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boost.interval for tracking floating point rounding errors
by Frank Hess 02 Sep '05

02 Sep '05

Hi, I'm curious if it is possible to make boost.interval more convenient to use for tracking floating point rounding errors. Currently, you run into problems if you do naive things like boost::numeric::interval<double> x(0.1); since the 0.1 value gets rounded once by the compiler before the interval constructor ever sees it. Also, things like boost::numeric::interval<double> y(2), z; z = 0.1 * y; have similar problems. -- Frank

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Operators with boost::reference_wrapper
by Edson Tadeu 02 Sep '05

02 Sep '05

Although boost::reference_wrapper has a casting operator to T&, when I use any operator on a reference_wrapper, I get a compiler error stating that "boost::reference_wrapper<T> does not define this operator or a conversion to a type acceptable to the predefined operator". E.g, this should compile, but doesn't: #include <string> #include <iostream> #include <boost/ref.hpp> using namespace std; using namespace boost; void main() { string s1 = "alfa"; string s2 = "beta"; reference_wrapper<string> rs1 (s1); reference_wrapper<string> rs2 (s2); bool test = rs1 < rs2; // Error here cout << rs1; // Error here too } Why is that? I'm using MSVC 7.1.

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Using bind / lambda to create a functor that (1) ignores arguments, and (2) returns a constant
by Stephen Gross 02 Sep '05

02 Sep '05

Is there a way to use bind and/or lambda to create a functor that: (1) Takes as input a single argument (that is ignored), and (2) Returns a constant value. Ideally, something along the lines of: bind(constant(5), _1) // _1 is passed but ignored. Thanks, --Steve Stephen Gross Case Western School of Medicine Cleveland, OH "By Grabthar's hammer, by the sons of Worvan, you shall be avenged." - Dr. Lazarus

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Reference information for lamba
by Stephen Gross 02 Sep '05

02 Sep '05

I'm trying to find reference documentation for the lambda library. I've found the main documentation on boost's website, but not reference information. Is it available somewhere? --Steve

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Error using boost_serialization
by Sebastien Gerega 02 Sep '05

02 Sep '05

Can anyone tell me what is wrong with the following code: #include <iomanip> #include <iostream> #include <fstream> #include <string> #include <boost/archive/tmpdir.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> #include <boost/serialization/base_object.hpp> #include <boost/serialization/utility.hpp> #include <boost/serialization/list.hpp> #include <boost/serialization/string.hpp> *class* ResData{ *friend* *class* boost::serialization::access; *friend* std::ostream& *operator*<<(std::ostream &os, const ResData& rD); *private*: std::string resName; int seqNum; int insNum; float sAS; *public*: ResData(); ResData(std::string, int, int); std::string getResName() const { *return* resName;} int getSeqNum() const { *return* seqNum;} int getInsNum() const { *return* insNum;} float getSAS() const { *return* sAS;} void setSAS(float sASP) { sAS = sASP;} *template*<*class* Archive> void serialize(Archive&, const unsigned int); }; std::ostream& *operator*<<(std::ostream& os, const ResData& rD){ *return* os << rD.getResName() << rD.getSeqNum() << rD.getInsNum() << rD.getSAS(); } int main(){ std::ofstream oFSBS("/home/Seb/Code/testData/results.dat"); boost::archive::text_oarchive oA(oFSBS); ResData temp("TEST", 1, 1); temp.setSAS(5555); oA << temp; oFSBS.close(); } I get the following error upon compilation: /usr/include/boost/archive/detail/oserializer.hpp: In function ‘void boost::archive::save(Archive&, T&) [with Archive = boost::archive::text_oarchive, T = ResData]’: /usr/include/boost/archive/basic_text_oarchive.hpp:78: instantiated from ‘void boost::archive::basic_text_oarchive<Archive>::save_override(T&, int) [with T = ResData, Archive = boost::archive::text_oarchive]’ /usr/include/boost/archive/detail/interface_oarchive.hpp:85: instantiated from ‘Archive& boost::archive::detail::interface_oarchive<Archive>::operator<<(T&) [with T = ResData, Archive = boost::archive::text_oarchive]’ test.cpp:54: instantiated from here /usr/include/boost/archive/detail/oserializer.hpp:566: error: invalid application of ‘sizeof’ to incomplete type ‘boost::STATIC_ASSERTION_FAILURE<false I am running FC4 with gcc4.0.1 thanks, Sebastien

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Regex compilation failure with MSVC .NET 2002 and bjam
by Ovanes Markarian 02 Sep '05

02 Sep '05

Dear all, I am trying to build the regex library from boost 1.33 release with Visual C++ .NET 2002 and bjam. I constantly get this error (while trying to build it with ICU and without). my command line is: bjam "--with-regex" "-sTOOLS=vc7" "--prefix=E:\projects\Automation\thirdparty\boost" "--builddir=E:\projects\Automation\thirdparty\boost\build" "-sHAVE_ICU=0" "-sICU_PATH=E:\projects\Automation\thirdparty\icu\source" install I was trying to switch -sHAVE_ICU option between 0 and 1 and always got this output for regex cpp files. The error(s) is in German (I don't know why MS decided to translate C++ compiler to German, but I have no other alternative at the moment and suffer very much with it as well...). The error means: cannot form a qualified name (=Ein qualifizierter Name kann nicht gebildet werden) see reference to class template instantiation boost::re_detail::regex_iterator_traits<T>' being compiled (=Siehe Verweis auf Instantiierung der kompilierten Klassenvorlage) Full output is: vc-C++ E:\projects\Automation\thirdparty\boost\build\bin\boost\libs\regex\build\ libboost_regex.lib\vc7\release\threading-multi\icu.obj cl : Befehlszeile warning D4029 : Die Optimierung ist im Standardcompiler nicht verf?gbar. icu.cpp E:\projects\Automation\thirdparty\boost_1_33_0\boost\regex\v4\iterator_traits.hp p(34) : error C2825: 'T::iterator_category': Ein qualifizierter Name kann nicht gebildet werden E:\projects\Automation\thirdparty\boost_1_33_0\boost\regex\v4\sub_match. hpp(31) : Siehe Verweis auf Instantiierung der kompilierten Klassenvorlage 'boos t::re_detail::regex_iterator_traits<T>' with [ T=const int * ] C:\Program Files\Microsoft Visual Studio .NET\Vc7\include\vector(259) : Siehe Verweis auf Instantiierung der kompilierten Klassenvorlage 'boost::sub_mat ch<BidiIterator>' with [ BidiIterator=const int * ] E:\projects\Automation\thirdparty\boost_1_33_0\boost\regex\v4\regex_form at.hpp(34) : Siehe Verweis auf Instantiierung der kompilierten Klassenvorlage 's td::vector<_Ty,_Ax>' with [ _Ty=boost::sub_match<const int *>, _Ax=std::allocator<boost::sub_match<const int *>> ] Does someone know what is the problem and how I can fix it? With Kind Regards, Ovanes Markarian

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[Test] Template specialization problems with BOOST_CHECK_EQUAL_COLLECTIONS
by Will Bryant 02 Sep '05

02 Sep '05

Hi all, I've been using Boost.Test lately and in general it's working well (thanks Gennadiy!). However, I'm having trouble with BOOST_CHECK_EQUAL_COLLECTIONS when my collections are of non-primitive types. For example, if I try: vector<wstring> test1, test2; BOOST_CHECK_EQUAL_COLLECTIONS(test1.begin(), test1.end(), test2.begin(), test2.end()); I get a compiler error along the lines of "h:\libraries\boost\boost\test\utils\wrap_stringstream.hpp(66) : error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'const std::basic_string<_Elem,_Traits,_Ax>' (or there is no acceptable conversion)" (with _Elem being wchar_t in this case, and _Traits and _Ax having the usual defaults). Looking at the source I see that BOOST_CHECK_EQUAL_COLLECTIONS is using equal_coll_impl, which is creating a predicate_result and using the stream insertion operator on the wrap_stripstream returned by its message() method. wrap_stringstream has an unspecialized template which delegates to the << operator of the backing ostringstream/ostrstream: template <typename CharT, typename T> inline basic_wrap_stringstream<CharT>& operator<<( basic_wrap_stringstream<CharT>& targ, T const& t ) { targ.stream() << t; return targ; } Since that backing ostringstream descends from ostream, I would have thought that all I needed to do was to ensure that there is a operator << (ostream&, wstring const&) defined, like this: ostream& operator << (ostream& ostr, wstring const& str) { ostr << "I'd put a wstring-to-string function here instead of this constant"; return ostr; } Hower this doesn't work - although I can now compile: ostringstream oss; oss << wstring(L"test"); successfully, if I try: boost::wrap_stringstream wss; wss << wstring(L"test"); or: boost::test_tools::predicate_result res(true); res.message() << wstring(L"test"); I get the same error as above. Interestingly, if I change that << operator implementation so that it takes and returns a wrap_stringstream, instead of an ostream: boost::wrap_stringstream& operator << (boost::wrap_stringstream& ostr, const wstring& str) { ostr << "I'd put a wstring-to-string function here instead of this constant"; return ostr; } then I can compile 'wss << wstring(L"test")' and ' res.message() << wstring(L"test")' OK. This is weird because it suggests to me that that unspecialized wrap_stringstream template that delegates to the ostringstream's << isn't working properly. But weirder is that even having done that, using BOOST_CHECK_EQUAL_COLLECTIONS still produces the same compilation error, even though it's making the same operator call - I can't see why. Am I missing something here? I also tried specializing print_log_value: namespace boost { namespace test_tools { namespace tt_detail { template<> struct print_log_value<std::wstring> { void operator()(std::ostream& ostr, const std::wstring& str) { ostr << "I'd put a wstring-to-string function here instead of this constant"; } }; }}} But that didn't help either - same error. I'm primarily using Visual Studio 2005, but I have exactly the same problems under gcc 3.3.5 too. Any suggestions? Cheers, Will -- Will Bryant http://carcino.gen.nz/ will(a)core-dev.co.nz +64 21 655 443

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[serialization] bug with new_cid != cid
by Sergey Skorniakov 01 Sep '05

01 Sep '05

Following code produced assert at line 444 in libs/serializatin/src/basic_iarchive with version 1.32.0, 1.33.0 and with every archive that's headers are included: #define BOOST_SERIALIZATION_DYN_LINK #include <boost/archive/polymorphic_iarchive.hpp> #include <boost/archive/polymorphic_oarchive.hpp> #include <boost/archive/polymorphic_text_iarchive.hpp> #include <boost/archive/polymorphic_text_oarchive.hpp> #include <boost/archive/polymorphic_xml_iarchive.hpp> #include <boost/archive/polymorphic_xml_oarchive.hpp> #include <boost/archive/polymorphic_binary_iarchive.hpp> #include <boost/archive/polymorphic_binary_oarchive.hpp> #include <boost/archive/xml_iarchive.hpp> #include <boost/archive/xml_oarchive.hpp> #include <boost/archive/binary_iarchive.hpp> #include <boost/archive/binary_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> #include <iostream> #include <sstream> #include <boost/serialization/map.hpp> int main(int argc, char* argv[]) { std::pair<int, int> a(11, 22); std::map<int, int> b; b[0] = 0; b[-1] = -1; b[1] = 1; std::stringstream ss; { std::pair<int, int> *pa = &a; std::map<int, int> *pb = &b; boost::archive::binary_oarchive oa(ss); oa << boost::serialization::make_nvp("B1", pb); oa << boost::serialization::make_nvp("A1", pa); } std::cout << ss.str(); { std::pair<int, int> *pa = 0; std::map<int, int> *pb = 0; boost::archive::binary_iarchive ia(ss); ia >> boost::serialization::make_nvp("B1", pb); ia >> boost::serialization::make_nvp("A1", pa); delete pa; delete pb; } return 0; } Similar program without nvp's has the same problem: int main(int argc, char* argv[]) { std::pair<int, int> a(11, 22); std::map<int, int> b; b[0] = 0; b[-1] = -1; b[1] = 1; std::stringstream ss; { std::pair<int, int> * const pa = &a; std::map<int, int> * const pb = &b; boost::archive::text_oarchive oa(ss); oa << pb; oa << pa; } std::cout << ss.str(); { std::pair<int, int> *pa = 0; std::map<int, int> *pb = 0; boost::archive::text_iarchive ia(ss); ia >> pb; ia >> pa; delete pa; delete pb; } return 0; }

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[boost.lambda] Problem with combining if_then_else_return and bind?
by Stuart Dootson 01 Sep '05

01 Sep '05

Hi - I've been trying to use the if_then_else_return feature of Boost.Lambda, and have run into a problem using Lambda's bind with this feature. My minimal example (at the end of the message) fails when compiled with the VC7.1 command line "cl -c -EHsc -DBAD" (the -DBAD is to compile the non-compiling code). The error message (attached as err.txt) indicates that return type deduction has failed at some point, I guess. The compiling version of the code differs from the non-compiling version by assigning the bind result to a variable. This seems to enable correct return type deduction. No other forms using lambda and bind that I've tried have exhibited this problem. So, the question is - is this a bug in Lambda or am I doing something wrong? Oh, I've also tried this with gcc 3.4.2 (Mingw version) and it behaved the same as VC7.1. Stuart Dootson #include <boost/lambda/lambda.hpp> #include <boost/lambda/bind.hpp> #include <boost/lambda/if.hpp> #include <boost/function.hpp> using namespace boost::lambda; bool Test1(char); void Fn(char c, bool b) { bool flag; #if defined(BAD) boost::function<bool(char)> fn = if_then_else_return(var(b), bind<bool>(&Test1, _1), constant(false) ) ; #else bool blah; boost::function<bool(char)> fn = if_then_else_return(var(b), var(blah)=bind(&Test1, _1), constant(false) ) ; #endif }

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Thread cancellation
by Sliwa, Przemyslaw (London) 01 Sep '05

01 Sep '05

Hi, Can anyone tell me if it is possible to cancel a thread using boost.thread library? Thanks Pshemek -------------------------------------------------------- If you are not an intended recipient of this e-mail, please notify the sender, delete it and do not read, act upon, print, disclose, copy, retain or redistribute it. Click here for important additional terms relating to this e-mail. http://www.ml.com/email_terms/ --------------------------------------------------------

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