November 2005 - Boost-users

Inheritance
by azam . 16 Nov '05

16 Nov '05

Hi, I want to use Boost Graph Library via inheritance. Actually I want to define a graph which is an adjacency_list graph and is created in a special way. I thought of making it a derived class of adjacency_list and then define constructors to construct objects of this class. But my problem is how to (for example) set vertex properties in the constructor? Regularly if I want to add properties to vertices on a graph g, I use vertices(g) to get iterator of vertices and then I use this iterator, but what can I do in the constructor? I have no such graph object there and I can't use "this" reference too. Any help would be really appreciated. Thanks Azam

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[IOStreams] Memory leaks when using zlib_compressor
by Christian Henning 16 Nov '05

16 Nov '05

Hi there, I couldn't find anything in the archives for my problem. Purify is showing several memory leaks when I execute the following program: int _tmain(int argc, _TCHAR* argv[]) { // prepare some data to write unsigned int nSize = 1000000; char* pBits = new char[nSize]; ::memset( pBits , 0 , nSize ); for( unsigned int i = 0; i < nSize; i++ ) { pBits[i] = i; } // write to file io::filtering_ostream out; out.push( io::zlib_compressor() ); out.push( io::file_sink( "test.zip", std::ios::binary )); out << nSize; out.write( pBits , nSize ); // clean up delete[] pBits; return 0; } I think the program is right. I'm using Boost 1.33 with VC 7.1. Here is what purify spits out: [I] Summary of all memory leaks... {268108 bytes, 6 blocks} [I] MPK: Potential memory leak of 196608 bytes from 3 blocks allocated in boost::iostreams::detail::zlib_base::do_init(zlib_params::iostreams::boost const&,bool,(*)(void *,UINT,UINT),(*)(void *,void *),void *) [IOStreams.exe] [W] MLK: Memory leak of 71360 bytes from 2 blocks allocated in boost::iostreams::detail::zlib_base::do_init(zlib_params::iostreams::boost const&,bool,(*)(void *,UINT,UINT),(*)(void *,void *),void *) [IOStreams.exe] Is that a know issue? I guess so, but has it been resolved? Thanks, Christian

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Too many library variants
by Merrill Cornish 15 Nov '05

15 Nov '05

When I built Boost 1.33.0 for MinGW, I just specified the toolset. As a result I got 28! variants on the set of Boost libraries. >From the various file names, I can figure out most of the variants: d = debug mt = multi-threaded s = static but there are other variants which aren't as obvious. For example, what's the distinction among boost-<libname>-mgw-1_33.dll boost-<libname>-mgw-1_33.lib boost-<libname>-mgw.lib The two .lib files have the same sizes and timestamps, so they appear to be the same file with and without the Boost version in the name. Is the idea that if you use the library WITHOUT the version number suffix, then you can upgrade to a new version without having to modify your make file? OK, what's the distinction between the .dll and .lib? I understand that they linker needs one set of information about library function names and entry points while the actual function bodies are needed at run time. However, I thought all of that information is in the .dll file. On the other hand, the .dll version is so much bigger than the .lib that there must be more than an entry point table involved. Then there are the libboost-* variations... I understand that in the Unix world, the -L linker option specifies the library directory while the -l<name> option tells the Unix linker to look for the lib<name>.a file. OK, but how does that work with MinGW's ld.exe linker on Windows. Some of the libraries are available only in the static version, but the only static libraries are the libboost-* variants. There is a statement somewhere in the Boost library documention that the selection of libraries should be automatic in Windows because of pragma's in the libraries. However, I haven't been able to find where MinGW supports that pragma. Merrill

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split() differences between 1.32.0 and 1.33.0
by Dave Dribin 15 Nov '05

15 Nov '05

Hello, I recently upgrade from Boost 1.32.0 to 1.33.0, since I just upgraded to Mac OS X 10.4 from 10.3. I noticed a slightly different behavior in boost::algorithm::split between these two versions. If you have a trailing delimiter, like: vector<string> results; ba::split(results, ",foo,", ba::is_any_of(",")); This returns 2 elements in 1.32.0 and 3 elements in 1.33.0. Was this changed intentionally? It does seem to make more sense to return 3 elements, but it currently breaks my program. -Dave

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[Review] Boost.Logging review result
by Hartmut Kaiser 15 Nov '05

15 Nov '05

Hi all, today I got the following message from John Torjo: <quote> Due to the feedback I got, I would like you to declare the library as rejected. In the light of what Gennady and others have said, indeed, another interface would be best suited for the Boost Log library. With what I know now, I would like to redesign the library from ground up, and ask for another review, probably 6 months from now or so. </quote> In the light of this announcement the review of the proposed Boost.Logging library submitted by John is closed. The library is not included into Boost. I very much hope John will find the time and energy to redesign and resubmit the library in the future. Regards Hartmut Review Manager

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[Boost][Serialization] reset_object_address in 1.33.1 beta?
by Topi Mäenpää 15 Nov '05

15 Nov '05

Hi, reset_object_address is no more a member of polymorphic_iarchive in 1.33.1 beta. Why not? -- Topi Mäenpää CTO, Intopii +358 40 774 7749

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Re: [Boost-users] Too many library variants
by Merrill Cornish 15 Nov '05

15 Nov '05

Jeff, Thanks for mentioning that. I am a bit weird in that I *do* RTFM. While the Boost documentation has a very professional look, I have found in a number of different libraries that the information seems disjoint. It is often difficult to figure out how to do any one thing without reading and comparing a bunch of different pages. For example, you build Boost with bjam, but try to find one listing of what the command line arguments are to bjam. Merrill

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Unit Test problem with wstrings
by Sean Rohead 15 Nov '05

15 Nov '05

I am using the Boost Unit Test library and have code that uses the BOOST_CHECK_EQUAL macro with std::wstring instances. I get a compilation error when I do this because there is no operator<< defined for a narrow ostream and a wide string. So, I created one as shown below, but I am still getting the exact same compilation error (using MSVC 2003). With my new operators, I am able to manually insert wide strings into a narrow ostream, but the BOOST_CHECK_EQUAL macro expansion still doesn't seem to be picking it up. Any ideas? Thanks, Sean Rohead <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< #include <string> #include <iostream> std::wstring widen(const std::string& source) { std::wstring result(source.size(), wchar_t(0)); typedef std::ctype<wchar_t> ctype_t; const ctype_t& ct = std::use_facet<ctype_t>(std::locale()); ct.widen(source.data(), source.data() + source.size(), &(*result.begin())); return result; } std::string narrow(std::wstring source) { std::string result(source.size(), char(0)); typedef std::ctype<wchar_t> ctype_t; const ctype_t& ct = std::use_facet<ctype_t>(std::locale()); ct.narrow(source.data(), source.data() + source.size(), '\u00B6', &(*result.begin())); return result; } std::ostream& operator<<(std::ostream& out, const std::wstring& value) { out << narrow(value); return out; } std::wostream& operator<<(std::wostream& out, const std::string& value) { out << widen(value); return out; } #include <boost/test/unit_test.hpp> void main() { std::string message("message"); std::wstring wmessage(L"MESSAGE"); // THESE TWO LINES COMPILE AND WORK FINE std::wcout << message << std::endl; std::cout << wmessage << std::endl; // THIS LINE STILL DOES NOT COMPILE BOOST_CHECK_EQUAL(wmessage, std::wstring(L"message")); } >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> ------ Build started: Project: boost, Configuration: Debug Win32 ------ Compiling... main.cpp c:\lib\boost_1_32_0\boost\test\test_tools.hpp(207) : error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'const std::wstring' (or there is no acceptable conversion) c:\lib\boost_1_32_0\boost\test\test_tools.hpp(206) : while compiling class-template member function 'void boost::test_tools::tt_detail::print_log_value<T>::operator ()(std::ostream &,const T &)' with [ T=std::wstring ] c:\lib\boost_1_32_0\boost\test\test_tools.hpp(251) : see reference to class template instantiation 'boost::test_tools::tt_detail::print_log_value<T>' being compiled with [ T=std::wstring ] c:\lib\boost_1_32_0\boost\test\detail\wrap_stringstream.hpp(69) : see reference to function template instantiation 'std::ostream &boost::test_tools::tt_detail::operator <<<Left>(std::ostream &,const boost::test_tools::tt_detail::print_helper<T> &)' being compiled with [ Left=std::wstring, T=std::wstring ] c:\lib\boost_1_32_0\boost\test\test_tools.hpp(438) : see reference to function template instantiation 'boost::basic_wrap_stringstream<CharT> &boost::operator <<<char,boost::test_tools::tt_detail::print_helper<T>>(boost::basic_wrap _stringstream<CharT> &,const boost::test_tools::tt_detail::print_helper<T> &)' being compiled with [ CharT=char, T=std::wstring ] c:\Documents and Settings\sean.rohead\My Documents\Visual Studio Projects\boost\main.cpp(43) : see reference to function template instantiation 'bool boost::test_tools::tt_detail::equal_and_continue_impl<std::wstring,std:: basic_string<_Elem,_Traits,_Ax>>(const Left &,const Right &,boost::wrap_stringstream &,boost::test_tools::const_string,size_t,boost::unit_test::log_level,siz e_t)' being compiled with [ _Elem=wchar_t, _Traits=std::char_traits<wchar_t>, _Ax=std::allocator<wchar_t>, Left=std::wstring, Right=std::basic_string<wchar_t,std::char_traits<wchar_t>,std::allocator <wchar_t>> ] Build log was saved at "file://c:\Documents and Settings\sean.rohead\My Documents\Visual Studio Projects\boost\Debug\BuildLog.htm" boost - 1 error(s), 0 warning(s) ---------------------- Done ---------------------- Build: 0 succeeded, 1 failed, 0 skipped

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Boost and fastcall
by Marcus Krantz 15 Nov '05

15 Nov '05

Hi. I'm trying to integrate two applications. The first is configured to use fastcall and the other is using cdecl... The thing is that I get linking errors which says that boost uses thiscall? eh. However, i can change the other application to use fastcall too, but when i try to link the integrated application it says as i mentioned earlier that boost uses thiscall. Can i configure boost to use whatever I want? regards Marcus

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[serialization] About NaNs
by Topi Mäenpää 15 Nov '05

15 Nov '05

Robert, The std::numeric_limits class template has functions for this. I have used the following definition in my code: #ifndef NAN /** * Double-precision not-a-number. Some systems don't have the * C99-standard macro @p NAN defined. GNU gcc does as an extension, * but MSVC doesn't. */ # define NAN std::numeric_limits<double>::quiet_NaN() #endif I don't think serializing signaling NaNs makes any sense, so I suggest using the quiet version. The difference is that computing anything with quiet NaN produces a quiet NaN, whereas signaling NaN raises a FP exception. Furthermore, the result of computation with sNaN is not very well defined. I'd like to add one to your count of NaN users. I'm using it in many occasions, typically indicating an "undefined" or "not applicable" situation. Due to the aforementioned property, it is easy to track back calculation errors if undefined values are involved. (Just find the first non-NaN intermediate result.) Saving "I haven't yet defined the value of this formula" with a NaN makes sense to me. BR, Topi On Sun, 2005-11-13 at 16:02 -0800, Robert Ramey wrote: > Truth is, I don't even know how one goes about assigning a NaN or a > +/inf to floating/double variable !! > > Robert Ramey -- Topi Mäenpää CTO, Intopii +358 40 774 7749

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