October 2007 - Boost-users - lists.preview.boost.org

Statechart serialization
by mbrodeur65 04 Mar '15

04 Mar '15

Hi, I'm looking for a solution to serialize boost::statechart objects. I'm aware that this feature is on the statechart library todo list but was wondering if there are any workaround to achieve this with the latest boost release (1.34) ? thanks for your help ! mbrodeur65 -- View this message in context: http://www.nabble.com/Statechart-serialization-tf4131326.html#a11749139 Sent from the Boost - Users mailing list archive at Nabble.com.

4 4

[asio] resolver::cancel() problem
by Matthew Edwards 14 Mar '14

14 Mar '14

In my application (and a separate test program) it seems as though the cancel() function on the resolver does not work as intended. For async resolves, the cancel functionality should abort them immediately and pass an 'operation aborted' error code to the callback handler. In my tests, I will resolve an invalid domain (this causes the resolve to take a few seconds, to demonstrate the problem), sleep for 100ms, then call cancel on the resolver object. No cancelling actually occurs, and the callback is simply triggered after a few seconds with a "No host found" error code, not the expected operation aborted. Has anyone experienced this before, or know how I might be using the resolver incorrectly?

3 2

[multi_array] operator= requires resize - why?
by Markus Werle 04 Jun '12

04 Jun '12

Hi! IMHO the behaviour of operator= for multi_array is a little bit broken. A lot of preconditions required: template <typename ConstMultiArray> multi_array_ref& operator=(const ConstMultiArray& other) { [...] // make sure the dimensions agree assert(other.num_dimensions() == this->num_dimensions()); assert(std::equal(other.shape(),other.shape()+this->num_dimensions(), this->shape())); Besides the fact that I get mad about asserts instead of exceptions (please change this to a way users may choose) why do we have such an odd behaviour here? >From page 1, line 3 of the docs I cite: "The interface design is in line with the precedent set by the C++ Standard Library containers" - this is not true for operator=, since std::<container>::operator= works fine for me all the time _without_ any resize. Could we please change the behaviour of multi_array::operator= to take care of resize where in need to? IMHO operator= should result in a true copy ignoring previous state. Markus

6 18

Design for boost::serialization of STL iterators.
by Carlo Wood 23 May '09

23 May '09

On Sat, Mar 11, 2006 at 11:45:36PM +0200, Peter Dimov wrote: > Carlo Wood wrote: > > > 1) WHY does boost::serialization not support serialization > > of iterators? > > It's very hard, if not impossible, in general. It is either impossible or possible. When it is possible, it can't be hard :p I think that at the moment of serialization, the actual container needs to be known. So, only concentrating on the syntax of the code that serializes an iterator, the following cannot work: ar & iter; However, the container will be known at that point (or at least, we might as well assume that). Therefore, I could imagine a syntax like: ar & foobar(container, iter); where 'foobar' is some template function (that will be part of boost::serialization in the future). Lets start with the last one (have to start somewhere). In order to deserialize the iterator (and taken into account that we already have the container) -- which makes me think that it might be better to pass a functor to operator& above. In other words, (at least for writing), use: template<class Container> struct Foobar { Foobar(Container const&, typename Container::const_iterator& iter) : M_container(container), M_iter(iter); private: Container const& M_container; Container::const_iterator& M_iter; }; and then assign to M_iter, whatever we find in M_container. > If you have access to the container to which the iterator i refers: > > a) if the container is a map, you can serialize i->first, then on > deserialization look up the key in the map using .find(); > > b) if the container is a sequence, and it has the same contents on > deserialization as it does on serialization, you can serialize the index of > the element - distance( c.begin(), i ). I don't think that it is a requirement that the whole container has to be read: either it's a map or set, in which case later insertions will not invalidate the container, or it is a vector, in which case we use an index, from which we can construct the end iterators before the whole container is reconstructed. Therefore, the following syntax can work imho: ar & FooBar(container, iter); Would you agree? There are a zillion questions and implementation details open - but I'd like to get anyones feedback about this type of interface for iterators before continuing. Current questions: What is a good name for Foobar? Am I right when I think that Foobar needs to be declared in boost::serialization? Now the hard part (for me) is that part that involves the internals of the boost library. At the moment one tries to serialize an iterator, it is possible (though not necessarily) that the object that the iterator points to is already serialized. In the case that we are dealing with an associative container (map or set etc), we don't want to store the contents of the object (or key part, in the case of a map) again: I'd like to just store that once, and store a reference in the archive at the other place. How can I make the library store an object only the first time and the store a reference the second time? This would be for an object of arbitrary type thus. I think that it is only feasible to do this when it's actually the same object (same memory address), which is the case; but while storing the object element of the container, the address of it isn't stored as well, is it? Is there a way to make: std::set<SomeData> s; [...] ar << s; Store the address of s (&s) along with the contents of s? And would that then automatically cause the library to not store that same object again when I do: std::set<SomeData>::iterator iter = s.find(...); [...] ar << *iter; Because then, &*iter would again be the same memory address as what was stored before. -- Carlo Wood <carlo(a)alinoe.com>

3 2

[BGL] citing the Boost Graph Library
by Alejandro Marcos Aragón 06 May '09

06 May '09

Can anyone point me how to cite the Boost Graph Library in a paper? Is there any information in the boost website? Thank you all, Alejandro Aragón

4 3

Boost Graph Library and Boehm Garbage Collector
by FBSL 08 Sep '08

08 Sep '08

Hello I am having trouble to garbage-collect adjacency_list<>. I have instanciated it with correctly garbage-collected vectors and lists (I have copied vecS and listS definitions, and added Boehm GC's default allocator so that they are garbage-collected). In my application I need to dynamically allocate many graphs, but it does not work, there is a (big) memory leak. Unfortunately, there is no template argument in adjacency_list<> to specify Boehm GC's allocator. Does anyone have a hint ? Snippet code "main.cpp" follows, compiled with Boost Graph Library 1.32, Boehm GC 6.4 and G++ 3.3.5, with command line : $ g++ -o main main.cpp -lgc -lgccpp -- #include <boost/graph/adjacency_list.hpp> #include <gc/gc_allocator.h> #include <gc/gc_cpp.h> #include <iostream> #include <vector> #include <list> using namespace std; using namespace boost; namespace boost { struct collected_vecS {}; struct collected_listS {}; template <class ValueType> struct container_gen<collected_vecS, ValueType> { typedef vector<ValueType,gc_allocator<ValueType> > type; }; template <class ValueType> struct container_gen<collected_listS, ValueType> { typedef list<ValueType,gc_allocator<ValueType> > type; }; template <> struct parallel_edge_traits<collected_vecS> { typedef allow_parallel_edge_tag type; }; template <> struct parallel_edge_traits<collected_listS> { typedef allow_parallel_edge_tag type; }; namespace detail { template <> struct is_random_access<collected_vecS> { enum { value = true }; typedef true_type type; }; } } typedef adjacency_list<collected_vecS, collected_vecS, directedS, no_property, no_property, no_property, collected_listS> graph; int main() { // leaks... while(true){ graph * g=new (UseGC) graph; for(unsigned int i=0; i<100; ++i){ add_vertex(*g); } for(unsigned int i=0; i<100; ++i){ for(unsigned int j=0; j<100; ++j){ add_edge(i,j,*g); } } } }

3 4

[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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[foreach][range] How would BOOST_REVERSE_FOREACH be implemented?
by Pete Bartlett 05 Mar '08

05 Mar '08

Boost.Foreach is such a great piece of kit that once you start using it you just can't stop. Indeed I like working directly with values rather than iterators so much that is feels normal for me to write something like BOOST_FOREACH( value_type x , make_iterator_range( rbegin( seq ) , rend( seq ) ) whenever I wish to reverse iterate over a sequence. My co-workers are not big fans of typing though, so they want a REVERSE_FOREACH. At first naïve glance it looks easy to implement in terms of the original FOREACH: template<typename C> inline iterator_range</* something */> make_reverse_iterator_range(C& c) { return make_iterator_range( rbegin(c) , rend(c) ); } #define REVERSE_FOREACH( x , container ) BOOST_FOREACH( x , make_reverse_iterator_range( container ) ) This works fine when container is an lvalue. But then co-workers, used to the wonders of the original FOREACH, inevitably start to use the new macro with rvalues and get a crash due to dangling references (- the iterator_range's members point to departed quantities.....) and if you could somehow work around that, there is the issue hidden inside the "/* something */" that you have to cope with fact that MSVC has no proper const rvalue detection. Finally the #define MACRO(x,y) ANOTHER_MACRO( f(x) , g(y) ) style is not recommended because they are brittle in the face of x and/or y themselves being macros. ... but all these issues are exactly the ones that BOOST_FOREACH itself solves! Thus surely it is technically possible to write a REVERSE_FOREACH that works with rvalues as well as lvalues, e.g. by essentially copying and pasting the FOREACH implementation and replacing "begin" and "end" by "rbegin" and "rend" in the vital places. However one feels there may be a better way... has anyone had a go at creating a "fully-functional" REVERSE_FOREACH and could offer me any advice? If indeed the task is fairly intricate and requires re-use of foreach internals, would the library author consider including something in the library itself? Many thanks for reading, Pete Bartlett

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MPL: flatten implementation not working
by Andreas Klöckner 25 Dec '07

25 Dec '07

Hi all, I came up with the following implementation of a "flatten" operation that turns a sequence of sequences into a flat list: 8< ------------------------------------------------------------------- #include <iostream> #include <boost/mpl/vector.hpp> #include <boost/mpl/vector_c.hpp> #include <boost/mpl/clear.hpp> #include <boost/mpl/fold.hpp> #include <boost/mpl/copy.hpp> #include <boost/mpl/placeholders.hpp> #include <boost/mpl/back_inserter.hpp> #include <boost/mpl/size.hpp> template<class Sequence> struct flatten { typedef typename boost::mpl::fold< Sequence, typename boost::mpl::clear<Sequence>::type, typename boost::mpl::copy< boost::mpl::_2, boost::mpl::back_inserter<boost::mpl::_1> >::type >::type type; }; typedef flatten< boost::mpl::vector< boost::mpl::vector_c<int, 0, 1, 2, 3>, boost::mpl::vector_c<int, 4, 5, 6> > >::type flatvec; int main() { std::cout << boost::mpl::size<flatvec>::value << std::endl; } 8< ------------------------------------------------------------------- It compiles (using gcc 4.2.1), but prints 0 instead of the expected 7. What am I doing wrong? Thanks for your help Andreas

2 1

Serialization - 'size_t' to 'std::streamsize' error
by Dave Nay 19 Nov '07

19 Nov '07

Ok....this is really confusing. I successfully created a small test project several months ago using the Boost Serialization library to serialize some binary data. I am now attempting to add binary serialization to a production project, and I receive a bunch of compiler warnings. I can still compile and execute the test application with no warnings or errors. I am using VS2005 with boost 1.34.1 I have included the first few compiler warnings below... 1>C:\Program Files\boost\boost_1_34_1\boost/archive/basic_binary_oprimitive.hpp(136) : warning C4267: 'argument' : conversion from 'size_t' to 'std::streamsize', possible loss of data 1> C:\Program Files\boost\boost_1_34_1\boost/archive/basic_binary_oprimitive.hpp(120) : while compiling class template member function 'void boost::archive::basic_binary_oprimitive<Archive,Elem,Tr>::save_binary(const void *,size_t)' 1> with 1> [ 1> Archive=boost::archive::binary_oarchive, 1> Elem=char, 1> Tr=std::char_traits<char> 1> ] 1> C:\Program Files\boost\boost_1_34_1\boost/archive/detail/oserializer.hpp(91) : see reference to function template instantiation 'void boost::archive::basic_binary_oprimitive<Archive,Elem,Tr>::save<T>(const T &)' being compiled 1> with 1> [ 1> Archive=boost::archive::binary_oarchive, 1> Elem=char, 1> Tr=std::char_traits<char>, 1> T=unsigned char 1> ] 1> C:\Program Files\boost\boost_1_34_1\boost/archive/detail/oserializer.hpp(244) : see reference to function template instantiation 'void boost::archive::save_access::save_primitive<Archive,T>(Archive &,const T &)' being compiled 1> with 1> [ 1> Archive=boost::archive::binary_oarchive, 1> T=unsigned char 1> ] Thanks, Dave -- Dave Nay CIVision, LLC

2 2

Copy from stream to vector
by Ricardo Mayerhofer 10 Nov '07

10 Nov '07

Hi all, I've started to use boost 1 month ago and I'm findind it very helpful indeed. Congratulations for the good job. I have one question, is it possible to use boost to copy from a stream to a container? If so, how do I? eg. with std copy: copy( istream_iterator<string>(FileSource), istream_iterator<FileSource> (), back_inserter( m_StringVector ) ) I wonder if boost copy would make it simpler, but I was not able to use it. It pops up a static assertion failure :( Any help? Thanks. Ricardo

5 10

[reflection] Compilation errors
by Christian Henning 08 Nov '07

08 Nov '07

Hi there, I just pulled the latest reflection code from the sandbox and tried to compile the example. But unfortunately there are compilation errors. For example: c:\boost-sandbox\boost\extension\impl\library_impl.hpp(37) : error C2664: 'LoadLibraryW' : cannot convert parameter 1 from 'const char *' to 'LPCWSTR' Is the relection lib in a usable stage? Thanks, Christian

6 10

[boost-users] [filesystem, format] ambgious overload error.
by chun ping wang 07 Nov '07

07 Nov '07

{ boost::scoped_ptr<boost::filesystem::ofstream> myfile(new boost::filesystem::ofstream(fileOutput)); BOOST_FOREACH(int element, (getKeys<std::vector, int, int>(pMap))) { if (pMap[element] >= min_sup) { std::vector<int> row(1, element); itemsContainer.push_back(row); // (*myfile) << "(" << element << ":" << pMap[element] << ")\n"; (*myfile) << boost::format("(%1%, %2%)\n") % element % pMap[element]; } } } ./cs522/c++/aprioriMain.cpp(79) : error C2593: 'operator <<' is ambiguous C:/boost_msvc/include\boost/format/free_funcs.hpp(33): could be 'std::basic_ostream<_Elem,_Traits> &boost::operator <<<char,std::char_traits<char>,std::allocator<_Ty>>(std::basic_ostream<_Elem,_Traits> &,const boost::basic_format<Ch> &)' [found using argument-dependent lookup] with [ _Elem=char, _Traits=std::char_traits<char>, _Ty=char, Ch=char ] C:/boost_msvc/include\boost/filesystem/path.hpp(617): or 'std::basic_ostream<_Elem,_Traits> &boost::filesystem::operator <<<boost::basic_format<Ch>>(std::basic_ostream<_Elem,_Traits> &,const Path &)' [found using argument-dependent lookup] with [ _Elem=char, _Traits=std::char_traits<char>, Ch=char, Path=boost::basic_format<char> ] while trying to match the argument list '(boost::filesystem::ofstream, boost::basic_format<Ch>)' with [ Ch=char ] note the commented out version works.. this only happens on msvc 2005. it passes on mingw devc++.

1 1

[filesystem] Apparent non-compliant code in current operations.hpp, ...
by Marty Fried 06 Nov '07

06 Nov '07

While building 1_34_1 on various platforms we support, I came across some compile errors for the AIX compiler, xlC/vacpp that weren't caught by gcc or MSVC, possibly due to being hidden by a level of indirection. The errors were mostly undefined classes where the template class was fully defined at the time of instantiation. I apologize if my explanation isn't clear or totally correct - I'm not an expert on the C++ standard, and got a lot of the actual explanation from coworkers that know it better than I do. But it's up to me to do the actual reporting and to try to get it to work for us on all the platforms we support. My original post was a few days ago, with the subject "[filesystem] vacpp errors building 1_34_1 filesystem library on AIX". I am because it may look like a vacpp problem, which is an unsupported compiler, but it's not really. It just happens that xlC was the only compiler that caught the error, I think. My original post can also be read at this link: http://permalink.gmane.org/gmane.comp.lib.boost.user/31028 The problem is that the class basic_directory_iterator is not fully defined until after it is used by remove_all(). There were a few other similar errors which I can provide if someone takes an interest in this. If I am wrong, or if there is a reason this won't be fixed, it would be helpful to know, so we can decide what to do. -- Marty Fried Senior Software Developer, Aldon USA http://www.aldon.com

3 7

SFINAE broken in Visual C++ Express?
by Ovanes Markarian 03 Nov '07

03 Nov '07

Hello! Does anybody else experience a problem using enable_if templates in Visual C++ Express 2005 SP1? I get compiler errors in this code: template<class LookUpType_> typename boost::enable_if_c<is_const, result_type>::type at(LookUpType_ const& key)const { return has_key(view_, key); } template<class LookUpType_> typename boost::disable_if_c<is_const, result_type>::type at(LookUpType_ const& key) { return has_key(view_, key); } It blames that type is not a member of enable_if_c or disable_if_c? This is really strance, since this should not be considered by compiler as a possible template instantiation. is_const is an enum value containing either true or false.

3 4

[boost-users] [program options]
by chun ping wang 02 Nov '07

02 Nov '07

HI how would I use program options to accept multiple input. Example I have a diffieHellmanKeyExchange program running through command prompt. // begin main program #include <iostream> #include <boost/tuple/tuple_io.hpp> #include <boost/program_options.hpp> #include "cppdef/BitOperation.cpp" #include "cppdef/mathfunc.cpp" #include "cppdef/IsPrime.cpp" #include "cppdef/DiffieHellman.cpp" #include <BigInteger.hpp> #include <BigIntegerUtils.hpp> int main( int ac, char* av[] ) { namespace po = boost::program_options; po::options_description desc("Allowed options"); boost::tuple<BigInteger, BigInteger> key_pair; desc.add_options() ("generate", "generates a pair of key") ("secert", po::value(&key_pair), "creates the share secret key"); po::variables_map vm; po::store(po::parse_command_line(ac, av, desc), vm); po::notify(vm); if (vm.count("generate")) { BigInteger my_prime = encryptcpw::random_prime<BigInteger>(&algocpw::Miller_Rabin<BigInteger>, 10); std::cout << "my prime: " << my_prime << "\n"; boost::tuple<BigInteger, BigInteger> pare(encryptcpw::dh_init<BigInteger>( my_prime )); std::cout << "pair of generated number: " << pare << "\n"; } if (vm.count("secert")) { const BigInteger p( encryptcpw::random_prime<BigInteger>(&algocpw::Miller_Rabin<BigInteger>, 10)); std::cout << encryptcpw::dh_secret<BigInteger>( p, boost::tuples::get<0>(key_pair), boost::tuples::get<1>(key_pair)); } } // end program The thing compiles but when I do DiffieHellman.exe --secert 817 697 I get this error. C:\CPW\cs_classes>DiffieHellmanEncrypt --secert 817 697 terminate called after throwing an instance of 'boost::program_options::invalid_ option_value' what(): in option 'secert': invalid option value '817' This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information.

3 4

custom formatting the current local date time into a string
by Jeff 02 Nov '07

02 Nov '07

Hello, How can I grab the current local date and time, and format it so that it looks like this: YYYY_MMM_DD_HH_MM_SS ? I can't seem to get the facet stuff to work right. Thanks, Jeff

2 1

[boost-users] [general question] deciding to use member function or not.
by chun ping wang 02 Nov '07

02 Nov '07

Hi is their a simple way *at compile time *to determine if a member function exist for a particular instance, if yes than use that function otherwise do not use it. example std::list<int> li; // check if unique is a member function of li, if yes use unique. li.unique(); // else use stl unique. std::unique(li.begin(), li.end());

2 1

Serialization of C dynamic data
by Lorenzo Cavallaro 31 Oct '07

31 Oct '07

Hi, I'm trying to serialize the following piece of code (a data structure whose object size is dynamically allocated and it should use the correct size/len which has been serialized). typedef struct data { char *payload; size_t len; } data_t; vector<data_t *> v; So I added the corresponding serialize function to the structure definition void serialize(Archive & ar, const unsigned int file_version) { ar & len; for (int i = 0; i < len; i++) ar & payload[i]; } Moreover, I added a default constructor which is invoked by the serialization library whenever the object has to be unserialized data::data() { /* no error checking */ payload = (char *)calloc(1, X); len = X; } Now, of course X is fixed. I'd like to reuse the serialized 'size' (ar & size) as argument to the calloc to be able to create an object with the right size instead of having to approximate (exceeding, of course) its real dimension. Do you have any idea how to get it work the way I'd like to, please? -- if it's possible, of course. Nevertheless to say that with a right X everything works fine. I was thinking to iterate over all the elements, after the unserialization step is over, to reallocate payload using the right len... but it sucks :-) TIA, bye Lorenzo -- Lorenzo `Gigi Sullivan' Cavallaro <sullivan(a)security.dico.unimi.it> GPG key at http://security.dico.unimi.it/~sullivan/sullivan.asc Until I loved, life had no beauty; I did not know I lived until I had loved. (Theodor Korner) See the reality in your eyes, when the hate makes you blind. (A.H.X)

2 1

[Boost users] [interprocess]: static_pointer_cast on offset_ptr
by Lars Hagström 31 Oct '07

31 Oct '07

Hi, In offset_ptr.hpp the static_pointer_cast<> &co are commented out. Why is this? I need something of the kind to do casts from a void* to a bool*, for example. Is there something I am missing? Lars

3 4

REGEXP - Serializing regexp ?
by Jacques-Olivier Goussard 31 Oct '07

31 Oct '07

Hi I'm trying to use the boost-regexp package and I'm facing an issue with this. I'm basically applying a replace algo on a list of strings using a huge list of regular expressions. It seems that the boost-regexp API allows me only to either load all regular expressions in memory (i.e creating the regexp at process start) or load one regexp at a time but re-compile it each time. Is there a way to save to disk the compiled version of the regexp (so that the regexp package would not have to re-create the statemachine) ? If not, what would be the best approach for doing this ? Thanks /jog

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Re: [Boost-users] Regex: Invalid preceding regular expression, problem
by Brian Krahmer 31 Oct '07

31 Oct '07

> Nope there's a bug in the options you are using - boost::regex::extended > enables the "POSIX extended" flavour of regular expressions - and these > don't support non-greedy repeats. Use boost::regex::perl if you want to use > these (since you are using Perl-style regexes). > > HTH, John. > That helps very much. Thanks for clearing that up for me, John. brian

1 0

Preprocessor lib question -- how to fold a macro that produces comma in its output across a sequence?
by Yu Di 31 Oct '07

31 Oct '07

Hi, I am trying to use the preprocessor lib to generate something like Cons<a, Cons<b, Cons<c, Cons<d, Nil> > > > from (a) (b) (c) (d) I tried something like #define START(x) Cons<x,Nil> #define ADD(s,state,x) Cons<x,state > #define GENERATE(x) BOOST_PP_SEQ_FOLD_RIGHT(ADD,START(BOOST_PP_SEQ_HEAD(BOOST_PP_SEQ_REVERSE(x))),BOOST_PP_SEQ_POP_BACK(x)) but immediately got into trouble with the commas. The best I can do is to add parentheses around the content of START and ADD, but that generated (Cons<a, (Cons<b, (Cons<c, (Cons<d, Nil>) >) >) >) which is not valid. Is there any way I can achieve the desired output? Thanks, Di, Yu 10.30 __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

2 1

FILE boost\preprocessor\arithmetic\dec.hpp
by question boost 31 Oct '07

31 Oct '07

Hi, I' ve the following error message: FILE C:\Documents and Settings\src\boost\preprocessor\arithmetic\decc.hpp LINE 17 boost/preprocessor/config/config.hpp no such file or directory So I look at decc.hpp, it contains the line # include <boost/preprocessor/config/config.hpp> and I look at the directory C:\Documents and Settings\src\boost\preprocessor\config, it contains the file config.hpp IS ANYONE GOING TO TELL ME WHAT IS THE PROBLEM WITH THOSE BOOST FILES? THANK YOU VERY MUCH David _________________________________________________________________ Vous êtes plutôt Desperate ou LOST ? Personnalisez votre PC avec votre série TV préférée ! http://specials.divertissements.fr.msn.com/SeriesTV.aspx

1 0

graph python bindings : unpickle hangs
by John Reid 31 Oct '07

31 Oct '07

Hi, Unpickling an empty boost.graph seems to hang. E.g. In [1]: import boost.graph as bgl In [2]: g=bgl.Graph() In [3]: import cPickle In [4]: cPickle.dumps(g) Out[4]: 'cboost.graph._graph\nGraph\np1\n(tRp2\n((dp3\nI0\n(l(d(dtb.' In [5]: cPickle.loads(cPickle.dumps(g)) *** never returns *** I'm using the latest SVN revision of bgl-python. John.

1 0

Extracting libraries from boost?
by Angel Tsankov 31 Oct '07

31 Oct '07

Can libraries in boost be used on their own, i.e. can I extract one of them and use it in a project? In particular, I only need the smart_ptr and ref libraries in one of my projects.

4 4

Regex: Invalid preceding regular expression problem
by Brian Krahmer 31 Oct '07

31 Oct '07

Hello, I'm a new member to the mailing list. BTW, thanks to everyone who contributes to boost. It's a fantastic software. I am having a problem with building an expression object. The line in question reads 'boost::regex expression(pattern, options);', where I'm using the boost::regex::extended option, and the pattern looks like this: "^([0-7]\\..*|8\\.0(\\.[0-3](\\.[0-3])?)?)[^.0-9]*?$". I fired up a ruby interpreter, and it handled the regex fine (using "8.0.0.1 (en-US)" as a positive, and "9.0.0.1 (en-US)" as a negative). Can anybody tell me what is wrong with this regex, or confirm that there may be a bug in the library? thanks, brian

2 1

[Regex] Why does this example code not compile?
by Mike Thornton 31 Oct '07

31 Oct '07

Using g++ on a GNU Ubuntu Linux 7.04 machine, I am unable to compile the boost example code (saved as test.cpp) at http://www.boost.org/libs/regex/example/snippets/partial_regex_match.cpp Although I can compile my own code which does not use boost, I get a lot of garbled output from the example code...part of which is listed below. Any ideas on what is wrong and how to fix it? test.cpp : (.text._ZN5boost9re_detail12perl_matcherIN9__gnu_cxx17__normal_iteratorIPKcSsEESaINS_9sub_matchIS6_EEENS_12regex_traitsIcNS_16cpp_regex_traitsIcEEEEEC1ES6_S6_RNS_13match_resultsIS6_S9_EERKNS_11basic_regexIcSD_EENS_15regex_constants12_match_flagsES6_[boost::re_detail::perl_matcher<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::perl_matcher(__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, __gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, boost::match_results<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > > >&, boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > > const&, boost::regex_constants::_match_flags, __gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >)]+0xea): undefined reference to `boost::re_detail::perl_matcher<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<boost::sub_match<__gnu_cxx::__normal_iterator<char const*, std::basic_string<char, std::char_traits<char>, std::allocator<char> > > > >, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::construct_init(boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > > const&, boost::regex_constants::_match_flags)' Thanks. Mike

4 4

Using date/time to format date strings
by Andrew 31 Oct '07

31 Oct '07

Hi all, I'm trying to use the date time library to to do some string formatting but I'm afraid there's something I'm missing. What I'd like to do is feed in a string "05/Aug/2007 11:30" and convert it to an ISO formatted string - could anyone point me in the right direction? I've examined both the documentation and the sample code in io_tutorial.cpp but I'm afraid it hasn't helped - the code below is as far as I've gotten and simply returns the input string unchanged. I'm using boost 1.34.1 with MSVC 2005. Thanks much, Andrew //Begin snippit string formatDate(string inpDate) { stringstream ss; local_date_time checkDate(not_a_date_time); local_time_input_facet* input_facet = new local_time_input_facet(); local_time_facet* output_facet = new local_time_facet(); ss.imbue(locale(locale::classic(), output_facet)); ss.imbue(locale(ss.getloc(), input_facet)); input_facet->format("%d/%b/%Y %H:%M"); output_facet->set_iso_format(); ss << inpDate; return ss.str(); }

2 2

[statechart] direct manipulation of event queue?
by Chris Paulse 30 Oct '07

30 Oct '07

How easy would it be to directly remove specific types of events from a state machine's event queue?

2 2

Beginner question about PocketPC 2003
by Dmytro Bogovych 30 Oct '07

30 Oct '07

Greetings. I downloaded 1.34.1 build from Boost Consulting. It comes with prebuilt libraries for VS 2005. I like it very much as I use Boost.Thread in my projects. But this package comes without prebuild libraries for PocketPC 2003 ARM target. How can I build them? I read about bjam but don't see what arguments I should set. This - bjam --v2 "-sTOOLS=msvc" "-sBUILD=release <windows>pocketpc2003 <charset>wide <architecture>arm4" install doesn't work. Sorry for stupid question.

1 0

[multi-index] bug or not?
by Ovanes Markarian 30 Oct '07

30 Oct '07

Hello! I have a question regarding the multi-index behaviour, Let's say I have a multi-index container containing some hashed keys. What should happen with this container is empty and I retrieve an indexed by hash view into it? I have on Visual C++ 2005 an access violation, since I am trying to retrieve a view by it's hashed keys into the const container. Many thanks, Ovanes

3 3

Errors in custom predicate support docu
by Jens Seidel 30 Oct '07

30 Oct '07

Hi, I tried a few times to report the following bug to trac but it was always rejected as spam!?? According to http://www.boost.org/libs/test/doc/components/test_tools/custom_predicate_s… there exists a class boost::test_tools::extended_predicate_value. (Or is it a user supplied class?) Nevertheless I didn't found such a class in Boost.test and even trunk contains only predicate_result which is different. This makes predicate support very hard to use for me. Please provide proper documentation for it! I hope this is the right way to run tests in a loop and to condense the output. Jens

2 1

serialization: curious un-serializing issue RFI
by Hugh Hoover 30 Oct '07

30 Oct '07

I have a curious problem that's just sprung up, after changing from using plain-old-pointers to using boost::shared_ptrs internally in my data structures (stl hash_map and map) The problem is that while the XML archive works correctly, both text and binary fail (they all used to work). This is using gcc 4.0.1 on darwin and VC8 on windows, boost version is 1.34.1 The failure occurs while unserializing an archive, specifically when trying to read back a shared_ptr to an already unserialized object. In the archive, it shows the object (pointer) as an object_reference (the same reference id in XML and text). While the XML version reads the pointer back correctly, the text version fails and returns NULL. I have not determined the exact reason why the text version fails (it doesn't throw, just returns NULL). The serialization does not appear to have any problems. Since my actual code is reasonably complicated, and I haven't created a simplified version that demonstrates the problem, I'm not including code now - I'd just like to find out if this sounds familiar to anyone, that is, working under XML but failing under text and binary. It does appear to be shared_ptr specific, too, since everything was working before replacing naked pointers with shared_ptrs.

2 4

Serialization and raw pointer arrays
by Eric 30 Oct '07

30 Oct '07

Hi, I've inherited some complex math code that makes large usage of Matrices based on raw pointer arrays. I need to serialize/deserialize these arrays as is and am looking to use boost::serialization package. My attempt at doing so results in the following errors (mostly about non integral array size). As I do not know the array size when it is created (and lots of code accesses the pointer directly as a chunk of memory that has been allocated, what are my options to get this to work? Errors: /usr/include/boost/archive/detail/oserializer.hpp: In function `void boost::archive::save(Archive&, T&) [with Archive = boost::archive::text_oarchive, T = Dummy]': /usr/include/boost/archive/basic_text_oarchive.hpp:78: instantiated from `void boost::archive::basic_text_oarchive<Archive>::save_override(T&, int) [with T = Dummy, Archive = boost::archive::text_oarchive]' /usr/include/boost/archive/detail/interface_oarchive.hpp:78: instantiated from `Archive& boost::archive::detail::interface_oarchive<Archive>::operator<<(T&) [with T = Dummy, Archive = boost::archive::text_oarchive]' serialize_array.cpp:56: instantiated from here /usr/include/boost/archive/detail/oserializer.hpp:567: error: incomplete type `boost::STATIC_ASSERTION_FAILURE< false>' used in nested name specifier /usr/include/boost/archive/detail/oserializer.hpp:567: error: size of array has non-integral type `<type error>' Code: #include <boost/serialization/split_member.hpp> #include <fstream> #include <iostream> #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> using namespace std; class Dummy { public: friend class boost::serialization::access; Dummy() {pVal=NULL;size=0;} ~Dummy() {delete [] pVal;} template<class Archive> void save(Archive & ar, const unsigned int version) const { ar & size; for (int i=0; i<size; i++) { ar & pVal[i]; } } template<class Archive> void load(Archive & ar, const unsigned int version) { ar & size; pVal = new int[size]; for (int i=0; i<size; i++) { ar & pVal[i]; } } int* pVal; int size; }; BOOST_CLASS_VERSION(Dummy, 1) int main(int argc, char** argv) { Dummy d; d.size = 5; d.pVal = new int[d.size]; for (int i=0; i< d.size; i++) { d.pVal[i] = i+10; } ofstream ofOut("testSer.txt"); { boost::archive::text_oarchive oa(ofOut); oa << d; } Dummy load; { ifstream ifIn("testSer.txt"); boost::archive::text_iarchive ia(ifIn); ia >> load; } cout << "size="<<load.size<<endl; for (int i=0; i< load.size; i++) { cout << load.pVal[i] <<endl; } return -1; } Thanks, Eric

3 2

boost.graph python bindings: read_graphml: No to_python (by-value) converter found for C++ type: struct boost::graph_exception
by John Reid 30 Oct '07

30 Oct '07

Hi, When I try to read a graphml file an exception is thrown but cannot be passed back to python through boost.python as no converter is registered. I'm using SVN version 338 from https://svn.osl.iu.edu/svn/projects_viz/bgl-python. The output is: c:\dev\python\boost\graph\__init__.py in read_graphml(filename) 624 """ 625 try: --> 626 graph = Digraph.read_graphml(filename) 627 except UndirectedGraphError: 628 graph = Graph.read_graphml(filename) <type 'exceptions.TypeError'>: No to_python (by-value) converter found for C++ type: struct boost::graph_exception If I just try the following: bgl.Graph.read_graphml(filename) I get something that might be a different symptom of the same problem: <type 'exceptions.SystemError'>: 'finally' pops bad exception The graphml file is: <?xml version="1.0" encoding="UTF-8"?>  <graphml xmlns="http://graphml.graphdrawing.org/xmlns/graphml" xmlns:y="http://www.yworks.com/xml/graphml" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://graphml.graphdrawing.org/xmlns/graphml http://www.yworks.com/xml/schema/graphml/1.0/ygraphml.xsd"> <key id="d0" for="node" yfiles.type="nodegraphics"/> <key id="d1" for="edge" yfiles.type="edgegraphics"/> <graph id="G" edgedefault="directed"> <node id="n0"> <data key="d0" > <y:ShapeNode > <y:Geometry x="0.0" y="0.0" width="30.0" height="30.0"/> <y:Fill color="#FFCC00" transparent="false"/> <y:BorderStyle type="line" width="1.0" color="#000000" /> <y:NodeLabel x="13.0" y="13.0" width="4.0" height="4.0" visible="true" alignment="center" fontFamily="Dialog" fontSize="13" fontStyle="plain" textColor="#000000" hasBackgroundColor="false" hasLineColor="false" modelName="internal" modelPosition="c" autoSizePolicy="content"></y:NodeLabel> <y:Shape type="ellipse"/> </y:ShapeNode> </data> </node> <node id="n1"> <data key="d0" > <y:ShapeNode > <y:Geometry x="18.0" y="68.0" width="30.0" height="30.0"/> <y:Fill color="#FFCC00" transparent="false"/> <y:BorderStyle type="line" width="1.0" color="#000000" /> <y:NodeLabel x="13.0" y="13.0" width="4.0" height="4.0" visible="true" alignment="center" fontFamily="Dialog" fontSize="13" fontStyle="plain" textColor="#000000" hasBackgroundColor="false" hasLineColor="false" modelName="internal" modelPosition="c" autoSizePolicy="content"></y:NodeLabel> <y:Shape type="rectangle"/> </y:ShapeNode> </data> </node> <edge id="e0" source="n0" target="n1"> <data key="d1" > <y:PolyLineEdge > <y:Path sx="0.0" sy="0.0" tx="0.0" ty="0.0"/> <y:LineStyle type="line" width="1.0" color="#000000" /> <y:Arrows source="none" target="standard"/> <y:BendStyle smoothed="false"/> </y:PolyLineEdge> </data> </edge> </graph> </graphml> Thanks for a great library, John.

1 0

Re: [Boost-users] [reflection] Compilation errors
by Ovanes Markarian 30 Oct '07

30 Oct '07

Hi Christian, I assume you need to use either wchar_t or set in Visual C++ the charset not to multi-byte but not implemented. Otherwise you are trying to use pass single-byte strings as multi-byte string params. Best Regards, Ovanes On 10/29/07, Christian Henning <chhenning(a)gmail.com> wrote: > > Hi there, I just pulled the latest reflection code from the sandbox > and tried to compile the example. But unfortunately there are > compilation errors. > > For example: > > c:\boost-sandbox\boost\extension\impl\library_impl.hpp(37) : error > C2664: 'LoadLibraryW' : cannot convert parameter 1 from 'const char *' > to 'LPCWSTR' > > Is the relection lib in a usable stage? > > Thanks, > Christian > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users >

1 0

using ref() with threads
by Andrey Tcherepanov 30 Oct '07

30 Oct '07

Hello folks, we recently got stuck with one minor inconvenience with boost thread (which we fixed), but somehow we cannot explain why it did not work. We are using 1.34.1 and VS 2005 SP1 the sample that did not work properly was aproximately like this (not compilable) class Super_Func { protected: bool * _die; SomeObscureIPWorksBasedDaemon _daemon; public: Super_Func(bool* t) : _die(t), _daemon("localhost", 12345) {} void operator()() { while (!*_die) { _daemon.do_background_stuff(); if (_daemon.has_data()) us_process_data(_daemon.get_data()); } } }; int main() { bool die = false; Super_Func sf(&die); boost::thread main_thread(boost::ref(sf)); main_thread.join(); return 0; } Everything compiled without hick-up, and even created the thread (well, at least debugger showed it, and stopped in while loop). But all the TCP/IP related stuff in thread did not work (was sort of stuck). Once we replaced above with void Super_Func(bool* die) { SomeObscureIPWorksBasedDaemon _daemon("localhost", 12345); while (!*_die) { _daemon.do_background_stuff(); if (_daemon.has_data()) us_process_data(_daemon.get_data()); } } int main() { bool die = false; boost::thread main_thread(boost::bind(Super_Func, &die)); main_thread.join(); return 0; } everything magically worked! Well, if I do not miss some obvious error somewhere in the first example (which I might)... then I do not know why it did not work. I was under impression that ref() is just a way to pass "reference" to the anything (including functional object), so it will create copy of ref, and not Super_Func class itself. Any insight is appreciated. Thank you very much, Andrey.

2 1

Request to know about "dynamic expression evaluation"
by Borse, Ganesh 29 Oct '07

29 Oct '07

Hi, I would like to perform the dynamic expression evaluation in my c++ application. The dynamic expressions are like the SQL queries. Since the expressions could be nested & hence the parsing & evaluation of such expressions is reducing the performance of my application. May I please know, whether BOOST provides a support for such dynamic expression evaluation in C++? Please guide. Thanks in advance for the guidance. Regards, Ganesh ============================================================================== Please access the attached hyperlink for an important electronic communications disclaimer: http://www.credit-suisse.com/legal/en/disclaimer_email_ib.html ==============================================================================

3 2

bis
by question boost 29 Oct '07

29 Oct '07

Hi, it seems the problem is at step 2. When I do: C:\Documents and Settings\src\boost\tools\build\v2> bjam --version I get the message: Mingwbing++ n'est pas reconnu en tant que command interne ou externe,un programme exécutable ou un fichier de commandes. Change the "\" by "/" is apparently not the solution. Thank you for your help. David _________________________________________________________________ Vous êtes plutôt Desperate ou LOST ? Personnalisez votre PC avec votre série TV préférée ! http://specials.divertissements.fr.msn.com/SeriesTV.aspx

2 5

Newbie: Building Boost.Python Libs Nomenclature
by Shawn Cook 29 Oct '07

29 Oct '07

I just need a sanity check: I would like to embed a Python interpreter in my C++ application. I am following all the instructions as accurately as I can (http://www.boost.org/more/getting_started/windows.html) When I build the Python library binary (as mentioned in the Boost.Python installation instructions) I do not get any errors. If necessary I can respond with my Boost.Build output - but it's rather lengthy. Anyway, this paragraph in the Boost.Python Embedding tutorial says I'm looking for a library file named "boost_python_debug.lib" which does not exist. Here is the paragraph in question: ' Boost.Python's library comes in two variants. Both are located in Boost's /libs/python/build/bin-stage subdirectory. On Windows, the variants are called boost_python.lib (for release builds) and boost_python_debug.lib (for debugging). If you can't find the libraries, you probably haven't built Boost.Python yet. See Building and Testing on how to do this.' (from: http://www.boost.org/libs/python/doc/tutorial/doc/html/python/embedding.html) But I'm not getting any build errors, in fact I'm building all the different MSVC runtime variants (debug, release, static, dynamic, etc) and they all appear to be built - but they are named different than "boost_python.lib" and are not in the /libs/python/build/bin-stage directory. Is this paragraph just deprecated and needing some revisiting by the faithful Boost Technical Writers? Thanks, folks, -S. _________________________________________________________________ Peek-a-boo FREE Tricks & Treats for You! http://www.reallivemoms.com?ocid=TXT_TAGHM&loc=us

2 1

START. Is anyone going to explain me the way to use BOOST in a C++ program?
by question boost 29 Oct '07

29 Oct '07

Hi, 1 My program under Code Blocks makes use of Boost. The arrangement of my files is the following: in the directory of the source files of my program there is the directory "boost" containing the following directories: "filesystem", "config", "iterator","range","detail", "mpl", "preprocessor", "tools" and the file boost-build.jam. 2 The file that makes use of boost in my project contains the following lines: #include <string> using namespace std; #include "boost\filesystem\path.hpp" #include "boost\filesystem\operations.hpp" using namespace boost::filesystem; 3 At build I get the message :"boost/preprocessor/config/config.hpp" no such file or directory and several other similar messages about other files of the same directory and about other files of the "mpl" directory. I've followed all the instructions here http://www.boost.org/doc/html/jam/building.html and here http://www.boost.org/doc/html/bbv2/installation.html At end of step 4 of http://www.boost.org/doc/html/bbv2/installation.html, the problem at build remains the same:I get the same message. Thank you for your help. David _________________________________________________________________ Découvrez le blog Messenger Le Meilleur du Web : toutes les vidéos qui buzzent le plus sur Internet ! http://meilleurduweb.spaces.live.com/

2 1

shared_ptr memory leak in VC2005?
by zzp good 29 Oct '07

29 Oct '07

hi, guys, I found memory leak using the following code: #include <boost\array.hpp> #include <boost\shared_ptr.hpp> using namespace boost; class C { public: shared_ptr<C> pNext; }; void test() { shared_ptr<C> c0(new C()); shared_ptr<C> c1(new C()); c0 -> pNext = c1; c1 -> pNext = c0; } void main() { test(); _CrtDumpMemoryLeaks(); } when running with F5, it said: Detected memory leaks! Dumping objects -> d:\program files\microsoft visual studio 8\vc\include\crtdbg.h(1147) : {126} normal block at 0x003A64B0, 16 bytes long. Data: < E hd: > C4 17 45 00 01 00 00 00 01 00 00 00 68 64 3A 00 d:\program files\microsoft visual studio 8\vc\include\crtdbg.h(1147) : {125} normal block at 0x003A6468, 8 bytes long. Data: < c: d: > D0 63 3A 00 18 64 3A 00 d:\program files\microsoft visual studio 8\vc\include\crtdbg.h(1147) : {124} normal block at 0x003A6418, 16 bytes long. Data: < E c: > C4 17 45 00 01 00 00 00 01 00 00 00 D0 63 3A 00 d:\program files\microsoft visual studio 8\vc\include\crtdbg.h(1147) : {123} normal block at 0x003A63D0, 8 bytes long. Data: <hd: d: > 68 64 3A 00 B0 64 3A 00 Object dump complete. Any body have an idea about this? Thanks very much.

3 2

[signal,bind] upgrade problem from 1.33 to 1.34
by David Angelo 29 Oct '07

29 Oct '07

Hi folks, I have a problem with upgrading from boost version 1.33 to 1.34. My code runs fine with 1.33, but when compiling and linking againt 1.34 I get the following runtime error (backtrace): <backtrace> #0 0x81d4c9b2 in void boost::function1<void, float, std::allocator<void> >::ass ign_to<boost::_bi::bind_t<void, boost::_mfi::mf1<void, fpCTPart, float>, boost:: _bi::list2<boost::_bi::value <fpCTPart*>, boost::arg<1> (*)()> > >(boost::_bi::bi nd_t<void, boost::_mfi::mf1<void, fpCTPart, float>, boost::_bi::list2<boost::_bi ::value<fpCTPart*>, boost::arg<1> (*)()> >)::stored_vtable () from /home/david/eclipseM6/toolManagement/lib/libfpCTToolPack.so #1 0xb4438841 in boost::function0<void, std::allocator<void> >::clear ( this=0xa1a03fc) at /usr/include/boost/function/function_template.hpp:388 #2 0xb4438879 in ~function0 (this=0xa1a03fc) at /usr/include/boost/function/function_template.hpp:313 #3 0xb443889d in ~function (this=0xa1a03fc) at /usr/include/boost/function/function_base.hpp:92 #4 0x81a34c39 in ~holder (this=0xa1a03f8) at /home/david/apps/boost_1_34_1/include/boost-1_34_1/boost/any.hpp:106 #5 0x81137b41 in boost::signals::detail::named_slot_map::insert () from /home/david/apps/boost_1_34_1/lib/libboost_signals-gcc41-1_34_1.so.1.34. 1 #6 0x8113b562 in boost::signals::detail::signal_base_impl::connect_slot () from /home/david/apps/boost_1_34_1/lib/libboost_signals-gcc41-1_34_1.so.1.34. 1 #7 0x81a36e58 in boost::signal0<void, boost::last_value<void>, int, std::less<i nt>, boost::function<void ()(), std::allocator<void> > >::connect ( this=0x82eac060, in_slot=@0xbfe145f0, at=boost::signals::at_back) ---Type <return> to continue, or q <return> to quit---bt at /home/david/apps/boost_1_34_1/include/boost-1_34_1/boost/signals/signal_template.hpp:286 #8 0x81b359f6 in fpCTPart::initPart (this=0x82eaa7f0) at /home/david/eclipseM6/toolManagement/extensions/fpCTToolPack/parts/src/fpCTPart.cpp:173 </backtrace> Line 173 in fpCTPart.cpp is: geomNode->sigPreLoad.connect(boost::bind(&fpCTPart::slotFilePreLoaded, this)); Are there any changes between these to versions in the bind/signal library? (Are they not backward compatible?) Thanks in advance. Regards, David

3 4

[signals] How not to ignore 'trackable'?
by Nat Goodspeed 27 Oct '07

27 Oct '07

I have a callback design based around Boost.Signals. The documentation says: http://boost.org/doc/html/signals/tutorial.html#id1627926 "Warning: User-defined function objects and function objects from other libraries (e.g., Boost.Function or Boost.Lambda) do not implement the required interfaces for trackable object detection, and will silently ignore any bound trackable objects. Future versions of the Boost libraries will address this limitation." I would like to define a filter function object to be used something like this: // define signal_t, handler_t typedef boost::signal<void()> signal_t; typedef signal_t::slot_type handler_t; signal_t mySignal; // straightforward use case struct Listener: public boost::signals::trackable { void someMethod() {} }; Listener* myListener = new Listener(); mySignal.connect(boost::bind(&Listener::someMethod, myListener)); // the following should disconnect delete myListener; mySignal(); // should do nothing // define filter function object struct Filter { Filter(const handler_t& handler, somedata_t somedata): mHandler(handler), mSomeData(somedata) {} void operator()() { if (mSomeData) { mHandler(); } } handler_t mHandler; somedata_t mSomeData; }; // use filter function object myListener = new Listener(); mySignal.connect(Filter(boost::bind(&Listener::someMethod, myListener), somedata)); // doc promises the following will NOT disconnect delete myListener; mySignal(); // the dreaded undefined behavior Unfortunately there are two hurdles to getting there. 1. How could I code Filter to honor the 'trackability' of the passed-in handler? 2. slot_type is not itself callable: mHandler() doesn't work. 2a. I could use boost::function for handler_t instead: typedef boost::function<void()> handler_t; but the documentation promises that this, too, will ignore Filter's trackable base class. 2b. I could make Filter store a signal_t instead of a handler_t. Filter's constructor could call mHandler.connect(handler) instead of initializing mHandler from handler. But that doesn't work because signal_t is noncopyable, and passing a Filter instance to connect() copies it. I'd be willing to make Filter trackable, stipulating that Filter instances must live on the heap: mySignal.connect(new Filter(etc.)); // or boost::bind() of same Then Filter could store signal_t because the Filter object wouldn't be copied. When the Listener object is destroyed, it would automatically disconnect from the Filter's signal_t. But that would leave me with an orphan Filter object with an empty signal_t permanently connected to mySignal. Could Filter be informed when slots are disconnected from its contained signal_t? When the last slot is disconnected, it could 'delete this'. With Filter trackable, that would disconnect it from mySignal, and everyone would be happy. (There's the performance cost of introducing another signal object through which the call must be forwarded, but I hope that will be negligible.) So: is there any way for Filter to intercept control when the last (only) slot disconnects from Filter::mHandler? (Filter stores a subclass of signal_t?) Is there any other way to accomplish what I'm trying to do here? Thanks.

1 0

RegExp - Callback function
by Golan Trevize 27 Oct '07

27 Oct '07

Hello. First... I'm sorry for my english. And second - I've got small problem. I need use regexp. The idea is that I use 'replace', it find some text like in expression and this will be an input for function... then in function something happen and output of the function replace in text the input of the function... For example I've got text "Solution: 5 and 4". Regular expression is "[0-9]" And the function is "add5" int add5(int input){return input+5} And the output of this function replace the number with number+5... And in the end text will be: "Solution: 10 and 9" In C++ with Boost? I don't know how can I do it... something like this.... #include <cstdlib> #include <iostream> #include <boost/regex.hpp> using namespace std; using namespace boost; // the callback function string add5(string x) { int v; v =atoi(x.c_str()) + 5; string vystup = (char *)v; return vystup; } int main(int argc, char *argv[]) { string t; string k; t = "Solution: 4"; regex expression("[0-9]"); k=regex_replace(t, expression,add5, boost::match_default|boost::format_all); cout << k << endl; system("PAUSE"); return EXIT_SUCCESS; } How can I rewrite this line: k=regex_replace(t, expression,add5, boost::match_default|boost::format_all); And how I change the callback function add5... If someone know, thank you for answers and advices.

3 3

[typeof] Duplicate definition of boost::type_of::push_back
by Dave Jenkins 27 Oct '07

27 Oct '07

Hi, I'm testing with BOOST_TYPEOF_LIMIT_SIZE greater than 50 and native typeof disabled. I get a "class template has already been defined" error on "template<class V, class T> struct push_back" whenever BOOST_TYPEOF_LIMIT_SIZE is *not* a multiple of 50. This is because push_back is defined in both "typeof/vector.hpp" and, for example, "typeof/vector50.hpp". My fix is to change the push_back definition in "typeof/vector.hpp" to: # if BOOST_TYPEOF_LIMIT_SIZE < 50 template<class V, class T> struct push_back { typedef V type; }; # endif Can someone please confirm that this is the correct fix? A tiny program demonstrating the problem is listed below. Thanks, Dave Jenkins #define BOOST_TYPEOF_COMPLIANT #define BOOST_TYPEOF_LIMIT_SIZE 51 #include <boost/typeof/typeof.hpp> int main(){ return 0; }

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[type_traits] upcoming standard question...
by Ovanes Markarian 26 Oct '07

26 Oct '07

Hello! I am just wondering, that the upcoming standard does not provide the is_rvalue type_trait. At least I did not find it in the mailings. Since there is an is_reference trait and rvalues are going to be added to the standard, don't you think the is_rvalue should be a part of upcoming standard type_traits? Many Thanks, Ovanes

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boost::serialization Qestion about versioning.
by Oleg Udovenko 26 Oct '07

26 Oct '07

Hi, As I can see from the documentation the library has only a forward compatibility. 3. Independent versioning for each class definition. That is, when a class definition changed, older files can still be imported to the new version of the class. Is there any way to achieve a backward compatibility? Thanks, Oleg.

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Boost.Test: problem with BOOST_CHECK_EQUAL for negative chars
by Mignon Belongie 26 Oct '07

26 Oct '07

The following causes a fatal error (at least for me): char c1 = -2; char c2 = -2; BOOST_CHECK_EQUAL(c1, c2); The message is: Assertion failed: (unsigned)(c + 1) <= 256 Thanks, Mignon

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