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

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