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[Serialization] Can I load two object from one input file?
by sjdf 02 Jan '08

02 Jan '08

Hi all, Code like this: // Save std::ofstream ofs( "c.out" ); A testA1; B testB1; testA1.Save( ofs ); testB1.Save( ofs ); ofs.close(); // Load std::ifstream ifs( "c.out" ); A testA11; B testB11; testA11.Load( ifs ); testB11.Load( ifs ); The testA1 and testB1 can save successful, and the testA11 can load successful, but when loading testB11, it throw a exception "invalid_signature". I have trace into the code, I found when the testA11 loading, the "file_signature" is "serialization::archive", but when testB11 loading, the "file_signature" is empty. Why it like this? What should I do? May be there is the same question before I ask, but I don't know what keyword could be search, sorry. Thanks!

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[Serialization] Is there anybody has experience in writting DBArchive?
by sjdf 02 Jan '08

02 Jan '08

Hi all, I'm working on a project, it consists of 2 parts: application & framework. The application uses the interfaces of the framework which based on a OODB. Now, my task is to replace the OODB with a relational database. So, I have to do the serialization of the object by myself. I don't know how to design the DBArchive, since I don't know how to deal with the inheritance relation and reference relation between the objects. The DBAchive is different from the TextArchive, the letter is a stream, but the former's storage unit is a record that consists of the object's data members and the field name in the database table. If the recursive model of the boost serialization can process this case? Could you give me any suggestions? Thanks a lot! sjdf

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Problems building 1.34 with Intel toolset on Win32
by Lipik Contact 02 Jan '08

02 Jan '08

Hi, I am trying to build 1.34 with Intel compiler (have tried with 9.0 as well as 10.1 - same results). bjam appears to skip building the library linked to debug runtime (libboost*-*gd*.lib), and autolink looks for these libraries when linking projects that use boost. I see the same problem with 9.0 as well. I added the icl.exe path to my user-config.jam, as suggested in an earlierpost on this list. I also got the 1.35 dev version from CVS, and it also has the same problem. Any help would be greatly appreciated. My bjam command-line is: bjam --v2 -a toolset=intel-10.1 variant=debug link=static --build-dir=C:\Exp\build-boost --without-graph --without-wave --without-serialization --without-python -sICU_PATH=C:\DevLibraries\icu stage On a related note, bjam seems to ignore compiler flags passed in the command line.i.e., I try to build the release as: .\bjam --v2 -a toolset=intel-10.1 variant=release link=static cxxflags=-QxO --build-dir=C:\Exp\build-boost --without-graph --without-wave --without-serialization --without-python -sICU_PATH=C:\DevLibraries\icu stage but /QxO compiler option is never enabled when compiling. Thanks Amit

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VS2005 with boost and /CLR
by Jason McGuidwin 02 Jan '08

02 Jan '08

I want to use the boost libraries with VS2005 and CLR option. how did you do this? how do you do this? I can get it to work without clr but I need to use managed and unmanaged code.

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Port QT call to BOOST
by j.c. 01 Jan '08

01 Jan '08

Hi, I am looking to port a single call of QT code: connect(m_task, SIGNAL(finished(task *)), this, SLOT(on_finished(task *))); I am not that familiar with QT, SLOTS or SIGNALS, but what I believe this to be doing is binding the SIGNAL function finished() from class "task" to my other "class" so that it will fire on_finished(). If anyone can give me some insight on how to boostify this, that would be great, as I have not touched that area just yet. Thanks, j

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boost::thread passing reference of the data object to thread func does not work
by Xiaofan Li 31 Dec '07

31 Dec '07

Hi, Sorry to disturb the list but I've been stuck with this problem for a while. The idea is to pass the reference of some data object to the thread function, in which the data object (by which the ref is passed in) will be modified. However I have found that this would not work at run-time, as the program compiled, ran but the modifying code silently failed to execute. I've written a small sample, which is self-contained and compilable: // // File: thread_test.cc // Author: xli // // Created on December 26, 2007, 12:26 AM // #include <boost/thread/thread.hpp> #include <boost/bind.hpp> #include <iostream> #include <vector> using namespace std; int s_count = 0; boost::mutex mutex; struct some_data_t { some_data_t() : m_int(0) {} int m_int; vector<int> m_vec; }; class threaded { public: void increment_count( some_data_t& data ) { boost::mutex::scoped_lock lock(mutex); std::cout << "count = " << ++s_count << std::endl; data.m_int += s_count; data.m_vec.push_back(s_count); } }; some_data_t a; int main(int argc, char* argv[]) { threaded _thrd; boost::thread_group threads; for (int i = 0; i < 10; ++i) threads.create_thread( boost::bind( boost::mem_fn( &threaded::increment_count ), &_thrd, a ) ); threads.join_all(); cout <<"All done. " <<a.m_int <<" " <<a.m_vec.size() <<endl; } ----------------- The output (g++4.3/linux) is count = 1 count = 2 ... count = 10 All done. 0 0 However I am expecting the last line as "All done. 55 10" as indicated in increment_count(). I have no idea why the "some_data_t a" did not undergo any change even increment_count() had clearly been called 10 times. I also wish to note that the way I make a member func version of increment_count() is purely for testing and changing it back to a global/static function will not alter the un-designated behaviour I've got. Any opinions on this are more than welcome. Regards, Xiaofan -- Xiaofan Li

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boost::shared_ptr question
by Michael Bradley Jr 31 Dec '07

31 Dec '07

Hi, i do have the following situation 3 independent classes A, B and C with the following requirements: 1. class A { private: A(int); ~A(); class deleter_t{ public: void operator()(A* p) { delete p; } }; friend class deleter_t; public: shared_ptr<A> create(int i) { return boost::shared_ptr<A>(new A(i),deleter_t()); } }; class B { boost::shared<A> obj_; }; class C { boost::shared_ptr<B> b_; boost::shared_ptr<A> a_; }; 2. Class C instantiates A and gets a boost::shared_ptr<A> through A::create Class B just need a boost::shared_ptr<A>. 3. C first release B and then A Now my question how can i achieve that goal, when A MUST obey to the singleton pattern? Thanks in advance for any help Cheers Michael

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Problem with boost::program_options
by Eswar K 31 Dec '07

31 Dec '07

Hi, I am a newbie to Boost. I am writing a sample code using the Boost libaries and am getting the following error during linking. *Command Line Usage * * **g++ -I /usr/include/boost/ example.cpp -o example.o* *Code* *#include <boost/lambda/lambda.hpp> #include <iostream> #include <iterator> #include <algorithm> #include <boost/program_options/options_description.hpp> #include <boost/program_options/positional_options.hpp> #include <boost/program_options/variables_map.hpp> #include <boost/program_options/parsers.hpp> #include <cstdlib> #include <iostream> #include <iomanip> #include <map> #include <string> using namespace boost::program_options; //namespace po = boost::program_options; int main() { using namespace boost::lambda; // using namespace boost::program_options; typedef std::istream_iterator<int> in; std::for_each( in(std::cin), in(), std::cout << (_1 * 3) << " " ); option_description opts; } * *Error Message* /tmp/ccO0HWa7.o(.text+0xb0): In function `main': example.cpp: undefined reference to `boost::program_options::option_description::option_description()' /tmp/ccO0HWa7.o(.text+0xbf):example.cpp: undefined reference to `boost::program_options::option_description::~option_description()' collect2: ld returned 1 exit status $LD_LIBRARY_PATH has the following value set. /home/suhas/boost/lib:/usr/lib:/usr/include/boost/ I am stuck, any help will be really appreciated. Thanks in advance. Regards, Eswar

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[review] Boost.Functional/Factory library result : accepted
by John Torjo 30 Dec '07

30 Dec '07

Hi all, The Boost.Functional/Factory library, submitted by Tobias Schwinger has been *accepted*. Thanks to all reviewers and to all who contributed before the review! We've received 3 reviews, all positive: Larry Evans, Stejan Rajko, and Detlef Wilkening*. *Suggested improvements * *Implementation *- Allocator should be inherited *Docs *- should include some hint about how to overcome the Lvalue constraint on the arguments that's mentioned in the docs: a0...aN - argument LValues to a constructor of T - separate the two templates (factory and value_factory) a little bit more in the introduction so that it reinforces that they are different in usage - better motivation - more detailed examples * note: I consider Detlef's review positive, even though he wanted 3 extensions (in light of Tobias's answer): - Better name for factory: factory_ptr or factory_pointer. - Better motivation for beginners in the docu. - Extension with a third template parameter for e.g. 2 phase construcion. Best, John -- http://John.Torjo.com -- C++ expert ... call me only if you want things done right

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Problame in "make"
by Suhas Majale 30 Dec '07

30 Dec '07

Hi, I am new to Boost C++, and want to install it to use Semantic Search engine. I am trying to run "make" but it gives me error when i run make. Please guid eme through this . I am using Cygwin,win XP. Following are the steps I performed. $ tar --bzip2 -xf /path/to/boost_1_34_1.tar.bz2 $ ./configure Building Boost.Jam with toolset gcc... tools/jam/src/bin.cygwinx86/bjam Detecting Python version... 2.5 Detecting Python root... /usr Unicode/ICU support for Boost.Regex?... not found. Backing up existing Boost.Build configuration in user-config.jam.4 Generating Boost.Build configuration in user-config.jam... Generating Makefile... $ make MAKE Version 2.0 Copyright (c) 1987, 1988 Borland International Error makefile 28: Command syntax error Available memory 547555 bytes *** 1 errors in compile *** The content of the Makefile is as follow: BJAM=./tools/jam/src/bin.cygwinx86/bjam BJAM_CONFIG= PREFIX=/usr/local EPREFIX=/usr/local LIBDIR=/usr/local/lib INCLUDEDIR=/usr/local/include LIBS= all: .dummy @echo "$(BJAM) $(BJAM_CONFIG) --user-config=user-config.jam $(LIBS)" @$(BJAM) $(BJAM_CONFIG) --user-config=user-config.jam $(LIBS) || \ echo "Not all Boost libraries built properly." clean: .dummy rm -rf bin.v2 distclean: clean rm -rf Makefile config.log check: .dummy @cd status && ../$(BJAM) $(BJAM_CONFIG) --user-config=../user-config.jam || echo "Some Boost regression tests failed. This is normal for many compilers." install: .dummy @echo "$(BJAM) $(BJAM_CONFIG) --user-config=user-config.jam--prefix=$(PREFIX) --exec-prefix=$(EPREFIX) --libdir=$(LIBDIR) --includedir=$(INCLUDEDIR) $(LIBS) install" @$(BJAM) $(BJAM_CONFIG) --user-config= user-config.jam --prefix=$(PREFIX) --exec-prefix=$(EPREFIX) --libdir=$(LIBDIR) --includedir=$(INCLUDEDIR) $(LIBS) install || echo "Not all Boost libraries built properly." .dummy: Regards, Suhas Majale

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