February 2009 - Boost - lists.preview.boost.org

[date_time] Trouble with operator+ and microsec(BIG_NUMBER)
by Christoph Mathys 19 Feb '09

19 Feb '09

Hello I'm using date_time on a 32b Ubuntu machine (1.36, gcc 4.2.4). The following code shows the problem (at least on my machine): (compiled with -O2 -Wall, without warnings) #include <iostream> #include <boost/date_time/posix_time/posix_time.hpp> #include <boost/date_time/gregorian/gregorian_types.hpp> using namespace std; namespace bpt = boost::posix_time; int main(int, char**) { const int64_t timeInNs = 1235051546649264674LL; const bpt::ptime EPOCH(boost::gregorian::date(1970, 1, 1)); bpt::ptime offset = EPOCH + bpt::microsec(timeInNs / 1000); cout << offset << std::endl; return 0; } I expect this program to print a date after 1.Jan 1970. However, I get the following output: 1969-Dec-21 19:28:13.710725 If I change timeInNs to 1235051546649264LL (I removed the last 3 digits), the date is after 1.1.1970. Whats wrong? Christoph

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[log] Review-ready version in the Vault
by Andrey Semashev 19 Feb '09

19 Feb '09

After a long time of documenting, polishing and testing I'm glad to announce that Boost.Log has reached the level where public review request can be submitted. The automatic tests aren't entirely complete, however, the basic functionality is covered and most of what is not covered has been tried by hand. Major changes since my last publicly announced version: * Substantial documentation improvement. * Added several Windows-specific sinks: Event Log (simplified and advanced), Windows debugger and experimental Event Trace for Windows Vista and later. * Loggers now consist of a number of independent features that can be composed the way the user needs. User-defined features can be developed and injected into the mix. * Attribute value extractors improved. With the new extract function attribute values can be extracted from the attribute values view by employing lambda functors. * Some files and classes were moved or renamed to improve code clarity and shorten names. * A number of bugs fixed. * Added tests. The archive with the library source code, tests and docs is available in the Vault: http://tinyurl.com/cm9lum The online docs are also available on the SourceForge page: http://boost-log.sourceforge.net The latest code snapshot can be downloaded from CVS on the SourceForge project page: http://sourceforge.net/projects/boost-log The code should be compatible with Boost 1.38. Might also work with 1.37, but I didn't try. Comments are welcome.

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Proposal: Post-Release Maintenance Team (WAS Re: [test] [gcc-4.3.2] check_is_close and check_is_small issues)
by Dean Michael Berris 19 Feb '09

19 Feb '09

On Thu, Feb 19, 2009 at 3:58 PM, Juergen Hunold <juergen.hunold(a)ivembh.de> wrote: > Hi Dean ! > > On Thursday 19 February 2009 02:34:05 Dean Michael Berris wrote: > >> Thanks for these links! Did they apply cleanly to Boost 1.38.0 for >> you? I tried both (in the given order above) and I got some rejections >> when I applied them to a cleanly unpacked distribution. > > Well, actually not ;-(( > I think you can safely ignore the patch to utils/runtime/cla/parameter.hpp as > this just fixes a regression which happened in between the changes. > I'll dig further into this and ask the maintainer for permission to merge at > least the warning fixes to the release branch. > Alright. Now this time, would there be any objections if I (or other people) tried managing a patch release for 1.38.0? Would anybody else be interested in helping release a 1.38.1 with fixes hand-ported from trunk to 1.38.0? I've found some Jamfile fixes required to work around the (I'm guessing, now defunct) 'message' function in Boost.Build v2 that's bundled with Boost 1.38 that might be worth looking at. I'm also interested in bringing in a newer version of Boost.Build from the nightly builds into the 1.38.0 release to be packaged as 1.38.1; HTH -- Dean Michael Berris | Software Engineer, Friendster, Inc. blog.cplusplus-soup.com | twitter.com/mikhailberis | linkedin.com/in/mikhailberis | profiles.friendster.com/mikhailberis | deanberris.com

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[Serialization] BOOST_CLASS_EXPORT regression on SunCC
by Sohail Somani 19 Feb '09

19 Feb '09

>From version 1.34 to 1.35, the export of classes was modified so that all the archives did not need to be included before calls to BOOST_CLASS_EXPORT. I don't know why this was a problem to begin with. Anyway, this feature used to work on SunCC but with the new changes, there is a regression. This is caused by the dependence on ADL to instantiate the ptr_serialization_support members: SunCC just doesn't do it. So the instantiations never occur and you get an assertion failure when running the serialization tests under debug: Assertion failed: it != boost::serialization::singleton< oserializer_map<Archive> >::get_const_instance().end(), file vendor/boost_1_37_0/boost/archive/impl/archive_pointer_oseri\ alizer.ipp, line 64 I know how to fix it (instantiating manually for each Archive,Serializable pair, not a huge problem). I would suggest that Boost Serialization should have a fallback mechanism for these compilers. Perhaps along the lines of the old export functionality where the user would define the archives they are interested in. Thoughts?

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Architecture Analysis of the boost libraries, e.g. spirit
by Bernhard Merkle 18 Feb '09

18 Feb '09

Hi boost developers, I have a question regarding the architecture of boost libraries. First some (short) background info: I have done some architectural analysis in the past for C++, C and Java projects. It is a static toolbased analysis approach and essentially it enables you to compare the "should"-architecture with the "is"-architecture. Nearly all projects suffer from some architectural decay over time (e.g. unwanted dependencies etc.) So I was interested how well those tools for architectural analysis cope with C++ template code and boost is an ideal candidate. :-) I have already successfully analyzed the boost spirit library. The architecture for spirit is documented under http://www.boost.org/doc/libs/1_38_0/libs/spirit/classic/doc/organization.h… and if that is still the "should"-architecture then i was already able to find some deviations/violations in the "is"-architecture. So my question: should all modules of Core (scanner, primitives, composite, non_terminal) be independent of each other ? other questions: - are there architectural documents for the other libraries ? - which would be good candidates from your point of view ? (I think e.g. analyzing dependencies to the mpl libs is interesting) - is there a common rule which parts are public and which are private ? (I saw some impl directories but am a bit unsure about the API stuff) - is there a document describing the dependencies between the different libs (the "should" architecture). (I know of the bcp tool but this documents the "is"architecture essentially) sorry for the long post, but I think this is really interesting stuff and I am open to contribute in the architectural area :-) kind regards, Berni.

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Re: [boost] Formal Review Request: Boost.String.Convert
by Vladimir.Batov＠wrsa.com.au 18 Feb '09

18 Feb '09

Upgraded to the version 0.10. Added boost::string::is_string<T> SFINAE-based check. That allowed to discriminate the applicability of conversion functions. Now they demand one of the parameters to be a string (in broad sense, like C strings, std::(w)string, chat/wchar_t-based containers) and the other *not* a string. Have straighten up the main boost::string::convert() interface (was quite broken) so that all the tests now run as expected. g++ 4.2.4 (Linux) and Visual Studio 2008 are happy. Thanks, Vladimir.

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[future|interprocess] Could futures live in shared memory and synchronize process?
by vicente.botet 18 Feb '09

18 Feb '09

Hi, I'm working on Boost.Synchro a synchronization library that try to provide generic synchronization mechanism that can be used so synchronize threads or process. As a future is a synchronization mechanism, I was wondering if futures are intrisic of mutil-threaded programs and so they live in the protected process memory or if the concept can be used in a multi-process context and have futures/promises living on shared memory. Ion, what do you think, could it be possible to use futures/promises to synchronize process? Have some one a specific use case for this? Best regards, _____________________ Vicente Juan Botet Escribá

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[alogrithm] compile error with VS2008 in debug build (boost 1.38)
by Hansi 18 Feb '09

18 Feb '09

Hello, I have a strange problem. When I make a debug build from my program which uses minmax_element I get the following compile error: 1>c:\program files\microsoft visual studio 9.0\vc\include\utility(57) : error C2664: 'std::_Vector_iterator<_Ty,_Alloc>::_Vector_iterator(const std::_Vector_iterator<_Ty,_Alloc> &)' : cannot convert parameter 1 from 'int *const ' to 'const std::_Vector_iterator<_Ty,_Alloc> &' 1> with 1> [ 1> _Ty=int, 1> _Alloc=std::allocator<int> 1> ] 1> Reason: cannot convert from 'int *const ' to 'const std::_Vector_iterator<_Ty,_Alloc>' 1> with 1> [ 1> _Ty=int, 1> _Alloc=std::allocator<int> 1> ] 1> No constructor could take the source type, or constructor overload resolution was ambiguous 1> d:\projects\sandbox\boosttests\statistic\statistic.cpp(43) : see reference to function template instantiation 'std::pair<_Ty1,_Ty2>::pair<int*,int*>(const std::pair<int *,int *> &)' being compiled 1> with 1> [ 1> _Ty1=std::_Vector_iterator<int,std::allocator<int>>, 1> _Ty2=std::_Vector_iterator<int,std::allocator<int>> 1> ] 1>c:\program files\microsoft visual studio 9.0\vc\include\utility(57) : error C2664: 'std::_Vector_iterator<_Ty,_Alloc>::_Vector_iterator(const std::_Vector_iterator<_Ty,_Alloc> &)' : cannot convert parameter 1 from 'int *const ' to 'const std::_Vector_iterator<_Ty,_Alloc> &' 1> with 1> [ 1> _Ty=int, 1> _Alloc=std::allocator<int> 1> ] 1> Reason: cannot convert from 'int *const ' to 'const std::_Vector_iterator<_Ty,_Alloc>' 1> with 1> [ 1> _Ty=int, 1> _Alloc=std::allocator<int> 1> ] 1> No constructor could take the source type, or constructor overload resolution was ambiguous Is this a know issue. Is something wrong in my program? Best regards Hansjörg #include <algorithm> #include <vector> #include <iostream> #include <boost/algorithm/minmax_element.hpp> #include <boost/array.hpp> #include <boost/timer.hpp> using namespace boost; using namespace std; typedef array<int,100000000> dataarray; void do_tests(dataarray& data) { { timer t; std::pair< std::vector<int>::iterator, std::vector<int>::iterator > result = boost::minmax_element(data.begin(), data.end()); cout<<"min_max: minmax_element:"<<t.elapsed()<<endl; cout<<"minVal="<<*result.first<<",maxVal="<<*result.second<<endl; } } dataarray data; int main(int argc, char const* const* argv) { cout << "sorted array:" << endl; for(unsigned int i = 0; i< data.size();i++) { data[i] = i; } do_tests(data); cout << "random array:" << endl; std::srand(0); for(unsigned int i = 0; i< data.size();i++) { data[i] = std::rand(); } do_tests(data); return 0; }

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_SECURE_SCL for msvc
by Hansi 18 Feb '09

18 Feb '09

Hello, the problem with _SECURE_SCL define was already discussed a few times on this list. But til now it came never to a end. Is there any interrest to get also compiled libraries for _SECURE_SCL enabled and _SECURE_SCL disabled? I think this would be really important because this compiler switch changes the abi and for that programs can crash. I think that a lot of people disable it already in their own programs, but may be they don't compile the boost libraries with this switch... Any comments? Regards Hansjörg

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Re: [boost] Review Request: Introduction of boost::string namespace and string-conversion functions
by Vladimir.Batov＠wrsa.com.au 18 Feb '09

18 Feb '09

Thank you all who replied so far. It is very much and truly appreciated. Tally for far 1. The idea in principle seems to be largely accepted. Phil Endecott raised a concern if the effort was not a wheel-reinvention due to string/number conversions in N2408. I feel N2408 does not have as broad scope and has serious limitations (no user-type conversions, no handling of any container<char>, etc.) 2. The name of the namespace. People largely seem content with "boost::string". Andrey Semashev expressed a concern that the name was too generic and could clash with std::string (using namespace boost; using namespace std). A fair point. However, I do not feel it is a boost::string "problem" per se but rather the "problem" with using-directives (or rather mis-using-directives). Using-directives beat the whole purpose on a namespace and best avoided (see Stroustrup 8.2.3). From my actual experience it was not an issue. Long time ago I've introduced aux::string in two sizeable projects and honestly did not have one single complain about name clashing. Bo Persson also expressed a concern siting it'll make it "very hard to propose the utilities for inclusion in a future language standard". May be. May be not. When things of that magnitude happen (which seem quite remote at present) components get moved from a namespace to a namespace (several times) anyway. Like some stuff from the "boost" namespace moving to the "tr1" namespace just ultimately to be moved to the "std" namespace. Therefore, unless something major comes up later we are settling on "boost::string". 3. Naming of the conversion functions. The "to/from/is" set seems to sit well with the majority of people. The to_string/from_string was floated around as alternatives. I feel that the "_string" extension indeed serves a mildly useful purpose when the "string" namespace is obfuscated. Like namespace boost::string obfuscated; string str = obfuscated::from(i); // What the...? string str = obfuscated::to_string(i); // Somewhat better but still... When used sensibly string str = boost::string::from(i); or namespace boost::string str; string str = str::from(i); the intention seems clear and the following feels like a tautology: string str = boost::string::to_string(i); Robert Stewart mentioned that "is" is a poor name choice. It doesn't imply "can convert to" and can be expensive to execute. Fair enough. I'll keep the name around as a placeholder for a rainy day. We might not need it at all if we agree on something along the following lines: // No throw, return default on failure, dunno if failed. int i = boost::string::to<int>(str, default_value); // No throw, return default on failure, can check if failed. boost::string::value i = boost::string::to<int>(str, default_value); if (i.good()) successfully converted 4. String-To-Something Conversion Interface. Considerable number of people were not exactly happy with my off the cuff int i = boost::string::to<int>(str)(default_value); Well, I do not like it either... I just like saying/suggesting things that I regret later. :-) I probably got carried away by the functional-chain-ability concept. The main reason (for me) it is not good is that it imposes the default-constructibility requirement. I think people on the original lexical_cast-realted thread were pretty content with int i = boost::string::to<int>(str, -1); syntax. If so, then we won't need int i = to(str).or_default(-1) int i = to(str, default_ = -1) Can we agree on the following interface: template<class T, class String> boost::string::value<T> boost::string::to(String const&, T const& =T()) throw(); The usage is // Does not throw, returns -1 on failure. Don't care if failed int i1 = boost::string::to<int>(str, -1); // Does not throw, returns -1 on failure. Care if failed boost::value<int> i2 = boost::string::to<int>(str, -1); if (i2.good()) successful conversion6. 5. Formatting with manipulators. I've implemented a prototype and it works just fine. string str = "0xFF"; int i1 = boost::string::to<int>(str, -1) >> std::hex; // returns 255 int i2 = boost::string::to<int>(str, -1)(std::hex); // Same as above For the time being I keep both interfaces (via () and >>). 6. Something-To-String Conversion Interface. That did not seem to generate much heat at all. I'll summarize to make sure we see it the same way: template<class T> boost::string::value<std::string> boost::string::from(T const&) throw(); Does not throw. No default value (do we need one?). Returns string() of failure. Usage: std::string s1 = boost::string::from(-1); // 'int' type deduced std::string s2 = boost::string::from<double>(-1); // 'double' type forced std::string s3 = boost::string::from(15) >> std::hex; // returns "0xF" if (s1.empty()) conversion failed boost::string::value<std::string> s4 = boost::string::from(-1); if (s4.good()) conversion succeeded 7. Check-Convertibility Interface. If we agree on the behavior above (using boost::string::value), then the separate boost::string::is does not seem needed. 8. Throw/No-Throw Behavior. You might have noticed that the interface above *never* throws anything on failure. I would like to highlight the fact (as it's different from lexical_cast behavior) and make sure people are happy with it. Those who need an exception thrown could do boost::value<int> i2 = boost::string::to<int>(str, -1); if (!i2.good()) throw something youself; Is it satisfactory? 9. Requested features. a) Handling any container<char> (Phil Endecott). I implemented a rough cut using boost::range and it handles std::(w)string, char/wchar_t const* with ease. To handle any container we might look into extending the interface with something like template<class T, class Range> boost::string::value<T> boost::string::to(Range const&, T const& =T()) throw(); I have not looked into it throughly yet though. b) Integration with Spirit (Hartmut Kaiser). My focus is currently on the interface. Then, we can look at Spirit+boost-string behind it as a separate issue as it requires Joel (and other Spirit developers) involved. c) locale. I have not looked into it at all and I am not sure I am well-qualified. OTOH I hope it'll fit into the proposed interface as string s3 = boost::string::from(15) >> std::hex >> locale-related-functionality; or string s3 = boost::string::from(15)(std::hex)(locale-related-functionality); If so, then we can return to the issue when we get all the above taken care of. Thanks, Vladimir.

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