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

How to write an IP address parser with actions to fill-in a simple struct?
by Lars Rohwedder 29 Mar '10

29 Mar '10

I have a rule like this: rule<> IP_Parser = int_p>>'.'>>int_p >>'.'>>int_p >>'.'>>int_p >> !( ('/'>>int_p)|(':'>>int_p)); Now I want to extend it that the user can use that parser to fill a simple struct: struct IP_address { std::string host; int port; int netmask; }; and use it this way: IP_address src; rule<> Source = str_p("source") >> +space_p >> IP_Parser(src) >> *space_p >> ';'; Any ideas how to do that with the old boost::spirit (boost version 1.35)? Lars R.

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A question on the preciseness of the double used in MTL. Can anyone with kindness help me?
by fmingu 29 Mar '10

29 Mar '10

I am using MTL(Matrix Template Library) for Matrix computing in Dev-C++ 4.9.8.0 and updated the gcc version from 3.2 to 4.4.1 by installing tdm-mingw-1.908.0-4.4.1-2 and the boost version is 1.37.0. The system is Windows xp The sample code is : #include <boost/numeric/mtl/mtl.hpp> #include "boost/random/normal_distribution.hpp" #include <boost/random.hpp> #include <boost/random/uniform_real.hpp> int main(int argc, char* argv[]) { using namespace mtl; using namespace mtl::matrix; const unsigned n= 5; dense2D<double> A(n, n), B(n, n); morton_dense<double, doppled_64_row_mask> C(n, n), D(n, n); dense2D<double> F(n, n), E(n, n); hessian_setup(A, 3.0); hessian_setup(B, 1.0); hessian_setup(C, 2.0); hessian_setup(D, 11.0); B(1,1)=9.9999; .......................... std::cout << "The matrices are: B=\n" << B <<"\n"; std::cout << "The result is " <<1.0/3.0 <<"\n"; ……………………. But the result is shown that B(1,1) is 10, and 1.0/3.0 is 0.33. How can I get the highest precision of the type double and dense2D<double> for scientific computation? The same question occurred in random number generation in boost random library. Can anyone with kindness help me?

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synchronization problem
by alev mutlu 28 Mar '10

28 Mar '10

Hi all, For the following code I want to stop early completing processes and wait for the others at the point with (world.barrier)(); statement. But the problem is stop- and stop+ do interleave. Am I doing something wrong with the synchronization, or there is something wrong with my code? if (world.rank() == MASTER){ m_mySize = n / world.size() + n % world.size(); w_mySize = n / world.size(); for(int p = 1; p < world.size(); p++){ world.send(p, 1, w_mySize); world.send(p, 2, n); } relMyValues = new possibleClause[w_mySize]; scatter(world, pC, relMyValues, w_mySize, 0); } else{ world.recv(0, 1, w_mySize); relMyValues = new possibleClause[w_mySize]; scatter(world, pC, relMyValues, w_mySize, 0); } for(i = 0; i < w_mySize; i++){ //do something } cout << world.rank() << " stop - " << world.rank() << endl; (world.barrier)(); cout << world.rank() << " stop + " << world.rank() << endl; if (world.rank() == MASTER){ relAllValues = new possibleClause[n - n % world.size()]; gather(world, relMyValues, w_mySize, relAllValues, 0); } else{ world.recv(0, 2, n); gather(world, relMyValues, w_mySize, relAllValues, 0); }

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new user: error: 'std::tr1' has not been declared
by Juan Vesa 28 Mar '10

28 Mar '10

hello, i'm a brand new user to boost, with xcode 2.4.1, os x 10.4.11 (intel), i686-apple-darwin8-gcc-4.0.1 i'm getting some errors trying to use a library (http:// www.cs.kuleuven.ac.be/~ares/libply/) which uses boost. however i am stuck at the error: error: 'std::tr1' has not been declared doing ./config from boot_root/libs/config, i get the following output related to tr1: checking std::tr1::array... no checking std::tr1::bind... no checking std::complex overloads... no checking std::complex inverse trig functions... no checking std::tr1::function... no checking std::tr1::hash... no checking std::tr1::mem_fn... no checking std::tr1::random... no checking std::tr1::reference_wrapper... no checking std::tr1::regex... no checking std::tr1::result_of... no checking std::tr1::shared_ptr... no checking std::tr1::tuple... no checking std::tr1::type_traits... no checking std::tr1::unordered_map... no checking std::tr1::unordered_set... no checking std::tr1::utility... no so, how can i enable the successful use of the std::tr1 libraries available with boost? regards,

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is it safe to do this with signals?
by Germán Diago 28 Mar '10

28 Mar '10

Hello. I have a class like this: class MyClass : public trackable { unique_ptr<void ()> Signal1; ... }; This class is movable. So I move everything when transferring the internals. I would like to know if this is safe to do in the presence of a trackable base class or if when the moved instance is destroyed this could cause problems. Thanks.

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overloaded const/non-const functions and bind
by Andrej van der Zee 28 Mar '10

28 Mar '10

Hi, I want to use a function in bind that has a const and non-const version named Node::get_parent. I am using the following expression: NodeSet nodes_whitespace = doc->get_root_node()->find("//text()[normalize-space()='']"); for_each(nodes_whitespace.begin(), nodes_whitespace.end(), bind(&Node::remove_child, bind(&Node::get_parent, _1))); I get the obvious error: ../parsers-refact/trans-full/main.cpp: In function ‘void remove_whitespace_nodes(xmlpp::Document*)’: ../parsers-refact/trans-full/main.cpp:56: error: call of overloaded ‘bind(<unresolved overloaded function type>, boost::arg<1>&)’ is ambiguous /usr/local/include/boost/bind/bind_mf_cc.hpp:20: note: candidates are: boost::_bi::bind_t<R, boost::_mfi::mf0<R, T>, typename boost::_bi::list_av_1<A1>::type> boost::bind(R (T::*)(), A1) [with R = xmlpp::Element*, T = xmlpp::Node, A1 = boost::arg<1>] /usr/local/include/boost/bind/bind_mf_cc.hpp:30: note: boost::_bi::bind_t<R, boost::_mfi::cmf0<R, T>, typename boost::_bi::list_av_1<A1>::type> boost::bind(R (T::*)()const, A1) [with R = const xmlpp::Element*, T = xmlpp::Node, A1 = boost::arg<1>] Is there a way to get the const_iterator? Or is there any other solution? Thank you, Andrej

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[iostreams] Truncate file?
by Adam Nielsen 28 Mar '10

28 Mar '10

Hi all, I'm trying to work out how to chop some data off the end of a file once I have finished modifying it. I'm not sure how to adjust the file size in a portable fashion, and although I'm using boost::iostreams I can't see how to either set the size of the underlying stream or how to otherwise indicate where the stream should end. Is this possible with boost:iostreams? If not, is there another portable way to remove data from the end of a file, causing its size to shrink? All I can find around the place are calls to ftruncate() and the like, but I would like my program to work on Windows as well as Linux, and hopefully other platforms too. Many thanks, Adam.

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Boost::ASIO Winsock.h already included?
by Sean McAllister 28 Mar '10

28 Mar '10

I'm getting this error when building on windows. Looking online it seems it can happen if you include windows.h before boost/asio.hpp without setting WIN32_LEAN_AND_MEAN. I've only got three places in my code that import windows.h on their own, and I prefixed them all with that macro, but I'm still getting one error. The only other thing I can think of is that one of the boost libraries is including it and that's throwing a wrench into things. Unforunately it's proving particularly pernicious to determine all the files that include windows.h. Does anyone know which libraries include it or have experience getting rid of this error?

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Find which boost header
by Mathijs Romans 27 Mar '10

27 Mar '10

Hi, I have trouble finding which header I should use when I want to use a part of boost. For instance, I wish to use boost::optional but am not entirely sure which header to use. In the documentation online I can find everything about boost::optional except which header is recommended. I'm sure it is boost/optional.hpp or boost/optional/optional.hpp but that's not really my question. Am I supposed to just browse through my local boost include dir to find an appropriate header? Or is there somewhere an overview of which header files are recommended for boost users? Thanks, Mathijs

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troubles deriving from using boost variant
by Greg Kellum 27 Mar '10

27 Mar '10

Hi all, I have been using boost's variant library in a project, and I've noticed that when I import the class using the variant class into other classes I start having the strangest compilation problems. I've been dealing with these problems for the last few months by isolating that code as much as possible. I've put it behind a factory which returns an abstract class which hides the fact that a variant is being used by the implementing class at all. This keeps other classes from having to import the implementing class and by extension the boost variant header, but it also makes it difficult to make full use of visitors together with the variant because creating new visitors that include the implementing class leads to these same strange compilation problems. I was hoping that someone might be able to give me a better diagnosis for the underlying reason for these problems. I've included the error output below. If anyone can give me any greater insight into what's causing these errors, I would be extremely grateful. Best, Greg 1>C:\Program Files (x86)\boost\boost_1_42\boost/mpl/aux_/integral_wrapper.hpp(80): error C2544: expected ')' for operator '()' 1> C:\Program Files (x86)\boost\boost_1_42\boost/mpl/aux_/integral_wrapper.hpp(81) : see reference to class template instantiation 'boost::mpl::integral_c<T,N>' being compiled 1>C:\Program Files (x86)\boost\boost_1_42\boost/mpl/aux_/integral_wrapper.hpp(80): error C2146: syntax error : missing ';' before identifier 'L' 1>C:\Program Files (x86)\boost\boost_1_42\boost/mpl/aux_/integral_wrapper.hpp(80): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int 1>C:\Program Files (x86)\boost\boost_1_42\boost/mpl/aux_/integral_wrapper.hpp(80): error C2059: syntax error : ')' 1>C:\Program Files (x86)\boost\boost_1_42\boost/mpl/aux_/integral_wrapper.hpp(80): error C2143: syntax error : missing ';' before 'const' 1>C:\Program Files (x86)\boost\boost_1_42\boost/mpl/aux_/integral_wrapper.hpp(80): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int 1>C:\Program Files (x86)\boost\boost_1_42\boost/mpl/aux_/integral_wrapper.hpp(80): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int 1>C:\Program Files (x86)\boost\boost_1_42\boost/mpl/aux_/integral_wrapper.hpp(80): error C2059: syntax error : '{' 1>C:\Program Files (x86)\boost\boost_1_42\boost/mpl/aux_/integral_wrapper.hpp(80): error C2334: unexpected token(s) preceding '{'; skipping apparent function body 1>C:\Program Files (x86)\boost\boost_1_42\boost/mpl/aux_/integral_wrapper.hpp(80): error C2544: expected ')' for operator '()' 1> C:\Program Files (x86)\boost\boost_1_42\boost/type_traits/integral_constant.hpp(21) : see reference to class template instantiation 'boost::mpl::integral_c<T,N>' being compiled 1> with 1> [ 1> T=size_t, 1> N=0 1> ] 1> C:\Program Files (x86)\boost\boost_1_42\boost/type_traits/alignment_of.hpp(109) : see reference to class template instantiation 'boost::integral_constant<T,val>' being compiled 1> with 1> [ 1> T=size_t, 1> val=0 1> ] 1>C:\Program Files (x86)\boost\boost_1_42\boost/mpl/aux_/integral_wrapper.hpp(80): error C2146: syntax error : missing ';' before identifier 'L' 1>C:\Program Files (x86)\boost\boost_1_42\boost/mpl/aux_/integral_wrapper.hpp(80): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int 1>C:\Program Files (x86)\boost\boost_1_42\boost/mpl/aux_/integral_wrapper.hpp(80): error C2059: syntax error : ')' 1>C:\Program Files (x86)\boost\boost_1_42\boost/mpl/aux_/integral_wrapper.hpp(80): error C2143: syntax error : missing ';' before 'const' 1>C:\Program Files (x86)\boost\boost_1_42\boost/mpl/aux_/integral_wrapper.hpp(80): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int 1>C:\Program Files (x86)\boost\boost_1_42\boost/mpl/aux_/integral_wrapper.hpp(80): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int 1>C:\Program Files (x86)\boost\boost_1_42\boost/mpl/aux_/integral_wrapper.hpp(80): error C2059: syntax error : '{' 1>C:\Program Files (x86)\boost\boost_1_42\boost/mpl/aux_/integral_wrapper.hpp(80): error C2334: unexpected token(s) preceding '{'; skipping apparent function body 1>C:\Program Files (x86)\boost\boost_1_42\boost/mpl/aux_/integral_wrapper.hpp(80): error C2544: expected ')' for operator '()' 1> C:\Program Files (x86)\boost\boost_1_42\boost/type_traits/integral_constant.hpp(21) : see reference to class template instantiation 'boost::mpl::integral_c<T,N>' being compiled 1> with 1> [ 1> T=size_t, 1> N=8 1> ] 1> C:\Program Files (x86)\boost\boost_1_42\boost/type_traits/alignment_of.hpp(89) : see reference to class template instantiation 'boost::integral_constant<T,val>' being compiled 1> with 1> [ 1> T=size_t, 1> val=8 1> ] 1> C:\Program Files (x86)\boost\boost_1_42\boost/type_traits/type_with_alignment.hpp(289) : see reference to class template instantiation 'boost::alignment_of<T>' being compiled 1> with 1> [ 1> T=boost::detail::max_align 1> ]

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