August 2009 - Boost-users - lists.preview.boost.org

[unit_test_framework] checkpoints for BOOST_CHECK*?
by rozelak＠volny.cz 28 Aug '09

28 Aug '09

Hallo, I need to write an unit test checking several various inputs. As there may be larger number of the inputs, I thought about a loop. The problem is how to know the input for which the test failed (if it failed). I wanted to write something like this: .... BOOST_AUTO_TEST_CASE(....) { // each tested_variant may be quite complicated structure for (tested_variants::iterator i) { BOOST_TEST_CHECKPOINT("variant:" << i); // not usable for what I need :-( BOOST_CHECK_EQUAL(i.expected, tested_method(i.data)); } } .... However, BOOST_TEST_CHECKPOINT() does not work in this situation (well, according to the documentation it works for exceptions only). Is there a way how to achieve what I am looking for? Thank you very much, Dan T.

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Copy of a C++ object extended with Boost.Python
by 4ian 28 Aug '09

28 Aug '09

I have a simple C++ object, exposed to python with Boost.python, like this : ------------------------------------------------- BOOST_PYTHON_MODULE(MyModule) { class_<MyObject>("MyObject")... } ------------------------------------------------- I call then python, making an instance of MyObject accessible : ------------------------------------------------- MyObject anInstance; object main_module((handle<>( borrowed( PyImport_AddModule ( "__main__" ) ) ) ) ); object main_namespace = main_module.attr( "__dict__" ); object myModule( (handle<>(PyImport_ImportModule("MyModule"))) ); main_namespace["anInstance"] = ptr(&anInstance); try { handle<> ignored(( PyRun_String( "anInstance.aNewMember = 1;print anInstance.aNewMember;", Py_file_input, main_namespace.ptr(), main_namespace.ptr() ) ) ); } catch ( error_already_set ) { PyErr_Print(); } ------------------------------------------------- You can observe that I've added a member ( aNewMember ) to MyObject instance. But if I make a copy of my object : ------------------------------------------------- MyObject anotherInstance = anInstance; main_namespace["anotherInstance"] = ptr(&anotherInstance); try { handle<> ignored(( PyRun_String( "print anotherInstance.aNewMember;", Py_file_input, main_namespace.ptr(), main_namespace.ptr() ) ) ); } catch ( error_already_set ) { PyErr_Print(); } ------------------------------------------------- I have a error saying that MyObject hasn't any "aNewMember" member. What I have added with python has not been copied/transfered. Is there a workaround to add permanently some new members to wrapped objects ?

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pathological regex?
by Michał Nowotka 28 Aug '09

28 Aug '09

Hello, I use boost regex v 1.37 on Ubuntu 9.04, g++-4.3. Because of performance issues i replaced defaut matching algorithm to BOOST_REGEX_RECURSIVE but then my program dont't work properly. So, is this expression pathological: (https?://)?([^/@]*[\\.@])?google.com[/\\?&#]* ? -- Regards Michał Nowotka

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Define a callback member function inside the object instance
by Daniele Barzotti 28 Aug '09

28 Aug '09

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, I would ask you a suggestion. In according with the FAQ (http://www.parashift.com/c++-faq-lite/pointers-to-members.html#faq-33.2) is better to not set a non-static member function like a callback. But If I need to pass that callback inside my object, I'm pretty sure that the object itself exist! So if I have a callback signature like this: int my_callback(void *outputBuffer, void *inputBuffer, unsigned int nFrames, double streamTime, int status, void *userData ) And I want to bind it to a member function: int MyObject::my_callback(....) Now, inside the object I have something like: MyObject::OneMethod() { p_AnotherObject->SetCallBack( ???? ); } How can I pass my MyObject::my_callback to SetCallBack using boost::function and/or boost::bind? Thanks! Daniele. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (MingW32) iD8DBQFKl65//l+kMioSZwgRAkA8AKCdk44mlTXESXQJUG7vzqVnUHFoXgCghGW5 Icf+E8uX8cLwwfkdnCFmoKs= =s1nk -----END PGP SIGNATURE-----

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Problem with serialization, load_wrapper
by Mikael Carlsson 28 Aug '09

28 Aug '09

Dear group, I am working with a observer pattern in a simulator and would like to restore the simulators state. This means that I need to restore the pointers to the observers in the subject. My simple example contains a composite that holds pointers to base class of the observers. The observable hold one of the observers using a base class pointer. The save part is OK but when I introduce restore I get compile time errors. Compiling (dbg) main.cpp obj/main.o /home/ecarmik/boost/include/boost-1_39/boost/archive/detail/iserializer.hpp: In function 'void boost::archive::load(Archive&, const T&) [with Archive = boost::archive::text_iarchive, T = composite]': /home/ecarmik/boost/include/boost-1_39/boost/archive/detail/common_iarchive.hpp:59: instantiated from 'void boost::archive::detail::common_iarchive<Archive>::load_override(T&, int) [with T = const composite, Archive = boost::archive::text_iarchive]' /home/ecarmik/boost/include/boost-1_39/boost/archive/basic_text_iarchive.hpp:62: instantiated from 'void boost::archive::basic_text_iarchive<Archive>::load_override(T&, int) [with T = const composite, Archive = boost::archive::text_iarchive]' /home/ecarmik/boost/include/boost-1_39/boost/archive/text_iarchive.hpp:65: instantiated from 'void boost::archive::text_iarchive_impl<Archive>::load_override(T&, int) [with T = const composite, Archive = boost::archive::text_iarchive]' /home/ecarmik/boost/include/boost-1_39/boost/archive/detail/interface_iarchive.hpp:61: instantiated from 'Archive& boost::archive::detail::interface_iarchive<Archive>::operator>>(T&) [with T = const composite, Archive = boost::archive::text_iarchive]' main.cpp:24: instantiated from here /home/ecarmik/boost/include/boost-1_39/boost/archive/detail/iserializer.hpp:560: error: no matching function for call to 'load_wrapper(boost::archive::text_iarchive&, const composite&, boost::serialization::is_wrapper<composite>)' make: *** [obj/main.o] Error 1 Is it possible to re-create objects during restore from file. Please note that composite class only contains base class pointers. Do I need to create a separate load to do this with constructors? Where can I read about this or even better, find an example? Please find the files included. / Mikael

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[asio] serial_port::async_read_some() and scalable buffers
by Robert Dailey 28 Aug '09

28 Aug '09

Hello, I have a std::vector of bytes that I am passing into boost::asio::buffer(). The vector originally is of size 0. Basically, I want the vector to be resized by asio depending on how much data is read in. I don't want to choose an arbitrary upper-limit for the buffer. Is this possible? Below is an example of what I am doing: std::vector<boost::uint8_t> stream; m_port.async_read_some( boost::asio::buffer( stream ), boost::bind( &SerialClient::ReadCompleted, this, stream, error, bytes_transferred ) ); However, the above code will never read any data because my vector is 0 and it expects it to have a size. --------- Robert Dailey

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Generically comparing structs
by Bill Buklis 28 Aug '09

28 Aug '09

Frequently I have to write comparison functions (usually of the "less" variety) that involve multiple keys or members of a struct. For example: struct s { A a; B b; C c; D d; // there may be other members not used in the comparison }; // operator< function or an equivalent function object bool operator<( const s& lhs, const s& rhs ) { if( lhs.a < rhs.a ) return(true); else if( lhs.a == rhs.a ) { if( lhs.b < rhs.b ) return(true); else if( lhs.b == rhs.b ) //and so on... } return(false); } This gets quite repetitive, especially if I have to write alternate sort orders (e.g. b,a,c,d or c,d,a,b) I'm thinking there has to an easier way to do this or a way to do a generic algorithm for this. Is there anything in boost that would help? I had an idea that one might be able to fill a vector with binders for each element and then call lexicographical_compare, but I'm not sure how to make it work.

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[iostreams] problems with operator<<
by Robert Dailey 28 Aug '09

28 Aug '09

Hello, I'm using the container_device class provided in the documentation. I'm creating my stream and device like so: typedef boost::iostreams::stream< container_device<std::vector<boost::uint8_t > > > ByteStream; ByteStream stream; stream << "Hello"; This compiles fine, however when I run this code I get an assertion deep inside of the << operator, which is in the std namespace. I thought that boost::iostreams would have its own global << and >> operators? I was expecting the << operator to directly call my device's write() method, but it doesn't. Perhaps I just don't understand how this works. I'm trying to write out binary data. The string should translate to a series of bytes in the container. The assertion I'm hitting is in optional.hpp in Boost. I'm using MSVC9 as my compiler: T& operator*() { assert(initialized_); return *static_cast<T*>(address()); } Above contains the code snippet where the assertion is happening. I have no idea what this assert means. Below is my callstack: > VFDTester.exe!boost::iostreams::detail::optional<boost::iostreams::detail::concept_adapter<container_device<std::vector<unsigned char,std::allocator<unsigned char> > > > >::operator*() Line 55 + 0x1f bytes C++ VFDTester.exe!boost::iostreams::detail::indirect_streambuf<container_device<std::vector<unsigned char,std::allocator<unsigned char> > >,std::char_traits<unsigned char>,std::allocator<unsigned char>,boost::iostreams::seekable>::obj() Line 104 + 0x19 bytes C++ VFDTester.exe!boost::iostreams::detail::indirect_streambuf<container_device<std::vector<unsigned char,std::allocator<unsigned char> > >,std::char_traits<unsigned char>,std::allocator<unsigned char>,boost::iostreams::seekable>::overflow(long c=72) Line 301 + 0x15 bytes C++ VFDTester.exe!std::basic_streambuf<unsigned char,std::char_traits<unsigned char> >::sputc(unsigned char _Ch='H') Line 163 + 0x4c bytes C++ VFDTester.exe!std::operator<<<unsigned char,std::char_traits<unsigned char> >(std::basic_ostream<unsigned char,std::char_traits<unsigned char> > & _Ostr={...}, const char * _Val=0x0074a7b0) Line 679 + 0x32 bytes C++ VFDTester.exe!MainFrame::OnConnectPressed(wxCommandEvent & event={...}) Line 82 + 0x36 bytes C++ --------- Robert Dailey

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[boost.function] conflict with tr1::function shipped with VC++10
by Tan, Tom (Shanghai) 28 Aug '09

28 Aug '09

Hi, I found a problem in using boost.function with VC++ 10, the code below reproduces the problem: #include <boost/function.hpp> #include <vector> typedef std::vector<int> test_type; template<class T> struct S { void test_g() { typedef S<T> this_class; boost::function<void (this_class*, test_type)> s(&this_class::g); } void g(test_type){} }; int main() { S<int> s; s.test_g(); } This code is OK with VC++ 2008, but with VC++ 2010, it yields the following message. Is there anything that I can do to solve the ambiguity? Thanks. C:\Boost\include\boost-1_39_0\boost/function/function_template.hpp(538) : error C2668: 'boost::mem_fn' : ambiguous call to overloaded function C:\Boost\include\boost-1_39_0\boost/bind/mem_fn_cc.hpp(25): could be 'bo ost::_mfi::mf1<R,T,A1> boost::mem_fn<void,S<int>,test_type>(R (__thiscall S<int> ::* )(A1))' with [ R=void, T=S<int>, A1=test_type ] C:\Program Files\Microsoft Visual Studio 10.0\VC\INCLUDE\xxmem_fn(32): o r 'std::tr1::_Mem_fn2<_Rx,_Pmf,_Arg0,_Arg1> std::tr1::mem_fn<void,S<T>,tes t_type>(_Rx (__thiscall S<T>::* )(_Arg1))' [found using argument-dependent looku p] with [ _Rx=void, _Pmf=void (__thiscall S<int>::* )(test_type), _Arg0=S<int>, _Arg1=test_type, T=int ] while trying to match the argument list '(void (__thiscall S<T>::* )(tes t_type))' with [ T=int ] .....

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using embedded stringstream on a single line.
by Avi Bahra 27 Aug '09

27 Aug '09

Is there anything in boost/design pattern that can help with following: std::stringstream ss; ss << "SUBMIT: Task(" << absPath << ") "; log( Log::DBG, ss ); The code I am working on does this all over the place, what I would like is : log( Log::DBG, "SUBMIT: Task(" << absPath << ") " ); Best regards, Ta, Avi

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