb.la ../../../library/DagdaCom/libdagdacom.la /home/jkr/Programming/C++/Danu/mingw/library/DanuBase/libdanubase.la /home/jkr/Programming/C++/Danu/mingw/library/DanuStream/libdanustream.la /home/jkr/Programming/C++/Danu/mingw/library/DanuDB/libdanudb.la -lboost_system-mt -lboost_serialization-mt -lboost_thread-mt -lboost_date_time-mt -lboost_filesystem-mt -lws2_32 -lmswsock libtool: link: i586-mingw32msvc-g++ -pipe -Wall -Wextra -Wundef -Wshadow -Wconversion -I/home/jkr/mingw/boost/include -g -O2 -Wl,--enable-runtime-pseudo-reloc -Wl,--enable-auto-import -o .libs/ORBRegistration.exe ORBRegistration-Main.o -L/home/jkr/mingw/boost/lib ../../../library/DagdaORB/.libs/libdagdaorb.a /home/jkr/Programming/C++/Dagda/mingw/library/DagdaCom/.libs/libdagdacom.a ../../../library/DagdaCom/.libs/libdagdacom.a /home/jkr/Programming/C++/Danu/mingw/library/DanuDB/.libs/libdanudb.a /home/jkr/Programming/C++/Danu/mingw/library/DanuStream/.libs/libdanustream.a /home/jkr/Programming/C++/Danu/mingw/library/DanuBase/.libs/libdanubase.a -lpthread -lodbc32 -lboost_system-mt -lboost_serialization-mt -lboost_thread-mt -lboost_date_time-mt -lboost_filesystem-mt -lws2_32 -lmswsock ../../../library/DagdaORB/.libs/libdagdaorb.a(libdagdaorb_la-IMRServer.o): In function `_ZN5boost6detail19basic_cv_list_entry4waitENS0_7timeoutE': /home/jkr/mingw/boost/include/boost/thread/win32/condition_variable.hpp:82: undefined reference to `boost::this_thread::interruptible_wait(void*, boost::detail::timeout)' collect2: ld returned 1 exit status I have no idea why I get this error, and hence no idea how to solve it. Does anyone have any idea? Additional info: - I cross-compiled Boost itself using the Debian's gcc-mingw32 4.4.4-0.1+b1 crosscompiler, - I used Pthreads-w32 release 2.8.0 (2006-12-22) - The full commandline I used was (the commandline is split for readability): PTW32_INCLUDE=/home/jkr/mingw/pthreads/include PTW32_LIB=/home/jkr/mingw/pthreads/lib bjam --prefix=/home/jkr/mingw/boost --layout=tagged link=shared variant=debug,release toolset=gcc target-os=windows threading=multi,single runtime-link=shared --without-python --without-mpi -sNO_BZIP2=1 -sNO_ZLIB=1 install TIA -- 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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unresolved external when building Boost.Thread
by Kenneth Riddile 25 Aug '10

25 Aug '10

OS - Windows7 x64 compiler - MSVC9 Boost version - 1.44 Running the following command fails to build the thread library with the following error: bjam variant=release link=shared threading=multi runtime-link=shared --layout=tagged install thread.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) pu blic: __thiscall boost::gregorian::greg_month::greg_month(unsigned short)" (__im p_??0greg_month@gregorian@boost@@QAE@G@Z) referenced in function "public: __this call boost::gregorian::date::date(enum boost::date_time::special_values)" (??0da te@gregorian@boost@@QAE@W4special_values@date_time@2@@Z) bin.v2\libs\thread\build\msvc-9.0\release\threading-multi\boost_thread-vc90-mt-1 _44.dll : fatal error LNK1120: 1 unresolved externals Removing "--layout=tagged" from the command results in the thread library building successfully, but of course that isn't what I want :)

2 1

Running mcgregor_common_subgraphs on a graph with bundled properties
by Saeed Nari 25 Aug '10

25 Aug '10

Hi, Is it possible to run mcgregor_common_subgraphs algorithm on a graph with bundled properties? Thanks Saeed

2 2

[MultiArray, Thread] Setting the _ITERATOR_DEBUG_LEVEL
by lfrfly＠icqmail.com 24 Aug '10

24 Aug '10

It's probably well-known by now that multi_array has a problem with Visual Studio 2010: due to the way it identifies its iterators, you get errors unless you set the _ITERATOR_DEBUG_LEVEL preprocessor symbol to 0. First of all, when can we expect a fix for this (or is there one already)? Secondly, even if I manually set the _ITERATOR_DEBUG_LEVEL to 0 in Debug configuration (that's the default in Release), I am unable to build because when I try to link in the Boost Thread library, I get 2>libboost_thread-vc100-mt-gd-1_43.lib(thread.obj) : error LNK2038: mismatch detected for '_ITERATOR_DEBUG_LEVEL': value '2' doesn't match value '0' in test.obj This indicates that I need to build Boost Thread with that variable set to 0 as well, even in the debug mode; or else I need to somehow get the Release version of the library linked in instead. I'm not sure how to do either one of these options. Can anyone help me configure bjam to override the variable, or else override which lib is linked?

2 2

[boost-users][asio] Interaction problem with signals2?
by Germán Diago 24 Aug '10

24 Aug '10

Hello. I'm trying to call a signal after an async_read from inside a function called by boost::asio::io_service. The run function runs in a thread, and the observers are connected in a different thread. This is causing errors. It's my program or it's not possible to invoke a handler that is running in another thread from io_service::run? Thanks in advance.

1 0

using Regex and other Boost libraries that require a build
by Bhushan Inamdar 24 Aug '10

24 Aug '10

Hi all, I am relatively new to Boost but was wanting to install and do development on it for long now. Finally, I can now spare some time for that. I am using Visual Studio 2008 professional edition as a development IDE. I have installed Visual Assist X to assist me with the intellisense as well. I am having Windows 7 ultimate installed on my machine and I am trying to install latest i.e. BOOST 1.44.0 version. So far I have had partial success. I am able to build and compile the sample program on Boost site that needs only headers. But I am facing problems while building programs that reference other libraries. So here is what I did: - Tried unsuccessfully to install it using BoostPro; installation broke quite a few times. - So I gave up and downloaded the Boost compressed version and extracted it successfully in C: drive - The current location is C:\Program Files\Boost\Boost_1_44_0\....and the respective dir structure thereafter. - Then I downloaded the bjam utility and extracted it and then copied it to the Boost root dir - Following this, I double clicked bjam.exe and it ran the build. However, a lot of projects were skipped and virtually nothing was build. - Then I realized that it was Windows 7 we were dealing with and then immediately ran Bjam.exe as an administrator. - This time, it took a lot longer and I was seeing the compilation in progress and I think that it was satisfactory. - Then comes the part of linking the libraries through VC++ compiler to the code. - I then navigated to Tools->Options->Projects and Solutions->VC++Directories and selected Win32 on first combo on top left - There I selected Includes in the other combo on top right and added the C:\Program Files\Boost\Boost_1_44_0\Boost to the list - Then on the same page I changed the top right combo to Libraries and added C:\Program Files\Boost\Boost_1_44_0\libs to the list - Considering that I should not miss out on any other libraries, I added C:\Program Files\Boost\Boost_1_44_0\bin.V2 to the list as well; this directory was constructed as a result of build by Bjam.exe - Following that, I quickly followed the 2 tutorials on Boost site 1 for simple iostream (which worked after some adjustments) and the other for regex (which did not work). - Considering I might still have missed something, I went on to add the path C:\Program Files\Boost\Boost_1_44_0 to System variables and made changes to VC IDE accordingly. - Also, to mention, I did not find any simple way to build the libraries that need a separate build and neither did I found any simple tutorial on Boost site...where they have put the regex sample that extracts matched text from a paragraph So my questions: - I want to know if I have missed anything to build any of Boost libraries or link to VC IDE or else? - Is there a better way to make sure if all the variants of all the libraries are build and linked with VC? - Is there a way to do this with CMake? - I read that, some libraries have some dependencies like libz...etc. where can I get the list for all Boost libraries? - Although this Question is not related to Boost, on a lighter note, I would just want ask this. Please ignore this if it does not hold ground. I have installed Boost after I installed Visual Assist for Visual Studio. Hence, whereever I use Boost members and classes, it keeps on saying that refactoring data is not available. Hence, I presume that, if I uninstall and reinstall Visual Assist, it should help? Or in other words, is there a better way to refactor boost library code so that intellisense can pick that? I will continue searching for this and hope that there is an option in Visual Assist itself. Nonetheless, it is not as important as Boost build related questions. Hope to hear from you soon... Thanks and Regards, Bhushan.

4 3

preprocessing error
by Arnaud GELAS 24 Aug '10

24 Aug '10

Hi all, When compiling some code using boost, I get the following error: /usr/include/boost/type_traits/type_with_alignment.hpp:142: error: Not a valid preprocessing token ")BOOST_PP_LIST_FOLD_LEFT_CHECK_BOOST_PP_IIF" For more details, I posted the log here: http://gofigure2.sourceforge.net/temp/boost-error.txt Any idea what I could do wrong? My machine is a Fedora 13 (64 bits), the installed version of boost is 1.41.0, and I used gcc 4.4.4... Thanks in advance, Arnaud

1 0

Boost.Format
by John Dlugosz 24 Aug '10

24 Aug '10

I'm using Boost.Format as a simple way to create strings to pass to exception constructors and primitive logging output during debugging (Windows' OutputDebugString). I see that the format object can be inserted into a stream, easily. But, with arguments, it's awkward to convert it to a string -- you need extra parens around the whole thing. Is there some good reason why there is no implicit conversion to string? E.g. string message= boost.format("blah") % argument % errorcode; OutputDebugStringA (message.c_str()); throw std::runtime_error (message); Or, is there some simple way that I'm missing? Thanks, --John TradeStation Group, Inc. is a publicly-traded holding company (NASDAQ GS: TRAD) of three operating subsidiaries, TradeStation Securities, Inc. (Member NYSE, FINRA, SIPC and NFA), TradeStation Technologies, Inc., a trading software and subscription company, and TradeStation Europe Limited, a United Kingdom, FSA-authorized introducing brokerage firm. None of these companies provides trading or investment advice, recommendations or endorsements of any kind. The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from any computer.

1 0

building all libs
by Kraus Philipp 24 Aug '10

24 Aug '10

Hi, I use boost with thread, iostreams and random. I compiled bjam first and uses them to compile all, but I must call every lib manual with ./bjam variant=release toolset=darwin threading=multi variant=release libs/iostreams/build How can I build the full boost with all libs in one run? Thanks Phil

4 4

cstdint.hpp causes warnings on VC10
by Michael Kaes 24 Aug '10

24 Aug '10

HI all, after switching to VC10 I recognized that including the cstdint.hpp header causes a warning. After looking into this header I saw that all defines like INT8_C are guarded to prevent multiple defines, except of the UINT8_C define (cstdint.hpp Line:400). Is this done on purpose because to me it looks as if the guard was just forgotten. Regards, Michael

2 1

[accumulators] chaining accumulator outputs
by Allen Chuang 24 Aug '10

24 Aug '10

Is there a way to chain the output of an accumulator and use it as the input of another accumulator? The sort of case I am thinking about is for example calculating the max of a rolling_mean. One obvious way to do this is to write a new rolling_mean_max accumulator and make it depend on rolling_mean, but the inner logic would be 99% duplicate of max. I was wondering if there was a way to do this without so much code duplication. -- GRATIS für alle GMX-Mitglieder: Die maxdome Movie-FLAT! Jetzt freischalten unter http://portal.gmx.net/de/go/maxdome01

1 0

number cores / cpu
by Kraus Philipp 24 Aug '10

24 Aug '10

Hello, can I determine how many physical cpu and cores are installed in a system with the boost lib? Under *nix I would read /proc but I would like to do that with boost, because of "os-less". Thanks Phil

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boost::asio SSL connection thru proxy server
by Kumar, Akhilesh 24 Aug '10

24 Aug '10

Hi, I am writing a boost socket client using boost::asio to do secure HTTP (HTTPS) communication. I Implemented my client based on the code sample based on (http://www.boost.org/doc/libs/1_39_0/doc/html/boost_asio/example/ssl/client…) with little changes as I am using sync socket. My client woks fine, when I am connecting to server directly, but I am not sure what changes I need to make when my communication going thru proxy. The unsecure connection(HTTP) work fine thru proxy, and here is what I do for unsecure connection, 1. Initialize boost socket(IO service and other stuff). 2. Resolve and Connect to Proxy server. 3. Start writing to actual server(HTTP send request). 4. Start uploading/downloading. 5. Close Socket. But I can't use this above procedure for (SSL) secure connection as I need to do handshaking with the server before I can write anything if my understanding is correct. Can somebody give me some pointer or code sample or step I need to do when I am doing secure connection thru proxy server. Just to clarify Microsoft WinInet does do (secure) HTTPS connection thru same proxy fine. If providing my code sample I am using for SSL might help understand the problem I can provide that. Thanks in advance for any help. Akhilesh Kumar

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Using boost::bind with stl algorithms
by przemyslaw.sliwa＠uk.bnpparibas.com 24 Aug '10

24 Aug '10

Hello, I have the following question. I have two containers std::set<std::string> insertedEvents; std::vector<std::string> eventNames; How I would like to copy all those elements from eventNames which are not in insertedEvents. Can this can be done somehow using the boost::bind feature? I am doing it at the moment using a silly loop: for(size_t i=0; i<eventNames.size(); i++) { if (m_insertedEvents.find(eventNames[i])==m_insertedEvents.end()) eventNamesDegraded.push_back(eventNames[i]); } Thanks for any kind of help, Pshemek ___________________________________________________________ This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error) please notify the sender immediately and delete this e-mail. Any unauthorised copying, disclosure or distribution of the material in this e-mail is prohibited. Please refer to http://www.bnpparibas.co.uk/en/information/legal_information.asp?Code=ECAS-… for additional disclosures.

4 4

bug in asio?
by Hei Chan 23 Aug '10

23 Aug '10

Hi, I am using a 3rd party library that uses boost::asio. The 3rd party library will call asyn_receive() with a callback handler, then when boost::asio::detail:: receive_op::do_complete() calls the callback handler, the handler consumes the message, calls asyn_receive() and then if there is no more message, it (the thread) waits for a condition -- the callback handler gets called again. The problem now is that once there is no more message, the thread enters the wait condition, and it never gets waken up again. Is it incorrect to enter the wait condition in the same thread that calls boost::asio::detail:: receive_op::do_complete()? Thanks in advance. Cheers, Hei

1 0

Getting started with Boost.Test
by Otto 23 Aug '10

23 Aug '10

Hi, I'm very new to C++ and Boost. I want to make a simple desktop application (a game editor, basically read/write a binary file) using QtCreator. Right now I'm only interested in Boost.Test for the unit tests. I tried to install using the instructions in "Getting started" but wasn't able to, probably because of bad english and lack of C++ knowledge. I unpacked Boost to /home/otto/boost_1_44_0/ >From there, I ran: $ mkdir dist $ ./bootstrap.sh --prefix=/home/otto/boost_1_44_0/dist --show-libraries --with-libraries=test $ ./bjam install It seems that config had no effect as it built everything (instead of just test) and to bin.v2/. A few "cp: cannot create regular file `/usr/local/lib/libboost_wave.a': Permission denied" errors too. What went wrong? Now I have bin.v2/libs/test/build/gcc-4.4.4/release with directories link-static and threading-multi. I also would like to configure it for usage with QtCreator. Thanks

3 5

Best method for making synchronous call from async handler
by David Daeschler 23 Aug '10

23 Aug '10

Good evening, Currently I have an application running on boost asio working very well. To simplify the heck out of it, it takes requests via tcp and passes back binary information stored on disk. However, I now need to add an extra step to processing. If the data is not available on the local disk, the server needs to contact one or more peer servers it knows about, send a query to each one via UDP asking if it has the data, and then use an existing TCP connection to that server to retrieve the asset. This step must be completed before any more processing can be done for the current client even though the client may be sending even more requests while we process. My question is, what is the best method for me to achieve the goal? Should I set up another io_service for the UDP query step along with retrieving the data from the other server? Is there a good wait to wait on that io_service to complete? Also in the case that one of the servers has gone away, can I use a deadline timer to cancel the UDP recvfrom if I don't get a response in time from one or more servers? I should also probably keep this second io_service alive throughout the lifetime of the application? Thank you in advance for advice on tackling this problem the right way with asio. -- David Daeschler

2 2

mpl::fold problems
by sergey kostanbaev 23 Aug '10

23 Aug '10

Hello everybody! I'm a newbie in boost and I've got some problems with boost::mpl #include <boost/mpl/vector.hpp> #include <boost/mpl/fold.hpp> #include <boost/mpl/arithmetic.hpp> template <class T, unsigned space=1> struct tr_field2 { static const unsigned count = space; } typedef boost::mpl::vector4< tr_field2<int, 4>, tr_field2<int, 7>, tr_field2<char, 1>, tr_field2<char, 1> > Test_description; I want to calculate a sum of all tr_field2::count I've read in the docs mpl::fold is for the case. I tried to compose typedef boost::mpl::fold<Test_description, boost::mpl::int_<0>, boost::mpl::plus<boost::mpl::_, boost::mpl::_::count > > >::type fcount; but it won't compile. It seems I misundestood something.

2 2

[BGL] Change order of edge iterator
by John Robertson 23 Aug '10

23 Aug '10

I want to be able to iterate through the edges in any given order, not just the order specified by tie(edge_iter, edges_end) = edges(g);. Is it possible to do something like the following. typename graph_traits<Graph>::edge_iterator edge_iter1, edges_end1, edge_iter2, edges_end2, edge_iter3, edges_end3; tie(edge_iter1, edges_end1) = edges(g); sort(edge_iter1, edges_end1, ordering_1()); tie(edge_iter2, edges_end2) = edges(g); sort(edge_iter2, edges_end2, ordering_2()); tie(edge_iter3, edges_end3) = edges(g); sort(edge_iter3, edges_end3, ordering_3()); (ordering_x() specified by some struct) Then I would have 3 different orderings of the edges available. Would this work or should I use an iterator adapter, or create a map and (if its possible) obtain an iterator from the mapping, or something else. Thanks

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