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[Review] Formal review of Boost.Convert library starts Saturday
by Edward Diener 21 Apr '11

21 Apr '11

This is a reminder that formal review of the Boost.Convert library by Vladimir Batov starts on Saturday, April 23, and is scheduled to last through May 2. *************** * Its Purpose * *************** From the introduction: Boost.Convert builds on the boost::lexical_cast experience and still offers a simple, minimal interface, familiar conversion behavior and more: * throwing and non-throwing behavior when conversion fails; * support for the default/fallback value to be returned when conversion fails; * two types of the conversion-failure check - basic/simple and better/safe; * formatting support based on the standard std::streams and std::stream-based manipulators (like std::hex, std::scientific, etc.); * support for different locales; * support for boost::range-compliant char and wchar_t-based string containers (std::string, std::wstring, char const*, wchar_t const*, char array[], etc.); * no DefaultConstructibility requirement for the Target/Destination type; * extendibility and additional room to grow. ******************* * Where to get it * ******************* You can find the Boost.Convert here: http://www.boostpro.com/vault/index.php?action=downloadfile&filename=boost-… The HTML documentation is part of the distribution and can be found at libs/convert/index.html in the distribution above. ******************** * Writing a review * ******************** The reviews and all comments should be submitted to the developers list, and the email should have "[convert] Review" at the beginning of the subject line to make sure it's not missed. Please explicitly state in your review whether the library should be accepted. The general review checklist: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With what compiler? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? And finally, every review should answer this question: - Do you think the library should be accepted as a Boost library? Be sure to say this explicitly so that your other comments don't obscure your overall opinion. Edward Diener, Review Manager

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BOOST_AUTO and boost::fusion
by Niitsuma Hirotaka 21 Apr '11

21 Apr '11

This cause err BOOST_AUTO(xx , boost::fusion::list<double,int,double>(1.12, 3 ,3.4) ); How to use BOOST_AUTO with boost::fusion ?

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[serialization] Best way to serialize to an old file version
by Richard Ulrich 21 Apr '11

21 Apr '11

What is the best way to write archives to an old version? Say I have version 23 of our product and want to write an archive that another user with version 22 can read. The serialization keeps track of the version on a class level. But in this use case I need to know the version of each class at a specific point in time. Sure, I could implement some global variable and completely work around the version system of boost serialization. But I hope there is a better, preferred way. Rgds Richard

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[Review] Type Traits Extension by Frederic Bron - Review summary and decision
by Joel Falcou 20 Apr '11

20 Apr '11

Hello all, Frederic Bron's type traits extension proposal review ended up last week. In so far, we received SEVEN reviews which are all voting YES for the inclusion of Type Traits extension in Boost. So the result is that the Type Traits Extension is ACCEPTED into Boost. Suggestions include: - some clean-up in the implementation like "Renam[ing] the detail classes inside the specific namespace without using number, i.e. with a clear meaning. The use of tag, tag 2 could be renamed check_pass, check_fail or something like that." - Sensibility on cv-ref qualifiers in traits call is important. This is being addressed by Frederic. - Frederic is OK to keep the detection of void as a valid return type by using some dont_check type as default. - small comprehensive example of some of the traits like a "maybe_print function, which prints a value if the appropriate operator<< ostream overload exists, else prints "<NOT PRINTABLE>". [...] a small example like this would show a practical use of the library, and how to make use of enable_if, or some other overload method." - The main recurring suggestions found was the choice of name for the operator traits with respect to the standard naming, naming in proto and other boost libraries. This topic is still hot and alive. An alternative to the naming scheme consensus was proposed in the form of alias of commonly used operator traits. This issue is I think beyond bikeshed-color argumentation and I think it is a good point if Frederic could step up and provide a definite and rationalized answer to this point. The current status is : * the namespace options is out casue the standard didnt choose this way; * Frederic and a few other seems to favor the proto naming scheme (more or less the negate issue and the pre/post operator) * the question of a common prefix is still open * the std:: like naming seems limited as not all operators are there. Thanks to all reviewers and people participating to the discussions. Thanks to Frederic for his work.

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boost::filesystem - replace_extension question
by Archie14 20 Apr '11

20 Apr '11

I am constructing full path out of directory (c:\temp), filename(test) and extension (txt). boost::filesystem::path mypath(dir); // mypath="c:\temp" mypath /= filename; // mypath="c:\temp\test" If I call mypath.replace_extension("txt") it will fail because there is no dot character yet. To proceed further I have to add "." using direct string manipulation, that kind of break the logic of using filesystem::path. Question: how to construct full path using directory, filename and extension strings using only filesystem::path methods?

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boost::filesystem::current_path().string()
by buster buster 20 Apr '11

20 Apr '11

(11:23:04 PM) epure_: hi (11:23:13 PM) epure_: i'm using "boost::filesystem::current_path().string()" from a dll (11:23:27 PM) epure_: windows 7, it prints the paths to the executable which uses the DLL (11:23:38 PM) epure_: window xp , it prints the path to my desktop (11:23:54 PM) epure_: how do I make it so that it behaves like windows 7 ? Thanks, epure

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[BGL] vis passed by value to depth_first_visit
by Shaun Jackman 20 Apr '11

20 Apr '11

Hi, I recently learned the hard way that the visitor parameter, vis, is passed by value to depth_first_visit, but passed by reference to detail::depth_first_visit_impl. I was writing a function that implemented depth_first_search, but starts each of the visits at vertices with indegree == 0. If my depth_first_search replacement calls boost::depth_first_visit, each call to depth_first_visit makes a copy of the output iterator, which doesn't work for an output iterator with any state (such as a pointer). Calling an internal boost function like detail::depth_first_visit_impl doesn't seem like a good plan. How should I solve this? My short-term work around is to use an output iterator that does not have any state, such as a back_inserter. Cheers, Shaun

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error C2825: 'F': must be a class or namespace when followed by '::'
by simone pilozzi 20 Apr '11

20 Apr '11

Dear Users, I am using a pointer to a function member with the std::transform alorithm. The class is a QuantLib class called DayCounter and the method is called yearFraction and takes in two mandatory dates and two optionals to return the corresponding year fraction. *yearFraction ( QuantLib::Date t1,QuantLib::Date t2,QuantLib::Date t3 = Date(),QuantLib::Date t4=Date())* Now I tried to fill a vector called yearfracs in this way boost::shared_ptr<QuantLib::DayCounter> dc( new QuantLib::ActualActual); QuantLib::Date t = todaysDate() std::vector<QuantLib::Time> yearfracs; std::transform(subsample.begin(),subsample.end(), yearfracs.begin(),boost::bind(&QuantLib::ActualActual::yearFraction,&dc,t,_2)) subsample is the originary vector of dates. The compiler reported the following error error C2825: 'F': must be a class or namespace when followed by '::' What is the correct syntax for doing this? Thanks in advance Simone

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A problem with using boost::regex
by Michael Lindner 20 Apr '11

20 Apr '11

I have been a boost users for years, but this is the first time I've come across a problem with using it. I'm posting this in the hopes that one of you will say "oh yeah you did 'X' wrong", because I have been beating my head against the wall with this for some time. Thanks for taking a look. -- Michael Lindner I have the following program: #include "boost/regex.hpp" #include <string> int main(int argc, char** argv) { std::string re("[123]abc"); boost::regex reg(re); return 0; } It compiles and runs just fine on my Mac and Linux machines. On Windows, however, it compiles fine, and runs fine compiled under the "Debug" configuration. When I change that to "Release" however, it crashes with the following stack trace: msvcr90.dll!7858cc9d() msvcr90.dll!7858ccb5() dme.exe!boost::re_detail::w32_ transform() + 0xd5 bytes C++ dme.exe!boost::re_detail::w32_regex_traits_implementation<char>::transform() + 0x21 bytes C++ dme.exe!boost::re_detail::find_sort_syntax<boost::re_detail::w32_regex_traits_implementation<char>,char>() + 0x64 bytes C++ dme.exe!boost::re_detail::w32_regex_traits_implementation<char>::w32_regex_traits_implementation<char>() + 0x399 bytes C++ dme.exe!boost::object_cache<unsigned int,boost::re_detail::w32_regex_traits_implementation<char> >::do_get() + 0x28f bytes C++ dme.exe!boost::object_cache<unsigned int,boost::re_detail::w32_regex_traits_implementation<char> >::get() + 0x69 bytes C++ dme.exe!boost::re_detail::create_w32_regex_traits<char>() + 0x1b bytes C++ dme.exe!boost::re_detail::regex_data<char,boost::regex_traits<char,boost::w32_regex_traits<char> > >::regex_data<char,boost::regex_traits<char,boost::w32_regex_traits<char> > >() + 0x5d bytes C++ dme.exe!boost::basic_regex<char,boost::regex_traits<char,boost::w32_regex_traits<char> > >::do_assign() + 0x5f bytes C++ > dme.exe!boost::basic_regex<char,boost::regex_traits<char,boost::w32_regex_traits<char> > >::assign(const char * p1=0x0012ff4c, const char * p2=0x0012ff54, unsigned int f=0) Line 380 C++ dme.exe!boost::basic_regex<char,boost::regex_traits<char,boost::w32_regex_traits<char> > >::assign<std::char_traits<char>,std::allocator<char> >(const std::basic_string<char,std::char_traits<char>,std::allocator<char> > & s="[123]abc", unsigned int f=0) Line 418 C++ dme.exe!boost::basic_regex<char,boost::regex_traits<char,boost::w32_regex_traits<char> > >::basic_regex<char,boost::regex_traits<char,boost::w32_regex_traits<char> > ><std::char_traits<char>,std::allocator<char> >(const std::basic_string<char,std::char_traits<char>,std::allocator<char> > & p="[123]abc", unsigned int f=0) Line 393 C++ dme.exe!main(int argc=1, char * * argv=0x00345628) Line 9 C++ I am using boost 1.46.0 Microsoft Visual Studio 2008 Version 9.0.30729.1 SP Microsoft .NET Framework Version 3.5 SP1

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Interval: checking for equality
by gast128 20 Apr '11

20 Apr '11

Hello all, I was (mis)using the interval library for time intervals. However the equality operator fails for a simple test: boost::numeric::interval<int> intv1(1, 3); boost::numeric::interval<int> intv2 = intv1; //throws bool b = (intv1 == intv2); probably i don't understand the whole idea about this interval arithmetic library then. Could somebody tell me what I do wrong?

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