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Concept check negation
by Alexander Stoyan 24 Jul '12

24 Jul '12

Hi all, Is there any way to negate concept check, so that it'd be possible to assert if a type is NOT DefaultConstructible, etc. ? Thanks in advance. ============================== Never lose heart! Regards, Alexander Stoyan e-mail: alexander.stoyan, you know, at google mail dot com gtalk: alexander.stoyan, you know, at google mail dot com skype: alexander.stoyan <http://alexander-stoyan.blogspot.com/> http://alexander-stoyan.blogspot.com

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Re: [Boost-users] Missing libboost_thread-vc100-mt-s-1_49.lib
by VimalMathew＠Eaton.com 24 Jul '12

24 Jul '12

Anybody? -- Vimal -----Original Message----- From: Mathew, Vimal Sent: Friday, July 20, 2012 2:32 PM To: boost-users(a)lists.boost.org Subject: Missing libboost_thread-vc100-mt-s-1_49.lib Hi, I'm trying to build a project using nmake. When I run nmake I get this error message: " LINK : fatal error LNK1104: cannot open file 'libboost_thread-vc100-mt-s-1_49.lib " Could someone tell me what I'm missing please? Thanks, Vimal

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[move] case study: simple cloning smart pointer
by Krzysztof Czainski 24 Jul '12

24 Jul '12

Hello, In order to learn how to implement move semantics, I decided to write a simple cloning smart pointer (called ptr) with diagnostic information, and an example showing all constructor and assignment use cases I could think of. I wanted the pointer to be convertible (and movable) to pointers to base classes. I've prepared two versions of conversion constructors and assignment operators in ptr. In the first version I tried to write everything like Boost.Move docs for implementing Copyable and Movable classes suggest, and then added the conversion constructors and assignment operators. Then I wrote a second version, using the pass-by-value and swap idiom. Any comments about my attempts here are welcome. Did I get it right in both versions? The attached file swap_idiom.zip contains: ptr.hpp - the deffinition of the ptr class template main.cpp - example for ptr<>, showing all constructor and assignment use cases I could think of 03.txt, 03_by_value.txt, 0x.txt, 0x_by_value.txt - the output I got for both versions of ptr, in two versions of C++: 03 and 0x. For this test I used MinGW-4.5.0. Here's how the ptr<> class looks like (ptr.hpp) (note: {{{this}}} is how I mark code): {{{ extern int ptr_s; // helper for diagnostics template < class T > T* clone_me( T const* p ); template < class T > class ptr { public: explicit ptr( T* p = 0 ) : p_(p) { ++ptr_s; std::cout << "_p "; } // copy ctor ptr( ptr const& b ) : p_( clone_me(b.get()) ) { ++ptr_s; std::cout << "cp "; } // move ctor ptr( BOOST_RV_REF(ptr) b ) : p_( b.release() ) { ++ptr_s; std::cout << "mp "; } }}} So far so good. This is where the hard part comes in - the conversion constructors and assignment operators. First version looks like this: {{{ private: #if !defined(BY_VALUE) BOOST_COPYABLE_AND_MOVABLE(ptr) public: // generalized copy ctor for pointers to derived template < class U > ptr( ptr const& b, typename boost::enable_if< boost::is_convertible<U*,T*> >::type* = 0 ) : p_( clone_me(b.get()) ) { ++ptr_s; std::cout << "Cp "; } // generalized move ctor for pointers to derived template < class U > ptr( BOOST_RV_REF(ptr) b, typename boost::enable_if< boost::is_convertible<U*,T*> >::type* = 0 ) : p_( b.release() ) { ++ptr_s; std::cout << "Mp "; } ptr& operator=( BOOST_COPY_ASSIGN_REF(ptr) b ) { T* tmp = clone_me(b.get()); // this can throw boost::checked_delete(p_); p_ = tmp; return *this; } ptr& operator=( BOOST_RV_REF(ptr) b ) { boost::checked_delete(p_); p_ = b.release(); return *this; } template < class U > typename boost::enable_if< boost::is_convertible<U*,T*>, ptr& >::type operator=( ptr const& b ) { T* tmp = clone_me(b.get()); // this could throw boost::checked_delete(p_); p_ = tmp; return *this; } template < class U > typename boost::enable_if< boost::is_convertible<U*,T*>, ptr& >::type operator=( BOOST_RV_REF(ptr) b ) { boost::checked_delete(p_); p_ = b.release(); return *this; } }}} This was long, and contains some tricky places, like the one commented 'this could throw'. Did I even get it right? I think so, but I'm just beginning to learn about move semantics here ;-) Anyway, next comes the second version: implementing conversion constructors and assignment operators in terms of pass-by-value and swap. Note the use of BOOST_COPYABLE_AND_MOVABLE_ALT macro so that an operator=(ptr&) isn't inserted. {{{ #else // BY_VALUE BOOST_COPYABLE_AND_MOVABLE_ALT(ptr) public: // generalized copy/move constructor implemented by pass-by-value & steal template < class U > ptr( ptr b, typename boost::enable_if< boost::is_convertible<U*,T*> >::type* = 0 ) : p_( b.release() ) { ++ptr_s; std::cout << "Vp "; } // assignment - works for all types convertible to ptr ptr& operator=( ptr b ) { swap(*this,b); return *this; } #endif // BY_VALUE }}} Compared to the first version, this is really simple. I see no tricky parts here. The rest of ptr<> follows: {{{ ~ptr() { boost::checked_delete(p_); ++ptr_s; std::cout << "~p "; } T* get() const { return p_; } T* release() { T* r = p_; p_ = 0; return r; } friend void swap( ptr& a, ptr& b ) { boost::swap(a.p_,b.p_); std::cout << "sp "; } // reset, operator* and -> private: T* p_; }; }}} Writing the conversion constructors and assignment operators in the second version was much simpler. While version 1 contains 6 functions, version 2 contains only 2 functions. But is this always correct, and what is the cost of simplifying things? I tried to answer that question by writing the example (main.cpp). I started by preparing two diagnostic classes: {{{ struct A { static int a, c; A() { ++a; ++c; cout << "_A "; } A( A const& ) { ++a; ++c; cout << "cA "; } virtual ~A() { ++a; --c; cout << "~A "; } }; int A::a = 0; int A::c = 0; struct B : A { static int b, d; B() { ++b; ++d; cout << "_B "; } B( B const& x ) : A(x) { ++b; ++d; cout << "cB "; } ~B() { ++b; --d; cout << "~B "; } }; int B::b = 0; int B::d = 0; ptr<A> make_a() { return ptr<A>( new A ); } ptr make_b() { return ptr( new B ); } }}} Then some machinery for printing and zeroing the static variables incremented/decremented by corresponding constructors/destructors. {{{ void trace( char const* msg ) { cout << endl << boost::format("%34s P:%d A:%d B:%d eA:%d eB:%d") % msg % ptr_s % A::a % B::b % A::c % B::d << endl; ptr_s = 0; A::a = 0; B::b = 0; } #define TRACE( x ) x; trace( #x ); }}} And now main() itself, containing all use cases of ptr<> I could think of: {{{ int main() { { TRACE( ptr<A> z ) TRACE( ptr<A> a( new A ) ) TRACE( ptr b( new B ) ) TRACE( ptr<A> c( new B ) ) TRACE( ptr<A> d( a ) ) TRACE( ptr<A> e( b ) ) TRACE( ptr<A> f( boost::move(a) ) ) TRACE( ptr<A> g( boost::move(b) ) ) TRACE( ptr h( new B ) ) TRACE( ptr<A> i( boost::move(c) ) ) TRACE( ptr<A> j( i ) ) // slice TRACE( ptr<A> x( new A ) ) TRACE( x = f ) TRACE( x = h ) TRACE( x = boost::move(f) ) TRACE( x = boost::move(g) ) TRACE( x = boost::move(h) ) TRACE( x = i ) // slice } trace( "" ); { TRACE( ptr<A> a = make_a() ) TRACE( ptr<A> b = make_b() ) TRACE( ptr<A> c( make_b() ) ) TRACE( a = make_a() ) TRACE( b = make_b() ) } trace( "" ); } }}} And now for the costs. I compiled the attached code with MinGW-4.5.0 in 4 configurations: -std=c++0x disabled/enabled, and version 1/2. I compared the program output to derive the conclusions: C++03: version 1 vs. version 2: - whenever a conversion is needed (about half of the use cases above), version 2 introduces an additional temporary ptr<> object (without a deep copy); in one case it's 2 additional temporary ptr<>s; - the last 4 use cases {{{ ptr<A> b = make_b(); ptr<A> c( make_b() ); a = make_a(); b = make_b(); }}} introduce a deep copy in version 1, while while the deep copy is avoided in version 2. C++0x: version 1. vs. version 2: - whenever a conversion is needed (about half of the use cases above), version 2 introduces an additional temporary ptr<> object (without a deep copy); in one case it's 2 additional temporary ptr<>s; - no unnecessary deep copies are introduced in either version. Version 1: C++03 vs. C++0x: - the last 4 use cases {{{ ptr<A> b = make_b(); ptr<A> c( make_b() ); a = make_a(); b = make_b(); }}} introduce a deep copy in version C++03, while while the deep copy is avoided in C++0x. Version 2: C++03 vs. C++0x: - no difference. General conclusion: 'pass-by-value and swap' idiom is cool ;-) Pros: - better move emulation, - simple implementation. Cons: - additional temporary objects, that are then swapped to the right place. Thanks for staying with me ;-) Regards, Kris

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[serialization - eceptions] Could not catch exceptions
by DaBoneCrack 24 Jul '12

24 Jul '12

Hi, i could not catch boost serialization exceptions. By default BOOST_NO_EXCEPTIONS is defined. All attempts to undefine it has no effect. What i try to do: <code> ... #include <boost/config.hpp> #ifdef BOOST_NO_EXCEPTIONS # undef BOOST_NO_EXCEPTIONS #endif ... more boost serialization headers included .... try { std::ifstream ifs("D:\\tmp.bin", std::ios::binary); boost::archive::binary_iarchive ia(ifs); int iIndex = 0; ia >> BOOST_SERIALIZATION_NVP("A", iIndex); ... } catch(std::exception) { ... } </code> Do i miss something to catch boost serialization exceptions? I am using vs2008. Thx for your help. -- View this message in context: http://boost.2283326.n4.nabble.com/serialization-eceptions-Could-not-catch-… Sent from the Boost - Users mailing list archive at Nabble.com.

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Error :Boost 1.48.0 with latest IBM compiler
by devika R S 24 Jul '12

24 Jul '12

Hi All, This post is regarding the issue we saw on IBM compiler using BOOST 1.48 version. Here is the sample code . *********************************Example Code************************************* #include <boost/config/warning_disable.hpp> #include <boost/spirit/include/qi.hpp> #include <boost/spirit/include/phoenix_operator.hpp> #include <boost/spirit/home/phoenix/statement/if.hpp> #include <boost/spirit/home/phoenix/bind/bind_function.hpp> #include <iostream> #include <string> namespace client { namespace qi = boost::spirit::qi; namespace ascii = boost::spirit::ascii; namespace phx = boost::phoenix; struct vars_ : qi::symbols<char, double> { vars_() { add("ans" , 0); } } vars; template <typename Iterator> struct parser : qi::grammar<Iterator, double()> { parser() : parser::base_type(function) { using qi::eps; using qi::lit; using qi::_val; using qi::_1; using ascii::char_; using qi::double_; using qi::string; using qi::lexeme; using boost::phoenix::if_; using qi::alpha; using qi::alnum; MAX = lexeme[string("max") | string("MAX")]; //define max symbol MIN = lexeme[string("min") | string("MIN")]; //define min symbol D = lexeme[string("d") | string("D")]; //define distance symbol function = expression [_val = _1] | declaration | assignment | ( MAX >> "(" >> function [_val = _1] >> +(',' >> function [if_(_1 > _val)[_val = _1]]) >> ')') // call : max(function,...) | ( MIN >> "(" >> function [_val = _1] >> +(',' >> function [if_(_1 < _val)[_val = _1]]) >> ')') // call : min(function,...) | ( D >> "(" >> (function >> ',' >> function) >> ')'); // call : d(point1,point2) not implemented yet expression = term [_val = _1] >> *( ('+' >> term [_val += _1]) | ('-' >> term [_val -= _1])); term = factor [_val = _1] >> *( ('*' >> factor [_val *= _1]) | ('/' >> factor [_val /= _1])); factor = double_ [_val = _1] | (vars [_val += _1] ) | '(' >> expression [_val = _1] >> ')' | ('-' >> factor [_val = -_1]) | ('+' >> factor [_val = _1]) | declaration; ; assignment = vars >> '=' >> function; var_decl = lexeme [ qi::raw [ ( alpha >> *( alnum | '_' ) ) - vars ] ] //[ phx::bind(vars.add, _1) ] ; declaration = "var " >> var_decl >> *( ',' >> var_decl ); } qi::rule<Iterator, double()> MAX, MIN, D,expression, term, factor, function, assignment, var_decl, declaration; }; } int main() { typedef std::string::const_iterator iterator_type; typedef client::parser<iterator_type> parser; parser _parser; // Our grammar std::string str; double result; while (std::getline(std::cin, str)) { if (str.empty() || str[0] == 'q' || str[0] == 'Q') break; std::string::const_iterator iter = str.begin(); std::string::const_iterator end = str.end(); bool r = parse(iter, end, _parser, result); if (r && iter == end) { std::cout << "Parsing succeeded\n"; std::cout << "result = " << result << std::endl; } else { std::string rest(iter, end); std::cout << "Parsing failed\n"; } } return 0; } *********************************END************************************************** When we compile this code on IBM with the compiler : IBM XL C/C++ for AIX, V11.1 (5724-X13).Version: 11.01.0000.0009 we end up with below error: xlC -I/usr/include/common/boost -o test2.o -O -c -qnoansialias -qnoro -qchars=signed -q64 -qrtti=all test2.cpp "/usr/include/common/boost/boost/integer_traits.hpp", line 83.56: 1540-0724 (W) The non-type template argument "-1" of type "T" has wrapped. "/usr/include/common/boost/boost/spirit/home/support/terminal.hpp", line 231.13: 1540-0407 (S) The base class "to_nonlazy_arg<const char [4]>" contains a circular reference back to "to_nonlazy_arg<const char [4]>". "/usr/include/boost/boost/spirit/home/support/terminal.hpp", line 288.46: 1540-0700 (I) The previous message was produced while processing "struct boost_1_48_0::spirit::detail::to_nonlazy_arg<const char [4]>". "/usr/include/common/boost/boost/spirit/home/support/terminal.hpp", line 281.16: 1540-0700 (I) The previous message was produced while processing "struct boost_1_48_0::spirit::terminal<struct boost_1_48_0::spirit::tag::char_code<boost_1_48_0::spirit::tag::string,boost_1_48_0::spirit::char_encoding::standard> >::result_helper<0,const char [4],boost_1_48_0::spirit::unused_type,boost_1_48_0::spirit::unused_type>". "/usr/include/common/boost/boost/spirit/home/support/terminal.hpp", line 316.16: 1540-0700 (I) The previous message was produced while processing "struct boost_1_48_0::spirit::terminal<struct boost_1_48_0::spirit::tag::char_code<boost_1_48_0::spirit::tag::string,boost_1_48_0::spirit::char_encoding::standard> >::result<const char [4],boost_1_48_0::spirit::unused_type,boost_1_48_0::spirit::unused_type>". "/usr/include/common/boost/boost/spirit/home/support/terminal.hpp", line 248.12: 1540-0700 (I) The previous message was produced while processing "struct boost_1_48_0::spirit::terminal<boost_1_48_0::spirit::tag::char_code<boost_1_48_0::spirit::tag::string,boost_1_48_0::spirit::char_encoding::standard> >". "/usr/include/common/boost/boost/spirit/home/support/common_terminals.hpp", line 230.1: 1540-0700 (I) The previous message was produced while processing "boost_1_48_0::spirit::standard::string". But this code works absolutely fine on g++ Linux. Is this is a known bug on IBM ?Is any patch available ? Thanks in advance, Abc

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Problems with boost::this_thread::sleep(boost::posix_time::milliseconds(100)) on 64 bit platform.
by Serg V. Gulko 23 Jul '12

23 Jul '12

Hello! I was trying to recompile code which was working perfectly on CentOS 6 32 bit under same version of CentOS but for 64bit. boost version is 1.49.0. Problem is that this_thread::sleep return immediately on 64 bit machine... Only increasing sleep time to 3000 i was able to see real sleep. I saw that many people have same problem but is there a way to easily resolve it? Serg

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[BGL] Encountering "bad lexical cast" exception when reading a class from graphviz file
by Nicholas Mario Wardhana 23 Jul '12

23 Jul '12

Hi all, I am trying to read a graphviz file into my graph implementation. The minimum working code as well as the graphviz file are at the end of this e-mail. The node of the graph is the Vertex struct, which contains a point object (Point p). For Point class, I overload two operators, >> and <<, and operator << was previously used to generate the graphviz file. The operator overloads work well with std::cin and std::cout, but with the code below, I receive an exception: bad lexical cast: source type value could not be interpreted as target . The culprit might be in the << overload. In particular, when reading from a file, the value of iToBool1 is true, whereas iToBool2 is false. That is to say, the variable i might change when inserting the stream data to the point. This does not happen when reading from std::cin, as both variables are true. I convert the i variable, originally an istream, to bool because when the program returns to the calling function, which is lexical_stream_limited_src::shr_using_base_class on line 1616 in lexical_cast.hpp, this functions uses the return value of << operator in a boolean comparison. The value of iToBool2 being false eventually leads to calling BOOST_LCAST_THROW_BAD_CAST on line 1975. I wonder if somebody can tell me what is wrong with my operator overload? I use Boost 1.50 and Visual Studio 2008 on Windows 7. Thanks! Best regards, Nicholas //--------------------Graphviz-------------------- graph G { 1 [Point="1 2 3"]; } //----------------------code---------------------- #include <boost/graph/adjacency_list.hpp> #include <boost/property_map/dynamic_property_map.hpp> #include <boost/graph/graphviz.hpp> #include <iostream> #include <fstream> #include <string> struct Point { float x; float y; float z; inline friend std::istream& operator >> ( std::istream& i, Point& p ) { bool iToBool1 = i; i >> p.x >> p.y >> p.z; bool iToBool2 = i; return i; } inline friend std::ostream& operator << ( std::ostream& o, const Point& p ) { o << p.x << " " << p.y << " " << p.z; return o; } }; struct Vertex { int ID; Point p; }; struct Edge { int ID; }; typedef boost::adjacency_list< boost::listS, boost::vecS, boost::undirectedS, Vertex, // bundled data Edge, // bundled data boost::no_property, // not needed boost::listS> Graph; int main() { // Part 1: input via std::cin Point p; std::cin >> p; Graph graph; // Part 2: input from graphviz boost::dynamic_properties dynamicProperties; dynamicProperties.property("NodeID", boost::get(&Vertex::ID, graph)); dynamicProperties.property("Point", boost::get(&Vertex::p, graph)); dynamicProperties.property("EdgeID", boost::get(&Edge::ID, graph)); std::ifstream file("graph.txt"); try { boost::read_graphviz(file, graph, dynamicProperties, "NodeID"); } catch (std::exception& e) { std::cout << e.what() << std::endl; } return 0; }

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state machine frequence detecting
by Kraus Philipp 23 Jul '12

23 Jul '12

Hello, I need an idea for detecting frequencies. I have got an audio signal and I would check if a sequence of frequences are in the signal eg: I have got this frequencies: 100Hz, 600Hz, 800Hz, so I would create a statemachine that accepts this sequence of frequencies like frequence statemachin st; for each audio sample if signal has st.getFrequence then st.next else st.reset if st.final then accept Frequences and the order of the frequences are stored in a configuration file, so the state machine can have a lot of states. In some cases I can have got something like 100Hz, 600Hz, 800Hz, delay, 100Hz, 600Hz, 800Hz | 1 | | 2 | So the sequence must be accepted if one of the frequence block (1 || 2) is in the final state. I have read the howto about the Boost finale statemachine, but I can not make a decision if the Boost statemaschine is the correct structure to solve this problem. Can anyone help me to discuss the pro / cons for the Boost statemachine in this case? Thanks a lot Phil

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Extracting "friendly" information from boost::exception
by Andreas M. Iwanowski 22 Jul '12

22 Jul '12

Dear boost experts. We are using boost::exception in a project of ours, and are trying to extract some information from an exception to display to the user. For example, diagnostic_information(e) returns this: d:\projects\<project>\ClassName.cpp(376): Throw in function void __thiscall ClassName::CInetExceptionHandler<struct ClassName::BadLoginException>(class CInternetException *) const Dynamic exception type: class boost::exception_detail::clone_impl<struct ClassName::BadLoginException> std::exception::what: Unknown exception [struct tag_implementation_ClassName_SpecificInfo_errstr *] = Error: 12014 Context: 0 Message: The password was not allowed [struct tag_interface_CDataInterface_errstr *] = ClassName reports: Bad FTP login What I want is to extract "Error: 12014 Context: 0 Message: The password was not allowed" or "ClassName reports: Bad FTP login" from that exception. However, these exceptions may be generated in DLLs that the main program know nothing about. To simplify, here is what I do and want ot be happening: 1. Main program calls method in DLL 2. Main program knows this method can throw expections of type boost::exception 3. Main program catches such exception 4. Main program obtains string that is user-friendly from this exception Has anyone acccomplished this or knows how to extract the information from above (ideally not by parsing the string?) Alternatively, could I somehow fill the std::exception::what and then get that information out of boost::exception somehow? Thanks everyone! Mit freundlichen Gr??en / With best regards Andreas Iwanowski - IT Administrator www.awato.de<http://www.awato.de> | namezero(a)afim.info<mailto:namezero@afim.info> T: +49 (0)2133 2969 28 | F: +49 (0)2133 2969 69 awato Software GmbH | Salm Reifferscheidt Allee 37 | D-41540 Dormagen avisor-Support | T: +49 (0)621 6094 043 | F: +49 (0)621 6071 447 [awato Software GmbH] [cid:qrCode-58869986-5cab-4997-b473-f0c11a0058ad21bff0] Gesch?ftsf?hrer: Ursula Iwanowski | HRB: Neuss 7208 | VAT-no.: DE 122796158

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filesystem - test failures
by Robert Ramey 22 Jul '12

22 Jul '12

The boost serialization library tests use boost.filesystem. A number of test scenarios in the serialization library tests suite are really manifestations of failures in the boost filesystem library. a) msvc- 9.0~wm5~stlport5.2 - this combination fails at some level for lack of a file "io.h". b) does filesystem really require RTTI? at least a subset (and maybe more) of the serialization library tests should function in the absense of RTTI but now they all fail since all the tests use filesystem and this in turn depends upon RTTI. Robert Ramey

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