January 2011 - Boost-users - lists.preview.boost.org

[Proto] Anything Callable
by Hossein Haeri 14 Jan '11

14 Jan '11

Dear all, How can I have a grammar that matches a terminal of any callable type? Be it a function, function object, or a Boost.Function (specifically). TIA, --Hossein

3 6

[version] boost version check, header (.hpp) vs binaries (libs)
by alfC 14 Jan '11

14 Jan '11

Hi, I work in at least 3 computers (home/work/cluster, in which the cluster is really a shared filesystem between different architectures, etc). Besides that, for some projects I use the default version of boost in that system and in others a locally (user space) installed boost (that is, ranging from boost 1.33 to boost 1.46svn). Therefore is not uncommon that I mess the compilation lines and end up including headers from a certain version an linking to a different one. Hopefully this fails at link time: e.g. undefined reference to `boost::filesystem3::path::extension() const' but it is confusing and potentially it could compile (and then crash unexpectedly) I am aware of 'boost/version.hpp' but this is only for header verification. The question is, is there a Boost mechanism to verify that the header and the library in boost are consistent? (Hopefully at compile/link time) Thank you, Alfredo

2 1

Error '__Unwind_Resume' when trying to link codeblocks to boost::thread
by Bruno Ferraz do Amaral 14 Jan '11

14 Jan '11

Hi, I'm a new user of Boost Libraries, and I'd use multithreading linking the boost::thread class into my projetct. I'm using Code::Blocks, and I've built the Boost in Windows, and then I followed a wiki guide to link the libraries of the Boost.Thread with my Project in CodeBlocks. However I found this reference errors: C:\boost_1_45_0\stage\lib\libboost_thread-mgw45-mt-1_45.a(thread.o):thread.cpp:(.text+0x7d)||undefined reference to `__Unwind_Resume'| C:\boost_1_45_0\stage\lib\libboost_thread-mgw45-mt-1_45.a(thread.o):thread.cpp:(.text+0x66f)||undefined reference to `__Unwind_Resume'| C:\boost_1_45_0\stage\lib\libboost_thread-mgw45-mt-1_45.a(thread.o):thread.cpp:(.text+0x771)||undefined reference to `__Unwind_Resume'| C:\boost_1_45_0\stage\lib\libboost_thread-mgw45-mt-1_45.a(thread.o):thread.cpp:(.text+0xdbe)||undefined reference to `__Unwind_Resume'| C:\boost_1_45_0\stage\lib\libboost_thread-mgw45-mt-1_45.a(thread.o):thread.cpp:(.text+0xe53)||undefined reference to `__Unwind_Resume'| C:\boost_1_45_0\stage\lib\libboost_thread-mgw45-mt-1_45.a(thread.o):thread.cpp:(.eh_frame+0x12)||undefined reference to `___gxx_personality_v0'| ||=== Build finished: 6 errors, 0 warnings ===| What I have to do? I tried a lot of tutorials and guides in Google, but no one works...

4 5

[Serialization][Variant] serialization of variant containing boost::blank
by dariomt＠gmail.com 14 Jan '11

14 Jan '11

Hi, In the following code I show how a boost::variant that has a boost::blank cannot be serialized, and a proposed fix. I argue that this should work out of the box. This is with Boost 1.42.0. Am I doing something wrong here, or is serialization of boost::blank somewhere already? Thanks #include <boost/variant/variant.hpp> #include <boost/serialization/variant.hpp> #include <boost/archive/text_oarchive.hpp> #include <sstream> #ifdef FIX // suggested fix: non-intrusive serialize() for boost::blank namespace boost { namespace serialization { template<class Archive> void serialize(Archive &, boost::blank &, const unsigned int) { // Nothing to do here } } } #endif int main() { boost::variant<int, double> v1 = 666; boost::variant<boost::blank, int, double> v2 = 666; std::ostringstream os; boost::archive::text_oarchive oa(os); // works! oa << v1; // compile error about boost::blank not having a serialize method // #define FIX to compile oa << v2; return 0; }

1 0

ASIO: What is the proper way to upload a LARGE file?
by Ramon F Herrera 13 Jan '11

13 Jan '11

I have successfully been using this code to upload small stuff: try { // open tcp connection tcp::iostream net_stream(strSubmitServer, "12345"); // send file name net_stream << strFile << endl; // copy file char ch; while ((ch = fgetc(f)) != EOF) net_stream << ch; } catch (std::exception& e) { std::cout << "Exception: " << e.what() << std::endl; } Needless to say, the code above is extremely slow/inefficient for bulky transfers. Now I need to upload some large fails, and tried this: tcp::iostream net_stream(SERVER_ADDR, "12345"); // send file name net_stream << IN_FILE << "\n"; // send tags data size net_stream << count << "\n"; // copy tags data net_stream.write((char *)data, count); <<== app crashes here I figured that TCP would break the delivery into packets... TIA, -Ramon

3 2

Implications of using Boost with different versions of Visual Studio in the same computer?
by Ramon F Herrera 13 Jan '11

13 Jan '11

I have installed MSVS-2005 and MSVS-2010 in my development PC. I noticed that contrary to other libraries, every boost installation seems to be specific for: - The Boost version (duh!) - The MSVC Version For instance: libboost_system-vc80-mt-1_43.lib I would prefer to have all the -vc80- and -vc100- library files in the same folder, but perhaps I am looking for trouble? Then there is the issue of the includes. If such strategy turns out to be ill-advised, I would like to somehow "hide" my MSVS-2010 (don't want to uninstall it!) and then install Boost, built bye the VS-2005 toolchain. Thanks for your kind assistance. -RFH ps: Boost rules!! :-)

5 5

Serialization Boost 1.45
by Andrei Popa 13 Jan '11

13 Jan '11

Hi, I was building my project until recently with Boost 1.42. I have upgraded my Boost Version to 1.45. First of all, I see that now by default is used the dynamic linking to the Boost/Serialization. How can I set my code/project to link it statically to the Boost/Serialization? Second, I can not open my old files, I used only binary archives. I read about fix_six, but when I run it with my files I got the message "library version not equal to six"? How is this possible? How can I found out what "library version " do I have? What can I do to fix this problem? Thank you very much in advance! Andrei.

2 1

Boost 1.42 TR1 With GCC 4.5 selects wrong overload
by Abir Basak 13 Jan '11

13 Jan '11

I am using the portable style boost headers for tr1 implementation from Boost 1.42 such as #include <boost/tr1/type_traits.hpp> When i use gcc implementation of tr1 (Mingw GCC 4.5.1 from TDM, BOOST_HAS_GCC_TR1 defined) everything works fine. However when i select boost tr1 implementation (i.e not define the above macro) some stdlib functions such as std::abs gets wrong overloaded selected. For. e.g. in gcc/tr1 std::abs((signed char)5) returns an int while in boost/tr1 it returns a double. A compilable example is like #include <cstdlib> #include <iostream> #include <typeinfo> #include <boost/tr1/type_traits.hpp> int main(){ std::cout<<typeid(std::abs((short)5)).name(); //prints i with gcc/tr1 while prints d with boost/tr1 } it happens with type_traits header (may be few other also) but not with all tr1 headers(such as array). Thank you. abir basak

2 1

Boost 1.45 Serialization : Getting archive exception while loading
by Tejaswin Macharla 13 Jan '11

13 Jan '11

Hi, I have changed the sample code given in the Boost site for Serialization and the saving of the file works fine. The code works fine without the switch case as it executes save and load in the same session. I can save and load in the same session. If I close the application and open the application again and try to load the saved(serialized) file, it is throwing an Archive Exception. I am trying this for a game that I am working on so as to save and load in different sessions. Code: ----------------------------------------------------------------------- #include <fstream> // include headers that implement a archive in simple text format #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/archive/binary_iarchive.hpp> #include <boost/archive/binary_oarchive.hpp> ///////////////////////////////////////////////////////////// // gps coordinate // // illustrates serialization for a simple type // class gps_position { private: friend class boost::serialization::access; // When the class Archive corresponds to an output archive, the // & operator is defined similar to <<. Likewise, when the class Archive // is a type of input archive the & operator is defined similar to >>. template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & degrees; ar & minutes; ar & seconds; } int degrees; int minutes; float seconds; public: gps_position(){}; gps_position(int d, int m, float s) : degrees(d), minutes(m), seconds(s) {} void gps_display() { std::cout << "\n Displaying....\n"; std::cout << degrees << " "<< minutes << " "<< seconds<<std::endl; } }; int main() { // create and open a character archive for output std::ofstream ofs("filename"); // create class instance const gps_position g(35, 59, 24.567f); gps_position newg; char ch; std::cout << "Enter an option\n 1. Save\n 2. Load\n 3. Display\n\n"; std::cin >> ch; switch(ch) { case '1': { // save data to archive boost::archive::text_oarchive oa(ofs); // write class instance to archive oa << g; // archive and stream closed when destructors are called } break; case '2': { // ... some time later restore the class instance to its orginal state // create and open an archive for input std::ifstream ifs("filename", std::ios::binary); boost::archive::text_iarchive ia(ifs); // read class state from archive ia >> newg; // archive and stream closed when destructors are called } break; case '3': newg.gps_display(); break; default: std::cout << "\nInvalid option\n"; } return 0; } ----------------------------------------------------------------------- Can we load a serialized file from the same program in a different session? -- Thanks & Regards ------------------------------ Tejaswin G Macharla -----------------------------

2 2

Portability on XBox, PS3, and iPhone
by Hossein Haeri 12 Jan '11

12 Jan '11

Dear all, 10 years ago, it was crucially important to know whether the Boost stuff one was about to use was compatible with the targeted C++ compiler. The Boost documentation was quite informative on that IIRC. With the recent shifts of the industry, the equivalent and more update information needs to be on portability of each Boost library on the modern platforms. Is there any chance I can get some sort of comparative table on that? As the subject-line suggests, I am specifically interested in XBox, PS3, and iPhone. TIA, --Hossein

4 10