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Mutually exclusive options in boost::program_options?
by Marshall Clow 09 Jan '06

09 Jan '06

I'm trying to use boost::program_options for the first time, and there's a couple things that I am tripping over. The first is the idea of mutually exclusive options. I can't find any support for them in the library, and that surprises me - to the point of asking for help. I have two options, only one of which can be specified; say -frtti and -fno_rtti (say). The other one is that program_options, by default, wants to use double hyphens to define options: "foo --option1 --option2" I'm a lot more comfortable with single hyphens: "foo -option1 -option2" Am I missing something basic here? -- -- Marshall Marshall Clow Idio Software <mailto:marshall@idio.com> It is by caffeine alone I set my mind in motion. It is by the beans of Java that thoughts acquire speed, the hands acquire shaking, the shaking becomes a warning. It is by caffeine alone I set my mind in motion.

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Error when including date_time files
by Rob Marsden 09 Jan '06

09 Jan '06

I am having trouble with some date_time files. The following code (from the boost documentation): #include "boost/date_time/posix_time/posix_time.hpp" #include "boost/date_time/local_time_adjustor.hpp" #include "boost/date_time/c_local_time_adjustor.hpp" #include <iostream> int main() { return(0); } gives me errors C:\LOCAL\INCLUDE/boost/date_time/posix_time/time_formatters_limited.hpp(77): error: more than one operator "<<" matches these operands: function "std::basic_ostream<_E, _Tr>::operator<<(std::_Bool={bool={bool}}) [with _E=char, _Tr=std::char_traits<char>]" function "std::basic_ostream<_E, _Tr>::operator<<(short) [with _E=char, _Tr=std::char_traits<char>]" function "std::basic_ostream<_E, _Tr>::operator<<(unsigned short) [with _E=char, _Tr=std::char_traits<char>]" function "std::basic_ostream<_E, _Tr>::operator<<(int) [with _E=char, _Tr=std::char_traits<char>]" function "std::basic_ostream<_E, _Tr>::operator<<(unsigned int) [with _E=char, _Tr=std::char_traits<char>]" function "std::basic_ostream<_E, _Tr>::operator<<(long) [with _E=char, _Tr=std::char_traits<char>]" function "std::basic_ostream<_E, _Tr>::operator<<(unsigned long) [with _E=char, _Tr=std::char_traits<char>]" function "std::basic_ostream<_E, _Tr>::operator<<(float) [with _E=char, _Tr=std::char_traits<char>]" function "std::basic_ostream<_E, _Tr>::operator<<(double) [with _E=char, _Tr=std::char_traits<char>]" function "std::basic_ostream<_E, _Tr>::operator<<(long double) [with _E=char, _Tr=std::char_traits<char>]" operand types are: std::basic_ostream<char, std::char_traits<char>> << boost::posix_time::time_duration::fractional_seconds_type << frac_sec; ^ C:\LOCAL\INCLUDE/boost/date_time/posix_time/time_formatters_limited.hpp(140): error: more than one operator "<<" matches these operands: ...similar ^ C:\LOCAL\INCLUDE/boost/lexical_cast.hpp(156): error: no operator ">>" matches these operands operand types are: std::basic_stringstream<char, std::char_traits<char>, std::allocator<char>> >> boost::int64_t stream >> output && ^ detected during: instantiation of "bool={bool} boost::detail::lexical_stream<Target, Source>::operator>>(InputStreamable &) [with Target=boost::int64_t={__int64}, Source=boost::detail::array_to_pointer_decay<std::basic_string<char, std::char_traits<char> , std::allocator<char>>>::type, InputStreamable=boost::int64_t={__int64}]" at line 221 instantiation of "Target boost::lexical_cast<Target,Source>(const Source &) [with Target=boost::int64_t={__int64}, Source=std::basic_string<char, std::char_traits<char>, std::allocator<char>>::_Myt]" at line 94 of "C:\LOCAL\INCLUDE/boost /date_time/time_parsing.hpp" instantiation of "time_duration boost::date_time::parse_delimited_time_duration<time_duration>(const std::string &) [with time_duration=boost::posix_time::time_duration]" compilation aborted for C:\Research\DogWood\TextAnalysis\Parser\BoostTest\BoostTest.cpp (code 2) Error executing xicl6.exe. The environment is compiler Intel v9.0 in the VC6 IDE under Win2k Can anyone suggest a solution? -- Rob Marsden Gistix (Northern) Limited

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[MPL] sorting sequence according to inheritance hierarchy
by Slawomir Lisznianski 09 Jan '06

09 Jan '06

Hello, I'm trying to find a solution to the following problem. Given types A, B and C such that C is derived from B and B is derived from A, and a sequence S1 which stores A, B and C (in arbitrary order): 1) transform S1 so resulting sequence S2 would have elements sorted according to their relative position within their inheritance hierarchy (say, most derived first). 2) when one introduces another type, D, which doesn't inherit from any of A, B or C, after sorting S1, it would end up at the end of S2. 3) the solution needs to be unintrusive for the "input" types, that is, it ought to work for existing types. Example ------- Input: S1 = { A, C, D, B }; Expected result, after sorting: S2 = { C, B, A, D }; Purpose ------- By finding a way to sort S1 according to predicates listed above, I hope to come up with a generic exception-handling mechanism (used in RPC-like library), example: typedef vector<E0, E1, .. ,En> sorted_exception_decl; try { func(); } catch(at<sorted_exception_decl, int_<0> >::value const & E0) { .. } catch(at<sorted_exception_decl, int_<1> >::value const & E1) { .. } catch(at<sorted_exception_decl, int_<n> >::value const & En) { .. } Your thoughts on how sane this idea is are greatly appreciated. -- Slawomir Lisznianski Paramay Group, LLC "Programs for Research Machinery"

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date_time: convert to and from a timeval
by Thomas Lemaire 09 Jan '06

09 Jan '06

Dear list, I would like to convert ptime and time_duration to and from the standard timeval type. So that I can use all the operators available for ptime and time_duration I found that this topic has already been discussed here: http://lists.boost.org/Archives/boost/2003/06/49197.php The conclusion was: "" Ok will do. I'll add some protections or rounding for when durations support higher than microsecond resolution. I'll let you know when this gets added. Thx, Jeff "" This message was sent on 2003-06-23. I cannot find any thing related to timeval in the doc of boost 1.33. Did I miss something ? Also doc about xtime in boost.threads does not help that much... http://www.boost.org/doc/html/xtime.html cheers, -- thomas

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iterators
by jens-theisen＠gmx.de 09 Jan '06

09 Jan '06

Hello, Say a library programmer wants to make a virtual interface to his class with a function that returns a collection of things. Usually one end up writing something silly like class interface { ... virtual std::vector< ... > give_stuff() const; }; which has some disadvantages, the most important being: - The implementing function must calculate the whole result, even if some of it might not be needed. Especially infinite collections of things are not possible in this way. - The vector is a container and that's a poorly defined concept. As a consequence, we can't do very much with it. For instance, you can't write give_stuff() + give_more_stuff() to concatenate. Though it's easy to implement that, we really don't want to do this on the basis of containers in general and we also don't want to do it again and again in every single project for std::vector in particular. - As the library gets used, it's poor interface is carved in stone, and so are the other two problems for it. The first problem can be addressed by using an iterator to some container. We obviouly can't use an iterator to a vector since that wouldn't solve any problems. It has to be a custom iterator class lib_iterator_impl : ... { ... virtual ... dereference() const; virtual ... advance() const; }; class lib_iterator { ... lib_iterator(lib_iterator_impl const* impl); }; class interface { ... virtual lib_iterator give_stuff() const; }; where lib_iterator_impl than has to be extended by the client of the library. Actually, there is no real need for lib_iterator to be a proper iterator in the standard sense. Especially, such iterators could be aware of there ends (or even their beginnings) to make it unnecessary to have always two of them. Both the virtualisation and halving the number of those iterators would also reduce the complexity of error messages. On such a framework, many small building blocks could be build, like concatenation, filtering, mapping, cartesian products, etc. In my opinion, at least the very low-level parts of such a framework are so important that they belong in boost. My question at this point is in what regard people share this opinion and to what extend we already have these things. I have heard of any_iterator in the past, but I can't find anything about it in the boost malings list archives or google, which would be related to this. Other than this, I'm not aware of anything in this regard. Cheers, Jens

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Re: [Boost-users] Please don't reply to digests
by Phil Endecott 08 Jan '06

08 Jan '06

David Abrahams wrote: > Please don't reply to digests. > > http://www.boost.org/more/discussion_policy.htm#quoting Which says: Do not reply to digests if you are a digest delivery subscriber. Your reply will not be properly threaded and will probably have the wrong subject line. Instead, you can reply through the GMane web interface. The GMane interface doesn't work for posting messages, I've tried it; the mailing list rejects messages from non-subscribers, including those that come via GMane. There is a trade-off here: - On one hand, replying to digests means that threaded views using references: headers will not work properly. (There is no need for the subject line to be wrong, but it isn't difficult to forget to change it when replying.) - On the other hand, prohibiting digest subscribers (like me) from sending replies means that you won't hear from me again. You may or may not consider that a good thing. I do try to reply to questions on the rare occassions that someone even newer to Boost than me asks a question that I have an answer to, and I do so in the hope that this lets the more expert readers (Dave!) concentrate on more important things. I'd like to encourage a debate - which is considered more important, better threading or more contributions? If you don't want to hear from me again, that's fine, I'll unsubscribe until I next have a question of my own to ask. Regards, --Phil.

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installing BGL-python
by Jeff Abrahamson 08 Jan '06

08 Jan '06

I'm installing the Boost Graph Library python bindings on a Debian testing machine. BGL-python appears not to be available as a .deb, so I am installing from source. http://www.osl.iu.edu/~dgregor/bgl-python/ The readme suggests I run $BOOST_ROOT/tools/build/jam_src/build.sh. This directory exists, but the file does not. It also suggests I run "bjam <options>". I can't think of any options I want a priori [ ;-) ] so I run bjam with no options, but to no avail: jeff@krypton:bgl-python-0.9 $ bjam Unable to load Boost.Build: could not find "boost-build.jam" --------------------------------------------------------------- Attempted search from /home/jeff/tmp/bgl-python-0.9 up to the root and in these directories from BOOST_BUILD_PATH and BOOST_ROOT: /usr/share/boost-build. Please consult the documentation at 'http://www.boost.org'. jeff@krypton:bgl-python-0.9 $ BTW, Boost.Build does not exist on my machine. I'm not clear on what should cause it to exist. Googling largely points me to the above. I'm a bit confused, clearly. Can anyone offer a pointer? Thanks much. -- Jeff Jeff Abrahamson <http://www.purple.com/jeff/> +1 215/837-2287 GPG fingerprint: 1A1A BA95 D082 A558 A276 63C6 16BF 8C4C 0D1D AE4B

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[Boost.Python] newbie: Lifetime of objects
by Sergey Sikorskiy 08 Jan '06

08 Jan '06

Hello everyone. I'm trying to map into python classes shown below. class A { friend class B; public: ~A(void) {} private: A(B& b) : m_B(&b) { } B* m_B; }; class B { friend class C; public: ~B(void) {} A* make_a(void) { return new A(*this); } private: B(C& c) : m_C(&c) { } C* m_C; }; class C { public: ~C(void) {} B* make_b(void) { return new B(*this); } }; C* make_c() { return new C(); } Objects are supposed to be created in the order C, B, A and destroyed in the order A, B, C. I do not want to map constructors of A, B and C. I can see three ways to do what I want: 1) class_<A>("A", no_init); class_<B>("B", no_init) .def("make_a", &B::make_a, return_internal_reference<>()) ; class_<C>("C", no_init) .def("make_b", &C::make_b, return_internal_reference<>()) ; def("make_c", make_c, return_value_policy<manage_new_object>()); 2) class_<A>("A", no_init); class_<B>("B", no_init) .def("make_a", &B::make_a, return_value_policy<manage_new_object>()) ; class_<C>("C", no_init) .def("make_b", &C::make_b, return_value_policy<manage_new_object>()) ; def("make_c", make_c, return_value_policy<manage_new_object>()); 3) class_<A, shared_ptr<A>, noncopyable>("A", no_init); class_<B, shared_ptr<B>, noncopyable>("B", no_init) .def("make_a", &B::make_a, return_value_policy<manage_new_object>()) ; class_<C, shared_ptr<C>, noncopyable>("C", no_init) .def("make_b", &C::make_b, return_value_policy<manage_new_object>()) ; def("make_c", make_c, return_value_policy<manage_new_object>()); C::make_b and B::make_a are supposed to return shared_ptr<B> and shared_ptr<A> respectively in this case. After debugging this code I've got strange results: - In case 1 objects aren't get deleted at all; - In case 2 objects are get deleted in wrong order; - In case 3 objects are get deleted in wrong order; Cases 2 and three seem to be identical to me. The only difference I can see is that in case 3 I should manage objects lifetime by myself from C++ code. In opposite, in case 2 objects lifetime will be managed by python. I couldn't get an answer to my problem neither from documentation nor from Boost.Python tests nor from Google. Any explanations or suggestions will be greatly appreciated. Thank you. -- Sergey Sikorskiy

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Re: [Boost-users] Boost-users Digest, Vol 760, Issue 2
by Ryan McGann 08 Jan '06

08 Jan '06

On Dec 19, 2005, at 9:00 AM, boost-users-request(a)lists.boost.org wrote: >> 1) The build.sh file for the boost bjam tool in the 1.33.0 and 1.33.1 >> release seems to have DOS line endings. I know there are prebuilt >> binaries of bjam up on the Web, but our build system builds it >> manually, and it choked on Darwin because sh didn't like the DOS line >> endings. I resaved the file with Unix line endings and it built fine. > > Did you download the tar.gz distribution? That should have Unix line > endings throughout where as the .zip file has DOS line endings > throughout > (intensionally). Well our build system uses whichever archive is checked in. I imagine the PC folks downloaded the .zip version. I can check in a different version for the Unix folks. >> 2) I get errors for multiply defined symbols for the placeholder >> symbols declared in boost/bind/placeholders.hpp. Every file that >> #include <boost/bind.hpp> contains actual instances of _1, _2, etc. >> Changing the declarations of these in boost/bind.hpp to static (I >> added a __APPLE__ to the #ifdef in the middle of the file) fixes this >> issue, but then I get warnings for unused static symbols if I don't >> use the placeholder objects. This issue in particular is quite >> annoying. > > What compiler are you using? The first #if says: > > #if defined(__BORLANDC__) || defined(__GNUC__) > > isn't this the branch that gets taken? Hm in my boost/placeholders.hpp, I see #if defined(__BORLANDC__) ... #elif defined(BOOST_MSVC) || (defined(__DECCXX_VER) && __DECCXX_VER <= 60590031) || defined(__MWERKS__) ... #else ... #endif I don't have a _GCC__ anywhere in there. This is from 1.33.1 (which I just newly expanded from the .tar.gz, not the .zip). If I add a defined(__GCC__) to the first or second set of #ifdefs, it works fine. >> 3) The header in boost/compatibility/cpp_c_headers/cstdio >> does not match up with the cstdio file included with the Mac OS X dev >> tools. >> In particular it is missing a using ::snprintf, which causes problems >> because this cstdio file is being included BEFORE the Mac OS X >> version of the same file, and other C++ header files rely on >> std::snprtinf being declared. I fixed this at first by deleting the >> boost/compatibility/cpp_c_headers folder, but then ending up just >> deleting that single file so that OS X always used the built-in >> header file. > > Why are those headers getting included? They were intended for use > only > with certain broken compilers that didn't have the c-prefixed std lib > headers. They're known not to work with several std conforming > compilers > (but shouldn't be included for these anyway). I'm not sure why they're being included. I'm guessing it's because we pass -I<path to boost> to GCC, which causes it to search inside of that directory before the standard directories get searched. I'll have to investigate that further. Thanks, Ryan

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[Graph] Maximum common subgraph
by Andreas Sæbjørnsen 08 Jan '06

08 Jan '06

Hi, Lately I have been looking for a good C/C++ implementation of an algorithm for finding the maximum common subgraph in Boost::Graph. The algorithms I have looked for is mainly Bron-Kerbosch and the MCS algorithm, but I am very open for alternatives. The implementation must be able to handle directed graphs containing self-loops (it is possible to have two edges at the same time between two nodes i->j, j->i). Do you know of any implementation? Thanks Andreas Saebjornsen

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