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[boost::log] how to format a record message
by Eric Prud'hommeaux 15 Aug '13

15 Aug '13

I have a project which has a handy stream filter in the formatter which indents newlines in logged messages to some depth à la: I/O [- 2 +] <loadedData> { <s> <p> <o> . <s> <p> <o2> . } </loadedData> (No, I'm not using an XML decorator above, though perhaps I should be.) I've maintained this for several generations of boost::log, e.g. #if (BOOST_VERSION > 104600) // could use (BOOST_LOG_COMPATIBILITY == "1.46") if cpp compared strings sink->set_formatter(&LineIndenter); #else backend->set_formatter(&LineIndenter); #endif but now that boost::log's released (1000s of thanks!!!), I'd like to switch to a channel_severity_filter. I had a custom formatter before in order to fiddle with the rec.message: inline void LineIndenter (std::ostream& strm, logging::record const& rec) { std::stringstream ss; oprfxnstream prfxstr(ss.rdbuf(), depth, ' '); ... stuff with attrs prfxstr << rec.message(); strm << ss.str(); } That member seems to be gone from logging::record and besides, it'd be nicer to use something like: boost::log::add_console_log (std::clog, boost::log::keywords::filter = min_severity || severity >= critical, boost::log::keywords::format = (boost::log::expressions::stream << line_id << ": <" << severity << "> [" << channel << "] " << lineIndenter(boost::log::expressions::smessage) ) ); I haven't figured out the signature for lineIndenter. I have the impression that I'm implementing a decorator like boost/log/expressions/formatters/c_decorator.hpp . So what's an easy way to wrap the attached stream filter (or a subclass constructed with some necessary constants) and pass it to a formatter? -- -ericP

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graph theoretical problem
by Peter Foelsche 15 Aug '13

15 Aug '13

Dear All, does the boost graph library provide a solution to the problem I'm trying to solve: I want to distribute a set of tasks to multiple CPUs/Threads. The tasks have predecessor and successor dependencies. There are no loops. More often than not, a task consists of only very few operations. So if I brute force program this, the resulting code is busy only with scheduling -- the real code does not show up in the profiling results. I think this can be solved by collapsing some tasks into a single task to minimize scheduling/communication. I've got a cost function associated with every task. Is this some well known algorithm which is already available in boost graph? Kind Regards Peter Foelsche

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[bgl] adding nodes recursively
by Littlefield, Tyler 14 Aug '13

14 Aug '13

Hello all: I have a game with multiple rooms, which I would like to map to a graph. Given this, I have a couple of questions. One of my goals is to separate each individual area and have it on it's own graph, then connect the graphs. Is this a possibility? I remember reading about connected graphs for my data structures class, but we didn't get to far with them. My second issue is I will have a vector of rooms, which all have exits. Each individual room will be a vertex with the exits being the edges. I can recursively add all the exits that a room points to, then come back and add the rest of the exits. But there may be two exits pointing to the same room. Is there a quick way that I could insure that rather than creating a new vertex, I could just point the edge to the preexisting vertex? Finally, i have one other question. I plan to create resources based on a bunch of different factors. Basically I need a way to determine the closest resources and perhaps get the shortest path to them, or the weight of all of the edges that would point to the n closest resources that were spawned. I want to use this weight to determine the density or find another way to determine density and spread the resources out across the world. -- Take care, Ty http://tds-solutions.net He that will not reason is a bigot; he that cannot reason is a fool; he that dares not reason is a slave.

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Stability of Boost::Serialization XML Output
by Andreas Neustifter 14 Aug '13

14 Aug '13

Hi List, I have to provide digital signatures of serialized C++ objects, I'm planing on using Boost::Serialization for the XML part. Since XML signatures and XMLDsig in particular are difficult [1] and littered with pitfalls I was wondering if maybe the XML output of Boost::Serialization is stable enough to do a plain byte-oriented PKCSwhatever signature? To summarize: - C++ objects are serialized to XML with Boost::Serialization (XML is used since date has to be as human readable as possible). - Serialized XML has to be digitally signed. - XMLDsig is complicated [1] Question: Does Boost::Serialization with the XML backend produce bytewise the same data every time? I sincerely hope that I made myself clear. Andreas [1] http://www.cs.auckland.ac.nz/~pgut001/pubs/xmlsec.txt

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[msm] exit points & favor compile time policy
by Alexander Mingalev 14 Aug '13

14 Aug '13

Hi, I faced to a strange problem. I'm working with root fsm & child fsm. Child fsm has an exit point called "End". I use vs2012u3, boost 1.54 transition table from root looks like that: struct Waiting : state<> {}; // Child is typedef for back-end struct transition_table : public boost::mpl::vector< ... Row < Waiting, begin, Child >, Row < Child::exit_pt<Child::End>, none, Waiting >, ... > {}; So, when I use F-C-T- policy, the Child fsm is stuck in Child::End state, the root fsm never moves to Waiting again. It doesn't happen with default policy. I noticed, that there is a note in msm's changelog From V2.24 to V2.25 (Boost 1.54) • Bugfix: Exit points broken for the favor_compile_time policy. looks similar to my case. Christophe, can you check that bugfix?

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Unicode regex example
by Stefan Schweter 14 Aug '13

14 Aug '13

Hi, here is an unicode regex example, which I want to get matched: #include <iostream> #include <boost/regex.hpp> #include <boost/regex/icu.hpp> int main() { std::setlocale(LC_ALL, ""); boost::wregex condition(L"\\p{u}"); std::wstring test_word(L"Ü"); if (boost::regex_match(test_word, condition)) { std::wcout << L"Matches!" << std::endl; } boost::wregex condition2(L"[[:upper:]]"); if (boost::regex_match(test_word, condition2)) { std::wcout << L"Matches!" << std::endl; } boost::u32regex condition3 = boost::make_u32regex(L"\\p{u}"); if (boost::u32regex_match(test_word, condition3)) { std::wcout << L"Matches using lib icu!" << std::endl; } return 0; } Compiled with -lboost_regex -licuuc. Result: Only the last regex condition matches. So I have a few questions: 1. Is u32regex + make_u32regex the *only* way to get my regex condition matched? 2. Why does "upper class" in the second regex condition not match. E.g. when I use: echo "Ü" | grep '[[:upper:]]' on command line - it works properly :) Thanks in advance + regards, Stefan

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[System]
by Geoff Shannon 14 Aug '13

14 Aug '13

Hey all, I've been looking over the Boost System library with an eye to making use of the system error codes functionality. Specifically, I want to use it to turn error codes returned by unix system calls like socket, accept, listen etc. into thrown exceptions. However, from the documentation I can't understand how I'm supposed to do this. Anybody know, or have good clear example code to share? Thanks, -- Geoff Nothing is ever easy.

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Re: [Boost-users] Boost.Asio, 0MQ, and Windows
by Damien Kick 13 Aug '13

13 Aug '13

On Aug 11, 2013, at 4:32 PM, Damien Kick <dkick(a)shoretel.com<mailto:dkick@shoretel.com>> wrote: Yeah, so far I've been having very good luck with Asio and 0MQ on POSIX. But I'm still stuck on Windows :( The code that I was able to get to compile is not happy at runtime. int main() { zmq::context_t zenv(1); zmq::socket_t zocket(zenv, ZMQ_PUSH); SOCKET zfd; std::size_t zfd_size = sizeof(zfd); zocket.getsockopt(ZMQ_FD, &zfd, &zfd_size); boost::asio::windows::stream_handle::native_handle_type zfd_native(&zfd); boost::asio::io_service ios; boost::asio::windows::stream_handle io(ios, zfd_native); } Stepping line-by-line in the debugger for Visual Studio 2010, when I get to the line attempting to create the windows::stream_handle, I get Unhandled exception at 0x77b815de in test-zee-zmq-socket.exe: Microsoft C++ exception: boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::system::system_error> > at memory location 0x00c1fc7c.. And so there obviously must be more to creating a windows::stream_handle than this but I'm still quite in the dark as to what that might be. The stack trace I'm getting doesn't help me much, either, but I am also am quite ignorant about most things Windows. ntdll.dll!77b815de() [Frames below may be incorrect and/or missing, no symbols loaded for ntdll.dll] ntdll.dll!77b815de() ntdll.dll!77b7014e() KernelBase.dll!7608c41f() > msvcr100d.dll!_nh_malloc_dbg_impl(unsigned int nSize=8, int nhFlag=0, int nBlockUse=1, const char * szFileName=0x00000000, int nLine=0, int * errno_tmp=0x00c1fb0c) Line 239 + 0x19 bytes C++ msvcr100d.dll!_nh_malloc_dbg(unsigned int nSize=8, int nhFlag=0, int nBlockUse=1, const char * szFileName=0x00000000, int nLine=0) Line 302 + 0x1d bytes C++ msvcr100d.dll!malloc(unsigned int nSize=12712804) Line 56 + 0x15 bytes C++ 00c1fb64() 00cc8220() I've also tried int main() { zmq::context_t zenv(1); zmq::socket_t zocket(zenv, ZMQ_PUSH); SOCKET zfd; std::size_t zfd_size = sizeof(zfd); zocket.getsockopt(ZMQ_FD, &zfd, &zfd_size); boost::asio::io_service ios; boost::asio::windows::stream_handle io(ios, GetStdHandle(zfd)); } Which also compiles but then I'm still getting the same exception at runtime. And so apparently a SOCKET is not the same as a HANDLE (?), even though <http://msdn.microsoft.com/en-us/library/windows/desktop/ms741476(v=vs.85).a…> tells me that The WPUCreateSocketHandle function creates a new socket handle. Syntax C++ SOCKET WPUCreateSocketHandle( _In_ DWORD dwCatalogEntryId, _In_ DWORD_PTR dwContext, _Out_ LPINT lpErrno ); <sigh/> It's so annoying because I have this feeling that there is probably just one stupid little conversion function that I need to be calling but it continues to elude me :( ________________________________ This e-mail and any attachments are confidential. If it is not intended for you, please notify the sender, and please erase and ignore the contents.

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Boost.Asio, 0MQ, and Windows
by Damien Kick 13 Aug '13

13 Aug '13

I have been following the excellent advice on using 0MQ and Boost.Asio on a POSIX-ish platform (MacOS) at <http://preview.tinyurl.com/jw4krek>. Unfortunately, though, I am writing code which needs to work on both POSIX-ish and Windows. I'm not having much luck, so far, with my attempts to translate this advice to the Windows side. I can't seem to figure out how to match the type returned by getsockopt(ZMQ_FD) on Windows and what I think should be the Windows equivalents of boost::asio::posix::stream_descriptor. Here is what I've tried: zmq::context_t zenv(1); zmq::socket_t zocket(zenv, ZMQ_PUSH); SOCKET zfd; std::size_t zfd_size = sizeof(zfd); zocket.getsockopt(ZMQ_FD, &zfd, &zfd_size); boost::asio::io_service ios; boost::asio::windows::stream_handle io(ios, zfd); And the error I get when I try to compile it. 2>Z:\zee-zmq-socket.cpp(14): error C2664: \ 'boost::asio::windows::basic_stream_handle<>::basic_stream_handle(\ boost::asio::io_service &,void *const &)' : cannot convert parameter \ 2 from 'SOCKET' to 'void *const &' 2> Reason: cannot convert from 'SOCKET' to 'void *const ' 2> Conversion from integral type to pointer type requires \ reinterpret_cast, C-style cast or function-style cast So far, my Google-fu has been weak; I can only seem to find examples which deal with Boost.Asio and 0MQ on POSIX-ish. I'm not sure what I need to do to correctly get from a SOCKET to a `void * const`. The closest advice that I've been able to find is about combining 0MQ and libcurl: <http://preview.tinyurl.com/lbffx64>. And this advice also makes me nervous that my compilation problems are only the tip of a much nastier iceberg hiding under the surface. In particular, > The reason why there is a assign, but no release-function for > boost::asio::ip::tcp::sockets is that once a socket is "bound" to a > completion port you cannot "unbound" it or "bound" it to another > completion-port. And so I'm worried there might be other gotchas about which I might not know and which would not even be so polite as to manifest themselves as compile-time errors. Thank you in advance for any help. ________________________________ This e-mail and any attachments are confidential. If it is not intended for you, please notify the sender, and please erase and ignore the contents.

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Iostreams with two filters throws exception
by NuSkooler 12 Aug '13

12 Aug '13

I've been attempting to use Boost.Iostreams with two filters to compress + encrypt ("out") and decrypt + uncompress ("in"). This works for some files, while others throw an exception during the "in" phase. If I remove either of the filters for out/in (e.g. remove the compress or the encrypt) everything works fine -- the issue only occurs with two filters chained. >From what I understand in the documentation, this should be supported, but I must be missing something. Below is the relevant portions of my code: Input & output cipher filters (note: I'm using Boost.Crypto, and boost::crypto::rc4_cipher specifically) template <typename StreamCipherT> class StreamCipherFilterBase { public: typedef char char_type; StreamCipherFilterBase(const std::string& key) { m_cipher.set_key(key.data(), static_cast<unsigned int>(key.length())); } protected: char m_buffer[1024 * 2]; // 2k internal buffer size StreamCipherT m_cipher; }; template <typename StreamCipherT> class StreamCipherEncryptFilter : public StreamCipherFilterBase<StreamCipherT> { public: typedef boost::iostreams::multichar_output_filter_tag category; StreamCipherEncryptFilter(const std::string& key) : StreamCipherFilterBase<StreamCipherT>(key) { } template<typename Sink> std::streamsize write(Sink& snk, const char* s, std::streamsize n) { std::streamsize written = 0; std::streamsize remain = n; std::streamsize eat; while(remain) { eat = remain < sizeof(StreamCipherFilterBase<StreamCipherT>::m_buffer) ? remain : sizeof(StreamCipherFilterBase<StreamCipherT>::m_buffer); StreamCipherFilterBase<StreamCipherT>::m_cipher.encrypt( s, StreamCipherFilterBase<StreamCipherT>::m_buffer, eat); written += boost::iostreams::write(snk, StreamCipherFilterBase<StreamCipherT>::m_buffer, eat); remain -= eat; s += eat; } return written; } }; template <typename StreamCipherT> class StreamCipherDecryptFilter : public StreamCipherFilterBase<StreamCipherT> { public: typedef boost::iostreams::multichar_input_filter_tag category; StreamCipherDecryptFilter(const std::string& key) : StreamCipherFilterBase<StreamCipherT>(key) { } template<typename Source> std::streamsize read(Source& src, char* s, std::streamsize n) { const std::streamsize read = boost::iostreams::read(src, s, n); if(EOF == read) { return EOF; } StreamCipherFilterBase<StreamCipherT>::m_cipher.decrypt(s, s, read); return read; } }; And compress + encrypt ("out") & decrypt + uncompress ("in"): (error checking removed for this post) // // Write out data compressing and encrypting as we go // boost::filesystem::ifstream inf(inFile.Get(), std::ios_base::binary | std::ios_base::in); boost::filesystem::ofstream outf(outFile.Get(), std::ios_base::binary | std::ios_base::out); StreamCipherEncryptFilter<CipherT> outCipherFilter(key); boost::iostreams::filtering_ostreambuf out; out.push(boost::iostreams::zlib_compressor()); // compress out.push(outCipherFilter); // then encrypt out.push(outf); // write to file boost::iostreams::copy(inf, out); // // Write out decrypted and uncompressed data: // boost::filesystem::ifstream inf(inFile.Get(), std::ios_base::binary | std::ios_base::in); boost::filesystem::ofstream outf(outFile.Get(), std::ios_base::binary | std::ios_base::out); StreamCipherDecryptFilter<CipherT> inCipherFilter(key); boost::iostreams::filtering_istreambuf in; in.push(boost::iostreams::zlib_decompressor()); in.push(inCipherFilter); in.push(inf); boost::iostreams::copy(in, outf); // <--- exception is thrown here for many files; some succeed with input md5 = output md5. Can anyone help? Bryan Ashby

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