July 2008 - Boost-users - lists.boost.org

[asio] Copying an asio::stream_buf question
by Graham Reitz 21 Jul '08

21 Jul '08

Is this a reasonable method to copy the contents of one asio::streambuf into another (i.e. in a copy constructor of a class that contains an asio::streambuf)? istreambuf_iterator<char> i( ostream_1.rdbuf() ); istreambuf_iterator<char> eos; // end-of-stream ostreambuf_iterator<char> o( ostream_2.rdbuf() ); std::copy( i, eos, o ); thanks, graham

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[format] error when used with DEBUG_NEW in VC7.1 MFC
by hongleij 21 Jul '08

21 Jul '08

when i comment these codes ,it will be OK. #ifdef _DEBUG #define new DEBUG_NEW #undef THIS_FILE static char THIS_FILE[] = __FILE__; #endif ////////////////////souce code #include <iostream> #include <tchar.h> #define WIN32_LEAN_AND_MEAN // #pragma warning(disable:4200) // nonstandard extension used : zero-sized array in struct/union #pragma warning(disable:4244) // 'conversion' conversion from 'type1' to 'type2', possible loss of data #pragma warning(disable:4800) // 'type' : forcing value to bool 'true' or 'false' (performance warning) // Windows Header Files: #ifndef WINVER #define WINVER 0x0400 // 0x0400 == Windows 98 and Windows NT 4.0 (because of '_WIN32_WINDOWS=0x0410') #endif #ifndef _WIN32_WINNT #define _WIN32_WINNT 0x0400 // 0x0400 == Windows NT 4.0 #endif #ifndef _WIN32_WINDOWS #define _WIN32_WINDOWS 0x0410 // 0x0410 == Windows 98 #endif #ifndef _WIN32_IE #define _WIN32_IE 0x0400 // 0x0400 == Internet Explorer 4.0 -> Comctl32.dll v4.71 #endif #define _ATL_CSTRING_EXPLICIT_CONSTRUCTORS #define _AFX_ALL_WARNINGS #include <afxwin.h> #include <afxext.h> #include <afxdisp.h> //#include <afxdtctl.h> #ifndef _AFX_NO_AFXCMN_SUPPORT #include <afxcmn.h> #endif // _AFX_NO_AFXCMN_SUPPORT #include <winsock2.h> #define _WINSOCKAPI_ #include <afxsock.h> #include <afxdhtml.h> #include <afxmt.h> #ifdef _DEBUG #define new DEBUG_NEW #undef THIS_FILE static char THIS_FILE[] = __FILE__; #endif #include <boost/format.hpp> void ipAddressToString(const unsigned int ip, std::string &str) { //char temp[64]; //_snprintf(temp,sizeof(temp),"%ld.%ld.%ld.%ld", // ((ip >> 24) & 0xFF), // ((ip >> 16) & 0xFF), // ((ip >> 8) & 0xFF), // ((ip ) & 0xFF) ); //str = temp; str = boost::str( boost::format("%ld.%ld.%ld.%ld") % ((ip >> 24) & 0xFF) % ((ip >> 16) & 0xFF) % ((ip >> 8) & 0xFF) % ((ip ) & 0xFF) ); } class A {}; int _tmain(int argc, _TCHAR* argv[]) { std::string str; ipAddressToString(0xf1c2d3e4,str); int *p = new int(32); // A *q = new(p)(A); return 0; } ////////////////////////errors e:\boost_1_35_0\boost\optional\optional.hpp(315) : error C2061: syntax error : identifier 'm_storage' e:\boost_1_35_0\boost\optional\optional.hpp(314) : while compiling class-template member function 'void boost::optional_detail::optional_base<T>::construct(boost::optional_detail::optional_base<T>::argument_type)' with [ T=boost::io::detail::locale_t ] e:\boost_1_35_0\boost\optional\optional.hpp(455) : see reference to class template instantiation 'boost::optional_detail::optional_base<T>' being compiled with [ T=boost::io::detail::locale_t ] e:\boost_1_35_0\boost\format\internals.hpp(56) : see reference to class template instantiation 'boost::optional<T>' being compiled with [ T=boost::io::detail::locale_t ] e:\boost_1_35_0\boost\format\internals.hpp(57) : see reference to class template instantiation 'boost::io::detail::stream_format_state<Ch,Tr>' being compiled Build log was saved at "file://c:\Documents and Settings\jiang\桌面\Voip\kademlia\Debug\BuildLog.htm" Kad - 1 error(s), 1 warning(s)

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Spirit: skip parser and rules
by Alessandro Re 21 Jul '08

21 Jul '08

Hello, I've this code: // w and space_signaler are a function objects which print out some info. bool read_str(const char *in, StrList &w) { rule<> identifier = +alnum_p; rule<> statement = identifier[w] >> ch_p(';')[w]; return parse( in, (statement)[w], space_p[space_signaler] // Called for initial spaces only ).full; } Well, I don't understand why if i use (statement)[w] where signaled, the space_signaler is never called for non-initial spaces, while if i write directly the rule, it does correctly: return parse( in, (identifier[w] >> ch_p(';')[w])[w], space_p[space_signaler] // Called for every space ).full; In the latter case, it parses (skipping spaces) inputs like: "hello;" "hello ;" " hello ; " while in the former it parses correctly inputs like " hello;" "hello;" disallowing spaces between the word and the semicolon. Can someone explain me why does this happens? Thanks very much

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question on boost-compliant code conventions
by Ákos Maróy 21 Jul '08

21 Jul '08

Hi, This is probably a lame question, but I have some open issues I don't know how are handled in contemporary C++ style, for example with using boost coding convetions. I've been using the CamelCase naming convention from Java recently, where the issues below are non-issues actually. for example: - how do I create an instance of the same name as its type? in CamelCase: class Foo; Foo foo; in C++: class foo; foo foo; // won't compile what's the solution here? add some prefix to the instance's name? - how do I declare accessor functions to private members? in Java / CamelCase: class Foo { private int bar; public int getBar() { return bar; } }; in C++: class foo { private: int bar; public: int bar() const { return bar; } // won't compile }; should I put some prefix to the private member's name? Sorry for the lame questions :) But I just want to follow the guideline of 'in Rome, do as the Romans do' :) Akos

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[spirit] reading vector of string
by Christian Henning 21 Jul '08

21 Jul '08

Hi there, can I use push_back_a with std::vector<std::string>? I want something like this: std::vector< std::string > lines; rule<> l_entry = blanks_p >> *print_p[push_back_a( lines )] >> blanks_p >> eol_p; Regards, Christian

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Fusion transform question
by Joel FALCOU 21 Jul '08

21 Jul '08

I started porting over some old codes that used hand-made MPL<->concrete object code to Fusion. I'm currently trying to have the following to work with no results so far : struct make_arg { template<class Type> struct result { typedef typename boost::add_reference<typename boost::add_const<Type>::type >::type type; }; }; template<class Args> struct tree { typedef Args children; typedef typename bf::result_of::transform<Args,make_arg>::type contents; template<class T0,class T1> tree( const T0& t0 , const T1& t1 ) : mArgs( /* what to put here ??? */ ) {} template<size_t I> typename bf::result_of::at_c<contents,I>::type get() const { return bf::at_c<I>(mArgs); } contents mArgs; }; int main() { int k=3; float u=7.2; tree< bf::vector<int, float> > tree(k,u); return 0; } The question - as stated - in the code is how to simply build the mArgs member from the t0,...,tn arguments ? Thanks in advance. -- Joel FALCOU Research Engineer @ Institut d'Electronique Fondamentale Université PARIS SUD XI France

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[Boost.thread] Interruption points ?
by Ruediger Berlich 21 Jul '08

21 Jul '08

Hi there, just a short question: http://www.boost.org/doc/libs/1_35_0/doc/html/thread/thread_management.html… lists the following interruption points: * boost::thread::join() * boost::thread::timed_join() * boost::condition_variable::wait() * boost::condition_variable::timed_wait() * boost::condition_variable_any::wait() * boost::condition_variable_any::timed_wait() * boost::thread::sleep() * boost::this_thread::sleep() * boost::this_thread::interruption_point() Is (and if so: why is) a lock on a mutex no interruption point ? Thanks and Best Regards, Ruediger

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Re: [Boost-users] [fusion] sequence conversion
by Zeljko Vrba 20 Jul '08

20 Jul '08

On Sun, Jul 20, 2008 at 07:34:29PM -0400, Daryle Walker wrote: > > I'm not really into the whole MPL scene myself, but I'll give you > examples where I used it. > Thanks for the long explanation.

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[dataflow] new frameworks and GUI editors + visually edit a BGL graph
by Stjepan Rajko 20 Jul '08

20 Jul '08

Hello, I uploaded some youtube videos of a new visual editor for the Dataflow library. There are three examples, each using a different underlying framework (the visual editor code is generic): visually editing a Dataflow.Signals network (data flows instantly): * http://www.youtube.com/watch?v=7a4HJ4zVPXc visually editing a Dataflow.Managed network (data flows on request): * http://www.youtube.com/watch?v=KwrnSjhJyf4 visually editing a BGL graph (this simple example lets you construct a directed graph and query the number of strongly connected components): * http://www.youtube.com/watch?v=gVLetAAnPrc The latter two examples use proof-of-concept implementations of alternate frameworks built on top of the generic framework that is part of the Dataflow library: Dataflow.Managed is unlike Dataflow.Signals in that doesn't couple data transfer with component invocation. In other words, if producer A is connected to consumer B, when A changes its value B will not be notified immediately. Instead, after any number of values in the network has changed, the network as a whole can be told to update (the network will then notify all components whose inputs have been modified, in the order of a topological sort of the components). Alternatively, components can be invoked individually, which gives them a chance to check their inputs / modify their outputs. The BGL support layer for the Dataflow library is an example of how something that is not strictly a dataflow thing (e.g., a graph) can still satisfy Dataflow concepts (there are Components (vertices) that can be connected), and be used with the framework (e.g., you get a GUI editor for free). If you're interested in playing with this: The new GUI uses GLV (http://mat.ucsb.edu/glv/) which is included with the dataflow library in the sandbox and integrated in the bjam build of the examples. As long as you have glut/freeglut available, it should build using gcc/darwin, MSVC8+, gcc/minGW, and if you are better than me at knowing which X libraries to link with and know how to manipulate a Jamfile, gcc/linux (any GCC version 4.x should work). If you run into any problems, please let me know. The latest code is currently available from the sandbox only, instructions/docs at: http://www.dancinghacker.com/code/dataflow/ Any feedback would be appreciated. Kind regards, Stjepan

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regular expressions and binary files
by Brad Tilley 20 Jul '08

20 Jul '08

I'm using boost regular expressions with good results on text files (html, xml, txt, etc), however, I'm having issues on binary file formats (i.e. MS Office files, etc). I've goggled around, but not found any hints. Just wondering if someone had experience doing REs on binary files. I've tried different open methods ios::binary, etc... still no luck. Thanks

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