March 2010 - Boost - lists.preview.boost.org

[statechart] Undefined type
by s_a_white＠email.com 16 Mar '10

16 Mar '10

Hi, I've inherited some code that currently compiles and runs under Linux (gcc 4.2.1) and am looking to switch to Windows using the vs 2003 with SP1. Unfortunately the code fails to compile with undefined symbols. An example of the code is as follows: #include <boost/statechart/event.hpp> #include <boost/statechart/state_machine.hpp> #include <boost/statechart/simple_state.hpp> #include <boost/statechart/transition.hpp> #include <iostream> namespace sc = boost::statechart; struct EvStartStop : sc::event< EvStartStop > {}; struct EvReset : sc::event< EvReset > {}; struct Active; struct Stopped; struct Running; struct StopWatch : sc::state_machine< StopWatch, Active > {}; struct Active : sc::simple_state< Active, StopWatch, Stopped > { typedef sc::transition< EvReset, Active > reactions; }; struct Stopped : sc::simple_state< Stopped, Active > { typedef sc::transition< EvStartStop, Running > reactions; }; int main() { return 0; } I'm aware that the code is incomplete as Running is only forward declared. It is provided this way since the real model under Linux is broken up across multiple headers rather than all being in one header. Under Linux the above code compiles without an issue but vs 2003 complains about Running being undefined. Removing sc::transition< EvStartStop, Running > makes the compilation problem disappear. A similiar issue exists for Windows if Running was defined but uses an inner state that was only foward declared. Again Linux seems to have no problems. For vs 2003 wrapping the reactions or inner state with mpl::list<> does not fix the problem. Can anyone suggest if what is being done here is broken under vs 2003, or should not be allowed under gcc? Are there workarounds for the boost headers for vs 2003 or recommendations to allow splitting the state machine across multiple headers? Best Regards, Simon

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[sandbox] need Apache/.htaccess/rsync help
by Eric Niebler 16 Mar '10

16 Mar '10

A bit off-topic, but I don't know who the maintainer of the boost-sandbox project on sourceforge.net is. I use this project to post updated documentation for my boost libraries. (For instance, see <http://boost-sandbox.sourceforge.net/libs/xpressive>.) Today, I tried to update Proto's docs using a script I wrote for this purpose eons ago: #!/bin/sh rsync --delete --rsh=ssh --recursive html/* eric_niebler,boost-sandbox@web.sourceforge.net:/home/groups/b/bo/boost-sandbox/htdocs/libs/proto/doc/html For ages, this has Just Worked, but for some reason, it has recently stopped working. I thought I'd check here before requesting support from SF.net. The behavior I'm now seeing is that I get 403 error for any page in Proto's docs. See: http://boost-sandbox.sourceforge.net/libs/proto/doc/html/index.html The error says: "3. Error notes: Server unable to read htaccess file, denying access to be safe" Wha'? Any help? FYI, here's sf.net's docs on rsync over ssh. From what I can tell, I'm doing everything right: http://sourceforge.net/apps/trac/sourceforge/wiki/Rsync%20over%20SSH#Projec… -- Eric Niebler BoostPro Computing http://www.boostpro.com

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Re: [boost] suggestion on assertion macros
by DE 16 Mar '10

16 Mar '10

hi all on 14.03.2010 at 18:15 Roland Bock wrote : > Hmm. I use gcc (4.2.4) and I get the warning (-Wall -Wextra). That's why > I proposed that code in the other part of this discussion (with great > help from Peter and Steven): > #include <cassert> > #ifdef NDEBUG > #ifdef assert > #undef assert > #define assert(cond) static_cast<void>(sizeof(cond? 0: 0)); > #endif > #endif > int main() { > int i = 0; > assert(i); > } > This way, I get no warning about variable i being unused, it is even > being made sure that the condition for the assertion is verifiable and > still the code results in nothing if NDEBUG is defined. > I plan on using that myself. I think it would be useful for others, too. i came to the same thing this solution works perfect with msvc80 and i feel like going to adopt it for my personal use but i think you missed the order of macro directives if i get it right it should be #ifdef NDEBUG #ifdef assert #undef assert #endif //swapped this and the following lines #define assert(cond) static_cast<void>(sizeof(cond? 0: 0)); #endif and i agree that defining an "advanced" project-specific macro is really a better solution than redefinition of 'assert()' on improving assertions: my only concern was to propose a solution to the warning issue while NDEBUG is defined (and similar situations) i picked 'assert()' only for illustration purposes of course any other assert-like system may (or may not?? i believe it does) be improved in this specific sense my opinion is that specific assertions (like contract statements mentioned) are defined the way the author prefer, i.e. there is no typical restrictions on that so the discussion on "improving assertions" or "contract programming implementation" is not my concern for now and i leave it up to you guys -- Pavel

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invalid null pointer error in serialization with MSVC2008
by h yh 16 Mar '10

16 Mar '10

Hi, I am getting a very strange runtime error using boost serialization library with MSVC2008. I called the following template in my program. template <class T> void loadData(std::string fileName, T &t) { std::ifstream ifs(fileName.c_str()); boost::archive::text_iarchive ia(ifs); t.clear(); ia >> t; ifs.close(); } it gets an assertion failed when running into boost::archive::text_iarchive ia(ifs); Debug Assertion failed: invalid null pointer Here is the stack frame: msvcr90d.dll!memcpy_s(void * dst=0x00000000, unsigned int sizeInBytes=4294967295, const void * src=0x07953f63, unsigned int count=22) Line 55 + 0x2f bytes msvcp90d.dll!std::char_traits<char>::_Copy_s(char * _First1=0x00000000, unsigned int _Size_in_bytes=4294967295, const char * _First2=0x07953f63, unsigned int _Count=22) Line 582 + 0x16 bytes msvcp90d.dll!std::_Traits_helper::copy_s<std::char_traits<char> >(char * _First1=0x00000000, unsigned int _Size=4294967295, const char * _First2=0x07953f63, unsigned int _Count=22, std::_Secure_char_traits_tag __formal={...}) Line 714 + 0x15 bytes msvcp90d.dll!std::_Traits_helper::copy_s<std::char_traits<char> >(char * _First1=0x00000000, unsigned int _Size=4294967295, const char * _First2=0x07953f63, unsigned int _Count=22) Line 706 + 0x22 bytes msvcp90d.dll!std::basic_streambuf<char,std::char_traits<char> >::_Xsgetn_s(char * _Ptr=0x00000000, unsigned int _Ptr_size=4294967295, int _Count=22) Line 342 + 0x1a bytes msvcp90d.dll!std::basic_streambuf<unsigned short,std::char_traits<unsigned short> >::_Sgetn_s(unsigned short * _Ptr=0x00000000, unsigned int _Ptr_size=4294967295, int _Count=22) Line 118 msvcp90d.dll!std::basic_istream<char,std::char_traits<char> >::_Read_s(char * _Str=0x00000000, unsigned int _Str_size=4294967295, int _Count=22) Line 698 + 0x27 bytes msvcp90d.dll!std::basic_istream<char,std::char_traits<char> >::read(char * _Str=0x00000000, int _Count=22) Line 712 MyProject.exe!boost::archive::text_iarchive_impl<boost::archive::text_iarchive>::load() + 0xad bytes MyProject.exe!loadData<std::set<GamingNote,GamingNote,std::allocator<GamingNote> > >(std::basic_string<char,std::char_traits<char>,std::allocator<char> > fileName="nocturne.gnt", std::set<GamingNote,GamingNote,std::allocator<GamingNote> > & t=[0]()) Line 14 + 0x14 bytes It happens when the text_iarchive class constructs, so I am sure it's nothing to do with the serialize function of T, but something between boost and std::ifstream. The wierd thing is I didn't come across this program at the first time. It appears suddenly during development. If I separate the serialization code to a single cpp file, it doesn't have any problem at all. By the way, I am intergrating Qt and Ogre with boost by the way, but that seems not to be quite helpful to identify this problem. Any ideas about that? Yuheng Huang

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boost::log review (printf style api)
by Tom Brinkman 16 Mar '10

16 Mar '10

>> It is actually more relevant than a "flame war." We are discussing how a log API should look to be most useful >> (in terms of depth and width), and that discussion pertains to all (new) libraries of Boost: do we want them >> to be used by the larger C populace? How much are we ready to sacrifice in expressivity (or succinctness) in >> order to widen our target? Should we have C wrappers for the most "utilitarian" libraries, such as a log library? >> My point is that Boost is a C++ library and should not care at all about the impact on C developers, or people >> who happen to be used to that "glue language," even for their C++ development. I still think it is a valid >> discussion to have. Well said. Good summary, although as noted, I disagree with your conclusion. The larger question is -- what has gone wrong with boost? Why do so many libraries languish in the review queue. Why has the the C++ standard taken so long to get enough momentum to pass through committee. In my view, C++ is tired. Boost is an experiment of a particular style of development, that being functional, generic, orthogonal and "non-hieararchical". Boost through its heavily template ladden libraries offered this style of development, and it had great appeal to those who had grown tired of object oriented style of development. The experience of those of us that have developed with this style over the years has been mixed. Like anything, somethings are nice, somethings are more trouble than there worth. Fortunately, for those of us that have an appreciation for functional programming will still be highly relevent in the future. The reason has primarily has to do with parralel programming which lends its self very nicely to functional programming, which is what boost is all about. The way I explain it, functional programming is just a variation of procedural programming with a different way of passing around state. Unfortunately, this advanced programming style is often abused in hideous ways. Particularly, when they are used in small utilty libraries which should be simple and general purpose, and not push a particular style of development. I've already made this point, but I'll make it again. Utility libraries should be agnositic and usable across the widest variety of programming styles, that being procedural, objected orienteated or functional. This boost::log library should not be approved without a simple "C" friendly api. That being a printf style api. Failure to include a "printf" style api will only continue to marginalize boost further to small subset of c++ developers. Most develpers will look at the api without a printf and go, HUH?

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Collection of Jamfiles for 3rd-parties?
by Mateusz Loskot 15 Mar '10

15 Mar '10

Hi, I'm wondering if would it make sense to have a directory in Sandbox or close where Jamfiles for various third-party programs and libraries could be maintained. I imagine it could make it easier to integrate various dependencies with Boost and Boost Sandbox libraries. For example, GIL makes use of libpng, libjpeg, libtiff, libz, gzip/bzip2 are used by others too. I found that HAIKU OS maintains collection of Boost Build enabled libraries: http://dev.haiku-os.org/browser/haiku/trunk/src/libs I'm not suggesting to do the same, but perhaps it would make sense to maintain Jamfiles only, so users can download them and refer to such libraries using symbolic targets. I'm curious of your comments? Best regards, -- Mateusz Loskot, http://mateusz.loskot.net Charter Member of OSGeo, http://osgeo.org

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base class for boost::array
by Peter Myerscough-Jackopson 15 Mar '10

15 Mar '10

Dear all, In using boost::array I have felt the need to pass around boost::array's of an unknown size (unknown to the function receiving the array). I have therefore created an abstract base class for boost::array so that I can create a pointer to a common base class for arrays of different sizes. Essentially std::vector's of different sizes can be passed into a function with a fixed prototype, but because boost::array constructs a different type for each array size, a single fixed prototype cannot be described such that it can be called with different sizes of boost::array. In code I can write (toy functions) : double sumTotal(const std::vector<double>* values) { double result = 0 ; BOOST_FOREACH(double v, values) { result += v; } return result; } But I can't write: double sumTotal(const boost::array<double>* values) { double result = 0 ; BOOST_FOREACH(double v, values) { result += v; } return result; } Without the second function being a template function, i.e. I cannot provide a library that takes a boost::array<double>. With the attached base class, I could define a function that takes a boost::array_base<double>. Since, I think, the ability to allow boost::array to be used in this way is that it requires the use of virtual functions, I have written it so that the inheritance is optional. It is enabled with a #define before including array.hpp . Is this useful? (I am aware that I maybe could use a boost::range) Thanks for your time, Peter Ps. On my current compiler, swap and operator= could not be uncommented in the array_base class. PPs. This is my first post to boost dev, please be kind... J Dr Peter Myerscough-Jackopson - Senior Engineer Tel: +44 (0)23 8076 7808 Fax: +44 (0)23 8076 0602 Web: http://www.macltd.com/ <BLOCKED::http://www.macltd.com/> Email: peter.myerscough-jackopson(a)macltd.com <mailto:peter.myerscough-jackopson@macltd.com> MULTIPLE ACCESS COMMUNICATIONS LIMITED is a company registered in England at Delta House, The University of Southampton Science Park, Southampton, SO16 7NS, United Kingdom with Company Number 1979185 and VAT Number GB 411942866

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[Boost.Locale] New Release
by Artyom 15 Mar '10

15 Mar '10

Hello Boost List! ================= I'm glad to introduce updated version of Boost.Locale library: This library was designed for Boost and created because of needs CppCMS framework. I'm looking forward to formal review and general inputs from Boost.Community. Documentation: http://cppcms.sourceforge.net/boost_locale/html/index.html Download: From: https://sourceforge.net/projects/cppcms/files/ File: https://sourceforge.net/projects/cppcms/files/boost_locale/boost_locale.zip… Boost.Locale is a library that brings high quality localization facilities in C++ way. It provides the natural glue between C++ locales framework, iostreams and powerful ICU library giving: * Correct case conversion, case folding and normalization * Collation including support of 4 Unicode collation levels. * Date, time, timezone and calendar manipulations, formatting and parsing including transparent support of calendars other then Gregorian. * Boundary analysis for characters, words, sentences and line-breaks. * Number formatting, spelling and parsing. * Monetary formatting and parsing. * Powerful message formatting including support plural forms, using GNU catalogs. * Character set conversion. * Transparent support of 8-bit character sets like Latin1. * Support of char, wchar_t and C++0x char16_t, char32_t strings and streams. New in this version: ==================== a. Fully redesigned break iterator interface b. Added date_time and calendar support that allow manipulating with dates over non-Gregorian calendars c. Implemented full set of unit-tests d. Added support of many platforms and compilers. e. Lots of bug fixes. f. Complete reference with Doxygen g. Many tutorial updates, thanks to Markus Raab inputs Tested compilers and platforms: =============================== - Compilers: - GCC 3.4, 4.1, 4.2, 4.3, 4.4 - Intel Compiler 11.0 - SunStudio 12 with STLPort - MSVC 2008 - Operating Systems: - Linux - FreeBSD - OpenSolaris - Windows XP - Windowns XP/Cygwin - ICU Versions: 3.6, 3.8, 4.2 Full list of tests: =================== - Linux: - Debian GNU/Linux 2.6.18, x86, GCC 4.1.2, ICU 3.6.1 - Debian GNU/Linux 2.6.26, x86_64, GCC 4.3.2, ICU 3.8.1 - Debian GNU/Linux 2.6.26, x86_64, GCC 4.4 -std=c++0x, ICU 3.8.1 (Some faults on char16_t/char32_t support) - Debian GNU/Linux 2.6.26, x86_64, Intel Compiler 11.0, ICU 3.8.1 - FreeBSD - FreeBSD 8.0, i386, GCC 4.2.1, ICU 3.8.1 - OpenSolaris: - SunOS OpenSolaris 5.11, i386; Sun Studio 12, with STLPort, ICU 4.2 - SunOS OpenSolaris 5.11, i386; GCC 3.4.3, ICU 4.2 - Windows XP/SP2 - Cygwin 1.5, GCC 3.4, ICU 3.8 - Cygwin 1.5, GCC 4.3, ICU 4.2 - Windows XP/SP2, Mingw/GCC 4.4, ICU 4.2 (Static build only) - Windows XP/SP2, MSVC9 (2008)

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[iterator] Help needed understanding output_iterator requirements
by Thomas Klimpel 15 Mar '10

15 Mar '10

Dear iterator experts, Jesse Perla recently reported that boost::multi_array fails compilation for many basic tasks on MSVC 2010. I investigated the failures, because I had already investigated other failures on MSVC 2010 reported by Jesse Perla for boost::ublas. While I'm quite familiar with boost::ublas, I'm a complete novice with respect to boost::multi_array and boost::iterator. I could track the failures to a specific (intentional?) behavior of iterator_facade from Boost.Iterator (more specifically of facade_iterator_category.hpp): http://lists.boost.org/Archives/boost/2010/03/163039.php Thomas Klimpel wrote: > What effectively happens it that the iterator gets the category > "input_iterator", but std::copy wants to have an "output_iterator". I > think I understand why the iterator doesn't satisfies the requirement > of a "forward_iterator", but it's unclear to me why it didn't qualify > as an "output_iterator". There is an "input_output_iterator_tag" in > "boost/iterator/detail/facade_iterator_category.hpp", so it would have > been possible for the iterator to be both "input_iterator" and > "output_iterator". However, it seems to me that > "input_output_iterator_tag" is never used in the Boost.Iterator > library. I would have to read more about "output_iterator" to > understand whether Boost.Iterator is correct here. With my current > understanding of "output_iterator", I would say it's a bug in > "boost/iterator/detail/facade_iterator_category.hpp". > > Perhaps somebody with more knowledge about "output_iterator" and > Boost.Iterator can explain to me why an iterator using the > "boost::random_access_traversal_tag" for the "CategoryOrTraversal" > template parameter of "iterator_facade" will never get the category > "output_iterator" (or "input_output_iterator_tag"). Of course I could go on and read more about "output_iterator", or find out whether the Boost.Iterator documentation has to say something about this issue, but since I only came to this problem because I wanted to help Jesse Perla on a problem with boost::multi_array, I would much prefer if an "iterator expert" could "take over". Regards, Thomas

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[log] Boost.Log formal review
by Vladimir Prus 15 Mar '10

15 Mar '10

Boosters, the formal review of the Boost.Log library, written by Andrey Semashev, starts now and will run through March 17, 2010. The documentation for the current version is available at: http://boost-log.sourceforge.net The downloads are at: http://sourceforge.net/projects/boost-log Here are the important points: 1. All comments are appreciated. Even if you don't have the time for in-depth study of everything, comments on parts of the library are welcome. In particular, if you are already using logging in your applications and have specialized requirements, you might want to directly check how the proposed library handles them. 2. The reviews and all comments should be submitted to the developers list, boost(a)lists.boost.org and the email should have "[log]" prefix in the subject to make sure it's not missed. The deadline for reviews is 23:59, March 17, PST = 2:59, March 18, EST = 7:59 March 18, GMT = 10:59, March 18 MSK 3. Please explicitly state in your review whether the library should be accepted. 4. The general review checklist is provided below: - 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? Thanks, Volodya

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