May 2008 - Boost-users - lists.preview.boost.org

Re: [Boost-users] Problems using pre-compiled boost libraries
by Fanara, Mark A (GE Infra, Transportation) 30 May '08

30 May '08

I tried changing Configuration Properties->Linker->Manifest File->Generate Manifest setting to No. When executing the program, I get the following error message. Debug Error! Program: ... R6034 An application has made an attempt to load the C runtime library without using a manifest. This is an unsupported way to load Visual C++ DLLs. You need to modify your application to build with a manifest. For more information, see the "Visual C++ Libraries as Shared Side-by-Side Assemblies" topic in the product documentation.

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Precompiled Boost.Thread libs for Linux?
by CSB 30 May '08

30 May '08

I see references to pre-compiled Boost libs but I'm unable to find them. I'm interested in the latest Boost.Thread for Linux. Can someone tell me where to find this? Thanks.

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filesystem headers
by Christian Holmquist 30 May '08

30 May '08

Hi, I found the filesystem headers to be very confusion, the grouping of classes and functions into headers seems to have been chosen arbitrary. basic_recursive_directory_iterator in convenience.hpp? basic_directory_iterator in operations.hpp? shouldn't they use headers of their own, or at least use filesystem/iterator.hpp ? create_directories is in convenience.hpp, but create_directory in operations.hpp? the free function extension(path) is in convenience.hpp, although I think most users would expect it to be a member of the basic_path class instead. a rather highlevel (IMO) function copy_file is in operations.hpp, while others like change_extension is in convenience.hpp. what should I expect to find in convenience.hpp that is not in operations.hpp? basic_filesystem_error, which is an std::exception derived class is in path.hpp, shouldn't it go into exceptions.hpp? maybe someone could shed some light on how I should understand the api in order to include the correct header.. More about path.hpp.. I think the use of iterator_facade in path.hpp is unfair to users, since it pulls in so much of complicated headers (have a look at iterator_facade.hpp) only to ease the task of implementing that path::iterator. I think that iterator_facade is a great tool for users that quickly wants to design a working iterator, but in a header such as filesystem::path that -should- be used everywhere where a file reference is needed, it should be rather lightweight (instead we use std::string, because it compiles with reasonable speed. I think we are not alone on this choice). The inclusion of iosfwd only for stream operators is again not what I would prefer, better off putting that stuff in path_io.hpp is type_traits/is_same.hpp, throw_exception.hpp, static_assert.hpp used in path.hpp at all? Sorry for all the complains, I wouldn't write them unless I really, really wanted to use boost::filesystem. Finally there's a better way to do file and path operations in c++, but it's not practical in its current form. I've been trying with no success incorporating filesystem more in our very large code base, but compilation times and confusion about headers have made me redraw most of that code. Regards, Christian

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[Serialization] Serialization of a class in a DLL
by Cyril Picat 29 May '08

29 May '08

Hi everybody, I have just tried a simple example of a class serialization in a DLL and did not manage to make it work. I have been using Boost serialization since a while but until now I was putting all the serialization code in the .hpp. By the way thanks Robert (and Boost) for this great library. I am using MSVC 8.0 and Boost 1.34.1. I have tried the same with Boost Serialization 1.36 (head of Boost) without any success. My test is the following. The class MyClass in declared in a DLL boost-example.dll built from Example.cpp. A test program Example.t.cpp linked with boost-example.dll try to serialize MyClass to an XML archive. The files are the following: //////// Example.hpp #if _MSC_VER > 1000 #pragma once #endif // Do NOT include any headers after this point #if (defined(__COMPILING_Example_CPP__) && defined(WIN32)) #define _LIBSPEC __declspec(dllexport) #else #define _LIBSPEC #endif class _LIBSPEC MyClass { public: MyClass(); private: friend class boost::serialization::access; template <class Archive> void serialize(Archive & ar, const unsigned int version); std::string m_str; }; //////// Example.cpp #include <string> #include "boost/archive/xml_oarchive.hpp" #include "boost/archive/xml_iarchive.hpp" #include "boost/serialization/nvp.hpp" #include "boost/serialization/export.hpp" #include "Example.hpp" using namespace std; BOOST_CLASS_EXPORT(MyClass); // should explicity instantiate template for // xml_oarchive and xml_iarchive MyClass::MyClass() : m_str("MyClass") {} template <class Archive> void MyClass::serialize(Archive & ar, const unsigned int version) { ar & BOOST_SERIALIZATION_NVP(m_str); } //////// Example.t.cpp #include <iostream> #include <fstream> #include "boost/archive/xml_oarchive.hpp" #include "boost/serialization/nvp.hpp" #include "Example.hpp" using namespace std; int main(int argc, char* argv[]) { MyClass myClass; // try to serialize MyClass using an XML archive ofstream ofs("myClass.xml"); if( !ofs ) { cout << "ERROR: Could not open myClass.xml for writing"; return EXIT_FAILURE; } try { boost::archive::xml_oarchive oa(ofs); oa << BOOST_SERIALIZATION_NVP(myClass); } catch (const std::exception& e) { cout << "failed to serialize MyClass with xml_oarchive: " << e.what(); ofs.setstate(ios::failbit); } return EXIT_SUCCESS; } When compiling this, I got an error at link time for Example.t: Example.t.obj : error LNK2019: unresolved external symbol "private: void __thisc all MyClass::serialize<class boost::archive::xml_oarchive>(class boost::archive: :xml_oarchive &,unsigned int)" (??$serialize@Vxml_oarchive@archive@boost@@@MyCla ss@@AAEXAAVxml_oarchive@archive@boost@@I@Z) referenced in function "public: stat ic void __cdecl boost::serialization::access::serialize<class boost::archive::xm l_oarchive,class MyClass>(class boost::archive::xml_oarchive &,class MyClass &,u nsigned int)" (??$serialize@Vxml_oarchive@archive@boost@@VMyClass@@@access@seria lization@boost@@SAXAAVxml_oarchive@archive@2@AAVMyClass@@I@Z) I have taken a look at boost-example.dll with Dependency Walker and there are quite a few symbols exported for MyClass and boost::archive::xml_oarchive. Any clue of what is going on? The strange thing is that I have another more complex example with an abstract class and derived classes in separate DLLs where I serialize to the base pointer and everything is compiling and working fine (both with 1.34.1 and HEAD). I have read the doc ('Exporting Class Serialization') and have seen in the logs that a lot have changed regarding export since 1.34.1. In what I have understood, the fix was concerning cases where the macro BOOST_CLASS_EXPORT() is used in the .hpp, leading to multiple registrations, and not in the .cpp as I am doing. Am I right? By the way, I have noticed a little typo in the doc concerning void_cast_register. In the doc the proposed syntax is 'boost::serialization::void_cast_register<derived, base>(static_cast<base *>(NULL), static_cast<derived *>(NULL))' although in my experience the correct syntax is: 'boost::serialization::void_cast_register<derived, base>(static_cast<derived*>(NULL),static_cast<base*>(NULL))' Thanks in advance, Cyril Picat

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Re: [Boost-users] Problems using pre-compiled boost libraries with Visual Studio 2005
by Igor R 29 May '08

29 May '08

> I am building a VC8.0 (Visual Studio 2005) application that is making > use of boost::program_options and boost::filesystem. My application > links fine, but when I try to execute the program, I get an error > message about a missing "MSVCP80D.dll" (or "MSVCP80.dll" when building > for release). I don't have those .dlls on my machine. MSVCPXX.dll is dynamically-linked STL. It's pretty strange that the standard VS installation didn't install it. > Next error message received is "This application has failed to start > because the application configuration is incorrect. Review the manifest > file for possible errors. Reinstalling the application may fix this > problem. For more details, please see the application event log." Well, you can just disable the manifest in your project properties (something like Properties-->Manifest-->generate manifest = No).

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Is there a limit for the number of threads created by thread_group.create_thread() ?
by Li, PingShan (Kansas City) 29 May '08

29 May '08

Here is what I learned for Linux. In Linux, a thread is the same as process. For redhat, the default stack size for a process is 10240k. this can be checked and changed by "ulimit " command. Setting different stack size will affect how many threads can be created for Linux.

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ASIO question
by Andrej van der Zee 29 May '08

29 May '08

Hi, I am thinking how to use ASIO for my specific situation. Well, I'll try to explain: I have a client that is connected to multiple remote daemons. Now the client can initiate alternating "start" and "stop" messages to it's daemons like this: * send a "start" message to all daemons * send a "stop" message to all the daemons * send a "start" message to all the daemons * send a "stop" message to all daemons etc I want to be able to have multiple threads sending a "start" or a "stop" to all connected daemons using boost::asio::async_write(). But this has to be in phases, so all threads handling a "start" should finish first before a "stop" can be initiated. I was wondering if this is solvable using ASIO and if so, hopefully somebody can point me in the right direction. Cheers, Andrej __________________________________________________________ Sent from Yahoo! Mail. A Smarter Email http://uk.docs.yahoo.com/nowyoucan.html

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what's up with the logging libraries?
by Jeff 29 May '08

29 May '08

Hello everyone, When will a logging library make it out of sandbox and into an official release? Can we expect to get a logging library in 1-36 ? Thanks!

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[Serialization][Archive] Namespace leakage problem
by Anders Sundman 29 May '08

29 May '08

Hi! The following code compiles fine with boost 1.34.1 (as it should) but fails to compile with 1.35.0 and the boost trunk (rev. 45896) #include "boost/archive/binary_iarchive.hpp" namespace detail { struct fu {}; } struct bar : detail::fu {}; Visual studio 2005 generates the following error message: 1>c:\dev\sandbox\using_scope_test\using_scope_test\test.cpp(7) : error C2872: 'detail' : ambiguous symbol 1> could be 'detail' 1> or 'boost::detail' It seems to me that the include file is some how leaking the boost namespace to it's surrounding? Explicitly qualifying the line: struct bar : ::detail::fu {}; works as expected. But I'm also allowed to write: struct bar : boost::detail::fu {}; which gives the error "'fu' : is not a member of 'boost::detail'" and not the expected "'boost' : is not a class or namespace name". Is this a known problem, and if so is there also a known patch? Best Regards, Anders Sundman

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[MPI] Serializing C++ objects for transmission using Python MPI module
by Adam Stephens 29 May '08

29 May '08

I'd like to write a class in C++, then use a tool like SWIG (or Boost.Python, if absolutely necessary) to make a shared library/Python module. Then, I want to write python code that uses the boost.mpi python module to pass messages containing instances of my C++ class. In other words, I want to do what's described here: "Boost.MPI also supports efficient serialization and transmission of C++ objects (that have been exposed to Python) through its C++ interface. Any C++ type that provides (de-)serialization routines that meet the requirements of the Boost.Serialization library is eligible for this optimization, but the type must be registered in advance. To register a C++ type, invoke the C++ function register_serialized. If your C++ types come from other Python modules (they probably will!), those modules will need to link against the boost_mpi and boost_mpi_python libraries as described in the installation section. Note that you do not need to link against the Boost.MPI Python extension module." ( from http://www.boost.org/doc/libs/1_35_0/doc/html/mpi/python.html#mpi.python_us… ) I've looked at the documentation for the function register_serialized, but I am evidentally using it incorrectly, because I get compile time errors. My class looks like this: #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/mpi/python/serialize.hpp> class Testclass { private: static bool registered; int data; friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & data; } public: Testclass() { if(!registered) { registered = true; boost::mpi::python::register_serialized(*this); } } void set_data(const int & in) { data = in; } int get_data() { return data; } }; bool Testclass::registered = false; I might be so far out in left field that what I'm trying to accomplish here needs explanation. According to the only documentation I can find, register_serialized is defined this way: template<typename T> void register_serialized(const T & value = T(), PyTypeObject * type = 0); The parameters have this meaning: type: "The Python type associated with the C++ type T. If not provided, it will be computed from the same value value." value: "A sample value of the type T. This may be used to compute the Python type associated with the C++ type T" So, I'm trying to register my class by passing in the object pointed to by this. I figure I only need to register it once; hence the static member. When I try to compile this to an object file, I get this error: /share/home/00791/adam/boost/include/boost-1_35/boost/mpi/python/serialize.hpp(323): error: no operator "<<" matches these operands operand types are: boost::mpi::packed_oarchive << Testclass ar << value; ^ detected during: instantiation of "void boost::python::detail::direct_serialization_table<IArchiver, OArchiver>::default_saver<T>::operator()(OArchiver &, const boost::python::api::object &, unsigned int) [with IArchiver=boost::mpi::packed_iarchive, OArchiver=boost::mpi::packed_oarchive, T=Testclass]" at line 158 of "/share/home/00791/adam/boost/include/boost-1_35/boost/function/function_template.hpp" Followed by several lines of similar messages, which I can attach if anyone needs to see them. There's one final wrinkle.. I've been trying to build boost for the past few days, and I kept getting a very simliar compile error at the same point. One of the authors of Boost.MPI took a look at it and submitted this change, which I made manually on my system: http://svn.boost.org/trac/boost/changeset/45825 Only after that change was I able to build Boost. Thanks

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