February 2010 - Boost-users - lists.preview.boost.org

XML Serialization: Putting Stylesheet tag inside XML file
by girish hilage 20 Feb '10

20 Feb '10

Hi, Using XML serialization I have created an XML file which I want to see through a browser using a stylesheet. So I want to put a statement : <?xml-stylesheet type="text/xsl" href="XSLTFile.xsl"?> in between below 2 statements : <?xml version="1.0" encoding="UTF-8" standalone="yes" ?> <!DOCTYPE boost_serialization> like this : <?xml version="1.0" encoding="UTF-8" standalone="yes" ?> <?xml-stylesheet type="text/xsl" href="XSLTFile.xsl"?> <!DOCTYPE boost_serialization> <boost_serialization signature="serialization::archive" version="5"> But the code for a init() function inside file boost/archive/impl/basic_xml_oarchive.ipp is as follows : basic_xml_oarchive<Archive>::init(){ // xml header this->This()->put("<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\" ?>\n"); this->This()->put("<!DOCTYPE boost_serialization>\n"); // xml document wrapper - outer root this->This()->put("<boost_serialization"); write_attribute("signature", BOOST_ARCHIVE_SIGNATURE()); write_attribute("version", BOOST_ARCHIVE_VERSION()); this->This()->put(">\n"); } File XSLTFile.xml contain stylesheet info. * So, how is it possible to put a stylesheet related statement just after the 1st statement? * Another query is, how to change the the tag name "boost_serialization" to something else? Regards, Girish

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Re: [Boost-users] boost::asio::read_until w/ boost::function
by marty 20 Feb '10

20 Feb '10

I'm following up my original post with some actual code an interested person might try to compile, as well as the specific errors I'm getting. boost 1.41.0, gcc 3.4.6 both here: http://www.pastebin.ca/1803396 any insight would be welcome, ...m > > ------------------------------------------------------------------------ > > Subject: > boost::asio::read_until w/ boost::function > From: > marty <marty(a)ice.org> > Date: > Fri, 19 Feb 2010 13:47:22 -0500 > To: > boost-users(a)lists.boost.org > > To: > boost-users(a)lists.boost.org > > > I'm having some trouble resolving the call to read_until > (see snippet below) > > Is there some reason I am not be able to use a boost::function > as the MatchCondition object? > > > Thanks, > ...m

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Re: [Boost-users] [boost] [Filesystem V3] Filesystem Version 3 beta 1 available for download and comment
by Beman Dawes 20 Feb '10

20 Feb '10

On Thu, Feb 18, 2010 at 11:30 AM, Zach Laine <whatwasthataddress(a)gmail.com> wrote: > On Thu, Feb 18, 2010 at 8:43 AM, Beman Dawes <bdawes(a)acm.org> wrote: >> The first beta release of Boost.Filesystem Version 3 is now available. >> >> The documentation can be viewed at http://mysite.verizon.net/beman/v3/index.htm > > The descriptions for portable_name() and portable_directory_name() > appear to be at odds. > > portable_name() : ... && (name is "." or "..", and the first character > not a period or hyphen) > > portable_directory_name(): ... && (name is "." or ".." or contains no periods) > > Should portable_name() be "... && (name is "." or "..", or contains no > periods) && (first character not a hyphen)"? Maybe I'm missing > something? I haven't looked at these in years. They need to be brought up to date. Added to do list. > > Also, in the tut3.cpp tutorial code, there's no mention of the dangers > of using "*it" inside the directory_iterator loop. IIRC, in previous > Filesystem revisions, this would throw if you did not have adequate > permissions to see the file to which "it" refers. Has this changed? Nice catch! No, nothing is changed. The code is not robust. > If not, I think that you should either wrap the body of the loop in a > try-catch block, or use one of the non-throwing function overloads, > and indicate to the user what the exception safety concerns are. Yes, this would be a great place to introduce the non-throwing function overloads. Added to do list. I > think the tutorial code should exhibit enough robustness that the user > can just cut-and-paste to get the basic code needed to use the > library. Definitely. If anyone spots other robustness issues, be sure to let me know. Thanks, --Beman

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mpl Generate integral sequence wrapper from 0 to N
by Hicham Mouline 20 Feb '10

20 Feb '10

Hi, Given a size_t N known at compile, what's the cleanest way to generate mpl::vector_c<size_t, 0, 1, .., N> what is the fastest way compile-time wise? what is the most mpl algos reusing way? Regards,

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Inconsistent unicode encoding between boost and wx on mac osx
by Sachin Garg 19 Feb '10

19 Feb '10

My project uses both boost and wxwidgets and unicode encoding by both is different on Mac OSX. Everything works fine on windows. Problem: Boost and WX do end up encoding the strings differently when converting to unicode on OSX. I am detailing an example: WX's encoding is same on both windows and osx but Boost's encoding is different on both platforms. It is probably not a bug but I am unable to figure out the reason and how to make them both work together. The string: 国際的な一流のホールダー (I don't know if this foreign language string will show up fine in your email client). Hex dumps of Unicode encodings of this string >From Boost on Mac (32-bit): e5 0 0 0 9b 0 0 0 bd 0 0 0 e9 0 0 0 9a 0 0 0 9b 0 0 0 e7 0 0 0... >From WX on Mac (32-bit): fd 56 0 0 9b 96 0 0 84 76 0 0 6a 30 0 0 0 4e 0 0.... >From WX and Boost on Windows (16-bit): fd 56 9b 96 84 76 6a 30 0 4e 41 6d 6e 30... (To be more exact, this is how boost::filesystem encodes a directory name it read from disk, and its the wxChar** argv value from wxApp for a Unicode build of wx). So wx does same thing on windows and mac, and boost does that same thing on windows. But boost encodes it differently on mac and I have no idea why. My wild guess is its due to locale etc settings but I don't know how check for this or fix it. SG

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[graph] boost::adj_list_edge_property_map
by Christine SINOQUET 19 Feb '10

19 Feb '10

Hello, I encounter some problems when porting an application using boost from Windows to Linux. I work with Ubuntu, I use codeblocks as a compiling environment. The boost library I use is boost_1_38 containing boost_1_38/boost/property_map.hpp boost_1_38/boost/config.hpp boost_1_38/boost/graph/adjacency_list.hpp boost_1_38/boost/graph/graph_utility.hpp. I believe the boost library is compatible with Windows and Linux. The compiler reports the following errror: .../structure_learning/src/graph_tools/GraphPDAG.cpp:295 erreur: conversion from "boost::adj_list_edge_property_map<boost::bidirectional::tag, boost::detail::error_property_not_found, boost::detail::error_property_not_found&, void*, boost::property<boost::edge_weight_t, long double, boost::no_property>, boost::edge_bundle_t" to non-scalar type "boost::no_edge_bundle" requested. Then, it finds a second error: .../structure_learning/src/graph_tools/GraphPDAG.cpp:296 erreur: "struct boost::no_edge_bundle" has no member named "ambiguous". Finally, the third error is (after verbose comments which I can not copy here): GraphPDAG.cpp:296: instantiated from here: boost_1_38/boost/graph/adjacency_list.hpp:463:erreur:invalid initialisation of reference of type "boost::no_edge_bundle&" from expression of type "boost::detail::error_property_not_found". Do you have any idea why this code is correct with Windows but not with Linux ? I would have thought that the boost C++ library is compatible with any system. Thank you in advance for considering my questions. Best regards, C.S. //============================================================================== void PDAG::putWeightPDAG(slBayesianNetwork* bn, slEdge e, int w) { unsigned int a, b; this->pBN = bn; this->getEdgeNodesIndex(e, a, b); this->putWeightPDAG(a, b, w); slGraph& graph = bn->get_graph(); property_map<slGraph, edge_weight_t>::type weightMap = get(edge_weight, graph); line 295 >>>>> edge_bundle_type<slGraph>::type ambiguousTypeMap = get(edge_bundle, graph); line 296 >>>>> graph[e].ambiguous = true; }

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MPL. Difference between variadic and numbered forms of sequences
by dilas dilas 19 Feb '10

19 Feb '10

When I write expressions like: template<class Seq, class Elem> struct pairs: fold<Seq, vector<>, push_back<_1,vector2<Elem, _2 > > >{}; Everything works just fine, but when I use variadic form: template<class Seq, class Elem> struct pairs: fold<Seq, vector<>, push_back<_1,vector<Elem, _2 > > >{}; I have a lot of errors. Can someone explain me what's the difference?

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Cost of constructing models of RandomDistribution
by Robert Patterson 19 Feb '10

19 Feb '10

I have a fairly large simulation code, that I need to get into a state in which I can multi-thread it. One of my problems is a global random number generator state. I am thinking that I should replace this global object with a collection of generator engines, one for each thread, which would be passed down by non-const reference from the top level of each thread to the places where random numbers are needed. In this case it seems best to pass around engines that model PseudoRandomNumberGenerator. In each place that I want a random number (I rarely need more than 1 or 2 at once or with the same parameters) I would then have to construct and use a RandomDistribution, such as uniform_int, exponential_distribution (or poisson, but that is a question for another day). This approach relies on these models of RandomDistribution being fairly cheap to construct. I cannot see any reason why this should not be the case, but equally I cannot see any promise in the docs that they will be cheap to construct. Am I proposing to use the library in a sensible way? Thanks Robert Patterson

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doubt on boost::bind and boost::function
by Conoscenza Silente 19 Feb '10

19 Feb '10

Hi all I am trying to use boost::function combined with boost::bind in order to be able to pass a callback to another function. The callback I want to pass is a member function of the class. The code is below class CA{ bool IsMemberFunction( const std::string& aLine ){ return true; } void testUseFooPtr( boost::function< bool(const std::string& ) > aFooPtr ){ std::string aLine; // read from somewhere if( aFooPtr( aLine ) ){ std::cout << "is fine" << std::endl; } } void testFooPtr(){ std::string ciao("aa"); boost::function< bool(const std::string& ) > fooPtr( boost::bind( &CA::IsMemberFunction, this ) ); // create // a boost function using the class memebr testUseFooPtr( fooPtr ); // pass it as callback to another // function } }; I have the following compilation error. /usr/local/include/boost/bind/mem_fn.hpp:342: error: invalid use of non-static member function Do you know what I am doing wrong? Is the signature fine? Thanks

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error: no matching function for call to ‘boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp> >::basic_stream_socket()’
by David Kaplan 19 Feb '10

19 Feb '10

Hi Why doesn't this work: _socket = tcp::socket(ioService); _socket is a private member of type tcp::socket. How can I store the socket as a class member (so I can access it when using read/write from other class methods)? Also, is there any way to define a timeout on a synchronous connect()? If not, what's the workaround? Can I do an async connect and then somehow return to synchronous mode of operation? Thanks, David

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