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Depth limited search in Boost
by diojenez 27 Jun '08

27 Jun '08

Hello, Is anyone aware of an implementation of depth-limited search (http://en.wikipedia.org/wiki/Depth-limited_search) in boost? I don't think it is possible to implement with the existing depth_first_search... Thanks! -- View this message in context: http://www.nabble.com/Depth-limited-search-in-Boost-tp18146533p18146533.html Sent from the Boost - Users mailing list archive at Nabble.com.

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DateTime: Request for additional time_duration methods
by Peter Klotz 27 Jun '08

27 Jun '08

time_duration in Boost 1.35.0 has an is_negative() method. I need exactly the opposite: time_duration td; while (td.is_positive()) { // reduce td in some way } I am aware, that I can use td.ticks()>0, but since is_negative() already exists, it would be nice to have also the following methods for completeness and symmetry: bool time_duration::is_positive() const bool time_duration::is_zero() const So for all non special value time_duration instances one of the above methods would return true, the other two false. Best regards, Peter.

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Obtain Locale Langage... more precisely LCID
by Germain BARRET 26 Jun '08

26 Jun '08

What is good way to obtain the locale settings of the system ? I've seen that test_locale.cpp is stored in regress... so if it is deprecated, what is the up to date method ? For example if I want to obtain the LCID (codes in 2 parts giving locale language) what can I use ? I don't want to treat numbers, money or so what.. but only get langage !!! Can I do it with boost ?

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[statechart] history transitions make state-local-storage "un-cool"
by Mick Hollins 26 Jun '08

26 Jun '08

Apologies if this has been discussed before, but I couldn't find any mention of it: I am currently using the history facility of boost::fsm. I've discovered that when I re-enter a state, X, via a history transition I don't actually re-enter the same instance of X that I was in before, but instead enter a newly constructed instance of X. I just checked the UML spec regarding history transitions and it says that "Any necessary entry actions are performed", so given that boost::fsm uses constructors to represent entry actions I guess a new instance of X has to be constructed to ensure UML compliance. My actual concern is the effect this has on the "coolness" of state-local-storage (see http://boost-sandbox.sourceforge.net/libs/statechart/doc/faq.html#Whats_so_…) It seems to me that state-local-storage, which I agree is generally cool, is particularly un-cool (and bug-inducing) in the presence of history transitions. I'm not sure what a good alternative is, but just thought I'd raise the discussion. cheers, mick PS: does the history facility display the same semantics in boost::statechart? I plan to move to statechart real soon now ...

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[program_options] does collect_unrecognized work for config files?
by Marty Fried 26 Jun '08

26 Jun '08

I've got program_options working for a program that has a configuration file. Aside for some program options, the file contains one or more aliases that the user defines for a server/port value, and we don't know what the alias might be until they run the program; then we search for the alias and use its value. I seems like the collect_unrecognized function would be convenient for us, but I can't seem to make it work. I passed it the parsed_options.options member, and I can see the values in there, with the string_key set correctly, and the value set correctly, and the unregistered flag set to true. But the string array result is empty. My code looks something like this: parsed_options parsed = parse_config_file(ifs, options_desc, true); vector<string> unregistered = collect_unrecognized(parsed.options, exclude_positional); What would really be convenient would be a flag to allow the unrecognized entries to be added to the map, so then, when the user enters the alias, I could just retrieve that entry from the map. Should this work for a config file? If so, what might I be doing wrong? And if not, any suggestions for how I might get it to work, aside from just parsing the file again? Thanks for your help, -- Marty Fried Senior software engineer Aldon http://www.aldon.com

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Boost::Multi_array performances
by Joel FALCOU 26 Jun '08

26 Jun '08

Hello, is there tests or references that deals with access speed to multi-array elements ? Thanks in advance -- Joel FALCOU Research Engineer @ Institut d'Electronique Fondamentale Université PARIS SUD XI France

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boost lambda problems
by Olaf Peter 26 Jun '08

26 Jun '08

Hi, the following code crashs: #include <boost/cstdint.hpp> #include <boost/lambda/lambda.hpp> #include <boost/lambda/algorithm.hpp> #include <cstring> // memset #include <iostream> union block { char buffer[512]; int integer[128]; }; std::size_t sum( block* blk ) { using namespace boost::lambda; std::size_t sum = 0; std::for_each( &blk->buffer, &blk->buffer + sizeof( blk->buffer ), sum += *_1 ); return sum; } int main() { using namespace boost::lambda; block blk; std::memset( &blk.buffer, '1', sizeof( blk.buffer ) ); std::for_each( &blk.buffer, &blk.buffer + sizeof( blk.buffer ), std::cout << *_1 << '\n' ); std::cout << sum( &blk ) << std::endl; } I'm not sure for the iterator initialization - maybe this fails. I did not wrote C style iterators for a long time and forgot this obviously. What's up here? The goal is the get the sum of the chat buffer. Do I have to protect the sum variable in function sum? Thanks, Olaf

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boost shared_ptr and parent child relation ships
by gast128 26 Jun '08

26 Jun '08

Dear all, maybe this an off-topic issue, because it does not directly relate to shared_ptr and is more related to life time of objects and their validity during construction and destruction. There were the following issues: 1) childs validity depends on availability of parent and vise versa 2) in ctor one can not use the shared_from_this() 3) in destructor of the child the parent shared_ptr was inaccesible ad 1) the doc's are clear: you can not make a cycle in shared_ptrs between parent -> child and child -> parent. Thus now we use a weak_ptr for child -> parent, but actually the child can not exist without parent. So if one shares a child through a shared_ptr, a hypothetical situation could exist that its parent get destroyed, but a child lifes on (in an invalid state due to missing parent) because a client has requested it. ad 2) this is quite unhandy, since I thought it would be handy to let the parent create the childs passing itself. I think this can only be solved by two way construction. This may well turn out to be a fundamental problem. Consider two classes A and B which are associated with each other. Object of class A is valid when it is valid itself and when its associated object of class B is valid. When A gets changed it is temporalily invalid. It updates first B, but if B asks services from A during that call, it asks an invalid object. Reversing the order may help, but A may have to update itself again after it calls B. For two related classes it can be overseen, but of course real life applications have 1000 or more classes. Btw to some extend Bertrand Meyer's book touches this subject, but he only mentions the problem within a class (with public and private members). ad 3) the destructor of the child needed the parent to call another class. However the parent was inaccessible because it was destroyed itself. This is of course also a fundamental problem because when an object gets destroyed not all of its members may be valid (the parent object is in an invalid state), so calling the parent at that time was questionable too. The real problem was that it needed form the parent its parent which was still valid, solutions are obvious (but ugly) Sample code: struct Child; struct Parent; struct Child { Child(boost::shared_ptr<Parent> ptrParent) { m_ptrParent = ptrParent; } ~Child() { boost::shared_ptr<Parent> ptrParent = m_ptrParent.lock(); if (ptrParent) { //never come here } } boost::weak_ptr<Parent> m_ptrParent; }; struct Parent : public boost::enable_shared_from_this<Parent> { Parent() { //won't work: //m_ptrChild.reset(new Child(shared_from_this())); } boost::shared_ptr<Child> m_ptrChild; }; void TestParentChild() { boost::shared_ptr<Parent> ptrParent(new Parent); ptrParent->m_ptrChild.reset(new Child(ptrParent)); } wkr, me

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[Serialization] OpenSUSE 11.0 / g++ 4.3.1 issues
by Ruediger Berlich 26 Jun '08

26 Jun '08

Hi there, when trying to compile Boost 1.35 on a vanilla OpenSUSE 11.0 system (which runs g++ 4.3.1), the serialization library fails to compile. The error messages are shown at the end of this mail. I did not find any corresponding reports on the mailing lists. Is this a known problem ? The serialization library seems to properly build in the current trunk version (as of June 26). Note, though, that I didn't test its functionality. The iostreams library fails to build in the trunk version, which I assume is due to the beta status. Best Regards, Ruediger P.S.: BTW: Is there some more or less automated way in which I can contribute to platform tests ? I.e., I'd just like to download a beta version of a new release, build it in my environment and let the build system deal with the specifics of reporting failures. OpenSUSE seems to frequently have problems with Boost, so this might be worth it. /************************************************************************/ Serialization-related error messages, Boost 1.35 on vanilla OpenSUSE 11.0 ------------------------------------------------------------------------- ...found 3940 targets... ...updating 4 targets... gcc.compile.c++ bin.v2/libs/serialization/build/gcc-4.3/release/threading-multi/polymorphic_iarchive.o In file included from libs/serialization/src/polymorphic_iarchive.cpp:18: ./boost/archive/polymorphic_iarchive.hpp:88: error: ‘virtual void boost::archive::polymorphic_iarchive_impl::load(int64_t&)’ cannot be overloaded ./boost/archive/polymorphic_iarchive.hpp:84: error: with ‘virtual void boost::archive::polymorphic_iarchive_impl::load(long int&)’ ./boost/archive/polymorphic_iarchive.hpp:89: error: ‘virtual void boost::archive::polymorphic_iarchive_impl::load(uint64_t&)’ cannot be overloaded ./boost/archive/polymorphic_iarchive.hpp:85: error: with ‘virtual void boost::archive::polymorphic_iarchive_impl::load(long unsigned int&)’ "g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline -Wall -fPIC -pthread -DBOOST_ALL_NO_LIB=1 -DBOOST_SERIALIZATION_DYN_LINK=1 -DNDEBUG -I"." -c -o "bin.v2/libs/serialization/build/gcc-4.3/release/threading-multi/polymorphic_iarchive.o" "libs/serialization/src/polymorphic_iarchive.cpp" ...failed gcc.compile.c++ bin.v2/libs/serialization/build/gcc-4.3/release/threading-multi/polymorphic_iarchive.o... gcc.compile.c++ bin.v2/libs/serialization/build/gcc-4.3/release/threading-multi/polymorphic_oarchive.o In file included from libs/serialization/src/polymorphic_oarchive.cpp:18: ./boost/archive/polymorphic_oarchive.hpp:86: error: ‘virtual void boost::archive::polymorphic_oarchive_impl::save(int64_t)’ cannot be overloaded ./boost/archive/polymorphic_oarchive.hpp:83: error: with ‘virtual void boost::archive::polymorphic_oarchive_impl::save(long int)’ ./boost/archive/polymorphic_oarchive.hpp:87: error: ‘virtual void boost::archive::polymorphic_oarchive_impl::save(uint64_t)’ cannot be overloaded ./boost/archive/polymorphic_oarchive.hpp:84: error: with ‘virtual void boost::archive::polymorphic_oarchive_impl::save(long unsigned int)’ "g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline -Wall -fPIC -pthread -DBOOST_ALL_NO_LIB=1 -DBOOST_SERIALIZATION_DYN_LINK=1 -DNDEBUG -I"." -c -o "bin.v2/libs/serialization/build/gcc-4.3/release/threading-multi/polymorphic_oarchive.o" "libs/serialization/src/polymorphic_oarchive.cpp" ...failed gcc.compile.c++ bin.v2/libs/serialization/build/gcc-4.3/release/threading-multi/polymorphic_oarchive.o... ...skipped <pbin.v2/libs/serialization/build/gcc-4.3/release/threading-multi>libboost_serialization-gcc43-mt-1_35.so.1.35.0 for lack of <pbin.v2/libs/serialization/build/gcc-4.3/release/threading-multi>polymorphic_iarchive.o... ...skipped <pbin.v2/libs/serialization/build/gcc-4.3/release/threading-multi>libboost_wserialization-gcc43-mt-1_35.so.1.35.0 for lack of <pbin.v2/libs/serialization/build/gcc-4.3/release/threading-multi>libboost_serialization-gcc43-mt-1_35.so.1.35.0... ...failed updating 2 targets... ...skipped 2 targets... Not all Boost libraries built properly.

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Re: [Boost-users] Mixing versions of boost
by dariomt＠gmail.com 26 Jun '08

26 Jun '08

Ovanes Markarian <om_boost <at> keywallet.com> writes: > > On Thu, Jun 26, 2008 at 9:35 AM, <dariomt <at> gmail.com> wrote: > [...] > > > > About versioning the boost namespace, I suppose you mean something like > > changing boost namespace to e.g. boost_1_35_0. Any thoughts on how much work > > it would take me to patch a given version of boost to do that? Is it even > > possible? > > > What I mean is: > > Version 1.34 might have a class A with one field of type int. Version > 1.35 might add to the class an additional field. What hapen if 1.34 > returns this type's instance to 1.35. And 1.35 will try to access the > additional field... > What I thought you meant was this: suppose boost namespace has a version number namespace boost_1_34_1 { // here are boost classes functions etc... } Then some boost header has a compatibility alias as in namespace boost = boost_1_34_1; User code would just use boost namespace, but now when two libraries use different versions of boost, the linker does not mix things, i.e. libA has symbols in boost_1_34_1 and libB has symbols in boost_1_35_0 As I said in my OP, no boost components are exposed in the library interface, so that should not be an issue. My question was regarding if namespace versioning was ever considered for boost, and if patching boost sources to produce it would be a lot of work or a piece of cake (with some automagic macro BOOST_VERSIONED_NAMESPACE ;). Thanks for your answers

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